linux/security/landlock/task.c

540 lines
14 KiB

landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Always allow signals between threads of the same process Because Linux credentials are managed per thread, user space relies on some hack to synchronize credential update across threads from the same process. This is required by the Native POSIX Threads Library and implemented by set*id(2) wrappers and libcap(3) to use tgkill(2) to synchronize threads. See nptl(7) and libpsx(3). Furthermore, some runtimes like Go do not enable developers to have control over threads [1]. To avoid potential issues, and because threads are not security boundaries, let's relax the Landlock (optional) signal scoping to always allow signals sent between threads of the same process. This exception is similar to the __ptrace_may_access() one. hook_file_set_fowner() now checks if the target task is part of the same process as the caller. If this is the case, then the related signal triggered by the socket will always be allowed. Scoping of abstract UNIX sockets is not changed because kernel objects (e.g. sockets) should be tied to their creator's domain at creation time. Note that creating one Landlock domain per thread puts each of these threads (and their future children) in their own scope, which is probably not what users expect, especially in Go where we do not control threads. However, being able to drop permissions on all threads should not be restricted by signal scoping. We are working on a way to make it possible to atomically restrict all threads of a process with the same domain [2]. Add erratum for signal scoping. Closes: https://github.com/landlock-lsm/go-landlock/issues/36 Fixes: 54a6e6bbf3be ("landlock: Add signal scoping") Fixes: c8994965013e ("selftests/landlock: Test signal scoping for threads") Depends-on: 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies") Link: https://pkg.go.dev/kernel.org/pub/linux/libs/security/libcap/psx [1] Link: https://github.com/landlock-lsm/linux/issues/2 [2] Cc: Günther Noack <gnoack@google.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Serge Hallyn <serge@hallyn.com> Cc: Tahera Fahimi <fahimitahera@gmail.com> Cc: stable@vger.kernel.org Acked-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20250318161443.279194-6-mic@digikod.net [mic: Add extra pointer check and RCU guard, and ease backport] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-18 17:14:40 +01:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Split denial logging from audit into common framework Tracepoint emission requires the denial framework (layer identification, request validation) without depending on CONFIG_AUDIT. Separate the denial logging infrastructure from the audit-specific code by introducing a common log framework. Create CONFIG_SECURITY_LANDLOCK_LOG, enabled by default when CONFIG_AUDIT is set; a following commit extends it to CONFIG_TRACEPOINTS when the first tracepoint consumer is added. Move the common framework (the request types, the layer identification and request validation, and the landlock_log_denial() and landlock_log_free_domain() entry points) into log.c and log.h, and keep the audit-specific record formatting in audit.c. log.o is built for CONFIG_SECURITY_LANDLOCK_LOG and audit.o for CONFIG_AUDIT, so the common framework is available to a tracepoints-only build. The entry points dispatch to no-op static inline audit stubs without CONFIG_AUDIT, so the call sites stay unconditional. Rename the former landlock_log_drop_domain() to landlock_log_free_domain() to match the landlock_free_domain tracepoint added in a following commit. landlock_log_denial() counts denials even without audit, so its declaration and no-op stub are guarded by CONFIG_SECURITY_LANDLOCK_LOG, not CONFIG_AUDIT; a CONFIG_AUDIT guard would expose the stub and clash with log.c's definition in a tracepoints-only build. Widen the ID allocation (id.o and the landlock_init_id() / landlock_get_id_range() declarations) and the log-state representation (the domain_exec and log_subdomains_off credential fields, the landlock_hierarchy log fields, and the code that maintains them) from CONFIG_AUDIT to CONFIG_SECURITY_LANDLOCK_LOG, so each field and its writer share one guard and are available to tracing without audit support. Widen the denial-path state that feeds the per-denial logging decision the same way, so the "logged" verdict is computed identically whether or not CONFIG_AUDIT is set. Widening fown_layer is what keeps the file-owner-signal path valid without audit: otherwise hook_file_send_sigiotask() would leave layer_plus_one at zero, tripping the is_valid_request() canary and dropping the LANDLOCK_SCOPE_SIGNAL denial from tracing. The ruleset-level quiet_masks stays on no CONFIG guard: it is builder state validated and stored from user input, kept available so LANDLOCK_ADD_RULE_QUIET flags are accepted and ignored, not rejected, when CONFIG_SECURITY_LANDLOCK_LOG is disabled. Cc: Günther Noack <gnoack@google.com> Link: https://patch.msgid.link/20260811094338.288094-5-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:18 +02:00
landlock: Split struct landlock_domain from struct landlock_ruleset Switch all domain users to the new struct landlock_domain type introduced by a previous commit, eliminating the conflation between mutable rulesets and immutable domains. landlock_merge_ruleset() now returns and allocates a struct landlock_domain, and the merge and inherit helpers move next to it; the former static insert_rule() is exported as landlock_store_rule() for its new caller across the translation-unit boundary. The merge destination is now a private struct landlock_domain still under construction (owned by the calling thread, not yet shared), so the merge and inherit helpers lock only the source ruleset: the previous lock of both destination and source collapses to a single mutex_lock(&src->lock). Rename the per-layer access-mask field from access_masks to handled_masks, naming it by the role it plays (the rights each layer handles) rather than by its type, paralleling the struct access_masks quiet_masks field. Drop the now domain-only fields (hierarchy, work_free, num_layers) from struct landlock_ruleset. The new struct landlock_domain field in cred.h pulls in domain.h, which includes audit.h, which previously included cred.h, forming an include cycle. Break it by having audit.h forward-declare the struct landlock_cred_security and struct landlock_hierarchy it uses instead of including cred.h. Cc: Günther Noack <gnoack@google.com> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-4-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:17 +02:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Split struct landlock_domain from struct landlock_ruleset