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linux/fs/backing-file.c

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fs: prepare for stackable filesystems backing file helpers In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-02 17:19:46 +03:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
fs: prepare for stackable filesystems backing file helpers In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-02 17:19:46 +03:00
fs: factor out backing_file_splice_{read,write}() helpers There is not much in those helpers, but it makes sense to have them logically next to the backing_file_{read,write}_iter() helpers as they may grow more common logic in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:13:12 +03:00
fs: factor out backing_file_mmap() helper Assert that the file object is allocated in a backing_file container so that file_user_path() could be used to display the user path and not the backing file's path in /proc/<pid>/maps. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:49:37 +03:00
lsm: add backing_file LSM hooks Stacked filesystems such as overlayfs do not currently provide the necessary mechanisms for LSMs to properly enforce access controls on the mmap() and mprotect() operations. In order to resolve this gap, a LSM security blob is being added to the backing_file struct and the following new LSM hooks are being created: security_backing_file_alloc() security_backing_file_free() security_mmap_backing_file() The first two hooks are to manage the lifecycle of the LSM security blob in the backing_file struct, while the third provides a new mmap() access control point for the underlying backing file. It is also expected that LSMs will likely want to update their security_file_mprotect() callback to address issues with their mprotect() controls, but that does not require a change to the security_file_mprotect() LSM hook. There are a three other small changes to support these new LSM hooks: * Pass the user file associated with a backing file down to alloc_empty_backing_file() so it can be included in the security_backing_file_alloc() hook. * Add getter and setter functions for the backing_file struct LSM blob as the backing_file struct remains private to fs/file_table.c. * Constify the file struct field in the LSM common_audit_data struct to better support LSMs that need to pass a const file struct pointer into the common LSM audit code. Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL() and supplying a fixup. Cc: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-unionfs@vger.kernel.org Cc: linux-erofs@lists.ozlabs.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-12-19 13:18:22 -05:00
fs: prepare for stackable filesystems backing file helpers In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-02 17:19:46 +03:00
backing-file: fix backing_file_open() kerneldoc parameter The kerneldoc for backing_file_open() documented a @user_path argument, but the function takes const struct file *user_file. The user path is derived as &user_file->f_path. Update the @-tag to @user_file and adjust the description accordingly. Also fix the "reuqested" typo to 'requested' in the old comment. Signed-off-by: Li Wang <liwang@kylinos.cn> Link: https://patch.msgid.link/20260528104208.395757-1-liwang@kylinos.cn Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-05-28 18:42:08 +08:00
fs: prepare for stackable filesystems backing file helpers In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-02 17:19:46 +03:00
backing-file: fix backing_file_open() kerneldoc parameter The kerneldoc for backing_file_open() documented a @user_path argument, but the function takes const struct file *user_file. The user path is derived as &user_file->f_path. Update the @-tag to @user_file and adjust the description accordingly. Also fix the "reuqested" typo to 'requested' in the old comment. Signed-off-by: Li Wang <liwang@kylinos.cn> Link: https://patch.msgid.link/20260528104208.395757-1-liwang@kylinos.cn Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-05-28 18:42:08 +08:00
fs: prepare for stackable filesystems backing file helpers In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-02 17:19:46 +03:00
lsm: add backing_file LSM hooks Stacked filesystems such as overlayfs do not currently provide the necessary mechanisms for LSMs to properly enforce access controls on the mmap() and mprotect() operations. In order to resolve this gap, a LSM security blob is being added to the backing_file struct and the following new LSM hooks are being created: security_backing_file_alloc() security_backing_file_free() security_mmap_backing_file() The first two hooks are to manage the lifecycle of the LSM security blob in the backing_file struct, while the third provides a new mmap() access control point for the underlying backing file. It is also expected that LSMs will likely want to update their security_file_mprotect() callback to address issues with their mprotect() controls, but that does not require a change to the security_file_mprotect() LSM hook. There are a three other small changes to support these new LSM hooks: * Pass the user file associated with a backing file down to alloc_empty_backing_file() so it can be included in the security_backing_file_alloc() hook. * Add getter and setter functions for the backing_file struct LSM blob as the backing_file struct remains private to fs/file_table.c. * Constify the file struct field in the LSM common_audit_data struct to better support LSMs that need to pass a const file struct pointer into the common LSM audit code. Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL() and supplying a fixup. Cc: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-unionfs@vger.kernel.org Cc: linux-erofs@lists.ozlabs.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-12-19 13:18:22 -05:00
