dirent modification events (create/delete/move) do not carry the
child entry name/inode information. Instead, we report FAN_ONDIR
for mkdir/rmdir so user can differentiate them from creat/unlink.
For backward compatibility and consistency, do not report FAN_ONDIR
to user in legacy fanotify mode (reporting fd) and report FAN_ONDIR
to user in FAN_REPORT_FID mode for all event types.
Unlike legacy fanotify events (open/access/close), dirent events
for subdir entries (mkdir/rmdir) will be reported regardless if
user requested FAN_ONDIR, but the FAN_ONDIR flag itself will only
be reported if the user asked for it.
Cc: <linux-api@xxxxxxxxxxxxxxx>
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/notify/fanotify/fanotify.c | 31 +++++++++++++++++++++++++++++--
include/linux/fanotify.h | 9 ++++++---
2 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 89c19db4d45f..1aa23cefae5d 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -112,6 +112,7 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
int data_type)
{
__u32 marks_mask = 0, marks_ignored_mask = 0;
+ __u32 test_mask, user_mask = FANOTIFY_EVENT_TYPES;
const struct path *path = data;
struct fsnotify_mark *mark;
int type;
@@ -145,12 +146,38 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
marks_ignored_mask |= mark->ignored_mask;
}
+ test_mask = event_mask & marks_mask & ~marks_ignored_mask;
+
+ /*
+ * dirent modification events (create/delete/move) do not carry the
+ * child entry name/inode information. Instead, we report FAN_ONDIR
+ * for mkdir/rmdir so user can differentiate them from creat/unlink.
+ *
+ * For backward compatibility and consistency, do not report FAN_ONDIR
+ * to user in legacy fanotify mode (reporting fd) and report FAN_ONDIR
+ * to user in FAN_REPORT_FID mode for all event types.
+ */
+ if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+ /* Do not report FAN_ONDIR without an event type */
+ BUILD_BUG_ON(FANOTIFY_EVENT_TYPES & FANOTIFY_EVENT_FLAGS);
+ if (!(test_mask & FANOTIFY_EVENT_TYPES))
+ return 0;
+
+ user_mask |= FAN_ONDIR;
+ }
+
+ /*
+ * Unlike legacy fanotify events (open/access/close), dirent events
+ * for subdir entries (mkdir/rmdir) will be reported regardless if
+ * user requested FAN_ONDIR, but the FAN_ONDIR flag itself will only
+ * be reported if the user asked for it.
+ */
if (event_mask & FS_ISDIR &&
+ !(event_mask & ALL_FSNOTIFY_DIRENT_EVENTS) &&
!(marks_mask & FS_ISDIR & ~marks_ignored_mask))
return 0;
- return event_mask & FANOTIFY_OUTGOING_EVENTS & marks_mask &
- ~marks_ignored_mask;
+ return test_mask & user_mask;
}
static int fanotify_encode_fid(struct fanotify_event *event,
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index e9d45387089f..f5f86566c277 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -61,13 +61,16 @@
#define FANOTIFY_PERM_EVENTS (FAN_OPEN_PERM | FAN_ACCESS_PERM | \
FAN_OPEN_EXEC_PERM)
+/* Events types that may be reported from vfs */
+#define FANOTIFY_EVENT_TYPES (FANOTIFY_EVENTS | \
+ FANOTIFY_PERM_EVENTS)
+
/* Extra flags that may be reported with event or control handling of events */
#define FANOTIFY_EVENT_FLAGS (FAN_EVENT_ON_CHILD | FAN_ONDIR)
/* Events that may be reported to user */
-#define FANOTIFY_OUTGOING_EVENTS (FANOTIFY_EVENTS | \
- FANOTIFY_PERM_EVENTS | \
- FAN_Q_OVERFLOW)
+#define FANOTIFY_OUTGOING_EVENTS (FANOTIFY_EVENT_TYPES | \
+ FAN_Q_OVERFLOW | FAN_ONDIR)
#define ALL_FANOTIFY_EVENT_BITS (FANOTIFY_OUTGOING_EVENTS | \
FANOTIFY_EVENT_FLAGS)
--
2.17.1