Switch all domain users to the new struct landlock_domain type introduced by a previous commit, eliminating the conflation between mutable rulesets and immutable domains. landlock_merge_ruleset() now returns and allocates a struct landlock_domain, and the merge and inherit helpers move next to it; the former static insert_rule() is exported as landlock_store_rule() for its new caller across the translation-unit boundary. The merge destination is now a private struct landlock_domain still under construction (owned by the calling thread, not yet shared), so the merge and inherit helpers lock only the source ruleset: the previous lock of both destination and source collapses to a single mutex_lock(&src->lock). Rename the per-layer access-mask field from access_masks to handled_masks, naming it by the role it plays (the rights each layer handles) rather than by its type, paralleling the struct access_masks quiet_masks field. Drop the now domain-only fields (hierarchy, work_free, num_layers) from struct landlock_ruleset. The new struct landlock_domain field in cred.h pulls in domain.h, which includes audit.h, which previously included cred.h, forming an include cycle. Break it by having audit.h forward-declare the struct landlock_cred_security and struct landlock_hierarchy it uses instead of including cred.h. Cc: Günther Noack <gnoack@google.com> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-4-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:17 +02:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add tracepoints for ptrace and scope denials Scope and ptrace denials follow a different code path (a domain hierarchy check) than access-right denials, so they need dedicated tracepoints with type-specific TP_PROTO arguments. Complete the denial coverage with: - landlock_deny_ptrace: ptrace access denied by a domain hierarchy mismatch. - landlock_deny_scope_signal: signal delivery denied by LANDLOCK_SCOPE_SIGNAL. - landlock_deny_scope_abstract_unix_socket: abstract unix socket access denied by LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET. TP_PROTO passes the raw kernel object (struct task_struct or struct sock) for eBPF BTF access; the comm and sun_path string fields use __print_untrusted_str() because they hold untrusted input. Unlike the deny_access events, these omit the blockers field: each maps to exactly one denial type named by the event, so the bitmask would always be zero. Like the deny_access events they carry same_exec and logged. Audit logs the task-targeted denials with generic field names (opid, ocomm), but a strongly typed trace event can use role-prefixed names (tracee_pid/tracee_comm, target_pid/target_comm) that match the mainline task-name convention (sched_process_fork's parent_comm/child_comm) and say whose name each field holds; a bare comm= would collide across events. The abstract-unix-socket event reports peer_pid instead, a tracepoint-only field with no audit counterpart. A scope or ptrace verdict compares the subject domain against the other party's domain, so each event also reports that other party's Landlock domain (tracee_domain=, target_domain=, or peer_domain=); the subject domain= alone does not let a consumer redo domain_is_scoped() or domain_ptrace(). It is reported as a scalar ID rather than a domain pointer: a domain object is immutable, but the other task can replace its credential and free the domain that credential referenced, so a stored foreign pointer could dangle before the event is consumed. The scalar ID also honors the tracepoint no-nullable-pointer rule, since the other party is frequently unsandboxed. Passing the foreign domain hierarchy object so an eBPF consumer could walk the other party's ancestry live would lengthen the RCU section on the shared denial path and needs a deferred refcount put, so it is left as a future enhancement. The relational domain-ID field (tracee_domain, target_domain, or peer_domain) is trace-only and is not added to audit records, so audit's denial format is unchanged by this series. Cc: Günther Noack <gnoack@google.com> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-14-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:27 +02:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Split struct landlock_domain from struct landlock_ruleset Switch all domain users to the new struct landlock_domain type introduced by a previous commit, eliminating the conflation between mutable rulesets and immutable domains. landlock_merge_ruleset() now returns and allocates a struct landlock_domain, and the merge and inherit helpers move next to it; the former static insert_rule() is exported as landlock_store_rule() for its new caller across the translation-unit boundary. The merge destination is now a private struct landlock_domain still under construction (owned by the calling thread, not yet shared), so the merge and inherit helpers lock only the source ruleset: the previous lock of both destination and source collapses to a single mutex_lock(&src->lock). Rename the per-layer access-mask field from access_masks to handled_masks, naming it by the role it plays (the rights each layer handles) rather than by its type, paralleling the struct access_masks quiet_masks field. Drop the now domain-only fields (hierarchy, work_free, num_layers) from struct landlock_ruleset. The new struct landlock_domain field in cred.h pulls in domain.h, which includes audit.h, which previously included cred.h, forming an include cycle. Break it by having audit.h forward-declare the struct landlock_cred_security and struct landlock_hierarchy it uses instead of including cred.h. Cc: Günther Noack <gnoack@google.com> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-4-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:17 +02:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add tracepoints for ptrace and scope denials Scope and ptrace denials follow a different code path (a domain hierarchy check) than access-right denials, so they need dedicated tracepoints with type-specific TP_PROTO arguments. Complete the denial coverage with: - landlock_deny_ptrace: ptrace access denied by a domain hierarchy mismatch. - landlock_deny_scope_signal: signal delivery denied by LANDLOCK_SCOPE_SIGNAL. - landlock_deny_scope_abstract_unix_socket: abstract unix socket access denied by LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET. TP_PROTO passes the raw kernel object (struct task_struct or struct sock) for eBPF BTF access; the comm and sun_path string fields use __print_untrusted_str() because they hold untrusted input. Unlike the deny_access events, these omit the blockers field: each maps to exactly one denial type named by the event, so the bitmask would always be zero. Like the deny_access events they