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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 D644CC742BA for ; Fri, 12 Jul 2019 12:29:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4282208E4 for ; Fri, 12 Jul 2019 12:29:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562934588; bh=im/5EH16z/2KM02dgV1PXQid8Mz1fZ2RuFwbckq6wCk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=x6e5gLlfMnzKE1kCnk7dNpS1siyKCGktfNtdD8jLaqzjcynQ0bvw9A/uXRlF+qzjK 8YiWb2v0gM1mj+e3ljPjclNahylbr6gbugcyI+SDInC/uNTKB5S9YILw0L/kkYEVSo 46dkDLnXmVk/CsSeLq93m7+m/64gkk8FRWVYUiPI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729036AbfGLM3r (ORCPT ); Fri, 12 Jul 2019 08:29:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:44750 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729022AbfGLM3l (ORCPT ); Fri, 12 Jul 2019 08:29:41 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 31D82208E4; Fri, 12 Jul 2019 12:29:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562934580; bh=im/5EH16z/2KM02dgV1PXQid8Mz1fZ2RuFwbckq6wCk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ai/anIo3fF168WMRQK/um+b05w4MSCl6TDv+1CwvAmAS7jq7oUJ89r46WajgbdeMU Z12A6065u0s2RbDOdcpiATKeJXG2KEtI0eN3R59Q798ztRUZCFyCuqoN4hm+1ICOTZ oABzWngn+3IH7e4+WOYnMrnwaMY7rHWSxBW30nlI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dianzhang Chen , Thomas Gleixner , bp@alien8.de, hpa@zytor.com Subject: [PATCH 5.1 102/138] x86/ptrace: Fix possible spectre-v1 in ptrace_get_debugreg() Date: Fri, 12 Jul 2019 14:19:26 +0200 Message-Id: <20190712121632.679106042@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190712121628.731888964@linuxfoundation.org> References: <20190712121628.731888964@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dianzhang Chen commit 31a2fbb390fee4231281b939e1979e810f945415 upstream. The index to access the threads ptrace_bps is controlled by userspace via syscall: sys_ptrace(), hence leading to a potential exploitation of the Spectre variant 1 vulnerability. The index can be controlled from: ptrace -> arch_ptrace -> ptrace_get_debugreg. Fix this by sanitizing the user supplied index before using it access thread->ptrace_bps. Signed-off-by: Dianzhang Chen Signed-off-by: Thomas Gleixner Cc: bp@alien8.de Cc: hpa@zytor.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/1561476617-3759-1-git-send-email-dianzhangchen0@gmail.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/ptrace.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -642,9 +643,11 @@ static unsigned long ptrace_get_debugreg { struct thread_struct *thread = &tsk->thread; unsigned long val = 0; + int index = n; if (n < HBP_NUM) { - struct perf_event *bp = thread->ptrace_bps[n]; + index = array_index_nospec(index, HBP_NUM); + struct perf_event *bp = thread->ptrace_bps[index]; if (bp) val = bp->hw.info.address;