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authorJan Kara <jack@suse.cz>2014-01-28 18:53:22 +0100
committerJan Kara <jack@suse.cz>2014-01-29 13:57:10 +0100
commit83c0e1b442b488571f4fef4a91c2fe52eed6c705 (patch)
treeb29a85223f2e5e166f075266edb1bf2e0ef5cf57 /fs/notify/fanotify
parent13116dfd13c8c9d60ea04ece13419af2de8e2e37 (diff)
downloadlinux-83c0e1b442b488571f4fef4a91c2fe52eed6c705.tar.bz2
fsnotify: Do not return merged event from fsnotify_add_notify_event()
The event returned from fsnotify_add_notify_event() cannot ever be used safely as the event may be freed by the time the function returns (after dropping notification_mutex). So change the prototype to just return whether the event was added or merged into some existing event. Reported-and-tested-by: Jiri Kosina <jkosina@suse.cz> Reported-and-tested-by: Dave Jones <davej@fedoraproject.org> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify/fanotify')
-rw-r--r--fs/notify/fanotify/fanotify.c18
1 files changed, 7 insertions, 11 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index cc78e2fbc8e4..c7e5e8f54748 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -28,8 +28,7 @@ static bool should_merge(struct fsnotify_event *old_fsn,
}
/* and the list better be locked by something too! */
-static struct fsnotify_event *fanotify_merge(struct list_head *list,
- struct fsnotify_event *event)
+static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
{
struct fsnotify_event *test_event;
bool do_merge = false;
@@ -43,7 +42,7 @@ static struct fsnotify_event *fanotify_merge(struct list_head *list,
* one we should check for permission response.
*/
if (event->mask & FAN_ALL_PERM_EVENTS)
- return NULL;
+ return 0;
#endif
list_for_each_entry_reverse(test_event, list, list) {
@@ -54,10 +53,10 @@ static struct fsnotify_event *fanotify_merge(struct list_head *list,
}
if (!do_merge)
- return NULL;
+ return 0;
test_event->mask |= event->mask;
- return test_event;
+ return 1;
}
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
@@ -153,7 +152,6 @@ static int fanotify_handle_event(struct fsnotify_group *group,
int ret = 0;
struct fanotify_event_info *event;
struct fsnotify_event *fsn_event;
- struct fsnotify_event *notify_fsn_event;
BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS);
BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY);
@@ -192,13 +190,11 @@ static int fanotify_handle_event(struct fsnotify_group *group,
event->response = 0;
#endif
- notify_fsn_event = fsnotify_add_notify_event(group, fsn_event,
- fanotify_merge);
- if (notify_fsn_event) {
+ ret = fsnotify_add_notify_event(group, fsn_event, fanotify_merge);
+ if (ret) {
/* Our event wasn't used in the end. Free it. */
fsnotify_destroy_event(group, fsn_event);
- if (IS_ERR(notify_fsn_event))
- return PTR_ERR(notify_fsn_event);
+ ret = 0;
}
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS