nfnetlink: do not ack malformed messages

Commit 0628b123c9 ("netfilter: nfnetlink: add batch support and use it
from nf_tables") introduced a bug leading to various crashes in netlink_ack
when netlink message with invalid nlmsg_len was sent by an unprivileged
user.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jiri Benc 2013-11-07 19:59:19 +01:00 committed by David S. Miller
parent 13eb2ab2d3
commit cdbe7c2d6d
1 changed files with 5 additions and 3 deletions

View File

@ -363,13 +363,15 @@ static void nfnetlink_rcv(struct sk_buff *skb)
struct net *net = sock_net(skb->sk);
int msglen;
if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
return netlink_ack(skb, nlh, -EPERM);
if (nlh->nlmsg_len < NLMSG_HDRLEN ||
skb->len < nlh->nlmsg_len)
return;
if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) {
netlink_ack(skb, nlh, -EPERM);
return;
}
if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) {
struct nfgenmsg *nfgenmsg;