From patchwork Thu Aug 8 08:15:23 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 817819 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 652A414430E; Thu, 8 Aug 2024 08:16:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723105006; cv=none; b=mbedpxhxj4tp1DrAHRQ+KTUUV7KaBEedCdgv1YVXTwue4y8xy1Yc1bamkC80TX+ao6iTPMc4KNVQKSZSyrRjUn1MaO79c/k1TffD4hA58bsoAKggiGGtascdjnF2lNGgLmAPRlF2FOt+dyrc4q0RAVJzrm1E7PnTsdSBi3fLvr8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723105006; c=relaxed/simple; bh=vdpMp/+tnPvEc9LtWm/ZG/N3nxsEXfR9pkA/QLvguxA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=n+Scvn16xeWwS+h1z2m3wQNbMWTdEpnZ2aShRVbaS0H9y1cALm/1ghumiAQFWf8awyVpBNyZrnWpTZIdO6oWLJMvDO57Mpb/FF/1JNCP5Ub/fnDTmxXIxuF8nVzHbny7fLgfybnLQthSX8wt/racCnL7B26D6UYUxQOla/E7/Ok= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dDQIY0VC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dDQIY0VC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C3F0C32782; Thu, 8 Aug 2024 08:16:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723105006; bh=vdpMp/+tnPvEc9LtWm/ZG/N3nxsEXfR9pkA/QLvguxA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=dDQIY0VClHUq8XtnbsNGmSdwpxzM9Qk8R5bmNDmSNBzyiJZpv+LYk7ADjBciqtgxv xTE7xMXTnEUkwFODvBVhLhCbzfrB0CoaBvO9zdf6e36LQKgxZ8/DV9hdiFVC/hMPwu u06AGru/QxRpXPCePmdDcyV3AGLvmQOgi+K+nPGEtpFK04jl2Y9u6qz0LAero3dHeZ hOAIPdhreh4h4Xuf551W+Yt310xWABnDMoXcimlv+kJpId30sb95KqpXYd6MMGOcP1 5W1ZiGVJb8eCFyYs7lL0q3Ob7ENzfrqp75m9DEfGn75PvU1aJExgWVNvxN0gk19fhk SMCC8S+jlpebA== From: Mark Brown Date: Thu, 08 Aug 2024 09:15:23 +0100 Subject: [PATCH RFT v8 2/9] selftests: Provide helper header for shadow stack testing Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240808-clone3-shadow-stack-v8-2-0acf37caf14c@kernel.org> References: <20240808-clone3-shadow-stack-v8-0-0acf37caf14c@kernel.org> In-Reply-To: <20240808-clone3-shadow-stack-v8-0-0acf37caf14c@kernel.org> To: "Rick P. Edgecombe" , Deepak Gupta , Szabolcs Nagy , "H.J. Lu" , Florian Weimer , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Christian Brauner , Shuah Khan Cc: linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , jannh@google.com, bsegall@google.com, linux-kselftest@vger.kernel.org, linux-api@vger.kernel.org, Mark Brown , Kees Cook X-Mailer: b4 0.15-dev-37811 X-Developer-Signature: v=1; a=openpgp-sha256; l=2590; i=broonie@kernel.org; h=from:subject:message-id; bh=vdpMp/+tnPvEc9LtWm/ZG/N3nxsEXfR9pkA/QLvguxA=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmtH7I20NyIlGU3wtphj3HE7SlF3ffRGlOk8RvT ON2TtJPxGGJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZrR+yAAKCRAk1otyXVSH 0CIwB/9uuSLGMZ8zaQT0kRE+2R3E1sTZIcPsdg98kHVxLAHhuhghaSL6bKqz/kIw08kNMIMCs1K mJ7ly8vfEeLle7yQitttGbSm9/vZfUjXQJ5DKsPp1my/wy3in42tzD3PfjymI7fkTEE16DU7XWb hpf9SOyz0G758YunBvxgYAUD8UK0OnKuBaJ/b564khO6frRT+EhhubsTnWg9qbEjSWnsHJMUTyG v7cuqEBbTvzEMMdoZuP+2n4sMsiQq01zLys3ToKHGa8uMqqQSlCqTsqsSRF9vZz2yU/mCsjBie2 vAQdoo2nfNua7CouxR0hHh6pVxREg2UGSzcxC3S3fzSiTFBP X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB While almost all users of shadow stacks should be relying on the dynamic linker and libc to enable the feature there are several low level test programs where it is useful to enable without any libc support, allowing testing without full system enablement. This low level testing is helpful during bringup of the support itself, and also in enabling coverage by automated testing without needing all system components in the target root filesystems to have enablement. Provide a header with helpers for this purpose, intended for use only by test programs directly exercising shadow stack interfaces. Reviewed-by: Rick Edgecombe Signed-off-by: Mark Brown --- tools/testing/selftests/ksft_shstk.h | 63 ++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) diff --git a/tools/testing/selftests/ksft_shstk.h b/tools/testing/selftests/ksft_shstk.h new file mode 100644 index 000000000000..85d0747c1802 --- /dev/null +++ b/tools/testing/selftests/ksft_shstk.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Helpers for shadow stack enablement, this is intended to only be + * used by low level test programs directly exercising interfaces for + * working with shadow stacks. + * + * Copyright (C) 2024 ARM Ltd. + */ + +#ifndef __KSFT_SHSTK_H +#define __KSFT_SHSTK_H + +#include + +/* This is currently only defined for x86 */ +#ifndef SHADOW_STACK_SET_TOKEN +#define SHADOW_STACK_SET_TOKEN (1ULL << 0) +#endif + +static bool shadow_stack_enabled; + +#ifdef __x86_64__ +#define ARCH_SHSTK_ENABLE 0x5001 +#define ARCH_SHSTK_SHSTK (1ULL << 0) + +#define ARCH_PRCTL(arg1, arg2) \ +({ \ + long _ret; \ + register long _num asm("eax") = __NR_arch_prctl; \ + register long _arg1 asm("rdi") = (long)(arg1); \ + register long _arg2 asm("rsi") = (long)(arg2); \ + \ + asm volatile ( \ + "syscall\n" \ + : "=a"(_ret) \ + : "r"(_arg1), "r"(_arg2), \ + "0"(_num) \ + : "rcx", "r11", "memory", "cc" \ + ); \ + _ret; \ +}) + +#define ENABLE_SHADOW_STACK +static inline __attribute__((always_inline)) void enable_shadow_stack(void) +{ + int ret = ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK); + if (ret == 0) + shadow_stack_enabled = true; +} + +#endif + +#ifndef __NR_map_shadow_stack +#define __NR_map_shadow_stack 453 +#endif + +#ifndef ENABLE_SHADOW_STACK +static inline void enable_shadow_stack(void) { } +#endif + +#endif + +