fs: prepare for stackable filesystems backing file helpers In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-02 17:19:46 +03:00
fs: fix user path of nested backing files backing_file_open() derives the path to be stored in the new backing file from user_file->f_path. This is incorrect when user_file itself is a backing file, which is the case for nested stacking filesystems, e.g. overlayfs mounts where the lowerdir of one overlayfs is the merged directory of another. Since commit def3ae83da02 ("fs: store real path instead of fake path in backing file f_path") the f_path of a backing file holds the real path of the intermediate layer, not the path that the user opened. Commit 924577e4f6ca ("ovl: Fix nested backing file paths") fixed this for such configurations by passing file_user_path() from ovl_open_realfile(). However, commit 6af36aeb147a ("lsm: add backing_file LSM hooks") changed the first argument of backing_file_open() from the user path back to the user file and derived the path from user_file->f_path again, silently re-introducing the problem. As a result, files mapped through a nested overlayfs show the wrong path in /proc/<pid>/maps and in perf/ftrace mmap records. For example, with two nested overlayfs mounts: mkdir -p /ovl/{lower,upper,work,merged} /ovl/nested echo hello > /ovl/lower/foo mount -t overlay overlay \ -o lowerdir=/ovl/lower,upperdir=/ovl/upper,workdir=/ovl/work \ /ovl/merged # at least two lowerdirs are needed when upperdir is nonexistent mount -t overlay overlay \ -o lowerdir=/ovl/merged:/ovl/lower /ovl/nested mapping /ovl/nested/foo shows a disconnected path instead of the user path: # readlink /proc/self/fd/3 /ovl/nested/foo # grep foo /proc/self/maps 7f6e2c100000-7f6e2c101000 r--s 00000000 00:24 15813027 /foo The bogus path is derived from the f_path of the intermediate backing file, whose mount is a private clone that d_path() cannot resolve. Fix this by using file_user_path(), which returns the outermost user-visible path for backing files and falls back to &user_file->f_path for regular files. This restores the behavior of commit 924577e4f6ca ("ovl: Fix nested backing file paths") for overlayfs and also fixes the same problem for the other backing_file_open() callers, fuse passthrough and erofs ishare, when their user file is itself a backing file. backing_tmpfile_open() has the same pattern but is not affected: it is only called by ovl_create_tmpfile() for the upper layer, and another overlayfs is rejected as upperdir by the DCACHE_OP_REAL check in ovl_mount_dir_check(), so its user_file can never be a backing file. Fixes: 6af36aeb147a ("lsm: add backing_file LSM hooks") Cc: stable@vger.kernel.org Signed-off-by: Baokun Li <libaokun@linux.alibaba.com> Link: https://patch.msgid.link/20260804034204.3487077-1-libaokun@linux.alibaba.com Tested-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-08-04 11:42:04 +08:00
fs: prepare for stackable filesystems backing file helpers In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-02 17:19:46 +03:00
lsm: add backing_file LSM hooks Stacked filesystems such as overlayfs do not currently provide the necessary mechanisms for LSMs to properly enforce access controls on the mmap() and mprotect() operations. In order to resolve this gap, a LSM security blob is being added to the backing_file struct and the following new LSM hooks are being created: security_backing_file_alloc() security_backing_file_free() security_mmap_backing_file() The first two hooks are to manage the lifecycle of the LSM security blob in the backing_file struct, while the third provides a new mmap() access control point for the underlying backing file. It is also expected that LSMs will likely want to update their security_file_mprotect() callback to address issues with their mprotect() controls, but that does not require a change to the security_file_mprotect() LSM hook. There are a three other small changes to support these new LSM hooks: * Pass the user file associated with a backing file down to alloc_empty_backing_file() so it can be included in the security_backing_file_alloc() hook. * Add getter and setter functions for the backing_file struct LSM blob as the backing_file struct remains private to fs/file_table.c. * Constify the file struct field in the LSM common_audit_data struct to better support LSMs that need to pass a const file struct pointer into the common LSM audit code. Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL() and supplying a fixup. Cc: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-unionfs@vger.kernel.org Cc: linux-erofs@lists.ozlabs.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-12-19 13:18:22 -05:00
