linux-kernel - Re: [PATCH] tcp: fix MSG_SENDPAGE

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 linux-cve-announce 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:	Sun, 06 Jan 2013 20:59:39 -0800 (PST)
From:	David Miller <davem@...emloft.net>
To:	eric.dumazet@...il.com
Cc:	w@....eu, netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tcp: fix MSG_SENDPAGE_NOTLAST logic

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Sun, 06 Jan 2013 20:21:49 -0800

> From: Eric Dumazet <edumazet@...gle.com>
> 
> commit 35f9c09fe9c72e (tcp: tcp_sendpages() should call tcp_push() once)
> added an internal flag : MSG_SENDPAGE_NOTLAST meant to be set on all
> frags but the last one for a splice() call.
> 
> The condition used to set the flag in pipe_to_sendpage() relied on
> splice() user passing the exact number of bytes present in the pipe,
> or a smaller one.
> 
> But some programs pass an arbitrary high value, and the test fails.
> 
> The effect of this bug is a lack of tcp_push() at the end of a
> splice(pipe -> socket) call, and possibly very slow or erratic TCP
> sessions.
> 
> We should both test sd->total_len and fact that another fragment
> is in the pipe (pipe->nrbufs > 1)
> 
> Many thanks to Willy for providing very clear bug report, bisection
> and test programs.
> 
> Reported-by: Willy Tarreau <w@....eu>
> Bisected-by: Willy Tarreau <w@....eu>
> Tested-by: Willy Tarreau <w@....eu>
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>

Applied and queued up for -stable, thanks everyone.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/