lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:   Thu, 16 Jan 2020 18:59:04 -0800
From:   Eric Dumazet <edumazet@...gle.com>
To:     "Li,Rongqing" <lirongqing@...du.com>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [RFC] tcp: remove BUG_ON in tcp_shifted_skb

On Thu, Jan 16, 2020 at 6:03 PM Li,Rongqing <lirongqing@...du.com> wrote:
>
> I think this BUG_ON in tcp_shifted_skb maybe be triggered if a GSO skb is
> sacked, but sack is faked, and not ack the whole mss length, only ack less
> than mss length
>
> Is it possible ?

I doubt it. Please provide a packetdrill test if you think otherwise.

>
> - Li RongQing <lirongqing@...du.com>
>
> ---
>  net/ipv4/tcp_input.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 1d1e3493965f..141bc85092b5 100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -1327,7 +1327,8 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *prev,
>         TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS);
>
>         if (skb->len > 0) {
> -               BUG_ON(!tcp_skb_pcount(skb));

I understand people can be worried about BUG_ON(), but they serve to
spot bugs when a patch breaks something horribly.

Powered by blists - more mailing lists