From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932520AbdGSR7S (ORCPT ); Wed, 19 Jul 2017 13:59:18 -0400 Received: from mail-pf0-f170.google.com ([209.85.192.170]:33737 "EHLO mail-pf0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753322AbdGSR7R (ORCPT ); Wed, 19 Jul 2017 13:59:17 -0400 From: Thomas Garnier To: Russell King , Thomas Garnier , Thomas Gleixner , Catalin Marinas , Will Deacon , Dave Martin , Chris Metcalf , Pratyush Anand , leonard.crestez@nxp.com Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [PATCH 1/3] arm/syscalls: Move address limit check in loop Date: Wed, 19 Jul 2017 10:58:58 -0700 Message-Id: <20170719175900.124074-1-thgarnie@google.com> X-Mailer: git-send-email 2.14.0.rc0.284.gd933b75aa4-goog Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The work pending loop can call set_fs after addr_limit_user_check removed the _TIF_FSCHECK flag. To prevent the infinite loop, move the addr_limit_user_check call at the beginning of the loop. Fixes: 73ac5d6a2b6a ("arm/syscalls: Check address limit on user-mode return") Reported-by: Leonard Crestez Signed-off-by: Thomas Garnier --- arch/arm/kernel/signal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 3a48b54c6405..f4574287d14b 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -573,10 +573,10 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) */ trace_hardirqs_off(); - /* Check valid user FS if needed */ - addr_limit_user_check(); - do { + /* Check valid user FS if needed */ + addr_limit_user_check(); + if (likely(thread_flags & _TIF_NEED_RESCHED)) { schedule(); } else { -- 2.14.0.rc0.284.gd933b75aa4-goog