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;a=summary
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@xxxxxxxxxxxxxxx> know about it.
>From 0d6ec079d6aaa098b978d6395973bb027c752a03 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Date: Mon, 30 Oct 2017 21:14:55 +0100
Subject: fsnotify: pin both inode and vfsmount mark
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Fixes: 9385a84d7e1f ("fsnotify: Pass fsnotify_iter_info into handle_event handler")
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxx 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