From: Eric Dumazet <edumazet@google.com>
Subject: netlink: fix uninit-value in netlink_sendmsg
Patch-mainline: v4.17-rc1
Git-commit: 6091f09c2f79730d895149bcfe3d66140288cd0e
References: git-fixes

syzbot reported :

BUG: KMSAN: uninit-value in ffs arch/x86/include/asm/bitops.h:432 [inline]
BUG: KMSAN: uninit-value in netlink_sendmsg+0xb26/0x1310 net/netlink/af_netlink.c:1851

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Denis Kirjanov <dkirjanov@suse.com>
---
 net/netlink/af_netlink.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 3e012d578ccd..70cf781ececb 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1812,6 +1812,8 @@ static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
 
 	if (msg->msg_namelen) {
 		err = -EINVAL;
+		if (msg->msg_namelen < sizeof(struct sockaddr_nl))
+			goto out;
 		if (addr->nl_family != AF_NETLINK)
 			goto out;
 		dst_portid = addr->nl_pid;
-- 
2.12.3