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authorAmir Goldstein <amir73il@gmail.com>2022-06-29 17:42:09 +0300
committerJan Kara <jack@suse.cz>2022-07-01 14:51:49 +0200
commit8afd7215aa97f8868d033f6e1d01a276ab2d29c0 (patch)
tree5e5db4b5d657460abb6165b38821d3de13464165 /fs/notify
parent31a371e419c885e0f137ce70395356ba8639dc52 (diff)
downloadlinux-8afd7215aa97f8868d033f6e1d01a276ab2d29c0.tar.gz
fanotify: cleanups for fanotify_mark() input validations
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@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify')
-rw-r--r--fs/notify/fanotify/fanotify_user.c30
1 files changed, 21 insertions, 9 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index a9eea037fee9..6781d46cd37c 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1187,6 +1187,19 @@ 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,
@@ -1208,13 +1221,11 @@ 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
@@ -1557,6 +1568,7 @@ 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;
@@ -1586,7 +1598,7 @@ 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)
@@ -1675,7 +1687,7 @@ 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);
@@ -1691,7 +1703,7 @@ 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;
@@ -1729,7 +1741,7 @@ 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,