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Commit b116697f authored by Tejaswi Tanikella's avatar Tejaswi Tanikella Committed by Gerrit - the friendly Code Review server
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nf: xt_socket: Fix out-of-bounds in xt_socket_lookup_slow_v{4,6} 



skb_header_pointer will copy data into the buffer if data is spread
across pages, else share pointer within skb->data. In
xt_socket_lookup_slow_v4, data is copied into udphdr, and later
th->doff is accessed, causing a out-of-bounds. This
access will only work if the data is not split across pages.

Copy data into tcphdr buffer for TCP packets instead.

Change-Id: Ifd6e15ece27fcf5bd02ae17571ab43f6df3ceb21
Fixes: a583636a ("inet: refactor inet[6]_lookup functions to take skb")
Signed-off-by: default avatarTejaswi Tanikella <tejaswit@codeaurora.org>
parent a56e768c

net/netfilter/xt_socket.c

+9 −4
Original line number Diff line number Diff line
@@ -158,10 +158,13 @@ struct sock *xt_socket_lookup_slow_v4(struct net *net, 
#endif



	if (iph->protocol == IPPROTO_UDP || iph->protocol == IPPROTO_TCP) {

		struct udphdr _hdr, *hp;

		struct udphdr *hp;

		struct tcphdr _hdr;



		hp = skb_header_pointer(skb, ip_hdrlen(skb),

					sizeof(_hdr), &_hdr);

					iph->protocol == IPPROTO_UDP ?

					sizeof(*hp) : sizeof(_hdr),

					&_hdr);

		if (hp == NULL)

			return NULL;
@@ -360,9 +363,11 @@ struct sock *xt_socket_lookup_slow_v6(struct net *net, 
	}



	if (tproto == IPPROTO_UDP || tproto == IPPROTO_TCP) {

		struct udphdr _hdr, *hp;

		struct udphdr *hp;

		struct tcphdr _hdr;



		hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);

		hp = skb_header_pointer(skb, thoff, tproto == IPPROTO_UDP ?

					sizeof(*hp) : sizeof(_hdr), &_hdr);

		if (hp == NULL)

			return NULL;