linux-kernel - [PATCH 5.12 133/677] ovl: fix missing revert

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Date:   Wed, 12 May 2021 16:42:59 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dan Carpenter <dan.carpenter@...cle.com>,
        Miklos Szeredi <mszeredi@...hat.com>
Subject: [PATCH 5.12 133/677] ovl: fix missing revert_creds() on error path

From: Dan Carpenter <dan.carpenter@...cle.com>

commit 7b279bbfd2b230c7a210ff8f405799c7e46bbf48 upstream.

Smatch complains about missing that the ovl_override_creds() doesn't
have a matching revert_creds() if the dentry is disconnected.  Fix this
by moving the ovl_override_creds() until after the disconnected check.

Fixes: aa3ff3c152ff ("ovl: copy up of disconnected dentries")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/overlayfs/copy_up.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -932,7 +932,7 @@ static int ovl_copy_up_one(struct dentry
 static int ovl_copy_up_flags(struct dentry *dentry, int flags)
 {
 	int err = 0;
-	const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
+	const struct cred *old_cred;
 	bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);
 
 	/*
@@ -943,6 +943,7 @@ static int ovl_copy_up_flags(struct dent
 	if (WARN_ON(disconnected && d_is_dir(dentry)))
 		return -EIO;
 
+	old_cred = ovl_override_creds(dentry->d_sb);
 	while (!err) {
 		struct dentry *next;
 		struct dentry *parent = NULL;