From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755204Ab2KIS3H (ORCPT ); Fri, 9 Nov 2012 13:29:07 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33493 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754622Ab2KIS3E (ORCPT ); Fri, 9 Nov 2012 13:29:04 -0500 Date: Fri, 9 Nov 2012 19:29:43 +0100 From: Oleg Nesterov To: Frederic Weisbecker , Ingo Molnar , Peter Zijlstra Cc: Amnon Shiloh , linux-kernel@vger.kernel.org Subject: [PATCH] arch_check_bp_in_kernelspace: fix the range check Message-ID: <20121109182943.GA2789@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org arch_check_bp_in_kernelspace() tries to avoid the overflow and does 2 TASK_SIZE checks but it needs OR, not AND. Consider va = TASK_SIZE -1 and len = 2 case. Note: TASK_SIZE doesn't look right at least on x86, I think it should be replaced by TASK_SIZE_MAX. Signed-off-by: Oleg Nesterov --- x/arch/arm64/kernel/hw_breakpoint.c +++ x/arch/arm64/kernel/hw_breakpoint.c @@ -293,7 +293,7 @@ int arch_check_bp_in_kernelspace(struct va = info->address; len = get_hbp_len(info->ctrl.len); - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); + return (va >= TASK_SIZE) || ((va + len - 1) >= TASK_SIZE); } /* --- x/arch/arm/kernel/hw_breakpoint.c +++ x/arch/arm/kernel/hw_breakpoint.c @@ -464,7 +464,7 @@ int arch_check_bp_in_kernelspace(struct va = info->address; len = get_hbp_len(info->ctrl.len); - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); + return (va >= TASK_SIZE) || ((va + len - 1) >= TASK_SIZE); } /* --- x/arch/sh/kernel/hw_breakpoint.c +++ x/arch/sh/kernel/hw_breakpoint.c @@ -132,7 +132,7 @@ int arch_check_bp_in_kernelspace(struct va = info->address; len = get_hbp_len(info->len); - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); + return (va >= TASK_SIZE) || ((va + len - 1) >= TASK_SIZE); } int arch_bp_generic_fields(int sh_len, int sh_type, --- x/arch/x86/kernel/hw_breakpoint.c +++ x/arch/x86/kernel/hw_breakpoint.c @@ -200,7 +200,7 @@ int arch_check_bp_in_kernelspace(struct va = info->address; len = get_hbp_len(info->len); - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); + return (va >= TASK_SIZE) || ((va + len - 1) >= TASK_SIZE); } int arch_bp_generic_fields(int x86_len, int x86_type,