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linux/security/landlock/limits.h

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landlock: Add ruleset and domain management A Landlock ruleset is mainly a red-black tree with Landlock rules as nodes. This enables quick update and lookup to match a requested access, e.g. to a file. A ruleset is usable through a dedicated file descriptor (cf. following commit implementing syscalls) which enables a process to create and populate a ruleset with new rules. A domain is a ruleset tied to a set of processes. This group of rules defines the security policy enforced on these processes and their future children. A domain can transition to a new domain which is the intersection of all its constraints and those of a ruleset provided by the current process. This modification only impact the current process. This means that a process can only gain more constraints (i.e. lose accesses) over time. Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20210422154123.13086-3-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:12 +02:00
landlock: Add LANDLOCK_RESTRICT_SELF_LOG_*_EXEC_* flags Most of the time we want to log denied access because they should not happen and such information helps diagnose issues. However, when sandboxing processes that we know will try to access denied resources (e.g. unknown, bogus, or malicious binary), we might want to not log related access requests that might fill up logs. By default, denied requests are logged until the task call execve(2). If the LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF flag is set, denied requests will not be logged for the same executed file. If the LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON flag is set, denied requests from after an execve(2) call will be logged. The rationale is that a program should know its own behavior, but not necessarily the behavior of other programs. Because LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF is set for a specific Landlock domain, it makes it possible to selectively mask some access requests that would be logged by a parent domain, which might be handy for unprivileged processes to limit logs. However, system administrators should still use the audit filtering mechanism. There is intentionally no audit nor sysctl configuration to re-enable these logs. This is delegated to the user space program. Increment the Landlock ABI version to reflect this interface change. Cc: Günther Noack <gnoack@google.com> Cc: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-18-mic@digikod.net [mic: Rename variables and fix __maybe_unused] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:07:06 +01:00
landlock: Add ruleset and domain management A Landlock ruleset is mainly a red-black tree with Landlock rules as nodes. This enables quick update and lookup to match a requested access, e.g. to a file. A ruleset is usable through a dedicated file descriptor (cf. following commit implementing syscalls) which enables a process to create and populate a ruleset with new rules. A domain is a ruleset tied to a set of processes. This group of rules defines the security policy enforced on these processes and their future children. A domain can transition to a new domain which is the intersection of all its constraints and those of a ruleset provided by the current process. This modification only impact the current process. This means that a process can only gain more constraints (i.e. lose accesses) over time. Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20210422154123.13086-3-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:12 +02:00
landlock: Add LANDLOCK_RESTRICT_SELF_LOG_*_EXEC_* flags Most of the time we want to log denied access because they should not happen and such information helps diagnose issues. However, when sandboxing processes that we know will try to access denied resources (e.g. unknown, bogus, or malicious binary), we might want to not log related access requests that might fill up logs. By default, denied requests are logged until the task call execve(2). If the LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF flag is set, denied requests will not be logged for the same executed file. If the LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON flag is set, denied requests from after an execve(2) call will be logged. The rationale is that a program should know its own behavior, but not necessarily the behavior of other programs. Because LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF is set for a specific Landlock domain, it makes it possible to selectively mask some access requests that would be logged by a parent domain, which might be handy for unprivileged processes to limit logs. However, system administrators should still use the audit filtering mechanism. There is intentionally no audit nor sysctl configuration to re-enable these logs. This is delegated to the user space program. Increment the Landlock ABI version to reflect this interface change. Cc: Günther Noack <gnoack@google.com> Cc: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-18-mic@digikod.net [mic: Rename variables and fix __maybe_unused] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:07:06 +01:00
landlock: Add ruleset and domain management A Landlock ruleset is mainly a red-black tree with Landlock rules as nodes. This enables quick update and lookup to match a requested access, e.g. to a file. A ruleset is usable through a dedicated file descriptor (cf. following commit implementing syscalls) which enables a process to create and populate a ruleset with new rules. A domain is a ruleset tied to a set of processes. This group of rules defines the security policy enforced on these processes and their future children. A domain can transition to a new domain which is the intersection of all its constraints and those of a ruleset provided by the current process. This modification only impact the current process. This means that a process can only gain more constraints (i.e. lose accesses) over time. Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20210422154123.13086-3-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:12 +02:00
landlock: Define access_mask_t to enforce a consistent access mask size Create and use the access_mask_t typedef to enforce a consistent access mask size and uniformly use a 16-bits type. This will helps transition to a 32-bits value one day. Add a build check to make sure all (filesystem) access rights fit in. This will be extended with a following commit. Reviewed-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20220506161102.525323-2-mic@digikod.net Cc: stable@vger.kernel.org Signed-off-by: Mickaël Salaün <mic@digikod.net>
2022-05-06 18:10:51 +02:00
landlock: Add ruleset and domain management A Landlock ruleset is mainly a red-black tree with Landlock rules as nodes. This enables quick update and lookup to match a requested access, e.g. to a file. A ruleset is usable through a dedicated file descriptor (cf. following commit implementing syscalls) which enables a process to create and populate a ruleset with new rules. A domain is a ruleset tied to a set of processes. This group of rules defines the security policy enforced on these processes and their future children. A domain can transition to a new domain which is the intersection of all its constraints and those of a ruleset provided by the current process. This modification only impact the current process. This means that a process can only gain more constraints (i.e. lose accesses) over time. Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20210422154123.13086-3-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:12 +02:00
landlock: Support filesystem access-control Using Landlock objects and ruleset, it is possible to tag inodes according to a process's domain. To enable an unprivileged process to express a file hierarchy, it first needs to open a directory (or a file) and pass this file descriptor to the kernel through landlock_add_rule(2). When checking if a file access request is allowed, we walk from the requested dentry to the real root, following the different mount layers. The access to each "tagged" inodes are collected according to their rule layer level, and ANDed to create access to the requested file hierarchy. This makes possible to identify a lot of files without tagging every inodes nor modifying the filesystem, while still following the view and understanding the user has from the filesystem. Add a new ARCH_EPHEMERAL_INODES for UML because it currently does not keep the same struct inodes for the same inodes whereas these inodes are in use. This commit adds a minimal set of supported filesystem access-control which doesn't enable to restrict all file-related actions. This is the result of multiple discussions to minimize the code of Landlock to ease review. Thanks to the Landlock design, extending this access-control without breaking user space will not be a problem. Moreover, seccomp filters can be used to restrict the use of syscall families which may not be currently handled by Landlock. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Kees Cook <keescook@chromium.org> Cc: Richard Weinberger <richard@nod.at> Cc: Serge E. Hallyn <serge@hallyn.com> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Link: https://lore.kernel.org/r/20210422154123.13086-8-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:17 +02:00
landlock: Add ruleset and domain management A Landlock ruleset is mainly a red-black tree with Landlock rules as nodes. This enables quick update and lookup to match a requested access, e.g. to a file. A ruleset is usable through a dedicated file descriptor (cf. following commit implementing syscalls) which enables a process to create and populate a ruleset with new rules. A domain is a ruleset tied to a set of processes. This group of rules defines the security policy enforced on these processes and their future children. A domain can transition to a new domain which is the intersection of all its constraints and those of a ruleset provided by the current process. This modification only impact the current process. This means that a process can only gain more constraints (i.e. lose accesses) over time. Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20210422154123.13086-3-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:12 +02:00
