I prepared a patch series of 3, I will send it soon.
490fac7d90caa9e987eaa0b7cbbc9c94a1a0f739 (HEAD) tcp: add sanity tests
to TCP_QUEUE_SEQ
d767f47dde2df49a8b6b7e9199e98be0e9650d6e tcp: annotate tp->write_seq
lockless reads
84a5987c38e374ea16c26cdbba9e622d86219366 tcp: annotate tp->copied_seq
lockless reads
030194a5b292bb7613407668d85af0b987bb9839 (tag: v4.19.180,
origin/linux-4.19.y) Linux 4.19.180
On Thu, Mar 11, 2021 at 7:22 PM <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
>
> The patch below does not apply to the 4.19-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> From 8811f4a9836e31c14ecdf79d9f3cb7c5d463265d Mon Sep 17 00:00:00 2001
> From: Eric Dumazet <edumazet@xxxxxxxxxx>
> Date: Mon, 1 Mar 2021 10:29:17 -0800
> Subject: [PATCH] tcp: add sanity tests to TCP_QUEUE_SEQ
>
> Qingyu Li reported a syzkaller bug where the repro
> changes RCV SEQ _after_ restoring data in the receive queue.
>
> mprotect(0x4aa000, 12288, PROT_READ) = 0
> mmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000
> mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000
> mmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000
> socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3
> setsockopt(3, SOL_TCP, TCP_REPAIR, [1], 4) = 0
> connect(3, {sa_family=AF_INET6, sin6_port=htons(0), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_scope_id=0}, 28) = 0
> setsockopt(3, SOL_TCP, TCP_REPAIR_QUEUE, [1], 4) = 0
> sendmsg(3, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="0x0000000000000003\0\0", iov_len=20}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 20
> setsockopt(3, SOL_TCP, TCP_REPAIR, [0], 4) = 0
> setsockopt(3, SOL_TCP, TCP_QUEUE_SEQ, [128], 4) = 0
> recvfrom(3, NULL, 20, 0, NULL, NULL) = -1 ECONNRESET (Connection reset by peer)
>
> syslog shows:
> [ 111.205099] TCP recvmsg seq # bug 2: copied 80, seq 0, rcvnxt 80, fl 0
> [ 111.207894] WARNING: CPU: 1 PID: 356 at net/ipv4/tcp.c:2343 tcp_recvmsg_locked+0x90e/0x29a0
>
> This should not be allowed. TCP_QUEUE_SEQ should only be used
> when queues are empty.
>
> This patch fixes this case, and the tx path as well.
>
> Fixes: ee9952831cfd ("tcp: Initial repair mode")
> Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
> Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=212005
> Reported-by: Qingyu Li <ieatmuttonchuan@xxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
>
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index dfb6f286c1de..de7cc8445ac0 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -3469,16 +3469,23 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname,
> break;
>
> case TCP_QUEUE_SEQ:
> - if (sk->sk_state != TCP_CLOSE)
> + if (sk->sk_state != TCP_CLOSE) {
> err = -EPERM;
> - else if (tp->repair_queue == TCP_SEND_QUEUE)
> - WRITE_ONCE(tp->write_seq, val);
> - else if (tp->repair_queue == TCP_RECV_QUEUE) {
> - WRITE_ONCE(tp->rcv_nxt, val);
> - WRITE_ONCE(tp->copied_seq, val);
> - }
> - else
> + } else if (tp->repair_queue == TCP_SEND_QUEUE) {
> + if (!tcp_rtx_queue_empty(sk))
> + err = -EPERM;
> + else
> + WRITE_ONCE(tp->write_seq, val);
> + } else if (tp->repair_queue == TCP_RECV_QUEUE) {
> + if (tp->rcv_nxt != tp->copied_seq) {
> + err = -EPERM;
> + } else {
> + WRITE_ONCE(tp->rcv_nxt, val);
> + WRITE_ONCE(tp->copied_seq, val);
> + }
> + } else {
> err = -EINVAL;
> + }
> break;
>
> case TCP_REPAIR_OPTIONS:
>
