backport TCP SACK mitigation refinement

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
This commit is contained in:
Thomas Lamprecht 2019-06-27 12:59:48 +02:00
parent b2a761cbba
commit 6ba8c6bc5d

View File

@ -0,0 +1,42 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 21 Jun 2019 06:09:55 -0700
Subject: [PATCH] tcp: refine memory limit test in tcp_fragment()
tcp_fragment() might be called for skbs in the write queue.
Memory limits might have been exceeded because tcp_sendmsg() only
checks limits at full skb (64KB) boundaries.
Therefore, we need to make sure tcp_fragment() wont punish applications
that might have setup very low SO_SNDBUF values.
Fixes: f070ef2ac667 ("tcp: tcp_fragment() should apply sane memory limits")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Christoph Paasch <cpaasch@apple.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
BugLink: https://bugs.launchpad.net/bugs/1831638
CVE-2019-11478
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
net/ipv4/tcp_output.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index e471ec48dcbc..de76eb94b4d2 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1321,7 +1321,8 @@ int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
if (nsize < 0)
nsize = 0;
- if (unlikely((sk->sk_wmem_queued >> 1) > sk->sk_sndbuf)) {
+ if (unlikely((sk->sk_wmem_queued >> 1) > sk->sk_sndbuf &&
+ tcp_queue != TCP_FRAG_IN_WRITE_QUEUE)) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPWQUEUETOOBIG);
return -ENOMEM;
}