From patchwork Thu Aug 8 08:15:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 818203 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 85EA01891D1; Thu, 8 Aug 2024 08:16:36 +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=1723104996; cv=none; b=d3az54dAt4NbqDgCqUtnEDEXvpnPY/bBwOYE9icIWtnc54SH9fq4lj12rUlHI4zk+DzA0liXgPkWXxeANQdq8sTS5hXChpSdcqj6HtsT1L0CwgJZOoIKSZglw5RMLQ2FyD/GGRAoOFZuL35RatJG1J3qiK3lNwnEiS+qxE5xWmc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723104996; c=relaxed/simple; bh=FizA8c9Fs3+e20frZgIdFeBpWm1//QTTbE58XxIvdwA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=bCbg2MYfCXJ6fSJ2VrNmcNgqHsZ4+nuADl9E+adIU5l8aviBGimEt3aa4Z30BQ7WXkFsVz+exIKIbgRcDJfgQWTp6HwwbS3mucWEVikUrDjnwSU1sYQNzTXuadCLVzjik7W7QOYqeauM7nyzEm5zPMoGhox+yFHxPPtymUJ3w44= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kLAJzT6W; 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="kLAJzT6W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80E89C32782; Thu, 8 Aug 2024 08:16:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723104996; bh=FizA8c9Fs3+e20frZgIdFeBpWm1//QTTbE58XxIvdwA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=kLAJzT6W7m/lM2zkNzq9U5SCJxu0MbBiSVPrWg9yX6uXMHuadiF/bV75GP8UWIQpG HVnSr79L9ylicm/uzK1uXL7DwTPtliVvK1aZPlRg5GaVuPQNJ9morrLNN2DcWpVm9X Bee8yYHih+1NZ5WdMiVp23HqmlYaeABIi8j2RhM/fuQrt3ik6qtHyAyIhn0JejSEwv FUICkup/wrgxVdCtPe6exe4jLaYjoSP4ryKjzdzqH/QEtZwx3TZyznxuIpwRuIum8x SzCXPWeoeMRwiWs5Yqr7XdAitt6BFUeICIWQ16i50hIuki+06tDxVTTAT5RPTCumIR F5HMTGMOxYijg== From: Mark Brown Date: Thu, 08 Aug 2024 09:15:22 +0100 Subject: [PATCH RFT v8 1/9] Documentation: userspace-api: Add shadow stack API documentation 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-v8-1-0acf37caf14c@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=2837; i=broonie@kernel.org; h=from:subject:message-id; bh=FizA8c9Fs3+e20frZgIdFeBpWm1//QTTbE58XxIvdwA=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmtH7GV/Qmw4MPNa/Yt+q3JnWEuqZVe6AYkX8fc mW5VJl0FpuJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZrR+xgAKCRAk1otyXVSH 0Kl3B/4oWEGLxUtMiKyuxu1YTC7an8I7PGkVCEcQ6ChkYL20j8nIMmyBne990Yi4ChtmhQIiekw TlXmzS4Vb4NdiUXd2nc4q+HH/rAaLkSSPT+EcF1d0jhc4X4xr67Io3UoF0zBgZytqYi+cZcFlcN 9nNate33T9LAqXQn/O/LauwxTW1ISe6PcToN++WRiq6AhYSahgEv/lcP6xtO1DkCB7a9i8Hp0Uu WnzQI6/PikZw0jR2gWUMd5lYyI3LVP0NAfhgtdryxnL3bb0mhOvdeQXNgh4BY3hfWXGg21Rk2IF hXn08S3bLE9AKqGpRK/OAY4BErTOSDDJKIaV2+h5/r7U1tYv X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB There are a number of architectures with shadow stack features which we are presenting to userspace with as consistent an API as we can (though there are some architecture specifics). Especially given that there are some important considerations for userspace code interacting directly with the feature let's provide some documentation covering the common aspects. Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas --- Documentation/userspace-api/index.rst | 1 + Documentation/userspace-api/shadow_stack.rst | 41 ++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+) diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst index 274cc7546efc..c39709bfba2c 100644 --- a/Documentation/userspace-api/index.rst +++ b/Documentation/userspace-api/index.rst @@ -59,6 +59,7 @@ Everything else ELF netlink/index + shadow_stack sysfs-platform_profile vduse futex2 diff --git a/Documentation/userspace-api/shadow_stack.rst b/Documentation/userspace-api/shadow_stack.rst new file mode 100644 index 000000000000..c576ad3d7ec1 --- /dev/null +++ b/Documentation/userspace-api/shadow_stack.rst @@ -0,0 +1,41 @@ +============= +Shadow Stacks +============= + +Introduction +============ + +Several architectures have features which provide backward edge +control flow protection through a hardware