diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2024-10-03 16:29:22 +0200 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2024-10-16 17:43:05 +0200 |
| commit | 522249f05c5551aec9ec0ba9b6438f1ec19c138d (patch) | |
| tree | 91770331ebee3329d4945d4cb87a11374b3196cd /include | |
| parent | 1cda52f1b4611f4daa9d89e69d9428fb4137dc3f (diff) | |
fanotify: allow reporting errors on failure to open fd
When working in "fd mode", fanotify_read() needs to open an fd
from a dentry to report event->fd to userspace.
Opening an fd from dentry can fail for several reasons.
For example, when tasks are gone and we try to open their
/proc files or we try to open a WRONLY file like in sysfs
or when trying to open a file that was deleted on the
remote network server.
Add a new flag FAN_REPORT_FD_ERROR for fanotify_init().
For a group with FAN_REPORT_FD_ERROR, we will send the
event with the error instead of the open fd, otherwise
userspace may not get the error at all.
For an overflow event, we report -EBADF to avoid confusing FAN_NOFD
with -EPERM. Similarly for pidfd open errors we report either -ESRCH
or the open error instead of FAN_NOPIDFD and FAN_EPIDFD.
In any case, userspace will not know which file failed to
open, so add a debug print for further investigation.
Reported-by: Krishna Vivek Vitta <kvitta@microsoft.com>
Link: https://lore.kernel.org/linux-fsdevel/SI2P153MB07182F3424619EDDD1F393EED46D2@SI2P153MB0718.APCP153.PROD.OUTLOOK.COM/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20241003142922.111539-1-amir73il@gmail.com
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/fanotify.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/fanotify.h | 1 |
2 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h index 4f1c4f603118..89ff45bd6f01 100644 --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -36,6 +36,7 @@ #define FANOTIFY_ADMIN_INIT_FLAGS (FANOTIFY_PERM_CLASSES | \ FAN_REPORT_TID | \ FAN_REPORT_PIDFD | \ + FAN_REPORT_FD_ERROR | \ FAN_UNLIMITED_QUEUE | \ FAN_UNLIMITED_MARKS) diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h index a37de58ca571..34f221d3a1b9 100644 --- a/include/uapi/linux/fanotify.h +++ b/include/uapi/linux/fanotify.h @@ -60,6 +60,7 @@ #define FAN_REPORT_DIR_FID 0x00000400 /* Report unique directory id */ #define FAN_REPORT_NAME 0x00000800 /* Report events with name */ #define FAN_REPORT_TARGET_FID 0x00001000 /* Report dirent target id */ +#define FAN_REPORT_FD_ERROR 0x00002000 /* event->fd can report error */ /* Convenience macro - FAN_REPORT_NAME requires FAN_REPORT_DIR_FID */ #define FAN_REPORT_DFID_NAME (FAN_REPORT_DIR_FID | FAN_REPORT_NAME) |