From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 18 Jan 2012 09:56:02 +0000 (+0300)
Subject: nfsd: don't allow zero length strings in cache_parse()
X-Git-Tag: v3.3.1~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7b6b691420ef8ec6f1531b60b5a4a6319096a29c;p=thirdparty%2Fkernel%2Fstable.git

nfsd: don't allow zero length strings in cache_parse()

commit 6d8d17499810479eabd10731179c04b2ca22152f upstream.

There is no point in passing a zero length string here and quite a
few of that cache_parse() implementations will Oops if count is
zero.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 465df9ae1046b..8c6598e0334a0 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -828,6 +828,8 @@ static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
 {
 	ssize_t ret;
 
+	if (count == 0)
+		return -EINVAL;
 	if (copy_from_user(kaddr, buf, count))
 		return -EFAULT;
 	kaddr[count] = '\0';