From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64AE2C71122 for ; Sun, 14 Oct 2018 15:54:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 382A820645 for ; Sun, 14 Oct 2018 15:54:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 382A820645 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727834AbeJNXL4 (ORCPT ); Sun, 14 Oct 2018 19:11:56 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36021 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727669AbeJNXLy (ORCPT ); Sun, 14 Oct 2018 19:11:54 -0400 Received: from [2a02:8011:400e:2:cbab:f00:c93f:614] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1gBiLh-0004cH-TS; Sun, 14 Oct 2018 16:30:34 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gBiLa-0000jg-HC; Sun, 14 Oct 2018 16:30:26 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Masami Hiramatsu" , "Russell King" Date: Sun, 14 Oct 2018 16:25:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 338/366] ARM: 8772/1: kprobes: Prohibit kprobes on get_user functions In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:cbab:f00:c93f:614 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Masami Hiramatsu commit 0d73c3f8e7f6ee2aab1bb350f60c180f5ae21a2c upstream. Since do_undefinstr() uses get_user to get the undefined instruction, it can be called before kprobes processes recursive check. This can cause an infinit recursive exception. Prohibit probing on get_user functions. Fixes: 24ba613c9d6c ("ARM kprobes: core code") Signed-off-by: Masami Hiramatsu Signed-off-by: Russell King [bwh: Backported to 3.16: Drop changes to __get_user_{8,32_t_8,64t_{1,2,4}}] Signed-off-by: Ben Hutchings --- --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -425,4 +425,14 @@ THUMB( orr \reg , \reg , #PSR_T_BIT ) #endif .endm +#ifdef CONFIG_KPROBES +#define _ASM_NOKPROBE(entry) \ + .pushsection "_kprobe_blacklist", "aw" ; \ + .balign 4 ; \ + .long entry; \ + .popsection +#else +#define _ASM_NOKPROBE(entry) +#endif + #endif /* __ASM_ASSEMBLER_H__ */ --- a/arch/arm/lib/getuser.S +++ b/arch/arm/lib/getuser.S @@ -38,6 +38,7 @@ ENTRY(__get_user_1) mov r0, #0 mov pc, lr ENDPROC(__get_user_1) +_ASM_NOKPROBE(__get_user_1) ENTRY(__get_user_2) check_uaccess r0, 2, r1, r2, __get_user_bad @@ -58,6 +59,7 @@ rb .req r0 mov r0, #0 mov pc, lr ENDPROC(__get_user_2) +_ASM_NOKPROBE(__get_user_2) ENTRY(__get_user_4) check_uaccess r0, 4, r1, r2, __get_user_bad @@ -65,12 +67,14 @@ ENTRY(__get_user_4) mov r0, #0 mov pc, lr ENDPROC(__get_user_4) +_ASM_NOKPROBE(__get_user_4) __get_user_bad: mov r2, #0 mov r0, #-EFAULT mov pc, lr ENDPROC(__get_user_bad) +_ASM_NOKPROBE(__get_user_bad) .pushsection __ex_table, "a" .long 1b, __get_user_bad