From: Andi Kleen <ak@suse.de>
To: Willy Tarreau <w@1wt.eu>
Cc: marcelo@kvack.org, linux-kernel@vger.kernel.org, pageexec@freemail.hu
Subject: Re: [PATCH] x86_64: another fix for canonical RIPs during signal handling
Date: Fri, 23 Jun 2006 00:17:35 +0200 [thread overview]
Message-ID: <200606230017.35668.ak@suse.de> (raw)
In-Reply-To: <20060622213313.GA22611@1wt.eu>
> What I understand from this is if code is mapped at 0 (eg by mmap(PROT_EXEC)),
> it would get executed instead of the program being killed. Although I don't
> see how this could be exploited to gain any privileges, I wonder if it can
> cause a process to loop indefinitely instead of being killed or nasty things
> like this. May be this is a stupid analysis from me, so I hope that PaX Team
> will have more precise info.
When you can inject a non canonical RIP into the stack frame you can likely
also inject other RIPs. So the whole thing is just a funny way for a program to
jump in its address space. 0 is as good as any other address for this.
The whole point of the check is just to protect the kernel/CPU against this.
What happens to the user space program itself is no concern because it is the program's
own doing.
-Andi
next prev parent reply other threads:[~2006-06-22 22:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-22 21:06 [PATCH] x86_64: another fix for canonical RIPs during signal handling Willy Tarreau
2006-06-22 21:26 ` Andi Kleen
2006-06-22 21:33 ` Willy Tarreau
2006-06-22 22:17 ` Andi Kleen [this message]
[not found] ` <449BC808.4174.277D15CF@pageexec.freemail.hu>
2006-06-23 12:29 ` Andi Kleen
[not found] ` <449C0616.4382.286F7C8C@pageexec.freemail.hu>
2006-06-23 13:32 ` Willy Tarreau
2006-06-23 13:46 ` Andi Kleen
2006-06-23 13:52 ` Willy Tarreau
2006-06-23 14:51 ` Alan Cox
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