[U-Boot] [PATCH 5/5] CVE-2019-14196: nfs: fix unbounded memcpy with a failed length check at nfs_lookup_reply

[Cheng Liu]

CVE-2019-14196: nfs: fix unbounded memcpy with a failed length check at nfs_lookup_reply

This patch adds a check to rpc_pkt.u.reply.data at nfs_lookup_reply.

Signed-off-by: Cheng Liu <liucheng32 at huawei.com>
---
 net/nfs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/nfs.c b/net/nfs.c
index 915acd9..89952ae 100644
--- a/net/nfs.c
+++ b/net/nfs.c
@@ -566,11 +566,15 @@ static int nfs_lookup_reply(uchar *pkt, unsigned len)
 	}
 
 	if (supported_nfs_versions & NFSV2_FLAG) {
+		if (((uchar *)&(rpc_pkt.u.reply.data[0]) - (uchar *)(&rpc_pkt) + NFS_FHSIZE) > len)
+			return -NFS_RPC_DROP;
 		memcpy(filefh, rpc_pkt.u.reply.data + 1, NFS_FHSIZE);
 	} else {  /* NFSV3_FLAG */
 		filefh3_length = ntohl(rpc_pkt.u.reply.data[1]);
 		if (filefh3_length > NFS3_FHSIZE)
 			filefh3_length  = NFS3_FHSIZE;
+		if (((uchar *)&(rpc_pkt.u.reply.data[0]) - (uchar *)(&rpc_pkt) + filefh3_length) > len)
+			return -NFS_RPC_DROP;
 		memcpy(filefh, rpc_pkt.u.reply.data + 2, filefh3_length);
 	}
 
-- 
1.8.5.6