netdev - [3/3] gso: Handle malicious GRO packets without crashing

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

Message-ID: <20131107070847.GC31638@gondor.apana.org.au>
Date:	Thu, 7 Nov 2013 15:08:47 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Ben Hutchings <bhutchings@...arflare.com>,
	David Miller <davem@...emloft.net>,
	christoph.paasch@...ouvain.be, netdev@...r.kernel.org,
	hkchu@...gle.com, mwdalton@...gle.com
Subject: [3/3] gso: Handle malicious GRO packets without crashing

As virtio_net can now generate GRO frag_list packets without
sufficient verification, we need to handle malicious GRO packets
thrown at us.

This patch converts to affected BUG_ONs in skb_segment to rate-
limited warnings.

Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index bcc3f1c..fb1106d 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2881,7 +2881,15 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
 			while (tail->next)
 				tail = tail->next;
 
-			BUG_ON(fskb && tail->len != len + doffset);
+			if (fskb && tail->len != len + doffset) {
+				net_warn_ratelimited(
+					"skb_segment: "
+					"illegal GSO fragment: %u %u\n",
+					tail->len, len + doffset);
+				kfree(nskb);
+				err = -EINVAL;
+				goto err;
+			}
 
 			len = nskb->len;
 			kfree(nskb);
@@ -2929,7 +2937,15 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
 		if (pos < offset + len) {
 			struct sk_buff *fskb2 = fskb;
 
-			BUG_ON(pos + fskb->len != offset + len);
+			if (pos + fskb->len != offset + len) {
+				net_warn_ratelimited(
+					"skb_segment: "
+					"illegal GSO trailer: %u %u\n",
+					pos + fskb->len, offset + len);
+				kfree(nskb);
+				err = -EINVAL;
+				goto err;
+			}
 
 			pos += fskb->len;
 			fskb = fskb->next;
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
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