netdev - [PATCH] ipv6: udp packets following an UFO enqueued packet need also be handled by UFO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20130921042700.GB8070@order.stressinduktion.org>
Date:	Sat, 21 Sep 2013 06:27:00 +0200
From:	Hannes Frederic Sowa <hannes@...essinduktion.org>
To:	netdev@...r.kernel.org
Cc:	yoshfuji@...ux-ipv6.org, davem@...emloft.net
Subject: [PATCH] ipv6: udp packets following an UFO enqueued packet need also be handled by UFO

In the following scenario the socket is corked:
If the first UDP packet is larger then the mtu we try to append it to the
write queue via ip6_ufo_append_data. A following packet, which is smaller
than the mtu would be appended to the already queued up gso-skb via
plain ip6_append_data. This causes random memory corruptions.

In ip6_ufo_append_data we also have to be careful to not queue up the
same skb multiple times. So setup the gso frame only when no first skb
is available.

This also fixes a shortcoming where we add the current packet's length to
cork->length but return early because of a packet > mtu with dontfrag set
(instead of sutracting it again).

Found with trinity.

Cc: YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <hannes@...essinduktion.org>
---

I could only test this with virtualized UFO enabled network cards. Could
someone test this on real hardware?

 net/ipv6/ip6_output.c | 53 +++++++++++++++++++++------------------------------
 1 file changed, 22 insertions(+), 31 deletions(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 3a692d5..a54c45c 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1015,6 +1015,8 @@ static inline int ip6_ufo_append_data(struct sock *sk,
 	 * udp datagram
 	 */
 	if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
+		struct frag_hdr fhdr;
+
 		skb = sock_alloc_send_skb(sk,
 			hh_len + fragheaderlen + transhdrlen + 20,
 			(flags & MSG_DONTWAIT), &err);
@@ -1036,12 +1038,6 @@ static inline int ip6_ufo_append_data(struct sock *sk,
 		skb->protocol = htons(ETH_P_IPV6);
 		skb->ip_summed = CHECKSUM_PARTIAL;
 		skb->csum = 0;
-	}
-
-	err = skb_append_datato_frags(sk,skb, getfrag, from,
-				      (length - transhdrlen));
-	if (!err) {
-		struct frag_hdr fhdr;
 
 		/* Specify the length of each IPv6 datagram fragment.
 		 * It has to be a multiple of 8.
@@ -1052,15 +1048,10 @@ static inline int ip6_ufo_append_data(struct sock *sk,
 		ipv6_select_ident(&fhdr, rt);
 		skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
 		__skb_queue_tail(&sk->sk_write_queue, skb);
-
-		return 0;
 	}
-	/* There is not enough support do UPD LSO,
-	 * so follow normal path
-	 */
-	kfree_skb(skb);
 
-	return err;
+	return skb_append_datato_frags(sk, skb, getfrag, from,
+				       (length - transhdrlen));
 }
 
 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
@@ -1227,27 +1218,27 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
 	 * --yoshfuji
 	 */
 
-	cork->length += length;
-	if (length > mtu) {
-		int proto = sk->sk_protocol;
-		if (dontfrag && (proto == IPPROTO_UDP || proto == IPPROTO_RAW)){
-			ipv6_local_rxpmtu(sk, fl6, mtu-exthdrlen);
-			return -EMSGSIZE;
-		}
-
-		if (proto == IPPROTO_UDP &&
-		    (rt->dst.dev->features & NETIF_F_UFO)) {
+	if ((length > mtu) && dontfrag && (sk->sk_protocol == IPPROTO_UDP ||
+					   sk->sk_protocol == IPPROTO_RAW)) {
+		ipv6_local_rxpmtu(sk, fl6, mtu-exthdrlen);
+		return -EMSGSIZE;
+	}
 
-			err = ip6_ufo_append_data(sk, getfrag, from, length,
-						  hh_len, fragheaderlen,
-						  transhdrlen, mtu, flags, rt);
-			if (err)
-				goto error;
-			return 0;
-		}
+	skb = skb_peek_tail(&sk->sk_write_queue);
+	cork->length += length;
+	if (((length > mtu) ||
+	     (skb && skb_is_gso(skb))) &&
+	    (sk->sk_protocol == IPPROTO_UDP) &&
+	    (rt->dst.dev->features & NETIF_F_UFO)) {
+		err = ip6_ufo_append_data(sk, getfrag, from, length,
+					  hh_len, fragheaderlen,
+					  transhdrlen, mtu, flags, rt);
+		if (err)
+			goto error;
+		return 0;
 	}
 
-	if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
+	if (!skb)
 		goto alloc_new_skb;
 
 	while (length > 0) {
-- 
1.8.3.1


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html