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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 9C589C433DF for ; Thu, 28 May 2020 20:16:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7B9492088E for ; Thu, 28 May 2020 20:16:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590696966; bh=BqmnFnU6JQ5sVJZD7pDiEmHsE9uhUAQzeEl2GAeaCaM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2jJ+Ddl7FOMVtR9MDoEn5nolvFvwKylhL7QiC26/Qd19Syktf76GKXSj+/s2bXIaa ivL3JD4zFeLIEOnyF+hwWs2gvzW53zd+VQWshOfFCM/SK4TcMtIoQI+VifVK/+oI+e nOkbifxp884m0qMKtKtZlfTu+SHLjpOPP7dF31J0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406882AbgE1UQE (ORCPT ); Thu, 28 May 2020 16:16:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:42378 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2407058AbgE1UOo (ORCPT ); Thu, 28 May 2020 16:14:44 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3124A2158C; Thu, 28 May 2020 20:14:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590696884; bh=BqmnFnU6JQ5sVJZD7pDiEmHsE9uhUAQzeEl2GAeaCaM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AOtWhQA4VrqO+lc1MKMukEK7nmnA+eVi2fNq1NkcbbUwMMc3eqNdzpgAxfIfQ5D5a KASFwA+3rjyN/D/6B/ArD03vIOuDguf5WpYCL8c9fCi0pj8LV83tacZJNDTIUhfSlh dBh5/bMADaGIaptsLbLHcC6kHxet2jrFpcT0LO7c= From: Sasha Levin To: tglx@linutronix.de, luto@kernel.org, ak@linux.intel.com Cc: corbet@lwn.net, mingo@redhat.com, bp@alien8.de, x86@kernel.org, shuah@kernel.org, gregkh@linuxfoundation.org, tony.luck@intel.com, chang.seok.bae@intel.com, dave.hansen@linux.intel.com, peterz@infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, jarkko.sakkinen@linux.intel.com, "H . Peter Anvin" , Dave Hansen , Sasha Levin Subject: [PATCH v13 16/16] selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE Date: Thu, 28 May 2020 16:14:02 -0400 Message-Id: <20200528201402.1708239-17-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200528201402.1708239-1-sashal@kernel.org> References: <20200528201402.1708239-1-sashal@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Chang S. Bae" This validates that GS selector and base are independently preserved in ptrace commands. Suggested-by: Andy Lutomirski Signed-off-by: Chang S. Bae Reviewed-by: Tony Luck Cc: Thomas Gleixner Cc: Borislav Petkov Cc: Andy Lutomirski Cc: H. Peter Anvin Cc: Dave Hansen Cc: Tony Luck Cc: Andi Kleen Signed-off-by: Sasha Levin --- tools/testing/selftests/x86/fsgsbase.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c index 950a48b2e366..9a4349813a30 100644 --- a/tools/testing/selftests/x86/fsgsbase.c +++ b/tools/testing/selftests/x86/fsgsbase.c @@ -465,7 +465,7 @@ static void test_ptrace_write_gsbase(void) wait(&status); if (WSTOPSIG(status) == SIGTRAP) { - unsigned long gs; + unsigned long gs, base; unsigned long gs_offset = USER_REGS_OFFSET(gs); unsigned long base_offset = USER_REGS_OFFSET(gs_base); @@ -481,6 +481,7 @@ static void test_ptrace_write_gsbase(void) err(1, "PTRACE_POKEUSER"); gs = ptrace(PTRACE_PEEKUSER, child, gs_offset, NULL); + base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL); /* * In a non-FSGSBASE system, the nonzero selector will load @@ -501,8 +502,14 @@ static void test_ptrace_write_gsbase(void) */ if (gs == 0) printf("\tNote: this is expected behavior on older kernels.\n"); + } else if (have_fsgsbase && (base != 0xFF)) { + nerrs++; + printf("[FAIL]\tGSBASE changed to %lx\n", base); } else { - printf("[OK]\tGS remained 0x%hx\n", *shared_scratch); + printf("[OK]\tGS remained 0x%hx", *shared_scratch); + if (have_fsgsbase) + printf(" and GSBASE changed to 0xFF"); + printf("\n"); } } -- 2.25.1