From cf3a4f1e86ecdd24f87b615051b49d8e1968c230 Mon Sep 17 00:00:00 2001
From: "liucheng (G)" <liucheng32@huawei.com>
Date: Thu, 29 Aug 2019 13:47:54 +0000
Subject: [PATCH] CVE-2019-14195: nfs: fix unbounded memcpy with unvalidated
 length at nfs_readlink_reply
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This patch adds a check to rpc_pkt.u.reply.data at nfs_readlink_reply.

Signed-off-by: Cheng Liu <liucheng32@huawei.com>
Reported-by: Fermín Serna <fermin@semmle.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
---
 net/nfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/nfs.c b/net/nfs.c
index 11941fad1a..915acd95cf 100644
--- a/net/nfs.c
+++ b/net/nfs.c
@@ -634,6 +634,9 @@ static int nfs_readlink_reply(uchar *pkt, unsigned len)
 	/* new path length */
 	rlen = ntohl(rpc_pkt.u.reply.data[1 + nfsv3_data_offset]);
 
+	if (((uchar *)&(rpc_pkt.u.reply.data[0]) - (uchar *)(&rpc_pkt) + rlen) > len)
+		return -NFS_RPC_DROP;
+
 	if (*((char *)&(rpc_pkt.u.reply.data[2 + nfsv3_data_offset])) != '/') {
 		int pathlen;
 
-- 
2.39.5