netdev - [RFC 1/2] udpv4: Support software UFO and handle large incoming UDP/IPv4 packets

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: <1245860210.23459.13.camel@w-sridhar.beaverton.ibm.com>
Date:	Wed, 24 Jun 2009 09:16:50 -0700
From:	Sridhar Samudrala <sri@...ibm.com>
To:	Herbert Xu <herbert@...dor.apana.org.au>,
	David Miller <davem@...emloft.net>,
	netdev <netdev@...r.kernel.org>
Subject: [RFC 1/2] udpv4: Support software UFO and handle large incoming
 UDP/IPv4 packets

[RFC 1/2] udpv4: Support software UFO and handle large incoming UDP/IPv4 packets

- validate and forward GSO UDP/IPv4 packets from untrusted sources(guests under KVM).
- do software UFO if the outgoing device doesn't support UFO.

Signed-off-by: Sridhar Samudrala <sri@...ibm.com>

diff --git a/include/net/udp.h b/include/net/udp.h
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -207,4 +207,7 @@ extern void udp4_proc_exit(void);
 #endif
 
 extern void udp_init(void);
+
+extern int udp4_ufo_send_check(struct sk_buff *skb);
+extern struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, int features);
 #endif	/* _UDP_H */
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1187,6 +1187,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
 	int proto;
 	int ihl;
 	int id;
+	unsigned int offset = 0;
 
 	if (!(features & NETIF_F_V4_CSUM))
 		features &= ~NETIF_F_SG;
@@ -1229,7 +1230,14 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
 	skb = segs;
 	do {
 		iph = ip_hdr(skb);
-		iph->id = htons(id++);
+		if (proto == IPPROTO_UDP) {
+			iph->id = htons(id);
+			iph->frag_off = htons(offset >> 3);
+			if (skb->next != NULL)
+				iph->frag_off |= htons(IP_MF);
+			offset += (skb->len - skb->mac_len - iph->ihl * 4);
+		} else
+			iph->id = htons(id++);
 		iph->tot_len = htons(skb->len - skb->mac_len);
 		iph->check = 0;
 		iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
@@ -1425,6 +1433,8 @@ static struct net_protocol tcp_protocol = {
 static struct net_protocol udp_protocol = {
 	.handler =	udp_rcv,
 	.err_handler =	udp_err,
+	.gso_send_check = udp4_ufo_send_check,
+	.gso_segment = udp4_ufo_fragment,
 	.no_policy =	1,
 	.netns_ok =	1,
 };
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1815,6 +1815,57 @@ void __init udp_init(void)
 	sysctl_udp_wmem_min = SK_MEM_QUANTUM;
 }
 
+int udp4_ufo_send_check(struct sk_buff *skb)
+{
+	const struct iphdr *iph;
+	struct udphdr *uh;
+
+	if (!pskb_may_pull(skb, sizeof(*uh)))
+		return -EINVAL;
+
+	iph = ip_hdr(skb);
+	uh = udp_hdr(skb);
+
+	uh->check = 0;
+	uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
+				       IPPROTO_UDP, 0);
+	skb->csum_start = skb_transport_header(skb) - skb->head;
+	skb->csum_offset = offsetof(struct udphdr, check);
+	skb->ip_summed = CHECKSUM_PARTIAL;
+	return 0;
+}
+
+struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, int features)
+{
+	struct sk_buff *segs = ERR_PTR(-EINVAL);
+	unsigned int mss;
+
+	mss = skb_shinfo(skb)->gso_size;
+	if (unlikely(skb->len <= mss))
+		goto out;
+
+	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
+		/* Packet is from an untrusted source, reset gso_segs. */
+		int type = skb_shinfo(skb)->gso_type;
+
+		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
+			     !(type & (SKB_GSO_UDP))))
+			goto out;
+
+		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
+
+		segs = NULL;
+		goto out;
+	}
+
+	/* Do software UFO. IP headers of the fragments are updated in 
+	 * inet_gso_segment()
+	 */
+	segs = skb_segment(skb, features);
+out:
+	return segs;
+}
+
 EXPORT_SYMBOL(udp_disconnect);
 EXPORT_SYMBOL(udp_ioctl);
 EXPORT_SYMBOL(udp_prot);


--
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