Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756220AbaFPVtZ (ORCPT ); Mon, 16 Jun 2014 17:49:25 -0400 Received: from terminus.zytor.com ([198.137.202.10]:53582 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756148AbaFPVtX (ORCPT ); Mon, 16 Jun 2014 17:49:23 -0400 Message-ID: <539F6646.4040605@zytor.com> Date: Mon, 16 Jun 2014 14:48:54 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Andy Lutomirski , Richard Weinberger , X86 ML CC: =?UTF-8?B?VG9yYWxmIEbDtnJzdGVy?= , Eric Paris , Linux Kernel Subject: Re: 3.15: kernel BUG at kernel/auditsc.c:1525! References: <539F1C59.6070308@gmx.de> <539F297F.7010904@nod.at> <539F2B2D.6050105@gmx.de> <539F3077.7040005@gmx.de> <539F35A0.2050002@gmx.de> <539F567F.2050802@gmx.de> <539F5702.5050104@nod.at> In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/16/2014 02:35 PM, Andy Lutomirski wrote: > > To hpa, etc: It appears that entry_32.S is missing any call to the > audit exit hook on the badsys path. If I'm diagnosing this bug report > correctly, this causes OOPSes. > > The the world at large: it's increasingly apparent that no one (except > maybe the blackhats) has ever scrutinized the syscall auditing code. > This is two old severe bugs in the code that have probably been there > for a long time. > Yes, the audit code is a total mess. > The bad syscall nr paths are their own incomprehensible route > through the entry control flow. Rearrange them to work just like > syscalls that return -ENOSYS. I have to admit... it sort of lends itself to a solution like this: /* For the 64-bit case, analogous code for 32 bits */ movl $__NR_syscall_max+1,%ecx # *Not* __NR_syscall_max cmpq %rcx,%rax cmovae %rcx,%rax movq %r10,%rcx call *sys_call_table(,%rax,8) ... and having an extra (invalid) system call slot in the syscall table beyond the end instead of branching off separately. (Note: we could use either cmova or cmovae, and either the 32- or 64-bit form... the reason why is left as an exercise to the reader.) -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/