fanotify: don't set FAN_ONDIR implicitly on a marks ignored mask

Currently FAN_ONDIR is always set on a mark's ignored mask when the
event mask is extended without FAN_MARK_ONDIR being set.  This may
result in events for directories being ignored unexpectedly for call
sequences like

  fanotify_mark(fd, FAN_MARK_ADD, FAN_OPEN | FAN_ONDIR , AT_FDCWD, "dir");
  fanotify_mark(fd, FAN_MARK_ADD, FAN_CLOSE, AT_FDCWD, "dir");

Also FAN_MARK_ONDIR is only honored when adding events to a mark's mask,
but not for event removal.  Fix both issues by not setting FAN_ONDIR
implicitly on the ignore mask any more.  Instead treat FAN_ONDIR as any
other event flag and require FAN_MARK_ONDIR to be set by the user for
both event mask and ignore mask.  Furthermore take FAN_MARK_ONDIR into
account when set for event removal.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 18 insertions, 9 deletions

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 30d3addfad75..51ceb8107284 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -140,7 +140,7 @@ static bool fanotify_should_send_event(struct fsnotify_mark *inode_mark,
         }
 
         if (S_ISDIR(path->dentry->d_inode->i_mode) &&
-            (marks_ignored_mask & FS_ISDIR))
+            !(marks_mask & FS_ISDIR & ~marks_ignored_mask))
                 return false;
 
         if (event_mask & marks_mask & ~marks_ignored_mask)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index f4d279807a96..cf275500a665 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -491,10 +491,17 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 
         spin_lock(&fsn_mark->lock);
         if (!(flags & FAN_MARK_IGNORED_MASK)) {
+                __u32 tmask = fsn_mark->mask & ~mask;
+
+                if (flags & FAN_MARK_ONDIR)
+                        tmask &= ~FAN_ONDIR;
+
                 oldmask = fsn_mark->mask;
-                fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask));
+                fsnotify_set_mark_mask_locked(fsn_mark, tmask);
         } else {
                 __u32 tmask = fsn_mark->ignored_mask & ~mask;
+                if (flags & FAN_MARK_ONDIR)
+                        tmask &= ~FAN_ONDIR;
 
                 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
         }
@@ -569,20 +576,22 @@ static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
 
         spin_lock(&fsn_mark->lock);
         if (!(flags & FAN_MARK_IGNORED_MASK)) {
+                __u32 tmask = fsn_mark->mask | mask;
+
+                if (flags & FAN_MARK_ONDIR)
+                        tmask |= FAN_ONDIR;
+
                 oldmask = fsn_mark->mask;
-                fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));
+                fsnotify_set_mark_mask_locked(fsn_mark, tmask);
         } else {
                 __u32 tmask = fsn_mark->ignored_mask | mask;
+                if (flags & FAN_MARK_ONDIR)
+                        tmask |= FAN_ONDIR;
+
                 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
                 if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
                         fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
         }
-
-        if (!(flags & FAN_MARK_ONDIR)) {
-                __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR;
-                fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
-        }
-
         spin_unlock(&fsn_mark->lock);
 
         return mask & ~oldmask;