tcp: refine memory limit test in tcp_fragment()

commit b6653b3 upstream. 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: f070ef2 ("tcp: tcp_fragment() should apply sane memory limits") Signed-off-by: Eric Dumazet <[email protected]> Reported-by: Christoph Paasch <[email protected]> Tested-by: Christoph Paasch <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
GalliumOS · Jun 27, 2019 · caa51ed · caa51ed
1 parent 72f67fd
commit caa51ed
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
@@ -1185,7 +1185,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
 	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 + 0x20000)) {
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPWQUEUETOOBIG);
 		return -ENOMEM;
 	}