Re: [PATCH] netlink: make sure nladdr has correct size in netlink_connect()

KMSAN reports use of uninitialized memory in the case when |alen| is
smaller than sizeof(struct netlink_sock), and therefore |nladdr| isn't
fully copied from the userspace.

Signed-off-by: Alexander Potapenko <glider@google.com>
Fixes: 1da177e4c3f41524 ("Linux-2.6.12-rc2")
---
 net/netlink/af_netlink.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 07e8478068f0..5d49b39e81c3 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c

@@ -1085,6 +1085,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
        if (addr->sa_family != AF_NETLINK)
                return -EINVAL;

+       if (alen < sizeof(struct netlink_sock))
+               return -EINVAL;
+