From: Al Viro <viro@ZenIV.linux.org.uk>
To: Chris Metcalf <cmetcalf@tilera.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: situation with signals
Date: Thu, 28 Oct 2010 00:30:12 +0100 [thread overview]
Message-ID: <20101027233012.GJ19804@ZenIV.linux.org.uk> (raw)
In-Reply-To: <4CC8ACE0.1040407@tilera.com>
On Wed, Oct 27, 2010 at 06:51:12PM -0400, Chris Metcalf wrote:
> > BTW, is everything in your pt_regs safe to modify?
>
> What an interesting observation. :-) In fact, it would be possible to
> overwrite the privilege level (the ex1 register) from within the signal
> handler and then return to run arbitrary code at kernel PL. I'll fix it.
Then you need to be careful with that in your ptrace as well (POKEUSR and
SETREGS).
next prev parent reply other threads:[~2010-10-27 23:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-23 22:11 situation with signals Al Viro
2010-09-24 13:33 ` Arnd Bergmann
[not found] ` <9lYpY1#WLHA.1516@exchange1.tad.internal.tilera.com>
2010-10-27 21:02 ` Chris Metcalf
2010-10-27 21:37 ` Al Viro
2010-10-27 22:51 ` Chris Metcalf
2010-10-27 23:30 ` Al Viro [this message]
2010-10-28 19:47 ` [PATCH] arch/tile: don't allow user code to set the PL via ptrace or signal return Chris Metcalf
2010-10-28 19:03 ` [PATCH] arch/tile: correct double syscall restart for nested signals Chris Metcalf
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