fs: prepare for stackable filesystems backing file helpers In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-02 17:19:46 +03:00
fs: constify file ptr in backing_file accessor helpers Add internal helper backing_file_set_user_path() for the only two cases that need to modify backing_file fields. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/20250607115304.2521155-2-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-06-07 13:53:03 +02:00
fs: prepare for stackable filesystems backing file helpers In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-02 17:19:46 +03:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
lsm: add backing_file LSM hooks Stacked filesystems such as overlayfs do not currently provide the necessary mechanisms for LSMs to properly enforce access controls on the mmap() and mprotect() operations. In order to resolve this gap, a LSM security blob is being added to the backing_file struct and the following new LSM hooks are being created: security_backing_file_alloc() security_backing_file_free() security_mmap_backing_file() The first two hooks are to manage the lifecycle of the LSM security blob in the backing_file struct, while the third provides a new mmap() access control point for the underlying backing file. It is also expected that LSMs will likely want to update their security_file_mprotect() callback to address issues with their mprotect() controls, but that does not require a change to the security_file_mprotect() LSM hook. There are a three other small changes to support these new LSM hooks: * Pass the user file associated with a backing file down to alloc_empty_backing_file() so it can be included in the security_backing_file_alloc() hook. * Add getter and setter functions for the backing_file struct LSM blob as the backing_file struct remains private to fs/file_table.c. * Constify the file struct field in the LSM common_audit_data struct to better support LSMs that need to pass a const file struct pointer into the common LSM audit code. Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL() and supplying a fixup. Cc: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-unionfs@vger.kernel.org Cc: linux-erofs@lists.ozlabs.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-12-19 13:18:22 -05:00
ovl: implement tmpfile Combine inode creation with opening a file. There are six separate objects that are being set up: the backing inode, dentry and file, and the overlay inode, dentry and file. Cleanup in case of an error is a bit of a challenge and is difficult to test, so careful review is needed. All tmpfile testcases except generic/509 now run/pass, and no regressions are observed with full xfstests. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com>
2024-05-02 20:35:57 +02:00
lsm: add backing_file LSM hooks Stacked filesystems such as overlayfs do not currently provide the necessary mechanisms for LSMs to properly enforce access controls on the mmap() and mprotect() operations. In order to resolve this gap, a LSM security blob is being added to the backing_file struct and the following new LSM hooks are being created: security_backing_file_alloc() security_backing_file_free() security_mmap_backing_file() The first two hooks are to manage the lifecycle of the LSM security blob in the backing_file struct, while the third provides a new mmap() access control point for the underlying backing file. It is also expected that LSMs will likely want to update their security_file_mprotect() callback to address issues with their mprotect() controls, but that does not require a change to the security_file_mprotect() LSM hook. There are a three other small changes to support these new LSM hooks: * Pass the user file associated with a backing file down to alloc_empty_backing_file() so it can be included in the security_backing_file_alloc() hook. * Add getter and setter functions for the backing_file struct LSM blob as the backing_file struct remains private to fs/file_table.c. * Constify the file struct field in the LSM common_audit_data struct to better support LSMs that need to pass a const file struct pointer into the common LSM audit code. Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL() and supplying a fixup. Cc: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-unionfs@vger.kernel.org Cc: linux-erofs@lists.ozlabs.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-12-19 13:18:22 -05:00
ovl: implement tmpfile Combine inode creation with opening a file. There are six separate objects that are being set up: the backing inode, dentry and file, and the overlay inode, dentry and file. Cleanup in case of an error is a bit of a challenge and is difficult to test, so careful review is needed. All tmpfile testcases except generic/509 now run/pass, and no regressions are observed with full xfstests. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com>
2024-05-02 20:35:57 +02:00
