[PATCH 4.15 128/168] netlink: make sure nladdr has correct size in netlink_connect()

[Greg Kroah-Hartman]

4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Potapenko <gli...@google.com>


[ Upstream commit 7880287981b60a6808f39f297bb66936e8bdf57a ]

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

Signed-off-by: Alexander Potapenko <gli...@google.com>
Fixes: 1da177e4c3f41524 ("Linux-2.6.12-rc2")
Reviewed-by: Eric Dumazet <eduma...@google.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/netlink/af_netlink.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1052,6 +1052,9 @@ static int netlink_connect(struct socket
        if (addr->sa_family != AF_NETLINK)
                return -EINVAL;
 
+       if (alen < sizeof(struct sockaddr_nl))
+               return -EINVAL;
+
        if ((nladdr->nl_groups || nladdr->nl_pid) &&
            !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
                return -EPERM;