linux-kernel - Re: [PATCHv3] ARM64:Fix MINSIGSTKSZ and SIGSTKSZ

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: <6205380.pxTZSIhjca@wuerfel>
Date:	Thu, 15 Oct 2015 14:44:05 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Szabolcs Nagy <nsz@...t70.net>
Cc:	Will Deacon <will.deacon@....com>,
	Manjeet Pawar <manjeet.p@...sung.com>, catalin.marinas@....com,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-arch@...r.kernel.org, linux-api@...r.kernel.org,
	pankaj.m@...sung.com, Akhilesh Kumar <akhilesh.k@...sung.com>,
	Rohit Thapliyal <r.thapliyal@...sung.com>
Subject: Re: [PATCHv3] ARM64:Fix MINSIGSTKSZ and SIGSTKSZ

On Thursday 15 October 2015 14:12:41 Szabolcs Nagy wrote:
> * Will Deacon <will.deacon@....com> [2015-10-09 11:33:52 +0100]:
> 
> > On Fri, Oct 09, 2015 at 03:59:40PM +0530, Manjeet Pawar wrote:
> > > MINSIGSTKSZ and SIGSTKSZ for ARM64 are not correctly set in latest kernel.
> > > This patch fixes this issue.
> > > 
> > > This issue is reported in LTP (testcase: sigaltstack02.c).
> > > Testcase failed when sigaltstack() called with stack size "MINSIGSTKSZ - 1"
> > > Since in Glibc-2.22, MINSIGSTKSZ is set to 5120 but in kernel
> > > it is set to 2048 so testcase gets failed.
> > > 
> > > Testcase Output:
> > > sigaltstack02 1  TPASS  :  stgaltstack() fails, Invalid Flag value,errno:22
> > > sigaltstack02 2  TFAIL  :  sigaltstack() returned 0, expected -1,errno:12
> > 
> > I'm still unable to reproduce this failure. Is this with defconfig?
> > 
> > > Reported Issue in Glibc Bugzilla:
> > > Bugfix in Glibc-2.22: [Bug 16850]
> > > https://sourceware.org/bugzilla/show_bug.cgi?id=16850
> > > 
> > > Signed-off-by: Akhilesh Kumar <akhilesh.k@...sung.com>
> > > Signed-off-by: Manjeet Pawar <manjeet.p@...sung.com>
> > > Signed-off-by: Rohit Thapliyal <r.thapliyal@...sung.com>
> > > ---
> > > v1 -> Changes in uapi overall header
> > > v2 -> Changes done in arm64 headers
> > > v3 -> Changes done in both uapi & arm64 headers
> > > 
> > >  arch/arm64/include/uapi/asm/signal.h |    3 +++
> > >  include/uapi/asm-generic/signal.h    |    2 ++
> > >  2 files changed, 5 insertions(+)
> > 
> > Acked-by: Will Deacon <will.deacon@....com>
> > 
> > Arnd: are you planning to take this via asm-generic, or shall I queue it
> > on the arm64 fixes branch?
> > 
> 
> i just noticed this and wanted to note that an old
> glibc can fail on a new kernel with this patch if
> an application uses MINSIGSTKSZ altstack.

Well worth noting, but I think we should consider this intentional:

If an application built against an old glibc uses MINSIGSTKSZ, it
current gets random data corruption of a segmentation fault that
are both hard to track down, while a new kernel would result in
more sensible error code that is easier to debug.

	Arnd
--
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/