diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2009-04-17 02:34:38 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-04-17 02:34:38 -0700 |
| commit | a0a69a0106dab8d20596f97f6674bed3b394d1ee (patch) | |
| tree | 2477a32cab5f8afdb1c158f0b151048ee7afc594 | |
| parent | 9dd014eb9804f19d6230c3cbc10fa25f5416bda7 (diff) | |
gro: Fix use after free in tcp_gro_receive
After calling skb_gro_receive skb->len can no longer be relied
on since if the skb was merged using frags, then its pages will
have been removed and the length reduced.
This caused tcp_gro_receive to prematurely end merging which
resulted in suboptimal performance with ixgbe.
The fix is to store skb->len on the stack.
Reported-by: Mark Wagner <mwagner@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/tcp.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index fafbec8b073..1d7f49c6f0c 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2511,6 +2511,7 @@ struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) struct sk_buff *p; struct tcphdr *th; struct tcphdr *th2; + unsigned int len; unsigned int thlen; unsigned int flags; unsigned int mss = 1; @@ -2531,6 +2532,7 @@ struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) skb_gro_pull(skb, thlen); + len = skb_gro_len(skb); flags = tcp_flag_word(th); for (; (p = *head); head = &p->next) { @@ -2561,7 +2563,7 @@ found: mss = skb_shinfo(p)->gso_size; - flush |= (skb_gro_len(skb) > mss) | !skb_gro_len(skb); + flush |= (len > mss) | !len; flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); if (flush || skb_gro_receive(head, skb)) { @@ -2574,7 +2576,7 @@ found: tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); out_check_final: - flush = skb_gro_len(skb) < mss; + flush = len < mss; flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST | TCP_FLAG_SYN | TCP_FLAG_FIN); |