kernel/git/stable/linux.git/fs/notify, branch linux-5.16.y

fanotify: Fix stale file descriptor in copy_event_to_user()

2022-02-05T11:39:57+00:00

commit ee12595147ac1fbfb5bcb23837e26dd58d94b15d upstream. This code calls fd_install() which gives the userspace access to the fd. Then if copy_info_records_to_user() fails it calls put_unused_fd(fd) but that will not release it and leads to a stale entry in the file descriptor table. Generally you can't trust the fd after a call to fd_install(). The fix is to delay the fd_install() until everything else has succeeded. Fortunately it requires CAP_SYS_ADMIN to reach this code so the security impact is less. Fixes: f644bc449b37 ("fanotify: fix copy_event_to_user() fid error clean up") Link: https://lore.kernel.org/r/20220128195656.GA26981@kili Signed-off-by: Dan Carpenter Reviewed-by: Mathias Krause Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

fanotify: Allow users to request FAN_FS_ERROR events

2021-10-27T10:53:45+00:00

Wire up the FAN_FS_ERROR event in the fanotify_mark syscall, allowing user space to request the monitoring of FAN_FS_ERROR events. These events are limited to filesystem marks, so check it is the case in the syscall handler. Link: https://lore.kernel.org/r/20211025192746.66445-29-krisman@collabora.com Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Jan Kara

fanotify: Emit generic error info for error event

2021-10-27T10:53:42+00:00

The error info is a record sent to users on FAN_FS_ERROR events documenting the type of error. It also carries an error count, documenting how many errors were observed since the last reporting. Link: https://lore.kernel.org/r/20211025192746.66445-28-krisman@collabora.com Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Jan Kara

fanotify: Report fid info for file related file system errors

2021-10-27T10:37:20+00:00

Plumb the pieces to add a FID report to error records. Since all error event memory must be pre-allocated, we pre-allocate the maximum file handle size possible, such that it should always fit. For errors that don't expose a file handle, report it with an invalid FID. Internally we use zero-length FILEID_ROOT file handle for passing the information (which we report as zero-length FILEID_INVALID file handle to userspace) so we update the handle reporting code to deal with this case correctly. Link: https://lore.kernel.org/r/20211025192746.66445-27-krisman@collabora.com Link: https://lore.kernel.org/r/20211025192746.66445-25-krisman@collabora.com Signed-off-by: Gabriel Krisman Bertazi Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara [Folded two patches into 2 to make series bisectable] Signed-off-by: Jan Kara

fanotify: WARN_ON against too large file handles

2021-10-27T10:37:20+00:00

struct fanotify_error_event, at least, is preallocated and isn't able to to handle arbitrarily large file handles. Future-proof the code by complaining loudly if a handle larger than MAX_HANDLE_SZ is ever found. Link: https://lore.kernel.org/r/20211025192746.66445-26-krisman@collabora.com Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Jan Kara

fanotify: Add helpers to decide whether to report FID/DFID

2021-10-27T10:37:20+00:00

Now that there is an event that reports FID records even for a zeroed file handle, wrap the logic that deides whether to issue the records into helper functions. This shouldn't have any impact on the code, but simplifies further patches. Link: https://lore.kernel.org/r/20211025192746.66445-24-krisman@collabora.com Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi Reviewed-by: Amir Goldstein Signed-off-by: Jan Kara

fanotify: Wrap object_fh inline space in a creator macro

2021-10-27T10:37:20+00:00

fanotify_error_event would duplicate this sequence of declarations that already exist elsewhere with a slight different size. Create a helper macro to avoid code duplication. Link: https://lore.kernel.org/r/20211025192746.66445-23-krisman@collabora.com Suggested-by: Jan Kara Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Jan Kara

fanotify: Support merging of error events

2021-10-27T10:37:13+00:00

Error events (FAN_FS_ERROR) against the same file system can be merged by simply iterating the error count. The hash is taken from the fsid, without considering the FH. This means that only the first error object is reported. Link: https://lore.kernel.org/r/20211025192746.66445-22-krisman@collabora.com Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Jan Kara

fanotify: Support enqueueing of error events

2021-10-27T10:35:10+00:00

Once an error event is triggered, enqueue it in the notification group, similarly to what is done for other events. FAN_FS_ERROR is not handled specially, since the memory is now handled by a preallocated mempool. For now, make the event unhashed. A future patch implements merging of this kind of event. Link: https://lore.kernel.org/r/20211025192746.66445-21-krisman@collabora.com Reviewed-by: Jan Kara Reviewed-by: Amir Goldstein Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Jan Kara

fanotify: Pre-allocate pool of error events

2021-10-27T10:35:05+00:00

Pre-allocate slots for file system errors to have greater chances of succeeding, since error events can happen in GFP_NOFS context. This patch introduces a group-wide mempool of error events, shared by all FAN_FS_ERROR marks in this group. Link: https://lore.kernel.org/r/20211025192746.66445-20-krisman@collabora.com Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Jan Kara