landlock: Add clang-format exceptions In preparation to a following commit, add clang-format on and clang-format off stanzas around constant definitions. This enables to keep aligned values, which is much more readable than packed definitions. Link: https://lore.kernel.org/r/20220506160513.523257-2-mic@digikod.net Cc: stable@vger.kernel.org Signed-off-by: Mickaël Salaün <mic@digikod.net>
2022-05-06 18:05:07 +02:00
landlock: Reduce the maximum number of layers to 16 The maximum number of nested Landlock domains is currently 64. Because of the following fix and to help reduce the stack size, let's reduce it to 16. This seems large enough for a lot of use cases (e.g. sandboxed init service, spawning a sandboxed SSH service, in nested sandboxed containers). Reducing the number of nested domains may also help to discover misuse of Landlock (e.g. creating a domain per rule). Add and use a dedicated layer_mask_t typedef to fit with the number of layers. This might be useful when changing it and to keep it consistent with the maximum number of layers. Reviewed-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20220506161102.525323-3-mic@digikod.net Cc: stable@vger.kernel.org Signed-off-by: Mickaël Salaün <mic@digikod.net>
2022-05-06 18:10:52 +02:00
landlock: Add ruleset and domain management A Landlock ruleset is mainly a red-black tree with Landlock rules as nodes. This enables quick update and lookup to match a requested access, e.g. to a file. A ruleset is usable through a dedicated file descriptor (cf. following commit implementing syscalls) which enables a process to create and populate a ruleset with new rules. A domain is a ruleset tied to a set of processes. This group of rules defines the security policy enforced on these processes and their future children. A domain can transition to a new domain which is the intersection of all its constraints and those of a ruleset provided by the current process. This modification only impact the current process. This means that a process can only gain more constraints (i.e. lose accesses) over time. Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20210422154123.13086-3-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:12 +02:00
landlock: Control pathname UNIX domain socket resolution by path * Add a new access right LANDLOCK_ACCESS_FS_RESOLVE_UNIX, which controls the lookup operations for named UNIX domain sockets. The resolution happens during connect() and sendmsg() (depending on socket type). * Change access_mask_t from u16 to u32 (see below) * Hook into the path lookup in unix_find_bsd() in af_unix.c, using a LSM hook. Make policy decisions based on the new access rights * Increment the Landlock ABI version. * Minor test adaptations to keep the tests working. * Document the design rationale for scoped access rights, and cross-reference it from the header documentation. With this access right, access is granted if either of the following conditions is met: * The target socket's filesystem path was allow-listed using a LANDLOCK_RULE_PATH_BENEATH rule, *or*: * The target socket was created in the same Landlock domain in which LANDLOCK_ACCESS_FS_RESOLVE_UNIX was restricted. In case of a denial, connect() and sendmsg() return EACCES, which is the same error as it is returned if the user does not have the write bit in the traditional UNIX file system permissions of that file. The access_mask_t type grows from u16 to u32 to make space for the new access right. This also doubles the size of struct layer_access_masks from 32 byte to 64 byte. To avoid memory layout inconsistencies between architectures (especially m68k), pack and align struct access_masks [2]. Document the (possible future) interaction between scoped flags and other access rights in struct landlock_ruleset_attr, and summarize the rationale, as discussed in code review leading up to [3]. This feature was created with substantial discussion and input from Justin Suess, Tingmao Wang and Mickaël Salaün. Cc: Tingmao Wang <m@maowtm.org> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Kuniyuki Iwashima <kuniyu@google.com> Suggested-by: Jann Horn <jannh@google.com> Link[1]: https://github.com/landlock-lsm/linux/issues/36 Link[2]: https://lore.kernel.org/all/20260401.Re1Eesu1Yaij@digikod.net/ Link[3]: https://lore.kernel.org/all/20260205.8531e4005118@gnoack.org/ Signed-off-by: Günther Noack <gnoack3000@gmail.com> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/20260327164838.38231-5-gnoack3000@gmail.com [mic: Fix kernel-doc formatting, pack and align access_masks] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-03-27 17:48:29 +01:00
