From 69a5c7ca2e62072bcf2de664fdf038b64133d5d5 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 2 Nov 2016 07:53:17 -0700 Subject: tcp: fix potential memory corruption MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit ac9e70b17ecd7c6e933ff2eaf7ab37429e71bf4d ] Imagine initial value of max_skb_frags is 17, and last skb in write queue has 15 frags. Then max_skb_frags is lowered to 14 or smaller value. tcp_sendmsg() will then be allowed to add additional page frags and eventually go past MAX_SKB_FRAGS, overflowing struct skb_shared_info. Fixes: 5f74f82ea34c ("net:Add sysctl_max_skb_frags") Signed-off-by: Eric Dumazet Cc: Hans Westgaard Ry Cc: Håkon Bugge Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net') diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 036a76ba2ac2..69daa81736f6 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1212,7 +1212,7 @@ new_segment: if (!skb_can_coalesce(skb, i, pfrag->page, pfrag->offset)) { - if (i == sysctl_max_skb_frags || !sg) { + if (i >= sysctl_max_skb_frags || !sg) { tcp_mark_push(tp, skb); goto new_segment; } -- cgit v1.2.3