[PATCH 4.4.y] tcp: Fix missing range_truesize enlargement in the backport

Takashi Iwai
2018-08-15T09:59:03Z

The 4.4.y stable backport dc6ae4dffd65 for the upstream commit
3d4bf93ac120 ("tcp: detect malicious patterns in
tcp_collapse_ofo_queue()") missed a line that enlarges the
range_truesize value, which broke the whole check.

Fixes: dc6ae4dffd65 ("tcp: detect malicious patterns in tcp_collapse_ofo_queue()")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

Greg, this is a fix-up specific to 4.4.y stable backport that had a
slightly different form from upstream fix. I haven't looked at the
older trees, but 4.9.y and later took the upstream fix as is, so this
patch isn't needed for them.

The patch hasn't been tested with the real test case, though; let me
know if the current code is intended. Thanks!

net/ipv4/tcp_input.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4a261e078082..9c4c6cd0316e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4835,6 +4835,7 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
end = TCP_SKB_CB(skb)->end_seq;
range_truesize = skb->truesize;
} else {
+ range_truesize += skb->truesize;
if (before(TCP_SKB_CB(skb)->seq, start))
start = TCP_SKB_CB(skb)->seq;
if (after(TCP_SKB_CB(skb)->end_seq, end))
--
2.18.0