carry same_exec and logged. Audit logs the task-targeted denials with generic field names (opid, ocomm), but a strongly typed trace event can use role-prefixed names (tracee_pid/tracee_comm, target_pid/target_comm) that match the mainline task-name convention (sched_process_fork's parent_comm/child_comm) and say whose name each field holds; a bare comm= would collide across events. The abstract-unix-socket event reports peer_pid instead, a tracepoint-only field with no audit counterpart. A scope or ptrace verdict compares the subject domain against the other party's domain, so each event also reports that other party's Landlock domain (tracee_domain=, target_domain=, or peer_domain=); the subject domain= alone does not let a consumer redo domain_is_scoped() or domain_ptrace(). It is reported as a scalar ID rather than a domain pointer: a domain object is immutable, but the other task can replace its credential and free the domain that credential referenced, so a stored foreign pointer could dangle before the event is consumed. The scalar ID also honors the tracepoint no-nullable-pointer rule, since the other party is frequently unsandboxed. Passing the foreign domain hierarchy object so an eBPF consumer could walk the other party's ancestry live would lengthen the RCU section on the shared denial path and needs a deferred refcount put, so it is left as a future enhancement. The relational domain-ID field (tracee_domain, target_domain, or peer_domain) is trace-only and is not added to audit records, so audit's denial format is unchanged by this series. Cc: Günther Noack <gnoack@google.com> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-14-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:27 +02:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Split struct landlock_domain from struct landlock_ruleset Switch all domain users to the new struct landlock_domain type introduced by a previous commit, eliminating the conflation between mutable rulesets and immutable domains. landlock_merge_ruleset() now returns and allocates a struct landlock_domain, and the merge and inherit helpers move next to it; the former static insert_rule() is exported as landlock_store_rule() for its new caller across the translation-unit boundary. The merge destination is now a private struct landlock_domain still under construction (owned by the calling thread, not yet shared), so the merge and inherit helpers lock only the source ruleset: the previous lock of both destination and source collapses to a single mutex_lock(&src->lock). Rename the per-layer access-mask field from access_masks to handled_masks, naming it by the role it plays (the rights each layer handles) rather than by its type, paralleling the struct access_masks quiet_masks field. Drop the now domain-only fields (hierarchy, work_free, num_layers) from struct landlock_ruleset. The new struct landlock_domain field in cred.h pulls in domain.h, which includes audit.h, which previously included cred.h, forming an include cycle. Break it by having audit.h forward-declare the struct landlock_cred_security and struct landlock_hierarchy it uses instead of including cred.h. Cc: Günther Noack <gnoack@google.com> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-4-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:17 +02:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Split struct landlock_domain from struct landlock_ruleset Switch all domain users to the new struct landlock_domain type introduced by a previous commit, eliminating the conflation between mutable rulesets and immutable domains. landlock_merge_ruleset() now returns and allocates a struct landlock_domain, and the merge and inherit helpers move next to it; the former static insert_rule() is exported as landlock_store_rule() for its new caller across the translation-unit boundary. The merge destination is now a private struct landlock_domain still under construction (owned by the calling thread, not yet shared), so the merge and inherit helpers lock only the source ruleset: the previous lock of both destination and source collapses to a single mutex_lock(&src->lock). Rename the per-layer access-mask field from access_masks to handled_masks, naming it by the role it plays (the rights each layer handles) rather than by its type, paralleling the struct access_masks quiet_masks field. Drop the now domain-only fields (hierarchy, work_free, num_layers) from struct landlock_ruleset. The new struct landlock_domain field in cred.h pulls in domain.h, which includes audit.h, which previously included cred.h, forming an include cycle. Break it by having audit.h forward-declare the struct landlock_cred_security and struct landlock_hierarchy it uses instead of including cred.h. Cc: Günther Noack <gnoack@google.com> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-4-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:17 +02:00
landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials Add a new AUDIT_LANDLOCK_ACCESS record type dedicated to an access request denied by a Landlock domain. AUDIT_LANDLOCK_ACCESS indicates that something unexpected happened. For now, only denied access are logged, which means that any AUDIT_LANDLOCK_ACCESS record is always followed by a SYSCALL record with "success=no". However, log parsers should check this syscall property because this is the only sign that a request was denied. Indeed, we could have "success=yes" if Landlock would support a "permissive" mode. We could also add a new field to AUDIT_LANDLOCK_DOMAIN for this mode (see following commit). By default, the only logged access requests are those coming from the same executed program that enforced the Landlock restriction on itself. In other words, no audit record are created for a task after it called execve(2). This is required to avoid log spam because programs may only be aware of their own restrictions, but not the inherited ones. Following commits will allow to conditionally generate AUDIT_LANDLOCK_ACCESS records according to dedicated landlock_restrict_self(2)'s flags. The AUDIT_LANDLOCK_ACCESS message contains: - the "domain" ID restricting the action on an object, - the "blockers" that are missing to allow the requested access, - a set of fields identifying the related object (e.g. task identified with "opid" and "ocomm"). The blockers are implicit restrictions (e.g. ptrace), or explicit access rights (e.g. filesystem), or explicit scopes (e.g. signal). This field contains a list of at least one element, each separated with a comma. The initial blocker is "ptrace", which describe all implicit Landlock restrictions related to ptrace (e.g. deny tracing of tasks outside a sandbox). Add audit support to ptrace_access_check and ptrace_traceme hooks. For the ptrace_access_check case, we log the current/parent domain and the child task. For the ptrace_traceme case, we log the parent domain and the current/child task. Indeed, the requester and the target are the current task, but the action would be performed by the parent task. Audit event sample: type=LANDLOCK_ACCESS msg=audit(1729738800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1729738800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 A following commit adds user documentation. Add KUnit tests to check reading of domain ID relative to layer level. The quick return for non-landlocked tasks is moved from task_ptrace() to each LSM hooks. It is not useful to inline the audit_enabled check because other computation are performed by landlock_log_denial(). Use scoped guards for RCU read-side critical sections. Cc: Günther Noack <gnoack@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-10-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:06:58 +01:00
