From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754331Ab2IQAvH (ORCPT ); Sun, 16 Sep 2012 20:51:07 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33488 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753157Ab2IQAtu (ORCPT ); Sun, 16 Sep 2012 20:49:50 -0400 Message-Id: <20120917003642.815668331@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 17 Sep 2012 01:38:25 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Will Deacon , Russell King Subject: [ 120/135] ARM: 7526/1: traps: send SIGILL if get_user fails on undef handling path In-Reply-To: <20120917003625.784119135@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon commit 2b2040af0b64cd93e5d4df2494c4486cf604090d upstream. get_user may fail to load from the provided __user address due to an unhandled fault generated by the access. In the case of the undefined instruction trap, this results in failure to load the faulting instruction, in which case we should send SIGILL to the task rather than continue with potentially uninitialised data. Signed-off-by: Will Deacon Signed-off-by: Russell King Signed-off-by: Ben Hutchings --- arch/arm/kernel/traps.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index f794521..b0179b8 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -420,20 +420,23 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) #endif instr = *(u32 *) pc; } else if (thumb_mode(regs)) { - get_user(instr, (u16 __user *)pc); + if (get_user(instr, (u16 __user *)pc)) + goto die_sig; if (is_wide_instruction(instr)) { unsigned int instr2; - get_user(instr2, (u16 __user *)pc+1); + if (get_user(instr2, (u16 __user *)pc+1)) + goto die_sig; instr <<= 16; instr |= instr2; } - } else { - get_user(instr, (u32 __user *)pc); + } else if (get_user(instr, (u32 __user *)pc)) { + goto die_sig; } if (call_undef_hook(regs, instr) == 0) return; +die_sig: #ifdef CONFIG_DEBUG_USER if (user_debug & UDBG_UNDEFINED) { printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",