blob: e9817f9e8ca2daf3b97f1fb7494c3b57bcd100fc [file] [log] [blame]
From f0b3eb493bf21fdddb7a5382e85ccec784d6314f Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 18 Mar 2020 19:21:02 -0700
Subject: [PATCH] tcp: repair: fix TCP_QUEUE_SEQ implementation
commit 6cd6cbf593bfa3ae6fc3ed34ac21da4d35045425 upstream.
When application uses TCP_QUEUE_SEQ socket option to
change tp->rcv_next, we must also update tp->copied_seq.
Otherwise, stuff relying on tcp_inq() being precise can
eventually be confused.
For example, tcp_zerocopy_receive() might crash because
it does not expect tcp_recv_skb() to return NULL.
We could add tests in various places to fix the issue,
or simply make sure tcp_inq() wont return a random value,
and leave fast path as it is.
Note that this fixes ioctl(fd, SIOCINQ, &val) at the same
time.
Fixes: ee9952831cfd ("tcp: Initial repair mode")
Fixes: 05255b823a61 ("tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 2abb74276ef9..cea071def651 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2918,8 +2918,10 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
err = -EPERM;
else if (tp->repair_queue == TCP_SEND_QUEUE)
WRITE_ONCE(tp->write_seq, val);
- else if (tp->repair_queue == TCP_RECV_QUEUE)
+ else if (tp->repair_queue == TCP_RECV_QUEUE) {
WRITE_ONCE(tp->rcv_nxt, val);
+ WRITE_ONCE(tp->copied_seq, val);
+ }
else
err = -EINVAL;
break;
--
2.7.4