commit cf3a4f1e86ecdd24f87b615051b49d8e1968c230
author liucheng (G) <liucheng32@huawei.com> Thu Aug 29 13:47:54 2019 +0000
committer Joe Hershberger <joe.hershberger@ni.com> Wed Sep 04 11:37:19 2019 -0500
tree 7ccee6d442944ff635fc3962b67ce641c104dd78
parent aa207cf3a6d68f39d64cd29057a4fb63943e9078

CVE-2019-14195: nfs: fix unbounded memcpy with unvalidated length at nfs_readlink_reply

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

diff --git a/net/nfs.c b/net/nfs.c
index 11941fa..915acd9 100644
--- a/net/nfs.c
+++ b/net/nfs.c
@@ -634,6 +634,9 @@
 	/* 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;