lsm: add backing_file LSM hooks Stacked filesystems such as overlayfs do not currently provide the necessary mechanisms for LSMs to properly enforce access controls on the mmap() and mprotect() operations. In order to resolve this gap, a LSM security blob is being added to the backing_file struct and the following new LSM hooks are being created: security_backing_file_alloc() security_backing_file_free() security_mmap_backing_file() The first two hooks are to manage the lifecycle of the LSM security blob in the backing_file struct, while the third provides a new mmap() access control point for the underlying backing file. It is also expected that LSMs will likely want to update their security_file_mprotect() callback to address issues with their mprotect() controls, but that does not require a change to the security_file_mprotect() LSM hook. There are a three other small changes to support these new LSM hooks: * Pass the user file associated with a backing file down to alloc_empty_backing_file() so it can be included in the security_backing_file_alloc() hook. * Add getter and setter functions for the backing_file struct LSM blob as the backing_file struct remains private to fs/file_table.c. * Constify the file struct field in the LSM common_audit_data struct to better support LSMs that need to pass a const file struct pointer into the common LSM audit code. Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL() and supplying a fixup. Cc: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-unionfs@vger.kernel.org Cc: linux-erofs@lists.ozlabs.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-12-19 13:18:22 -05:00
ovl: implement tmpfile Combine inode creation with opening a file. There are six separate objects that are being set up: the backing inode, dentry and file, and the overlay inode, dentry and file. Cleanup in case of an error is a bit of a challenge and is difficult to test, so careful review is needed. All tmpfile testcases except generic/509 now run/pass, and no regressions are observed with full xfstests. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com>
2024-05-02 20:35:57 +02:00
fs: constify file ptr in backing_file accessor helpers Add internal helper backing_file_set_user_path() for the only two cases that need to modify backing_file fields. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/20250607115304.2521155-2-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-06-07 13:53:03 +02:00
ovl: implement tmpfile Combine inode creation with opening a file. There are six separate objects that are being set up: the backing inode, dentry and file, and the overlay inode, dentry and file. Cleanup in case of an error is a bit of a challenge and is difficult to test, so careful review is needed. All tmpfile testcases except generic/509 now run/pass, and no regressions are observed with full xfstests. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com>
2024-05-02 20:35:57 +02:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
backing-file: use credential guards for reads Use credential guards for scoped credential override with automatic restoration on scope exit. Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-3-a3e156839e7f@kernel.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03 12:26:51 +01:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
backing-file: use credential guards for reads Use credential guards for scoped credential override with automatic restoration on scope exit. Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-3-a3e156839e7f@kernel.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03 12:26:51 +01:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
backing-file: use credential guards for writes Use credential guards for scoped credential override with automatic restoration on scope exit. Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-4-a3e156839e7f@kernel.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03 12:26:52 +01:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
backing-file: use credential guards for writes Use credential guards for scoped credential override with automatic restoration on scope exit. Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-4-a3e156839e7f@kernel.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03 12:26:52 +01:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_splice_{read,write}() helpers There is not much in those helpers, but it makes sense to have them logically next to the backing_file_{read,write}_iter() helpers as they may grow more common logic in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:13:12 +03:00
backing-file: use credential guards for splice read Use credential guards for scoped credential override with automatic restoration on scope exit. Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-5-a3e156839e7f@kernel.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03 12:26:53 +01:00
fs: factor out backing_file_splice_{read,write}() helpers There is not much in those helpers, but it makes sense to have them logically next to the backing_file_{read,write}_iter() helpers as they may grow more common logic in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:13:12 +03:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_splice_{read,write}() helpers There is not much in those helpers, but it makes sense to have them logically next to the backing_file_{read,write}_iter() helpers as they may grow more common logic in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:13:12 +03:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_splice_{read,write}() helpers There is not much in those helpers, but it makes sense to have them logically next to the backing_file_{read,write}_iter() helpers as they may grow more common logic in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:13:12 +03:00
