2021-10-25 19:34:51

by Gabriel Krisman Bertazi

[permalink] [raw]
Subject: [PATCH v9 28/31] fanotify: Allow users to request FAN_FS_ERROR events

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.

Reviewed-by: Amir Goldstein <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Gabriel Krisman Bertazi <[email protected]>

---
Changes since v7:
- Move the verification closer to similar code (Amir)
---
fs/notify/fanotify/fanotify.c | 2 +-
fs/notify/fanotify/fanotify_user.c | 4 ++++
include/linux/fanotify.h | 6 +++++-
3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index af61425e6e3b..b6091775aa6e 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -822,7 +822,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM);
BUILD_BUG_ON(FAN_FS_ERROR != FS_ERROR);

- BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19);
+ BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 20);

mask = fanotify_group_event_mask(group, iter_info, mask, data,
data_type, dir);
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 97ec5b005b50..77a77064f3c9 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1519,6 +1519,10 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
group->priority == FS_PRIO_0)
goto fput_and_out;

+ if (mask & FAN_FS_ERROR &&
+ mark_type != FAN_MARK_FILESYSTEM)
+ goto fput_and_out;
+
/*
* Events that do not carry enough information to report
* event->fd require a group that supports reporting fid. Those
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index 52d464802d99..616af2ea20f3 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -91,9 +91,13 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */
#define FANOTIFY_INODE_EVENTS (FANOTIFY_DIRENT_EVENTS | \
FAN_ATTRIB | FAN_MOVE_SELF | FAN_DELETE_SELF)

+/* Events that can only be reported with data type FSNOTIFY_EVENT_ERROR */
+#define FANOTIFY_ERROR_EVENTS (FAN_FS_ERROR)
+
/* Events that user can request to be notified on */
#define FANOTIFY_EVENTS (FANOTIFY_PATH_EVENTS | \
- FANOTIFY_INODE_EVENTS)
+ FANOTIFY_INODE_EVENTS | \
+ FANOTIFY_ERROR_EVENTS)

/* Events that require a permission response from user */
#define FANOTIFY_PERM_EVENTS (FAN_OPEN_PERM | FAN_ACCESS_PERM | \
--
2.33.0