From 2b98149c2377bff12be5dd3ce02ae0506e2dd613 Mon Sep 17 00:00:00 2001 From: Aleksa Sarai Date: Sat, 7 Dec 2019 01:13:26 +1100 Subject: [PATCH] namei: only return -ECHILD from follow_dotdot_rcu() It's over-zealous to return hard errors under RCU-walk here, given that a REF-walk will be triggered for all other cases handling ".." under RCU. The original purpose of this check was to ensure that if a rename occurs such that a directory is moved outside of the bind-mount which the resolution started in, it would be detected and blocked to avoid being able to mess with paths outside of the bind-mount. However, triggering a new REF-walk is just as effective a solution. Cc: "Eric W. Biederman" Fixes: 397d425dc26d ("vfs: Test for and handle paths that are unreachable from their mnt_root") Suggested-by: Al Viro Signed-off-by: Aleksa Sarai Signed-off-by: Al Viro --- fs/namei.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/namei.c b/fs/namei.c index d6c91d1e88cb..17ebaac2da49 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1365,7 +1365,7 @@ static int follow_dotdot_rcu(struct nameidata *nd) nd->path.dentry = parent; nd->seq = seq; if (unlikely(!path_connected(&nd->path))) - return -ENOENT; + return -ECHILD; break; } else { struct mount *mnt = real_mount(nd->path.mnt);