landlock: Split struct landlock_domain from struct landlock_ruleset Switch all domain users to the new struct landlock_domain type introduced by a previous commit, eliminating the conflation between mutable rulesets and immutable domains. landlock_merge_ruleset() now returns and allocates a struct landlock_domain, and the merge and inherit helpers move next to it; the former static insert_rule() is exported as landlock_store_rule() for its new caller across the translation-unit boundary. The merge destination is now a private struct landlock_domain still under construction (owned by the calling thread, not yet shared), so the merge and inherit helpers lock only the source ruleset: the previous lock of both destination and source collapses to a single mutex_lock(&src->lock). Rename the per-layer access-mask field from access_masks to handled_masks, naming it by the role it plays (the rights each layer handles) rather than by its type, paralleling the struct access_masks quiet_masks field. Drop the now domain-only fields (hierarchy, work_free, num_layers) from struct landlock_ruleset. The new struct landlock_domain field in cred.h pulls in domain.h, which includes audit.h, which previously included cred.h, forming an include cycle. Break it by having audit.h forward-declare the struct landlock_cred_security and struct landlock_hierarchy it uses instead of including cred.h. Cc: Günther Noack <gnoack@google.com> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-4-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:17 +02:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add tracepoints for ptrace and scope denials Scope and ptrace denials follow a different code path (a domain hierarchy check) than access-right denials, so they need dedicated tracepoints with type-specific TP_PROTO arguments. Complete the denial coverage with: - landlock_deny_ptrace: ptrace access denied by a domain hierarchy mismatch. - landlock_deny_scope_signal: signal delivery denied by LANDLOCK_SCOPE_SIGNAL. - landlock_deny_scope_abstract_unix_socket: abstract unix socket access denied by LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET. TP_PROTO passes the raw kernel object (struct task_struct or struct sock) for eBPF BTF access; the comm and sun_path string fields use __print_untrusted_str() because they hold untrusted input. Unlike the deny_access events, these omit the blockers field: each maps to exactly one denial type named by the event, so the bitmask would always be zero. Like the deny_access events they carry same_exec and logged. Audit logs the task-targeted denials with generic field names (opid, ocomm), but a strongly typed trace event can use role-prefixed names (tracee_pid/tracee_comm, target_pid/target_comm) that match the mainline task-name convention (sched_process_fork's parent_comm/child_comm) and say whose name each field holds; a bare comm= would collide across events. The abstract-unix-socket event reports peer_pid instead, a tracepoint-only field with no audit counterpart. A scope or ptrace verdict compares the subject domain against the other party's domain, so each event also reports that other party's Landlock domain (tracee_domain=, target_domain=, or peer_domain=); the subject domain= alone does not let a consumer redo domain_is_scoped() or domain_ptrace(). It is reported as a scalar ID rather than a domain pointer: a domain object is immutable, but the other task can replace its credential and free the domain that credential referenced, so a stored foreign pointer could dangle before the event is consumed. The scalar ID also honors the tracepoint no-nullable-pointer rule, since the other party is frequently unsandboxed. Passing the foreign domain hierarchy object so an eBPF consumer could walk the other party's ancestry live would lengthen the RCU section on the shared denial path and needs a deferred refcount put, so it is left as a future enhancement. The relational domain-ID field (tracee_domain, target_domain, or peer_domain) is trace-only and is not added to audit records, so audit's denial format is unchanged by this series. Cc: Günther Noack <gnoack@google.com> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-14-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:27 +02:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Always allow signals between threads of the same process Because Linux credentials are managed per thread, user space relies on some hack to synchronize credential update across threads from the same process. This is required by the Native POSIX Threads Library and implemented by set*id(2) wrappers and libcap(3) to use tgkill(2) to synchronize threads. See nptl(7) and libpsx(3). Furthermore, some runtimes like Go do not enable developers to have control over threads [1]. To avoid potential issues, and because threads are not security boundaries, let's relax the Landlock (optional) signal scoping to always allow signals sent between threads of the same process. This exception is similar to the __ptrace_may_access() one. hook_file_set_fowner() now checks if the target task is part of the same process as the caller. If this is the case, then the related signal triggered by the socket will always be allowed. Scoping of abstract UNIX sockets is not changed because kernel objects (e.g. sockets) should be tied to their creator's domain at creation time. Note that creating one Landlock domain per thread puts each of these threads (and their future children) in their own scope, which is probably not what users expect, especially in Go where we do not control threads. However, being able to drop permissions on all threads should not be restricted by signal scoping. We are working on a way to make it possible to atomically restrict all threads of a process with the same domain [2]. Add erratum for signal scoping. Closes: https://github.com/landlock-lsm/go-landlock/issues/36 Fixes: 54a6e6bbf3be ("landlock: Add signal scoping") Fixes: c8994965013e ("selftests/landlock: Test signal scoping for threads") Depends-on: 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies") Link: https://pkg.go.dev/kernel.org/pub/linux/libs/security/libcap/psx [1] Link: https://github.com/landlock-lsm/linux/issues/2 [2] Cc: Günther Noack <gnoack@google.