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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 322E3C433EF for ; Fri, 13 May 2022 14:29:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380965AbiEMO3Q (ORCPT ); Fri, 13 May 2022 10:29:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381108AbiEMO0i (ORCPT ); Fri, 13 May 2022 10:26:38 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61C0750B1C; Fri, 13 May 2022 07:26:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1D0A1B8305B; Fri, 13 May 2022 14:26:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 432FDC34100; Fri, 13 May 2022 14:26:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652451994; bh=arJTKN6Rb4CHGdT1xDXtM3SZJ76Ck5SXwxLc4XVG6h0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Lkj2UAFs1vyUgNw/OznDpD3UdBVqNE8K6RAGjcXiZQCZEK2nLckNHvZ2JSX7w9XQR 2zCCsajBmD87WM3JZKnp+P4hwCHqObdQNspqV1ZZhhbcwPjJchztmAo7B1qVwi83FN 5d/y+2eEEMXvBV1OgINjBSgL470b4SpjEs26yluY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Masami Hiramatsu , "Peter Zijlstra (Intel)" , Juergen Gross , x86@kernel.org, Boris Ostrovsky , Ingo Molnar , Stefano Stabellini , Andrew Cooper , Borislav Petkov , xen-devel@lists.xenproject.org, Randy Dunlap , Josh Poimboeuf , Maximilian Heyne Subject: [PATCH 5.4 13/18] x86: kprobes: Prohibit probing on instruction which has emulate prefix Date: Fri, 13 May 2022 16:23:39 +0200 Message-Id: <20220513142229.541060503@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220513142229.153291230@linuxfoundation.org> References: <20220513142229.153291230@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Masami Hiramatsu commit 004e8dce9c5595697951f7cd0e9f66b35c92265e upstream. Prohibit probing on instruction which has XEN_EMULATE_PREFIX or KVM's emulate prefix. Since that prefix is a marker for Xen and KVM, if we modify the marker by kprobe's int3, that doesn't work as expected. Signed-off-by: Masami Hiramatsu Signed-off-by: Peter Zijlstra (Intel) Cc: Juergen Gross Cc: x86@kernel.org Cc: Boris Ostrovsky Cc: Ingo Molnar Cc: Stefano Stabellini Cc: Andrew Cooper Cc: Borislav Petkov Cc: xen-devel@lists.xenproject.org Cc: Randy Dunlap Cc: Josh Poimboeuf Link: https://lkml.kernel.org/r/156777566048.25081.6296162369492175325.stgit@devnote2 Signed-off-by: Maximilian Heyne Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/kprobes/core.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -358,6 +358,10 @@ int __copy_instruction(u8 *dest, u8 *src kernel_insn_init(insn, dest, MAX_INSN_SIZE); insn_get_length(insn); + /* We can not probe force emulate prefixed instruction */ + if (insn_has_emulate_prefix(insn)) + return 0; + /* Another subsystem puts a breakpoint, failed to recover */ if (insn->opcode.bytes[0] == BREAKPOINT_INSTRUCTION) return 0;