This is a note to let you know that I've just added the patch titled
fanotify: cleanups for fanotify_mark() input validations
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fanotify-cleanups-for-fanotify_mark-input-validation.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5534855241721d2e5ad5667139646a8fde7b933e
Author: Amir Goldstein <amir73il@xxxxxxxxx>
Date: Wed Jun 29 17:42:09 2022 +0300
fanotify: cleanups for fanotify_mark() input validations
[ Upstream commit 8afd7215aa97f8868d033f6e1d01a276ab2d29c0 ]
Create helper fanotify_may_update_existing_mark() for checking for
conflicts between existing mark flags and fanotify_mark() flags.
Use variable mark_cmd to make the checks for mark command bits
cleaner.
Link: https://lore.kernel.org/r/20220629144210.2983229-3-amir73il@xxxxxxxxx
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 9367216263cab..870db0f361f4c 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1183,6 +1183,19 @@ static int fanotify_group_init_error_pool(struct fsnotify_group *group)
sizeof(struct fanotify_error_event));
}
+static int fanotify_may_update_existing_mark(struct fsnotify_mark *fsn_mark,
+ unsigned int fan_flags)
+{
+ /*
+ * Non evictable mark cannot be downgraded to evictable mark.
+ */
+ if (fan_flags & FAN_MARK_EVICTABLE &&
+ !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF))
+ return -EEXIST;
+
+ return 0;
+}
+
static int fanotify_add_mark(struct fsnotify_group *group,
fsnotify_connp_t *connp, unsigned int obj_type,
__u32 mask, unsigned int fan_flags,
@@ -1204,13 +1217,11 @@ static int fanotify_add_mark(struct fsnotify_group *group,
}
/*
- * Non evictable mark cannot be downgraded to evictable mark.
+ * Check if requested mark flags conflict with an existing mark flags.
*/
- if (fan_flags & FAN_MARK_EVICTABLE &&
- !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF)) {
- ret = -EEXIST;
+ ret = fanotify_may_update_existing_mark(fsn_mark, fan_flags);
+ if (ret)
goto out;
- }
/*
* Error events are pre-allocated per group, only if strictly
@@ -1567,6 +1578,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
__kernel_fsid_t __fsid, *fsid = NULL;
u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
+ unsigned int mark_cmd = flags & FANOTIFY_MARK_CMD_BITS;
bool ignore = flags & FAN_MARK_IGNORED_MASK;
unsigned int obj_type, fid_mode;
u32 umask = 0;
@@ -1596,7 +1608,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
return -EINVAL;
}
- switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
+ switch (mark_cmd) {
case FAN_MARK_ADD:
case FAN_MARK_REMOVE:
if (!mask)
@@ -1685,7 +1697,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
if (mask & FAN_RENAME && !(fid_mode & FAN_REPORT_NAME))
goto fput_and_out;
- if (flags & FAN_MARK_FLUSH) {
+ if (mark_cmd == FAN_MARK_FLUSH) {
ret = 0;
if (mark_type == FAN_MARK_MOUNT)
fsnotify_clear_vfsmount_marks_by_group(group);
@@ -1701,7 +1713,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
if (ret)
goto fput_and_out;
- if (flags & FAN_MARK_ADD) {
+ if (mark_cmd == FAN_MARK_ADD) {
ret = fanotify_events_supported(group, &path, mask, flags);
if (ret)
goto path_put_and_out;
@@ -1739,7 +1751,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
}
/* create/update an inode mark */
- switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) {
+ switch (mark_cmd) {
case FAN_MARK_ADD:
if (mark_type == FAN_MARK_MOUNT)
ret = fanotify_add_vfsmount_mark(group, mnt, mask,
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index 4f6cbe6c6e235..c9e185407ebcb 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -61,15 +61,16 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */
#define FANOTIFY_MARK_TYPE_BITS (FAN_MARK_INODE | FAN_MARK_MOUNT | \
FAN_MARK_FILESYSTEM)
+#define FANOTIFY_MARK_CMD_BITS (FAN_MARK_ADD | FAN_MARK_REMOVE | \
+ FAN_MARK_FLUSH)
+
#define FANOTIFY_MARK_FLAGS (FANOTIFY_MARK_TYPE_BITS | \
- FAN_MARK_ADD | \
- FAN_MARK_REMOVE | \
+ FANOTIFY_MARK_CMD_BITS | \
FAN_MARK_DONT_FOLLOW | \
FAN_MARK_ONLYDIR | \
FAN_MARK_IGNORED_MASK | \
FAN_MARK_IGNORED_SURV_MODIFY | \
- FAN_MARK_EVICTABLE | \
- FAN_MARK_FLUSH)
+ FAN_MARK_EVICTABLE)
/*
* Events that can be reported with data type FSNOTIFY_EVENT_PATH.