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Serge Hallyn <serge@hallyn.com> Cc: Tahera Fahimi <fahimitahera@gmail.com> Cc: stable@vger.kernel.org Acked-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20250318161443.279194-6-mic@digikod.net [mic: Add extra pointer check and RCU guard, and ease backport] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-18 17:14:40 +01:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add tracepoints for ptrace and scope denials Scope and ptrace denials follow a different code path (a domain hierarchy check) than access-right denials, so they need dedicated tracepoints with type-specific TP_PROTO arguments. Complete the denial coverage with: - landlock_deny_ptrace: ptrace access denied by a domain hierarchy mismatch. - landlock_deny_scope_signal: signal delivery denied by LANDLOCK_SCOPE_SIGNAL. - landlock_deny_scope_abstract_unix_socket: abstract unix socket access denied by LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET. TP_PROTO passes the raw kernel object (struct task_struct or struct sock) for eBPF BTF access; the comm and sun_path string fields use __print_untrusted_str() because they hold untrusted input. Unlike the deny_access events, these omit the blockers field: each maps to exactly one denial type named by the event, so the bitmask would always be zero. Like the deny_access events they carry same_exec and logged. Audit logs the task-targeted denials with generic field names (opid, ocomm), but a strongly typed trace event can use role-prefixed names (tracee_pid/tracee_comm, target_pid/target_comm) that match the mainline task-name convention (sched_process_fork's parent_comm/child_comm) and say whose name each field holds; a bare comm= would collide across events. The abstract-unix-socket event reports peer_pid instead, a tracepoint-only field with no audit counterpart. A scope or ptrace verdict compares the subject domain against the other party's domain, so each event also reports that other party's Landlock domain (tracee_domain=, target_domain=, or peer_domain=); the subject domain= alone does not let a consumer redo domain_is_scoped() or domain_ptrace(). It is reported as a scalar ID rather than a domain pointer: a domain object is immutable, but the other task can replace its credential and free the domain that credential referenced, so a stored foreign pointer could dangle before the event is consumed. The scalar ID also honors the tracepoint no-nullable-pointer rule, since the other party is frequently unsandboxed. Passing the foreign domain hierarchy object so an eBPF consumer could walk the other party's ancestry live would lengthen the RCU section on the shared denial path and needs a deferred refcount put, so it is left as a future enhancement. The relational domain-ID field (tracee_domain, target_domain, or peer_domain) is trace-only and is not added to audit records, so audit's denial format is unchanged by this series. Cc: Günther Noack <gnoack@google.com> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-14-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:27 +02:00
landlock: Add tracepoints for ptrace and scope denials Scope and ptrace denials follow a different code path (a domain hierarchy check) than access-right denials, so they need dedicated tracepoints with type-specific TP_PROTO arguments. Complete the denial coverage with: - landlock_deny_ptrace: ptrace access denied by a domain hierarchy mismatch. - landlock_deny_scope_signal: signal delivery denied by LANDLOCK_SCOPE_SIGNAL. - landlock_deny_scope_abstract_unix_socket: abstract unix socket access denied by LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET. TP_PROTO passes the raw kernel object (struct task_struct or struct sock) for eBPF BTF access; the comm and sun_path string fields use __print_untrusted_str() because they hold untrusted input. Unlike the deny_access events, these omit the blockers field: each maps to exactly one denial type named by the event, so the bitmask would always be zero. Like the deny_access events they carry same_exec and logged. Audit logs the task-targeted denials with generic field names (opid, ocomm), but a strongly typed trace event can use role-prefixed names (tracee_pid/tracee_comm, target_pid/target_comm) that match the mainline task-name convention (sched_process_fork's parent_comm/child_comm) and say whose name each field holds; a bare comm= would collide across events. The abstract-unix-socket event reports peer_pid instead, a tracepoint-only field with no audit counterpart. A scope or ptrace verdict compares the subject domain against the other party's domain, so each event also reports that other party's Landlock domain (tracee_domain=, target_domain=, or peer_domain=); the subject domain= alone does not let a consumer redo domain_is_scoped() or domain_ptrace(). It is reported as a scalar ID rather than a domain pointer: a domain object is immutable, but the other task can replace its credential and free the domain that credential referenced, so a stored foreign pointer could dangle before the event is consumed. The scalar ID also honors the tracepoint no-nullable-pointer rule, since the other party is frequently unsandboxed. Passing the foreign domain hierarchy object so an eBPF consumer could walk the other party's ancestry live would lengthen the RCU section on the shared denial path and needs a deferred refcount put, so it is left as a future enhancement. The relational domain-ID field (tracee_domain, target_domain, or peer_domain) is trace-only and is not added to audit records, so audit's denial format is unchanged by this series. Cc: Günther Noack <gnoack@google.com> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-14-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:27 +02:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add tracepoints for ptrace and scope denials Scope and ptrace denials follow a different code path (a domain hierarchy check) than access-right denials, so they need dedicated tracepoints with type-specific TP_PROTO arguments. Complete the denial coverage with: - landlock_deny_ptrace: ptrace access denied by a domain hierarchy mismatch. - landlock_deny_scope_signal: signal delivery denied by LANDLOCK_SCOPE_SIGNAL. - landlock_deny_scope_abstract_unix_socket: abstract unix socket