From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Fri, 12 Apr 2019 10:53:38 +0000 (+0900)
Subject: net: netlink: Check address length before reading groups field
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=d852be84770c0611f8b76bd7046c6a814c5b9f11;p=linux.git

net: netlink: Check address length before reading groups field

KMSAN will complain if valid address length passed to bind() is shorter
than sizeof(struct sockaddr_nl) bytes.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index f28e937320a3b..216ab915dd54d 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -988,7 +988,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
 	struct netlink_sock *nlk = nlk_sk(sk);
 	struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
 	int err = 0;
-	unsigned long groups = nladdr->nl_groups;
+	unsigned long groups;
 	bool bound;
 
 	if (addr_len < sizeof(struct sockaddr_nl))
@@ -996,6 +996,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
 
 	if (nladdr->nl_family != AF_NETLINK)
 		return -EINVAL;
+	groups = nladdr->nl_groups;
 
 	/* Only superuser is allowed to listen multicasts */
 	if (groups) {