linux-kernel - [PATCH] overlayfs: fix ovl_get

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Message-Id: <20161122142921.1801734-1-arnd@arndb.de>
Date:   Tue, 22 Nov 2016 15:29:13 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Miklos Szeredi <miklos@...redi.hu>
Cc:     Arnd Bergmann <arnd@...db.de>, Vivek Goyal <vgoyal@...hat.com>,
        Andreas Gruenbacher <agruenba@...hat.com>,
        Al Viro <viro@...iv.linux.org.uk>,
        Konstantin Khlebnikov <koct9i@...il.com>,
        Antonio Murdaca <amurdaca@...hat.com>,
        Maxim Patlasov <mpatlasov@...tuozzo.com>,
        linux-unionfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] overlayfs: fix ovl_get_redirect() error handling

The newly introduced ovl_get_redirect() function returns an unintialized
variable when kmalloc() fails:

fs/overlayfs/dir.c: In function ‘ovl_set_redirect’:
fs/overlayfs/overlayfs.h:92:6: error: ‘ret’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

This makes it return -ENOMEM instead.

Fixes: 496654b0792e ("ovl: redirect on rename-dir")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 fs/overlayfs/dir.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index bc7c62c7a72f..fb9fce0112f0 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -798,8 +798,10 @@ static char *ovl_get_redirect(struct dentry *dentry, bool samedir)
 	}
 
 	buf = kmalloc(buflen, GFP_TEMPORARY);
-	if (!buf)
+	if (!buf) {
+		ret = ERR_PTR(-ENOMEM);
 		goto out;
+	}
 
 	buflen--;
 	buf[buflen] = '\0';
-- 
2.9.0