Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759007AbYBRK0x (ORCPT ); Mon, 18 Feb 2008 05:26:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752686AbYBRK0q (ORCPT ); Mon, 18 Feb 2008 05:26:46 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:64050 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752597AbYBRK0p (ORCPT ); Mon, 18 Feb 2008 05:26:45 -0500 Message-ID: <47B95CF9.60005@cn.fujitsu.com> Date: Mon, 18 Feb 2008 18:24:57 +0800 From: Shi Weihua User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Ingo Molnar CC: linux-kernel@vger.kernel.org, Thomas Gleixner , "H. Peter Anvin" Subject: [PATCH 2/5] signal(x86_64): add a signal stack overflow check Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1371 Lines: 38 The similar check has been added to x86_32(i386) in commit id 83bd01024b1fdfc41d9b758e5669e80fca72df66. So we add this check to x86_64 and improve it a liitle bit in that we need to check for stack overflow only when the signal is on stack. Signed-off-by: Shi Weihua --- --- linux-2.6.25-rc2.orig/arch/x86/kernel/signal_64.c 2008-02-16 04:57:20.000000000 +0800 +++ linux-2.6.25-rc2/arch/x86/kernel/signal_64.c 2008-02-18 18:06:48.000000000 +0800 @@ -205,8 +205,19 @@ get_stack(struct k_sigaction *ka, struct /* This is the X/Open sanctioned signal stack switching. */ if (ka->sa.sa_flags & SA_ONSTACK) { - if (sas_ss_flags(sp) == 0) + int onstack = sas_ss_flags(sp); + + if (onstack == 0) sp = current->sas_ss_sp + current->sas_ss_size; + else if (onstack == SS_ONSTACK) { + /* + * If we are on the alternate signal stack and would + * overflow it, don't return an always-bogus address + * instead so we will die with SIGSEGV. + */ + if (!likely(on_sig_stack(sp - size))) + return (void __user *) -1L; + } } return (void __user *)round_down(sp - size, 16); -- 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/