fanotify: cleanups for fanotify_mark() input validations

[sfrench/cifs-2.6.git] / fs / notify / fanotify / fanotify_user.c

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index a9eea037fee955e439120491a31566f44aef92a4..6781d46cd37c10208b421e512772a4bb3e5a643e 100644 (file)
--- 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,