linux-kernel - Re: [PATCHSET x86/master] add stack protector support for x86

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 Feb 2009 23:16:28 +0900
From:	Tejun Heo <tj@...nel.org>
To:	Ingo Molnar <mingo@...e.hu>
CC:	hpa@...or.com, jeremy@...p.org, tglx@...utronix.de,
	linux-kernel@...r.kernel.org, x86@...nel.org, rusty@...tcorp.com.au
Subject: Re: [PATCHSET x86/master] add stack protector support for x86_32

Tejun Heo wrote:
> Ingo Molnar wrote:
>> * Ingo Molnar <mingo@...e.hu> wrote:
>>
>>> [...] I might not get around testing it today and pushing it out into tip:master, 
>>> but i pushed out the core/percpu bits, should you queue up further changes.
>> ok, activated it for -tip testing, and there's a 64-bit build failure caused by 
>> it:
>>
>> arch/x86/kernel/head64.o: In function `x86_64_start_reservations':
>> head64.c:(.init.text+0x26): undefined reference to `__stack_chk_guard'
>> head64.c:(.init.text+0xc2): undefined reference to `__stack_chk_guard'
>> arch/x86/kernel/head64.o: In function `x86_64_start_kernel':
>> head64.c:(.init.text+0x104): undefined reference to `__stack_chk_guard'
>> head64.c:(.init.text+0x1cd): undefined reference to `__stack_chk_guard'
>> arch/x86/kernel/head.o: In function `reserve_ebda_region':
>> head.c:(.init.text+0xb): undefined reference to `__stack_chk_guard'
>> arch/x86/kernel/head.o:head.c:(.init.text+0x87): more undefined references to 
>> `__stack_chk_guard' follow
> 
> Call to __stack_chk_guard is probably generated automatically.
> Strangely, my gcc only generates calls to __stack_chk_fail.
> 
>  > gcc --version
>  gcc (SUSE Linux) 4.3.2 [gcc-4_3-branch revision 141291]
>  Copyright (C) 2008 Free Software Foundation, Inc.
>  This is free software; see the source for copying conditions.  There is NO
>  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>  > nm build/vmlinux|grep __stack_chk_
>  00000000f0fdf6cb A __crc___stack_chk_fail
>  ffffffff80d53e50 r __kcrctab___stack_chk_fail
>  ffffffff80d5ff81 r __kstrtab___stack_chk_fail
>  ffffffff80d3d140 r __ksymtab___stack_chk_fail
>  ffffffff80248619 T __stack_chk_fail
> 
> I'll try other compilers but which version are you using?  The
> difference is that before the patchset, -fno-stack-protector was
> always added whether stackprotector was enabled or not so this problem
> wasn't visible (at the cost of bogus stackprotector of course).  We'll
> probably need to add __stack_chk_guard or disable if gcc generates
> such symbol.  I'll play with different gccs.

Can't reproduce with gcc-4.1 or 4.2.  Any chance you're using distcc
w/ a build machine w/ glibc < 2.4?  __stack_chk_guard is the symbol
gcc fetches stack canary from if TLS is not supported, so somehow gcc
thought that TLS wasn't available while building head64.

Thanks.

-- 
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/