landlock: Support filesystem access-control Using Landlock objects and ruleset, it is possible to tag inodes according to a process's domain. To enable an unprivileged process to express a file hierarchy, it first needs to open a directory (or a file) and pass this file descriptor to the kernel through landlock_add_rule(2). When checking if a file access request is allowed, we walk from the requested dentry to the real root, following the different mount layers. The access to each "tagged" inodes are collected according to their rule layer level, and ANDed to create access to the requested file hierarchy. This makes possible to identify a lot of files without tagging every inodes nor modifying the filesystem, while still following the view and understanding the user has from the filesystem. Add a new ARCH_EPHEMERAL_INODES for UML because it currently does not keep the same struct inodes for the same inodes whereas these inodes are in use. This commit adds a minimal set of supported filesystem access-control which doesn't enable to restrict all file-related actions. This is the result of multiple discussions to minimize the code of Landlock to ease review. Thanks to the Landlock design, extending this access-control without breaking user space will not be a problem. Moreover, seccomp filters can be used to restrict the use of syscall families which may not be currently handled by Landlock. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Kees Cook <keescook@chromium.org> Cc: Richard Weinberger <richard@nod.at> Cc: Serge E. Hallyn <serge@hallyn.com> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Link: https://lore.kernel.org/r/20210422154123.13086-8-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:17 +02:00
landlock: Define access_mask_t to enforce a consistent access mask size Create and use the access_mask_t typedef to enforce a consistent access mask size and uniformly use a 16-bits type. This will helps transition to a 32-bits value one day. Add a build check to make sure all (filesystem) access rights fit in. This will be extended with a following commit. Reviewed-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20220506161102.525323-2-mic@digikod.net Cc: stable@vger.kernel.org Signed-off-by: Mickaël Salaün <mic@digikod.net>
2022-05-06 18:10:51 +02:00
landlock: Support filesystem access-control Using Landlock objects and ruleset, it is possible to tag inodes according to a process's domain. To enable an unprivileged process to express a file hierarchy, it first needs to open a directory (or a file) and pass this file descriptor to the kernel through landlock_add_rule(2). When checking if a file access request is allowed, we walk from the requested dentry to the real root, following the different mount layers. The access to each "tagged" inodes are collected according to their rule layer level, and ANDed to create access to the requested file hierarchy. This makes possible to identify a lot of files without tagging every inodes nor modifying the filesystem, while still following the view and understanding the user has from the filesystem. Add a new ARCH_EPHEMERAL_INODES for UML because it currently does not keep the same struct inodes for the same inodes whereas these inodes are in use. This commit adds a minimal set of supported filesystem access-control which doesn't enable to restrict all file-related actions. This is the result of multiple discussions to minimize the code of Landlock to ease review. Thanks to the Landlock design, extending this access-control without breaking user space will not be a problem. Moreover, seccomp filters can be used to restrict the use of syscall families which may not be currently handled by Landlock. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Kees Cook <keescook@chromium.org> Cc: Richard Weinberger <richard@nod.at> Cc: Serge E. Hallyn <serge@hallyn.com> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Link: https://lore.kernel.org/r/20210422154123.13086-8-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:17 +02:00
landlock: Add UDP send+connect access control Add support for a second fine-grained UDP access right. LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP controls the ability to set the remote port of a socket (via connect()) and to specify an explicit destination when sending a datagram, to override any remote peer set on a UDP socket (e.g. in sendto() or sendmsg()). It will be useful for applications that send datagrams, and for some servers too (those creating per-client sockets, which want to receive traffic only from a specific address). Similarly as for bind(), this access control is performed when configuring sockets, not in hot code paths. Add detection of when autobind is about to be required, and deny the operation if the process would not be allowed to call bind(0) explicitly. Autobind can only be performed in udp_lib_get_port() from code paths already controlled by LSM hooks: when connect()ing, sending a first datagram, and in some splice() EOF edge case which, afaiu, can only happen after a remote peer has been set. This invariant needs to be preserved to keep bind policies actually enforced. Signed-off-by: Matthieu Buffet <matthieu@buffet.re> Link: https://patch.msgid.link/20260611162107.49278-3-matthieu@buffet.re [mic: Add quick return for non-sandboxed tasks, fix sa_family dereferencing, fix comment formatting] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-06-11 18:21:02 +02:00
