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Commit cdbe7c2d authored by Jiri Benc's avatar Jiri Benc Committed by David S. Miller
Browse files

nfnetlink: do not ack malformed messages 



Commit 0628b123 ("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: default avatarJiri Benc <jbenc@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 13eb2ab2

net/netfilter/nfnetlink.c

+5 −3
Original line number Diff line number Diff line
@@ -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;