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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        Miklos Szeredi <mszeredi@redhat.com>
Subject: [PATCH 5.4 063/244] ovl: fix missing revert_creds() on error path
Date:   Wed, 12 May 2021 16:47:14 +0200
Message-Id: <20210512144745.056843137@linuxfoundation.org>
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From: Dan Carpenter <dan.carpenter@oracle.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@oracle.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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
@@ -852,7 +852,7 @@ static int ovl_copy_up_one(struct dentry
 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);
 
 	/*
@@ -863,6 +863,7 @@ int ovl_copy_up_flags(struct dentry *den
 	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;