From: Eric Dumazet <edumazet@google.com> stable inclusion from stable-v6.6.41 commit b75f281bddebdcf363884f0d53c562366e9ead99 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAD4B4 CVE: CVE-2024-41007 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... --------------------------- commit 36534d3c54537bf098224a32dc31397793d4594d upstream. Due to timer wheel implementation, a timer will usually fire after its schedule. For instance, for HZ=1000, a timeout between 512ms and 4s has a granularity of 64ms. For this range of values, the extra delay could be up to 63ms. For TCP, this means that tp->rcv_tstamp may be after inet_csk(sk)->icsk_timeout whenever the timer interrupt finally triggers, if one packet came during the extra delay. We need to make sure tcp_rtx_probe0_timed_out() handles this case. Fixes: e89688e3e978 ("net: tcp: fix unexcepted socket die when snd_wnd is 0") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Menglong Dong <imagedong@tencent.com> Acked-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Link: https://lore.kernel.org/r/20240607125652.1472540-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> --- net/ipv4/tcp_timer.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 984ab4a0421e..a92ddcb22d57 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -459,8 +459,13 @@ static bool tcp_rtx_probe0_timed_out(const struct sock *sk, { const struct tcp_sock *tp = tcp_sk(sk); const int timeout = TCP_RTO_MAX * 2; - u32 rcv_delta, rtx_delta; + u32 rtx_delta; + s32 rcv_delta; + /* Note: timer interrupt might have been delayed by at least one jiffy, + * and tp->rcv_tstamp might very well have been written recently. + * rcv_delta can thus be negative. + */ rcv_delta = inet_csk(sk)->icsk_timeout - tp->rcv_tstamp; if (rcv_delta <= timeout) return false; -- 2.34.1