[PATCH net 2/8] netlink: fix uninit-value in netlink_sendmsg

[Eric Dumazet]

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 <eduma...@google.com>
Reported-by: syzbot <syzkal...@googlegroups.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 
fa556fdef57d8a684bd73de05821514482db2eea..55342c4d5cec6a999065aa1c9607bdf476c59d36
 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1844,6 +1844,8 @@ 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;
-- 
2.17.0.484.g0c8726318c-goog