access denied by LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET. TP_PROTO passes the raw kernel object (struct task_struct or struct sock) for eBPF BTF access; the comm and sun_path string fields use __print_untrusted_str() because they hold untrusted input. Unlike the deny_access events, these omit the blockers field: each maps to exactly one denial type named by the event, so the bitmask would always be zero. Like the deny_access events they carry same_exec and logged. Audit logs the task-targeted denials with generic field names (opid, ocomm), but a strongly typed trace event can use role-prefixed names (tracee_pid/tracee_comm, target_pid/target_comm) that match the mainline task-name convention (sched_process_fork's parent_comm/child_comm) and say whose name each field holds; a bare comm= would collide across events. The abstract-unix-socket event reports peer_pid instead, a tracepoint-only field with no audit counterpart. A scope or ptrace verdict compares the subject domain against the other party's domain, so each event also reports that other party's Landlock domain (tracee_domain=, target_domain=, or peer_domain=); the subject domain= alone does not let a consumer redo domain_is_scoped() or domain_ptrace(). It is reported as a scalar ID rather than a domain pointer: a domain object is immutable, but the other task can replace its credential and free the domain that credential referenced, so a stored foreign pointer could dangle before the event is consumed. The scalar ID also honors the tracepoint no-nullable-pointer rule, since the other party is frequently unsandboxed. Passing the foreign domain hierarchy object so an eBPF consumer could walk the other party's ancestry live would lengthen the RCU section on the shared denial path and needs a deferred refcount put, so it is left as a future enhancement. The relational domain-ID field (tracee_domain, target_domain, or peer_domain) is trace-only and is not added to audit records, so audit's denial format is unchanged by this series. Cc: Günther Noack <gnoack@google.com> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-14-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:27 +02:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Fix LANDLOCK_SCOPE_SIGNAL bypass on the SIGIO path LANDLOCK_SCOPE_SIGNAL must prevent a sandboxed process from signaling processes outside its Landlock domain. It can be bypassed through the asynchronous SIGIO delivery path. A sandboxed process that owns any file or socket can arm it with fcntl(fd, F_SETOWN, -pgid), fcntl(fd, F_SETSIG, SIGKILL) and O_ASYNC, so that an I/O event makes the kernel deliver the chosen signal to the whole process group. As the head of its process group's task list (the default position right after fork()) that group can also hold the non-sandboxed process that launched it, e.g. a supervisor or a security monitor. The sandbox can thus kill or signal the processes LANDLOCK_SCOPE_SIGNAL is meant to protect from it. The scope is enforced in hook_file_send_sigiotask() against the Landlock domain recorded at F_SETOWN time, not the live domain of the sender. control_current_fowner() decides whether to record that domain and skips recording it when the fowner target is in the caller's thread group, which is safe only for a single-task target (PIDTYPE_PID, PIDTYPE_TGID). For a process group (PIDTYPE_PGID) pid_task() returns only one member; recording is skipped whenever that member shares the caller's thread group, and hook_file_send_sigiotask() then lets the signal fan out to the whole group unchecked. Record the domain for every non single-process target so the scope is enforced against each group member at delivery time. That recording is necessary but not sufficient on its own: the kernel signals a process group through its members' thread-group leaders, and the leader of the registrant's own process can carry a different Landlock domain than the sibling thread that armed the owner. domain_is_scoped() would then deny that leader, even though commit 18eb75f3af40 ("landlock: Always allow signals between threads of the same process") requires same-process delivery to be allowed. hook_task_kill() avoids this by evaluating same_thread_group() live, per recipient; the SIGIO path instead delegates the whole decision to a single registration-time check, which a process-group fan-out cannot honor. So also record the registrant's thread group next to its domain and exempt it at delivery: hook_file_send_sigiotask() allows the signal whenever the recipient belongs to the registrant's own process, restoring the same-process guarantee while keeping out-of-domain group members blocked. The direct kill() path (hook_task_kill) already evaluates the live domain and is unaffected. Fixes: 18eb75f3af40 ("landlock: Always allow signals between threads of the same process") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me> Reviewed-by: Günther Noack <gnoack3000@gmail.com> Link: https://patch.msgid.link/56bffc24f3d0d08b45a686a48e99766b0a0821fa.1780614610.git.hexlabsecurity@proton.me [mic: Check pid_type earlier and improve comment, fix commit message, fix comment formatting] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-06-04 23:16:56 +00:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Add tracepoints for ptrace and scope denials Scope and ptrace denials follow a different code path (a domain hierarchy check) than access-right denials, so they need dedicated tracepoints with type-specific TP_PROTO arguments. Complete the denial coverage with: - landlock_deny_ptrace: ptrace access denied by a domain hierarchy mismatch. - landlock_deny_scope_signal: signal delivery denied by LANDLOCK_SCOPE_SIGNAL. - landlock_deny_scope_abstract_unix_socket: abstract unix socket access denied by LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET. TP_PROTO passes the raw kernel object (struct task_struct or struct sock) for eBPF BTF access; the comm and sun_path string fields use __print_untrusted_str() because they hold untrusted input. Unlike the deny_access events, these omit the blockers field: each maps to exactly one denial type named by the event, so the bitmask would always be zero. Like the deny_access events they carry same_exec and logged. Audit logs the task-targeted denials with generic field names (opid, ocomm), but a strongly typed trace event can use role-prefixed names (tracee_pid/tracee_comm, target_pid/target_comm) that match the mainline task-name convention (sched_process_fork's parent_comm/child_comm) and say whose name each field holds; a bare comm= would collide across events. The abstract-unix-socket event reports peer_pid instead, a tracepoint-only field with no audit counterpart. A scope or ptrace verdict compares the subject domain