backing-file: convert to using fops->splice_write Filesystems may define their own splice write. Therefore, use the file fops instead of invoking iter_file_splice_write() directly. Signed-off-by: Ed Tsai <ed.tsai@mediatek.com> Link: https://lore.kernel.org/r/20240708072208.25244-1-ed.tsai@mediatek.com Fixes: 5ca73468612d ("fuse: implement splice read/write passthrough") Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-07-08 15:22:06 +08:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_splice_{read,write}() helpers There is not much in those helpers, but it makes sense to have them logically next to the backing_file_{read,write}_iter() helpers as they may grow more common logic in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:13:12 +03:00
backing-file: use credential guards for splice write Use credential guards for scoped credential override with automatic restoration on scope exit. Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-6-a3e156839e7f@kernel.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03 12:26:54 +01:00
fs: factor out backing_file_splice_{read,write}() helpers There is not much in those helpers, but it makes sense to have them logically next to the backing_file_{read,write}_iter() helpers as they may grow more common logic in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:13:12 +03:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_splice_{read,write}() helpers There is not much in those helpers, but it makes sense to have them logically next to the backing_file_{read,write}_iter() helpers as they may grow more common logic in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:13:12 +03:00
fs: factor out backing_file_mmap() helper Assert that the file object is allocated in a backing_file container so that file_user_path() could be used to display the user path and not the backing file's path in /proc/<pid>/maps. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:49:37 +03:00
fs/backing_file: fix wrong argument in callback Commit 48b50624aec4 ("backing-file: clean up the API") unintentionally changed the argument in the ->accessed() callback from the user file to the backing file. Fixes: 48b50624aec4 ("backing-file: clean up the API") Reported-by: syzbot+8d1206605b05ca9a0e6a@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-unionfs/67447b3c.050a0220.1cc393.0085.GAE@google.com/ Tested-by: syzbot+8d1206605b05ca9a0e6a@syzkaller.appspotmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20241126145342.364869-1-amir73il@gmail.com Acked-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-11-26 15:53:42 +01:00
fs: factor out backing_file_mmap() helper Assert that the file object is allocated in a backing_file container so that file_user_path() could be used to display the user path and not the backing file's path in /proc/<pid>/maps. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:49:37 +03:00
backing-file: clean up the API - Pass iocb to ctx->end_write() instead of file + pos - Get rid of ctx->user_file, which is redundant most of the time - Instead pass iocb to backing_file_splice_read and backing_file_splice_write Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-10-21 12:33:38 +02:00
fs: factor out backing_file_mmap() helper Assert that the file object is allocated in a backing_file container so that file_user_path() could be used to display the user path and not the backing file's path in /proc/<pid>/maps. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:49:37 +03:00
fs: consistently use can_mmap_file() helper Since commit c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file callback"), the f_op->mmap() hook has been deprecated in favour of f_op->mmap_prepare(). Additionally, commit bb666b7c2707 ("mm: add mmap_prepare() compatibility layer for nested file systems") permits the use of the .mmap_prepare() hook even in nested filesystems like overlayfs. There are a number of places where we check only for f_op->mmap - this is incorrect now mmap_prepare exists, so update all of these to use the general helper can_mmap_file(). Most notably, this updates the elf logic to allow for the ability to execute binaries on filesystems which have the .mmap_prepare hook, but additionally we update nested filesystems. Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Link: https://lore.kernel.org/b68145b609532e62bab603dd9686faa6562046ec.1750099179.git.lorenzo.stoakes@oracle.com Acked-by: Kees Cook <kees@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-06-16 20:33:22 +01:00
fs: factor out backing_file_mmap() helper Assert that the file object is allocated in a backing_file container so that file_user_path() could be used to display the user path and not the backing file's path in /proc/<pid>/maps. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:49:37 +03:00