landlock: Support network rules with TCP bind and connect Add network rules support in the ruleset management helpers and the landlock_create_ruleset() syscall. Extend user space API to support network actions: * Add new network access rights: LANDLOCK_ACCESS_NET_BIND_TCP and LANDLOCK_ACCESS_NET_CONNECT_TCP. * Add a new network rule type: LANDLOCK_RULE_NET_PORT tied to struct landlock_net_port_attr. The allowed_access field contains the network access rights, and the port field contains the port value according to the controlled protocol. This field can take up to a 64-bit value but the maximum value depends on the related protocol (e.g. 16-bit value for TCP). Network port is in host endianness [1]. * Add a new handled_access_net field to struct landlock_ruleset_attr that contains network access rights. * Increment the Landlock ABI version to 4. Implement socket_bind() and socket_connect() LSM hooks, which enable to control TCP socket binding and connection to specific ports. Expand access_masks_t from u16 to u32 to be able to store network access rights alongside filesystem access rights for rulesets' handled access rights. Access rights are not tied to socket file descriptors but checked at bind() or connect() call time against the caller's Landlock domain. For the filesystem, a file descriptor is a direct access to a file/data. However, for network sockets, we cannot identify for which data or peer a newly created socket will give access to. Indeed, we need to wait for a connect or bind request to identify the use case for this socket. Likewise a directory file descriptor may enable to open another file (i.e. a new data item), but this opening is also restricted by the caller's domain, not the file descriptor's access rights [2]. [1] https://lore.kernel.org/r/278ab07f-7583-a4e0-3d37-1bacd091531d@digikod.net [2] https://lore.kernel.org/r/263c1eb3-602f-57fe-8450-3f138581bee7@digikod.net Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> Link: https://lore.kernel.org/r/20231026014751.414649-9-konstantin.meskhidze@huawei.com [mic: Extend commit message, fix typo in comments, and specify endianness in the documentation] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-10-26 09:47:47 +08:00
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 abstract UNIX socket scoping Introduce a new "scoped" member to landlock_ruleset_attr that can specify LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET to restrict connection to abstract UNIX sockets from a process outside of the socket's domain. Two hooks are implemented to enforce these restrictions: unix_stream_connect and unix_may_send. Closes: https://github.com/landlock-lsm/linux/issues/7 Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/5f7ad85243b78427242275b93481cfc7c127764b.1725494372.git.fahimitahera@gmail.com [mic: Fix commit message formatting, improve documentation, simplify hook_unix_may_send(), and cosmetic fixes including rename of LANDLOCK_SCOPED_ABSTRACT_UNIX_SOCKET] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-04 18:13:55 -06:00
landlock: Add LANDLOCK_RESTRICT_SELF_LOG_*_EXEC_* flags Most of the time we want to log denied access because they should not happen and such information helps diagnose issues. However, when sandboxing processes that we know will try to access denied resources (e.g. unknown, bogus, or malicious binary), we might want to not log related access requests that might fill up logs. By default, denied requests are logged until the task call execve(2). If the LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF flag is set, denied requests will not be logged for the same executed file. If the LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON flag is set, denied requests from after an execve(2) call will be logged. The rationale is that a program should know its own behavior, but not necessarily the behavior of other programs. Because LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF is set for a specific Landlock domain, it makes it possible to selectively mask some access requests that would be logged by a parent domain, which might be handy for unprivileged processes to limit logs. However, system administrators should still use the audit filtering mechanism. There is intentionally no audit nor sysctl configuration to re-enable these logs. This is delegated to the user space program. Increment the Landlock ABI version to reflect this interface change. Cc: Günther Noack <gnoack@google.com> Cc: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-18-mic@digikod.net [mic: Rename variables and fix __maybe_unused] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:07:06 +01:00
