netdev - Re: [Bugme-new] [Bug 33502] New: Caught 64-bit read from uninitialized memory in __alloc

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]

Date:	Tue, 10 May 2011 19:14:42 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Christoph Lameter <cl@...ux.com>
Cc:	Vegard Nossum <vegardno@....uio.no>,
	Pekka Enberg <penberg@...helsinki.fi>,
	casteyde.christian@...e.fr,
	Andrew Morton <akpm@...ux-foundation.org>,
	netdev@...r.kernel.org, bugzilla-daemon@...zilla.kernel.org,
	bugme-daemon@...zilla.kernel.org
Subject: Re: [Bugme-new] [Bug 33502] New: Caught 64-bit read from
 uninitialized memory in __alloc_skb

Le mardi 10 mai 2011 à 11:39 -0500, Christoph Lameter a écrit :

> #ifdef CONFIG_DEBUG_PAGE_ALLOC
> 	if (illegal_page_alloc-address(object))
> 		goto redo;
> #endif
> 
> before the cmpxchg should do the trick.
> 

Again, it wont work...

You can have an IRQ right after the check and before cmpxchg

This interrupt can allocate this block of memory, free it, and unmap
page from memory.

cmpxchg() reads unmapped memory -> BUG



--
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