against the other party's domain, so each event also reports that other party's Landlock domain (tracee_domain=, target_domain=, or peer_domain=); the subject domain= alone does not let a consumer redo domain_is_scoped() or domain_ptrace(). It is reported as a scalar ID rather than a domain pointer: a domain object is immutable, but the other task can replace its credential and free the domain that credential referenced, so a stored foreign pointer could dangle before the event is consumed. The scalar ID also honors the tracepoint no-nullable-pointer rule, since the other party is frequently unsandboxed. Passing the foreign domain hierarchy object so an eBPF consumer could walk the other party's ancestry live would lengthen the RCU section on the shared denial path and needs a deferred refcount put, so it is left as a future enhancement. The relational domain-ID field (tracee_domain, target_domain, or peer_domain) is trace-only and is not added to audit records, so audit's denial format is unchanged by this series. Cc: Günther Noack <gnoack@google.com> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-14-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:27 +02:00
landlock: Add tracepoints for ptrace and scope denials Scope and ptrace denials follow a different code path (a domain hierarchy check) than access-right denials, so they need dedicated tracepoints with type-specific TP_PROTO arguments. Complete the denial coverage with: - landlock_deny_ptrace: ptrace access denied by a domain hierarchy mismatch. - landlock_deny_scope_signal: signal delivery denied by LANDLOCK_SCOPE_SIGNAL. - landlock_deny_scope_abstract_unix_socket: abstract unix socket access denied by LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET. TP_PROTO passes the raw kernel object (struct task_struct or struct sock) for eBPF BTF access; the comm and sun_path string fields use __print_untrusted_str() because they hold untrusted input. Unlike the deny_access events, these omit the blockers field: each maps to exactly one denial type named by the event, so the bitmask would always be zero. Like the deny_access events they carry same_exec and logged. Audit logs the task-targeted denials with generic field names (opid, ocomm), but a strongly typed trace event can use role-prefixed names (tracee_pid/tracee_comm, target_pid/target_comm) that match the mainline task-name convention (sched_process_fork's parent_comm/child_comm) and say whose name each field holds; a bare comm= would collide across events. The abstract-unix-socket event reports peer_pid instead, a tracepoint-only field with no audit counterpart. A scope or ptrace verdict compares the subject domain against the other party's domain, so each event also reports that other party's Landlock domain (tracee_domain=, target_domain=, or peer_domain=); the subject domain= alone does not let a consumer redo domain_is_scoped() or domain_ptrace(). It is reported as a scalar ID rather than a domain pointer: a domain object is immutable, but the other task can replace its credential and free the domain that credential referenced, so a stored foreign pointer could dangle before the event is consumed. The scalar ID also honors the tracepoint no-nullable-pointer rule, since the other party is frequently unsandboxed. Passing the foreign domain hierarchy object so an eBPF consumer could walk the other party's ancestry live would lengthen the RCU section on the shared denial path and needs a deferred refcount put, so it is left as a future enhancement. The relational domain-ID field (tracee_domain, target_domain, or peer_domain) is trace-only and is not added to audit records, so audit's denial format is unchanged by this series. Cc: Günther Noack <gnoack@google.com> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tingmao Wang <m@maowtm.org> Link: https://patch.msgid.link/20260811094338.288094-14-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:27 +02:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
landlock: Split denial logging from audit into common framework Tracepoint emission requires the denial framework (layer identification, request validation) without depending on CONFIG_AUDIT. Separate the denial logging infrastructure from the audit-specific code by introducing a common log framework. Create CONFIG_SECURITY_LANDLOCK_LOG, enabled by default when CONFIG_AUDIT is set; a following commit extends it to CONFIG_TRACEPOINTS when the first tracepoint consumer is added. Move the common framework (the request types, the layer identification and request validation, and the landlock_log_denial() and landlock_log_free_domain() entry points) into log.c and log.h, and keep the audit-specific record formatting in audit.c. log.o is built for CONFIG_SECURITY_LANDLOCK_LOG and audit.o for CONFIG_AUDIT, so the common framework is available to a tracepoints-only build. The entry points dispatch to no-op static inline audit stubs without CONFIG_AUDIT, so the call sites stay unconditional. Rename the former landlock_log_drop_domain() to landlock_log_free_domain() to match the landlock_free_domain tracepoint added in a following commit. landlock_log_denial() counts denials even without audit, so its declaration and no-op stub are guarded by CONFIG_SECURITY_LANDLOCK_LOG, not CONFIG_AUDIT; a CONFIG_AUDIT guard would expose the stub and clash with log.c's definition in a tracepoints-only build. Widen the ID allocation (id.o and the landlock_init_id() / landlock_get_id_range() declarations) and the log-state representation (the domain_exec and log_subdomains_off credential fields, the landlock_hierarchy log fields, and the code that maintains them) from CONFIG_AUDIT to CONFIG_SECURITY_LANDLOCK_LOG, so each field and its writer share one guard and are available to tracing without audit support. Widen the denial-path state that feeds the per-denial logging decision the same way, so the "logged" verdict is computed identically whether or not CONFIG_AUDIT is set. Widening fown_layer is what keeps the file-owner-signal path valid without audit: otherwise hook_file_send_sigiotask() would leave layer_plus_one at zero, tripping the is_valid_request() canary and dropping the LANDLOCK_SCOPE_SIGNAL denial from tracing. The ruleset-level quiet_masks stays on no CONFIG guard: it is builder state validated and stored from user input, kept available so LANDLOCK_ADD_RULE_QUIET flags are accepted and ignored, not rejected, when CONFIG_SECURITY_LANDLOCK_LOG is disabled. Cc: Günther Noack <gnoack@google.com> Link: https://patch.msgid.link/20260811094338.288094-5-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:18 +02:00
