linux-kernel - Re: [PATCH v2 3/3] pppoatm: protect against freeing of vcc

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

Message-Id: <201211300138.qAU1c8sE003388@thirdoffive.cmf.nrl.navy.mil>
Date:	Thu, 29 Nov 2012 20:38:08 -0500
From:	"Chas Williams (CONTRACTOR)" <chas@....nrl.navy.mil>
To:	David Woodhouse <dwmw2@...radead.org>
cc:	Krzysztof Mazur <krzysiek@...lesie.net>,
	David Laight <David.Laight@...LAB.COM>, davem@...emloft.net,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	nathan@...verse.com.au
Subject: Re: [PATCH v2 3/3] pppoatm: protect against freeing of vcc

In message <1354227428.21562.230.camel@...nybook.infradead.org>,David Woodhouse writes:
>At this point, I think we're better off as we are (with Krzysztof's
>patch 1/7 dropped, and leaving vcc->dev->ops->close() being called
>before vcc->push(NULL). We've fairly much solved the issues with that
>arrangement, by checking ATM_VF_READY in the protocols' ->push()
>functions.

it isnt clear to me that fixes the race entirely either.
vcc_destroy_socket() and any of the push()/sends()'s are not serialized.
while you may clear the ATM_VF_READY flag, you might not clear it soon
enough for any particular push() that is already running.  so it still
seems like you are racing close() against push() at this point.  the
window is greatly reduced, but it still exists.
--
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/