landlock: Add a place for flags to layer rules To avoid unnecessarily increasing the size of struct landlock_layer, we make the layer level a u8 and use the space to store the flags struct. struct layer_access_masks is renamed to struct layer_masks, and a new field is added to track whether a quiet flag rule is seen for each layer. Through use of bitfields, this does not increase the size of the struct. Cc: Justin Suess <utilityemal77@gmail.com> Assisted-by: GitHub-Copilot:claude-opus-4.8 copilot-review Signed-off-by: Tingmao Wang <m@maowtm.org> Co-developed-by: Justin Suess <utilityemal77@gmail.com> Signed-off-by: Justin Suess <utilityemal77@gmail.com> Tested-by: Justin Suess <utilityemal77@gmail.com> Link: https://patch.msgid.link/be3fec3927bc9faaacd4ce0e7f0d1ff5474e2210.1781228815.git.m@maowtm.org [mic: Fix comment formatting] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-06-12 02:48:47 +01:00
landlock: Add LANDLOCK_RESTRICT_SELF_NO_NEW_PRIVS Add a landlock_restrict_self(2) flag to set the no_new_privs attribute of the calling thread only after enforcement of the ruleset: no_new_privs is set if and only if the call succeeds. This removes the need for a prior prctl(2) PR_SET_NO_NEW_PRIVS call and guarantees that a failed enforcement leaves the attribute unchanged. Because no_new_privs is set by the call itself, the no_new_privs / CAP_SYS_ADMIN requirement of landlock_restrict_self(2) is fulfilled by construction, and the related EPERM check is skipped. Unlike LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF, this flag always requires a valid ruleset: with a ruleset_fd of -1, such a call would be nothing more than a Landlock-flavored prctl(2) PR_SET_NO_NEW_PRIVS, and there is no valid use case for setting no_new_privs (possibly with LANDLOCK_RESTRICT_SELF_TSYNC) without also enforcing Landlock restrictions. Rejecting these calls also keeps the option of giving them a meaning later. The attribute is only set past the last point of failure, just before committing the new credentials. When combined with LANDLOCK_RESTRICT_SELF_TSYNC, no_new_privs is set on the sibling threads as well, in their commit phase, with the same ordering. Bump the Landlock ABI version to 11, and include the minimal related test changes to keep the tests bisectable. Cc: Mickaël Salaün <mic@digikod.net> Signed-off-by: Justin Suess <utilityemal77@gmail.com> Link: https://patch.msgid.link/20260809212459.2427878-1-utilityemal77@gmail.com Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-08-09 17:24:59 -04:00
landlock: Add LANDLOCK_RESTRICT_SELF_LOG_*_EXEC_* flags Most of the time we want to log denied access because they should not happen and such information helps diagnose issues. However, when sandboxing processes that we know will try to access denied resources (e.g. unknown, bogus, or malicious binary), we might want to not log related access requests that might fill up logs. By default, denied requests are logged until the task call execve(2). If the LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF flag is set, denied requests will not be logged for the same executed file. If the LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON flag is set, denied requests from after an execve(2) call will be logged. The rationale is that a program should know its own behavior, but not necessarily the behavior of other programs. Because LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF is set for a specific Landlock domain, it makes it possible to selectively mask some access requests that would be logged by a parent domain, which might be handy for unprivileged processes to limit logs. However, system administrators should still use the audit filtering mechanism. There is intentionally no audit nor sysctl configuration to re-enable these logs. This is delegated to the user space program. Increment the Landlock ABI version to reflect this interface change. Cc: Günther Noack <gnoack@google.com> Cc: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20250320190717.2287696-18-mic@digikod.net [mic: Rename variables and fix __maybe_unused] Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-20 20:07:06 +01:00
landlock: Add clang-format exceptions In preparation to a following commit, add clang-format on and clang-format off stanzas around constant definitions. This enables to keep aligned values, which is much more readable than packed definitions. Link: https://lore.kernel.org/r/20220506160513.523257-2-mic@digikod.net Cc: stable@vger.kernel.org Signed-off-by: Mickaël Salaün <mic@digikod.net>
2022-05-06 18:05:07 +02:00
landlock: Add ruleset and domain management A Landlock ruleset is mainly a red-black tree with Landlock rules as nodes. This enables quick update and lookup to match a requested access, e.g. to a file. A ruleset is usable through a dedicated file descriptor (cf. following commit implementing syscalls) which enables a process to create and populate a ruleset with new rules. A domain is a ruleset tied to a set of processes. This group of rules defines the security policy enforced on these processes and their future children. A domain can transition to a new domain which is the intersection of all its constraints and those of a ruleset provided by the current process. This modification only impact the current process. This means that a process can only gain more constraints (i.e. lose accesses) over time. Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20210422154123.13086-3-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 17:41:12 +02:00