landlock: Split denial logging from audit into common framework Tracepoint emission requires the denial framework (layer identification, request validation) without depending on CONFIG_AUDIT. Separate the denial logging infrastructure from the audit-specific code by introducing a common log framework. Create CONFIG_SECURITY_LANDLOCK_LOG, enabled by default when CONFIG_AUDIT is set; a following commit extends it to CONFIG_TRACEPOINTS when the first tracepoint consumer is added. Move the common framework (the request types, the layer identification and request validation, and the landlock_log_denial() and landlock_log_free_domain() entry points) into log.c and log.h, and keep the audit-specific record formatting in audit.c. log.o is built for CONFIG_SECURITY_LANDLOCK_LOG and audit.o for CONFIG_AUDIT, so the common framework is available to a tracepoints-only build. The entry points dispatch to no-op static inline audit stubs without CONFIG_AUDIT, so the call sites stay unconditional. Rename the former landlock_log_drop_domain() to landlock_log_free_domain() to match the landlock_free_domain tracepoint added in a following commit. landlock_log_denial() counts denials even without audit, so its declaration and no-op stub are guarded by CONFIG_SECURITY_LANDLOCK_LOG, not CONFIG_AUDIT; a CONFIG_AUDIT guard would expose the stub and clash with log.c's definition in a tracepoints-only build. Widen the ID allocation (id.o and the landlock_init_id() / landlock_get_id_range() declarations) and the log-state representation (the domain_exec and log_subdomains_off credential fields, the landlock_hierarchy log fields, and the code that maintains them) from CONFIG_AUDIT to CONFIG_SECURITY_LANDLOCK_LOG, so each field and its writer share one guard and are available to tracing without audit support. Widen the denial-path state that feeds the per-denial logging decision the same way, so the "logged" verdict is computed identically whether or not CONFIG_AUDIT is set. Widening fown_layer is what keeps the file-owner-signal path valid without audit: otherwise hook_file_send_sigiotask() would leave layer_plus_one at zero, tripping the is_valid_request() canary and dropping the LANDLOCK_SCOPE_SIGNAL denial from tracing. The ruleset-level quiet_masks stays on no CONFIG guard: it is builder state validated and stored from user input, kept available so LANDLOCK_ADD_RULE_QUIET flags are accepted and ignored, not rejected, when CONFIG_SECURITY_LANDLOCK_LOG is disabled. Cc: Günther Noack <gnoack@google.com> Link: https://patch.msgid.link/20260811094338.288094-5-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-11 11:43:18 +02:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
selinux: remove the runtime disable functionality After working with the larger SELinux-based distros for several years, we're finally at a place where we can disable the SELinux runtime disable functionality. The existing kernel deprecation notice explains the functionality and why we want to remove it: The selinuxfs "disable" node allows SELinux to be disabled at runtime prior to a policy being loaded into the kernel. If disabled via this mechanism, SELinux will remain disabled until the system is rebooted. The preferred method of disabling SELinux is via the "selinux=0" boot parameter, but the selinuxfs "disable" node was created to make it easier for systems with primitive bootloaders that did not allow for easy modification of the kernel command line. Unfortunately, allowing for SELinux to be disabled at runtime makes it difficult to secure the kernel's LSM hooks using the "__ro_after_init" feature. It is that last sentence, mentioning the '__ro_after_init' hardening, which is the real motivation for this change, and if you look at the diffstat you'll see that the impact of this patch reaches across all the different LSMs, helping prevent tampering at the LSM hook level. From a SELinux perspective, it is important to note that if you continue to disable SELinux via "/etc/selinux/config" it may appear that SELinux is disabled, but it is simply in an uninitialized state. If you load a policy with `load_policy -i`, you will see SELinux come alive just as if you had loaded the policy during early-boot. It is also worth noting that the "/sys/fs/selinux/disable" file is always writable now, regardless of the Kconfig settings, but writing to the file has no effect on the system, other than to display an error on the console if a non-zero/true value is written. Finally, in the several years where we have been working on deprecating this functionality, there has only been one instance of someone mentioning any user visible breakage. In this particular case it was an individual's kernel test system, and the workaround documented in the deprecation notice ("selinux=0" on the kernel command line) resolved the issue without problem. Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-17 12:43:07 -04:00
landlock: Add signal scoping Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-06 15:30:03 -06:00
LSM: Identify modules by more than name Create a struct lsm_id to contain identifying information about Linux Security Modules (LSMs). At inception this contains the name of the module and an identifier associated with the security module. Change the security_add_hooks() interface to use this structure. Change the individual modules to maintain their own struct lsm_id and pass it to security_add_hooks(). The values are for LSM identifiers are defined in a new UAPI header file linux/lsm.h. Each existing LSM has been updated to include it's LSMID in the lsm_id. The LSM ID values are sequential, with the oldest module LSM_ID_CAPABILITY being the lowest value and the existing modules numbered in the order they were included in the main line kernel. This is an arbitrary convention for assigning the values, but none better presents itself. The value 0 is defined as being invalid. The values 1-99 are reserved for any special case uses which may arise in the future. This may include attributes of the LSM infrastructure itself, possibly related to namespacing or network attribute management. A special range is identified for such attributes to help reduce confusion for developers unfamiliar with LSMs. LSM attribute values are defined for the attributes presented by modules that are available today. As with the LSM IDs, The value 0 is defined as being invalid. The values 1-99 are reserved for any special case uses which may arise in the future. Cc: linux-security-module <linux-security-module@vger.kernel.org> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Mickael Salaun <mic@digikod.net> Reviewed-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Kees Cook <keescook@chromium.org> Nacked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> [PM: forward ported beyond v6.6 due merge window changes] Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-09-12 13:56:46 -07:00