linux-kernel - Re: [PATCH 2/5] selftests/x86: fix vDSO selftest segfault for vsyscall=none

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: <20180211121714.GA11096@isilmar-4.linta.de>
Date:   Sun, 11 Feb 2018 13:17:14 +0100
From:   Dominik Brodowski <linux@...inikbrodowski.net>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
        x86@...nel.org, shuah@...nel.org,
        Andrew Lutomirski <luto@...nel.org>
Subject: Re: [PATCH 2/5] selftests/x86: fix vDSO selftest segfault for
 vsyscall=none

On Sun, Feb 11, 2018 at 12:21:53PM +0100, Ingo Molnar wrote:
> 
> * Dominik Brodowski <linux@...inikbrodowski.net> wrote:
> 
> > +		char name[128];
> > +		if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s",
> > +			   &start, &end, &r, &x, name) != 5)
> 
> So that's a buffer overflow waiting to happen, if a line in 'maps' gets too large, 
> right?

... as does tools/testing/selftests/x86/test_vsyscall.c already now, right?
Will fix both up with an additional patch.

But a more generic question: Is there a quick, easy but reliable test
available in userspace to determine whether
	int $0x80
	vsyscall
is available on a given system, or will cause a segfault?

Thanks,
	Dominik