This is a note to let you know that I've just added the patch titled
fsnotify: pin both inode and vfsmount mark
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: fsnotify-pin-both-inode-and-vfsmount-mark.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 0d6ec079d6aaa098b978d6395973bb027c752a03 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi mszeredi@redhat.com Date: Mon, 30 Oct 2017 21:14:55 +0100 Subject: fsnotify: pin both inode and vfsmount mark
From: Miklos Szeredi mszeredi@redhat.com
commit 0d6ec079d6aaa098b978d6395973bb027c752a03 upstream.
We may fail to pin one of the marks in fsnotify_prepare_user_wait() when dropping the srcu read lock, resulting in use after free at the next iteration.
Solution is to store both marks in iter_info instead of just the one we'll be sending the event for.
Reviewed-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Miklos Szeredi mszeredi@redhat.com Fixes: 9385a84d7e1f ("fsnotify: Pass fsnotify_iter_info into handle_event handler") Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/notify/fsnotify.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
--- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -335,6 +335,13 @@ int fsnotify(struct inode *to_tell, __u3 struct fsnotify_mark, obj_list); vfsmount_group = vfsmount_mark->group; } + /* + * Need to protect both marks against freeing so that we can + * continue iteration from this place, regardless of which mark + * we actually happen to send an event for. + */ + iter_info.inode_mark = inode_mark; + iter_info.vfsmount_mark = vfsmount_mark;
if (inode_group && vfsmount_group) { int cmp = fsnotify_compare_groups(inode_group, @@ -348,9 +355,6 @@ int fsnotify(struct inode *to_tell, __u3 } }
- iter_info.inode_mark = inode_mark; - iter_info.vfsmount_mark = vfsmount_mark; - ret = send_to_group(to_tell, inode_mark, vfsmount_mark, mask, data, data_is, cookie, file_name, &iter_info);
Patches currently in stable-queue which might be from mszeredi@redhat.com are
queue-4.14/fsnotify-clean-up-fsnotify_prepare-finish_user_wait.patch queue-4.14/fsnotify-fix-pinning-group-in-fsnotify_prepare_user_wait.patch queue-4.14/fanotify-fix-fsnotify_prepare_user_wait-failure.patch queue-4.14/fsnotify-pin-both-inode-and-vfsmount-mark.patch queue-4.14/ovl-put-upperdentry-if-ovl_check_origin-fails.patch