netdev - Re: [PATCH] net: Fix security_socket

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:	Thu, 4 Aug 2011 22:56:15 +1000
From:	Anton Blanchard <anton@...ba.org>
To:	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Cc:	davem@...emloft.net, eparis@...isplace.org, casey@...aufler-ca.com,
	mjt@....msk.ru, netdev@...r.kernel.org,
	linux-security-module@...r.kernel.org
Subject: Re: [PATCH] net: Fix security_socket_sendmsg() bypass problem.


Hi,

> > [PATCH] net: Cap number of elements for recvmmsg and sendmmsg
> > 
> > To limit the amount of time we can spend in recvmmsg and sendmmsg,
> > cap the number of elements to UIO_MAXIOV (currently 1024).
> 
> Looks reasonable value. But it will return less than requested
> without setting error code. Programmers would needlessly call
> getsockopt(SO_ERROR) and get 0. Maybe -EINVAL or something is better
> than returning less than requested?

Having to call getsockopt(SO_ERROR) at all is confusing. We should
change sendmmsg to only return an error if no messages are sent. If we
do this, then the application will have already have to handle the case
where we send less messages than requested.

Returning EINVAL adds complexity to the system call that I think we
should avoid. Will send out the patches for review after some sleep.

Anton
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html