linux-kernel - Re: [PATCH] x86, signals: add missing signal

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: <20160520070559.GA4003@gmail.com>
Date:	Fri, 20 May 2016 09:05:59 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Dave Hansen <dave@...1.net>
Cc:	linux-kernel@...r.kernel.org, dave.hansen@...ux.intel.com,
	tony.luck@...el.com, bp@...en8.de, linux-edac@...r.kernel.org,
	x86@...nel.org, luto@...nel.org
Subject: Re: [PATCH] x86, signals: add missing signal_compat code for x86
 features


* Dave Hansen <dave@...1.net> wrote:

> Sending this out early so folks can have a look.  I haven't let
> it run through a full set of tests, so buyer beware, but it would
> have a hard time hurting anything other than the already-broken
> 32-bit compat signal code.
> 
> ---
> 
> From: Dave Hansen <dave.hansen@...ux.intel.com>
> 
> The 32-bit siginfo is a different binary format than the 64-bit
> one.  So, when running 32-bit binaries on 64-bit kernels, we have
> to convert the kernel's 64-bit version to a 32-bit version that
> userspace can grok.
> 
> We've added a few features to siginfo over the past few years and
> neglected to add them to arch/x86/kernel/signal_compat.c:
> 
>    1. The si_addr_lsb used in SIGBUS's sent for machine checks
>    2. The upper/lower bounds for MPX SIGSEGV faults
>    3. The protection key for pkey faults
> 
> I caught this with some protection keys unit tests and realized
> it affected a few more features.

Hm, while fixing this, could we please also add individual unit tests to 
tools/testing/selftests/x86/, and also structure the code in a fashion or add a 
comment or so to make sure future extensions add both a compat handler and a unit 
test as well?

I.e. perhaps do a (build time) fixed-size check of siginfo structure in the compat 
code, and break the build if that check has not been updated? Or something like 
that.

Thanks,

	Ingo