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authorHerbert Xu <herbert@gondor.apana.org.au>2009-01-14 20:41:12 -0800
committerDavid S. Miller <davem@davemloft.net>2009-01-14 20:41:12 -0800
commit4e704ee3c2cd38748ca59d835435d6a7e7f6f613 (patch)
tree24d4f83bb55748fa5ae79f302b641663fa0488ba
parentf557206800801410c30e53ce7a27219b2c4cf0ba (diff)
downloadlwn-4e704ee3c2cd38748ca59d835435d6a7e7f6f613.tar.gz
lwn-4e704ee3c2cd38748ca59d835435d6a7e7f6f613.zip
gso: Ensure that the packet is long enough
When we get a GSO packet from an untrusted source, we need to ensure that it is sufficiently long so that we don't end up crashing. Based on discovery and patch by Ian Campbell. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Tested-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/tcp.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 48ada1b2d2c4..0cd71b84e483 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2389,7 +2389,7 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
unsigned int seq;
__be32 delta;
unsigned int oldlen;
- unsigned int len;
+ unsigned int mss;
if (!pskb_may_pull(skb, sizeof(*th)))
goto out;
@@ -2405,10 +2405,13 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
oldlen = (u16)~skb->len;
__skb_pull(skb, thlen);
+ 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;
- int mss;
if (unlikely(type &
~(SKB_GSO_TCPV4 |
@@ -2419,7 +2422,6 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
!(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
goto out;
- mss = skb_shinfo(skb)->gso_size;
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
segs = NULL;
@@ -2430,8 +2432,7 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
if (IS_ERR(segs))
goto out;
- len = skb_shinfo(skb)->gso_size;
- delta = htonl(oldlen + (thlen + len));
+ delta = htonl(oldlen + (thlen + mss));
skb = segs;
th = tcp_hdr(skb);
@@ -2447,7 +2448,7 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
csum_fold(csum_partial(skb_transport_header(skb),
thlen, skb->csum));
- seq += len;
+ seq += mss;
skb = skb->next;
th = tcp_hdr(skb);