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authorAmir Goldstein <amir73il@gmail.com>2020-11-08 13:59:06 +0300
committerJan Kara <jack@suse.cz>2020-11-09 17:03:08 +0300
commit7372e79c9eb9d7034e498721eb2861ae4fdbc618 (patch)
treecf7bed398f1f0dc95f9dfec6f5b7119a0df1f972 /fs/notify
parentb7cbaf59f62f8ab8f157698f9e31642bff525bd0 (diff)
downloadlinux-7372e79c9eb9d7034e498721eb2861ae4fdbc618.tar.xz
fanotify: fix logic of reporting name info with watched parent
The victim inode's parent and name info is required when an event needs to be delivered to a group interested in filename info OR when the inode's parent is interested in an event on its children. Let us call the first condition 'parent_needed' and the second condition 'parent_interested'. In fsnotify_parent(), the condition where the inode's parent is interested in some events on its children, but not necessarily interested the specific event is called 'parent_watched'. fsnotify_parent() tests the condition (!parent_watched && !parent_needed) for sending the event without parent and name info, which is correct. It then wrongly assumes that parent_watched implies !parent_needed and tests the condition (parent_watched && !parent_interested) for sending the event without parent and name info, which is wrong, because parent may still be needed by some group. For example, after initializing a group with FAN_REPORT_DFID_NAME and adding a FAN_MARK_MOUNT with FAN_OPEN mask, open events on non-directory children of "testdir" are delivered with file name info. After adding another mark to the same group on the parent "testdir" with FAN_CLOSE|FAN_EVENT_ON_CHILD mask, open events on non-directory children of "testdir" are no longer delivered with file name info. Fix the logic and use auxiliary variables to clarify the conditions. Fixes: 9b93f33105f5 ("fsnotify: send event with parent/name info to sb/mount/non-dir marks") Cc: stable@vger.kernel.org#v5.9 Link: https://lore.kernel.org/r/20201108105906.8493-1-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/fsnotify.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index a960ec3a569a..8d3ad5ef2925 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -178,6 +178,7 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
struct inode *inode = d_inode(dentry);
struct dentry *parent;
bool parent_watched = dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED;
+ bool parent_needed, parent_interested;
__u32 p_mask;
struct inode *p_inode = NULL;
struct name_snapshot name;
@@ -193,7 +194,8 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
return 0;
parent = NULL;
- if (!parent_watched && !fsnotify_event_needs_parent(inode, mnt, mask))
+ parent_needed = fsnotify_event_needs_parent(inode, mnt, mask);
+ if (!parent_watched && !parent_needed)
goto notify;
/* Does parent inode care about events on children? */
@@ -205,17 +207,17 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
/*
* Include parent/name in notification either if some notification
- * groups require parent info (!parent_watched case) or the parent is
- * interested in this event.
+ * groups require parent info or the parent is interested in this event.
*/
- if (!parent_watched || (mask & p_mask & ALL_FSNOTIFY_EVENTS)) {
+ parent_interested = mask & p_mask & ALL_FSNOTIFY_EVENTS;
+ if (parent_needed || parent_interested) {
/* When notifying parent, child should be passed as data */
WARN_ON_ONCE(inode != fsnotify_data_inode(data, data_type));
/* Notify both parent and child with child name info */
take_dentry_name_snapshot(&name, dentry);
file_name = &name.name;
- if (parent_watched)
+ if (parent_interested)
mask |= FS_EVENT_ON_CHILD;
}