From: jonathan@jonmasters•org (Jon Masters)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: Fix restoration of IP scratch register when auditing syscalls
Date: Wed, 02 May 2012 02:22:08 -0400 [thread overview]
Message-ID: <4FA0D290.90300@jonmasters.org> (raw)
In-Reply-To: <20120430100746.GA11080@mudshark.cambridge.arm.com>
Hi will,
First, for the record, I want to note that I had an actual nightmare
about this last night. Woke up at 5am in a cold sweat with a fear that
"register 12" was out to get me (WTF?). I am *not* joking... ;)
On 04/30/2012 06:07 AM, Will Deacon wrote:
>> The fix is simply to have an additional out when not ptracing.
I retract that. The way to avoid trashing userspace is to do that. But
now that this is identified, I've spent some quality time reading the
audit code and I now even understand what it's trying to do :)
> Actually, I don't understand why we have to update pt_regs so early given
> that I don't think the saved ip is used by audit_syscall_{entry,exit} at
> all. Perhaps we could just move the ip manipulation until after the thread
> flag checks [completely untested patch below]?
Yea. There's no reason I can see to include the IP there, even for the
mach-specific macros we'll use later to pull stuff out of regs (e.g.
regs_return_value, or r0 to its friends). Your patch boots on my test
system running auditd, and more to the point - paraphrasing what Russell
said - the existing code wasn't exactly the best there, since it wants
to use "why" (set in common) and not ip as a conditional.
Ship it. Or er, I dunno, perhaps:
Reported-by: Jon Masters <jcm@jonmasters•org>
Tested-by: Jon Masters <jcm@jonmasters•org>
(or whatever else you want to shove in there for my signoff)
Jon.
prev parent reply other threads:[~2012-05-02 6:22 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-29 6:38 Fixing audit on ARM Jon Masters
2012-04-29 6:38 ` [PATCH] ARM: Fix restoration of IP scratch register when auditing syscalls Jon Masters
2012-04-30 10:07 ` Will Deacon
2012-04-30 18:55 ` Jon Masters
2012-05-01 11:07 ` Will Deacon
2012-05-01 11:37 ` Russell King - ARM Linux
2012-05-01 16:52 ` Jon Masters
2012-05-02 6:27 ` Jon Masters
2012-05-02 8:58 ` Will Deacon
2012-05-02 14:10 ` Jon Masters
2012-05-02 14:48 ` Eric Paris
2012-05-02 15:39 ` Will Deacon
2012-05-02 17:37 ` Jon Masters
2012-04-30 19:00 ` Russell King - ARM Linux
2012-05-03 2:59 ` Jon Masters
2012-05-03 3:03 ` Al Viro
2012-05-03 8:55 ` Will Deacon
2012-05-03 7:34 ` Russell King - ARM Linux
2012-05-02 6:22 ` Jon Masters [this message]
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