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| author | Miklos Szeredi <mszeredi@redhat.com> | 2017-10-30 21:14:55 +0100 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2017-10-31 17:54:56 +0100 |
| commit | 0d6ec079d6aaa098b978d6395973bb027c752a03 (patch) | |
| tree | 681a9c667b5cf48e6166eecf12c9745ffc717fc4 | |
| parent | fsnotify: clean up fsnotify_prepare/finish_user_wait() (diff) | |
| download | linux-0d6ec079d6aaa098b978d6395973bb027c752a03.tar.xz linux-0d6ec079d6aaa098b978d6395973bb027c752a03.zip | |
fsnotify: pin both inode and vfsmount mark
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")
Cc: <stable@vger.kernel.org> # v4.12
Signed-off-by: Jan Kara <jack@suse.cz>
| -rw-r--r-- | fs/notify/fsnotify.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 0c4583b61717..074716293829 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -335,6 +335,13 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, 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, __u32 mask, const void *data, int data_is, } } - 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); |