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sch_sfq: add sanity check for the packet length

PATCH New Changli Gao 1 participant 1 message Aug 4, 2010

Subsystems (3)
Networking Network drivers Traffic control (tc)
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Changli Gao

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#0 lore raw

PATCH 1/1 sch_sfq: add sanity check for the packet length

The packet length should be checked before the packet data is dereferenced.

Signed-off-by Changli Gao <[email protected]>
---
 net/sched/sch_sfq.c |   31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)
net/sched/sch_sfq.c +22 -9
index c657628..018c528 100644
@@ -122,7 +122,11 @@ static unsigned sfq_hash(struct sfq_sched_data *q, struct sk_buff *skb)
 	switch (skb->protocol) {
 	case htons(ETH_P_IP):
 	{
-		const struct iphdr *iph = ip_hdr(skb);
+		const struct iphdr *iph;
+
+		if (!pskb_may_pull(skb, skb_network_offset(skb) + sizeof(*iph)))
+			goto err;
+		iph = ip_hdr(skb);
 		h = (__force u32)iph->daddr;
 		h2 = (__force u32)iph->saddr ^ iph->protocol;
 		if (!(iph->frag_off&htons(IP_MF|IP_OFFSET)) &&

@@ -131,25 +135,34 @@ static unsigned sfq_hash(struct sfq_sched_data *q, struct sk_buff *skb)
 		     iph->protocol == IPPROTO_UDPLITE ||
 		     iph->protocol == IPPROTO_SCTP ||
 		     iph->protocol == IPPROTO_DCCP ||
-		     iph->protocol == IPPROTO_ESP))
+		     iph->protocol == IPPROTO_ESP) &&
+		     pskb_may_pull(skb, skb_network_offset(skb) +
+					iph->ihl * 4 + 4))
 			h2 ^= *(((u32*)iph) + iph->ihl);
 		break;
 	}
 	case htons(ETH_P_IPV6):
 	{
-		struct ipv6hdr *iph = ipv6_hdr(skb);
+		struct ipv6hdr *iph;
+
+		if (!pskb_may_pull(skb, skb_network_offset(skb) + sizeof(*iph)))
+			goto err;
+		iph = ipv6_hdr(skb);
 		h = (__force u32)iph->daddr.s6_addr32[3];
 		h2 = (__force u32)iph->saddr.s6_addr32[3] ^ iph->nexthdr;
-		if (iph->nexthdr == IPPROTO_TCP ||
-		    iph->nexthdr == IPPROTO_UDP ||
-		    iph->nexthdr == IPPROTO_UDPLITE ||
-		    iph->nexthdr == IPPROTO_SCTP ||
-		    iph->nexthdr == IPPROTO_DCCP ||
-		    iph->nexthdr == IPPROTO_ESP)
+		if ((iph->nexthdr == IPPROTO_TCP ||
+		     iph->nexthdr == IPPROTO_UDP ||
+		     iph->nexthdr == IPPROTO_UDPLITE ||
+		     iph->nexthdr == IPPROTO_SCTP ||
+		     iph->nexthdr == IPPROTO_DCCP ||
+		     iph->nexthdr == IPPROTO_ESP) &&
+		    pskb_may_pull(skb, skb_network_offset(skb) + sizeof(*iph) +
+				       4))
 			h2 ^= *(u32*)&iph[1];
 		break;
 	}
 	default:
+err:
 		h = (unsigned long)skb_dst(skb) ^ (__force u32)skb->protocol;
 		h2 = (unsigned long)skb->sk;
 	}