lsm: add backing_file LSM hooks Stacked filesystems such as overlayfs do not currently provide the necessary mechanisms for LSMs to properly enforce access controls on the mmap() and mprotect() operations. In order to resolve this gap, a LSM security blob is being added to the backing_file struct and the following new LSM hooks are being created: security_backing_file_alloc() security_backing_file_free() security_mmap_backing_file() The first two hooks are to manage the lifecycle of the LSM security blob in the backing_file struct, while the third provides a new mmap() access control point for the underlying backing file. It is also expected that LSMs will likely want to update their security_file_mprotect() callback to address issues with their mprotect() controls, but that does not require a change to the security_file_mprotect() LSM hook. There are a three other small changes to support these new LSM hooks: * Pass the user file associated with a backing file down to alloc_empty_backing_file() so it can be included in the security_backing_file_alloc() hook. * Add getter and setter functions for the backing_file struct LSM blob as the backing_file struct remains private to fs/file_table.c. * Constify the file struct field in the LSM common_audit_data struct to better support LSMs that need to pass a const file struct pointer into the common LSM audit code. Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL() and supplying a fixup. Cc: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-unionfs@vger.kernel.org Cc: linux-erofs@lists.ozlabs.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-12-19 13:18:22 -05:00
backing-file: use credential guards for mmap Use credential guards for scoped credential override with automatic restoration on scope exit. Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-7-a3e156839e7f@kernel.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03 12:26:55 +01:00
lsm: add backing_file LSM hooks Stacked filesystems such as overlayfs do not currently provide the necessary mechanisms for LSMs to properly enforce access controls on the mmap() and mprotect() operations. In order to resolve this gap, a LSM security blob is being added to the backing_file struct and the following new LSM hooks are being created: security_backing_file_alloc() security_backing_file_free() security_mmap_backing_file() The first two hooks are to manage the lifecycle of the LSM security blob in the backing_file struct, while the third provides a new mmap() access control point for the underlying backing file. It is also expected that LSMs will likely want to update their security_file_mprotect() callback to address issues with their mprotect() controls, but that does not require a change to the security_file_mprotect() LSM hook. There are a three other small changes to support these new LSM hooks: * Pass the user file associated with a backing file down to alloc_empty_backing_file() so it can be included in the security_backing_file_alloc() hook. * Add getter and setter functions for the backing_file struct LSM blob as the backing_file struct remains private to fs/file_table.c. * Constify the file struct field in the LSM common_audit_data struct to better support LSMs that need to pass a const file struct pointer into the common LSM audit code. Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL() and supplying a fixup. Cc: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-unionfs@vger.kernel.org Cc: linux-erofs@lists.ozlabs.org Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-12-19 13:18:22 -05:00
fs: factor out backing_file_mmap() helper Assert that the file object is allocated in a backing_file container so that file_user_path() could be used to display the user path and not the backing file's path in /proc/<pid>/maps. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:49:37 +03:00
fs/backing_file: fix wrong argument in callback Commit 48b50624aec4 ("backing-file: clean up the API") unintentionally changed the argument in the ->accessed() callback from the user file to the backing file. Fixes: 48b50624aec4 ("backing-file: clean up the API") Reported-by: syzbot+8d1206605b05ca9a0e6a@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-unionfs/67447b3c.050a0220.1cc393.0085.GAE@google.com/ Tested-by: syzbot+8d1206605b05ca9a0e6a@syzkaller.appspotmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20241126145342.364869-1-amir73il@gmail.com Acked-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-11-26 15:53:42 +01:00
fs: factor out backing_file_mmap() helper Assert that the file object is allocated in a backing_file container so that file_user_path() could be used to display the user path and not the backing file's path in /proc/<pid>/maps. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-13 12:49:37 +03:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00
fs: Use KMEM_CACHE instead of kmem_cache_create commit 0a31bd5f2bbb ("KMEM_CACHE(): simplify slab cache creation") introduces a new macro. Use the new KMEM_CACHE() macro instead of direct kmem_cache_create to simplify the creation of SLAB caches. Signed-off-by: Kunwu Chan <chentao@kylinos.cn> Link: https://lore.kernel.org/r/20240131070941.135178-1-chentao@kylinos.cn Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-01-31 15:09:41 +08:00
fs: factor out backing_file_{read,write}_iter() helpers Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-22 17:48:52 +02:00