From: Eric Dumazet edumazet@google.com
[ Upstream commit 6cd6cbf593bfa3ae6fc3ed34ac21da4d35045425 ]
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: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/tcp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2870,8 +2870,10 @@ static int do_tcp_setsockopt(struct sock err = -EPERM; else if (tp->repair_queue == TCP_SEND_QUEUE) 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;