netdev - Re: [PATCH] tcp: really ignore MSG_ZEROCOPY if no SO

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <20180907.231142.274109264940766007.davem@davemloft.net>
Date:   Fri, 07 Sep 2018 23:11:42 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     vincent.whitchurch@...s.com
Cc:     netdev@...r.kernel.org, willemb@...gle.com, rabinv@...s.com
Subject: Re: [PATCH] tcp: really ignore MSG_ZEROCOPY if no SO_ZEROCOPY

From: Vincent Whitchurch <vincent.whitchurch@...s.com>
Date: Thu,  6 Sep 2018 15:54:59 +0200

> According to the documentation in msg_zerocopy.rst, the SO_ZEROCOPY
> flag was introduced because send(2) ignores unknown message flags and
> any legacy application which was accidentally passing the equivalent of
> MSG_ZEROCOPY earlier should not see any new behaviour.
> 
> Before commit f214f915e7db ("tcp: enable MSG_ZEROCOPY"), a send(2) call
> which passed the equivalent of MSG_ZEROCOPY without setting SO_ZEROCOPY
> would succeed.  However, after that commit, it fails with -ENOBUFS.  So
> it appears that the SO_ZEROCOPY flag fails to fulfill its intended
> purpose.  Fix it.
> 
> Fixes: f214f915e7db ("tcp: enable MSG_ZEROCOPY")
> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@...s.com>

Applied and queued up for -stable, thanks.