From 3c05d92ed49f644d1f5a960fa48637d63b946016 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 14 Sep 2005 20:50:35 -0700 Subject: [PATCH] [TCP]: Compute in_sacked properly when we split up a TSO frame. The problem is that the SACK fragmenting code may incorrectly call tcp_fragment() with a length larger than the skb->len. This happens when the skb on the transmit queue completely falls to the LHS of the SACK. And add a BUG() check to tcp_fragment() so we can spot this kind of error more quickly in the future. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 16 +++++++++------- net/ipv4/tcp_output.c | 2 ++ 2 files changed, 11 insertions(+), 7 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 29222b9649..a7537c7bbd 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -979,14 +979,19 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ if (!before(TCP_SKB_CB(skb)->seq, end_seq)) break; + in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) && + !before(end_seq, TCP_SKB_CB(skb)->end_seq); + pcount = tcp_skb_pcount(skb); - if (pcount > 1 && - (after(start_seq, TCP_SKB_CB(skb)->seq) || - before(end_seq, TCP_SKB_CB(skb)->end_seq))) { + if (pcount > 1 && !in_sack && + after(TCP_SKB_CB(skb)->end_seq, start_seq)) { unsigned int pkt_len; - if (after(start_seq, TCP_SKB_CB(skb)->seq)) + in_sack = !after(start_seq, + TCP_SKB_CB(skb)->seq); + + if (!in_sack) pkt_len = (start_seq - TCP_SKB_CB(skb)->seq); else @@ -999,9 +1004,6 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ fack_count += pcount; - in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) && - !before(end_seq, TCP_SKB_CB(skb)->end_seq); - sacked = TCP_SKB_CB(skb)->sacked; /* Account D-SACK for retransmitted packet. */ diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index c10e4435e3..b018e31b65 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -435,6 +435,8 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss int nsize, old_factor; u16 flags; + BUG_ON(len >= skb->len); + nsize = skb_headlen(skb) - len; if (nsize < 0) nsize = 0; -- 2.39.5