From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-by2nam03on0127.outbound.protection.outlook.com ([104.47.42.127]:45712 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S966182AbeCHFFP (ORCPT ); Thu, 8 Mar 2018 00:05:15 -0500 From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Masami Hiramatsu , Ananth N Mavinakayanahalli , Andrey Ryabinin , Anil S Keshavamurthy , Borislav Petkov , Brian Gerst , "David S . Miller" , Denys Vlasenko , "H . Peter Anvin" , Josh Poimboeuf , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ye Xiaolong , Ingo Molnar , Sasha Levin Subject: [PATCH AUTOSEL for 4.4 007/101] kprobes/x86: Fix kprobe-booster not to boost far call instructions Date: Thu, 8 Mar 2018 05:01:11 +0000 Message-ID: <20180308050023.8548-7-alexander.levin@microsoft.com> References: <20180308050023.8548-1-alexander.levin@microsoft.com> In-Reply-To: <20180308050023.8548-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Masami Hiramatsu [ Upstream commit bd0b90676c30fe640e7ead919b3e38846ac88ab7 ] Fix the kprobe-booster not to boost far call instruction, because a call may store the address in the single-step execution buffer to the stack, which should be modified after single stepping. Currently, this instruction will be filtered as not boostable in resume_execution(), so this is not a critical issue. Signed-off-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Andrey Ryabinin Cc: Anil S Keshavamurthy Cc: Borislav Petkov Cc: Brian Gerst Cc: David S . Miller Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ye Xiaolong Link: http://lkml.kernel.org/r/149076340615.22469.14066273186134229909.stgi= t@devbox Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- arch/x86/kernel/kprobes/core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.= c index 99d293ea2b49..5d11d01f75de 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -196,6 +196,8 @@ int can_boost(kprobe_opcode_t *opcodes, void *addr) return (opcode !=3D 0x62 && opcode !=3D 0x67); case 0x70: return 0; /* can't boost conditional jump */ + case 0x90: + return opcode !=3D 0x9a; /* can't boost call far */ case 0xc0: /* can't boost software-interruptions */ return (0xc1 < opcode && opcode < 0xcc) || opcode =3D=3D 0xcf; --=20 2.14.1