maintained stack, only +writeable by userspace through very limited operations. This feature +is referred to as shadow stacks on Linux, on x86 it is part of Intel +Control Enforcement Technology (CET), on arm64 it is Guarded Control +Stacks feature (FEAT_GCS) and for RISC-V it is the Zicfiss extension. +It is expected that this feature will normally be managed by the +system dynamic linker and libc in ways broadly transparent to +application code, this document covers interfaces and considerations. + + +Enabling +======== + +Shadow stacks default to disabled when a userspace process is +executed, they can be enabled for the current thread with a syscall: + + - For x86 the ARCH_SHSTK_ENABLE arch_prctl() + +It is expected that this will normally be done by the dynamic linker. +Any new threads created by a thread with shadow stacks enabled will +themselves have shadow stacks enabled. + + +Enablement considerations +========================= + +- Returning from the function that enables shadow stacks without first + disabling them will cause a shadow stack exception. This includes + any syscall wrapper or other library functions, the syscall will need + to be inlined. +- A lock feature allows userspace to prevent disabling of shadow stacks. +- Those that change the stack context like longjmp() or use of ucontext + changes on signal return will need support from libc. 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 + + From patchwork Thu Aug 8 08:15:24 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 818202 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 82B1C1422DC; Thu, 8 Aug 2024 08:16:56 +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=1723105016; cv=none; b=rytcPJRJlIVcsB2ty4wO7bl4EaFFU9J72m5YUdcRDdQde8Jhzhb7RCmTUbSB0FFrPnaUZ0XP7uLmL2gtNas+gPWt9f5p4twBmaWK76jlDR05BMGR/HBa19eQgBgHSYTNooLryfJVoUmPCy3Up2dx4iTiXvak8qWz82eQdg+W6Q4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723105016; c=relaxed/simple; bh=+orwRfvizHfGXDNjTwUwjThxjP5rZLiehiVTLaa/d1s=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=EBgJ7LwM2N0AiWlbPF3umXtiYs7JzqnKSJAbTSSlm0QaoyVncBgPf3ZaoIHbaJgUeRub6QBnxLZ1FwBgqjEEx+tzGcMFdNTFvRbTsfOJlKj5fjK2z/eGvi3gQCOsbu74PMSi9C3jvuEaZRr4Jakq/yb2GPl8HD6ZDYLKwf8EU5Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PlUbUBzq; 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="PlUbUBzq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A0D0C32786; Thu, 8 Aug 2024 08:16:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723105016; bh=+orwRfvizHfGXDNjTwUwjThxjP5rZLiehiVTLaa/d1s=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=PlUbUBzqRlmP7xWmBTT579aeaF/As23HS8Gtv6Uvc83iRvn8tGvVmCIlB21QYsK8h dHXW3CtBsZ0H5k5kq+sVB5ADTyiMi2ZPgtMqw5lW7nqKkHtKpghK2ZdZeR44NLC4Kv uwkQfbXtfJlsQO/PUkqZXqTRpOO4/5Z4BcWOMCyvUYLg6vM1R52P6wVhtw0sIbjO9/ jZ5LToy4NMqv2cI8lGXq0JuELBRsB80Q6CqDc83gVTI0KeDijpFEUc1ss68vhBYLfB dQPIzY70zo6WIVOOCrjg3EQVA4VVzfUihWz/1GmD93caG6BeoimG6JSPQxgPXgc1S/ FAa4TqvUIPBNg== From: Mark Brown Date: Thu, 08 Aug 2024 09:15:24 +0100 Subject: [PATCH RFT v8 3/9] mm: Introduce ARCH_HAS_USER_SHADOW_STACK 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-v8-3-0acf37caf14c@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 , David Hildenbrand X-Mailer: b4 0.15-dev-37811 X-Developer-Signature: v=1; a=openpgp-sha256; l=2453; i=broonie@kernel.org; h=from:subject:message-id; bh=+orwRfvizHfGXDNjTwUwjThxjP5rZLiehiVTLaa/d1s=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmtH7JYGKmwMqFqel6gaUd06JMx0Dcs1EPMb2Px xS8sBUaNuKJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZrR+yQAKCRAk1otyXVSH 0A0qB/49bgle+hs90M96hEmr0SlTYk61h0S+da0Etb4uI9yufHVWC9eL284rHqFEYGsDSvP3H6f 22dCUD1A8lowtEyvjV59TLqZSfW5v+nt+41FfFDXgroaegf3oHULyJpymwfd7Jil1tsWE53GmzJ mNBARyh3qymxlN43r1iDZVDBEITN+FnGBuF7VWUNrdJP8whHgkpVX3Um9/KnfFomebAxW9Tx+fs VKTcGfkSmDGgpzp4UGcnh3AtKqzFRlmMnfw/1wsb9P5Iz9P3gbGROpYjCUTYiR8TNJVmn01k5z0 l+I+o6SP2KRmmzp/ZwEutgE257SMt8OdNuIMEVhVSXQUL6V1 X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Since multiple architectures have support for shadow stacks and we need to select support for this feature in several places in the generic code provide a generic config option that the architectures can select. Suggested-by: David Hildenbrand Acked-by: David Hildenbrand Reviewed-by: Deepak Gupta Reviewed-by: Rick Edgecombe Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas --- arch/x86/Kconfig | 1 + fs/proc/task_mmu.c | 2 +- include/linux/mm.h | 2 +- mm/Kconfig | 6 ++++++ 4 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 007bab9f2a0e..320e1f411163 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1957,6 +1957,7 @@ config X86_USER_SHADOW_STACK depends on AS_WRUSS depends on X86_64 select ARCH_USES_HIGH_VMA_FLAGS + select ARCH_HAS_USER_SHADOW_STACK select X86_CET help Shadow stack protection is a hardware feature that detects function diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 5f171ad7b436..0ea49725f524 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -984,7 +984,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR [ilog2(VM_UFFD_MINOR)] = "ui", #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ -#ifdef CONFIG_X86_USER_SHADOW_STACK +#ifdef CONFIG_ARCH_HAS_USER_SHADOW_STACK [ilog2(VM_SHADOW_STACK)] = "ss", #endif #ifdef CONFIG_64BIT diff --git a/include/linux/mm.h b/include/linux/mm.h index c4b238a20b76..3357625c1db3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -342,7 +342,7 @@ extern unsigned int kobjsize(const void *objp); #endif #endif /* CONFIG_ARCH_HAS_PKEYS */ -#ifdef CONFIG_X86_USER_SHADOW_STACK +#ifdef CONFIG_ARCH_HAS_USER_SHADOW_STACK /* * VM_SHADOW_STACK should not be set with VM_SHARED because of lack of * support core mm. diff --git a/mm/Kconfig b/mm/Kconfig index b72e7d040f78..3167be663bca 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1263,6 +1263,12 @@ config IOMMU_MM_DATA config EXECMEM bool +config ARCH_HAS_USER_SHADOW_STACK + bool + help + The architecture has hardware support for userspace shadow call + stacks (eg, x86 CET, arm64 GCS or RISC-V Zicfiss). + source "mm/damon/Kconfig" endmenu From patchwork Thu Aug 8 08:15:25 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 817818 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 190B61891C3; Thu, 8 Aug 2024 08:17:05 +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=1723105026; cv=none; b=k/laHwWEBmcN64Km7Cu9bMBYkZlvZx5y4ibl+Nv7vu7vdfWOiEaZRuldy2k9dBeUQKUUsDDS5m02V7x19DUYlWDrRIpiO3ANA3sdAWwf/HJXiidcvKYB7ZiShMo5TlFkghFyXD27m/bN1SB2bZSKwoTh/HSecFhJ57pgIp6sU50= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723105026; c=relaxed/simple; bh=m1OnABhLONczjQkxBBi2It7JqY7+XgeKr6lD4OO/u/8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=VW8RvtqMHBzYbDX6d90StMkLRsUEK2igLeklw5+UeTTreOa6yc4nYzjN5ln7PlmxXmiX3BWcMyHT/jzd0mawExzjrHH1alHaLkILuvG7Jxe8EAWv7KRaxhLUyxX6IFdIMKxLh13yRNIzGz2hgmJrSFU5JmRD1DwESOjEuUHQeNc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Yj3jyLSt; 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="Yj3jyLSt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ACADEC32786; Thu, 8 Aug 2024 08:16:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723105025; bh=m1OnABhLONczjQkxBBi2It7JqY7+XgeKr6lD4OO/u/8=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Yj3jyLSta2Ps19/Cl2PIE5TslolvaeX/halTHBI7wRc6ccOovyycQPZMgakU5em27 s81yZhD7/l3Y/i/63KpBYYalwraF8ZkUc+UVaYxVT53LnEsIRW79ATmILYVFGd7eLw emoXdHysnTN0rsUuc/Je0pBkEHmH822kAYhydIouD+ZKLmwR6Kykg10CSXBGj3CTCJ ++HyNQkj9WvSerIQuDhgagsk6lkT+5CLBSZVhwHI7EtS34swOkhr+03UBK1KDMqHpv nXD5kMt9NTXMj6XbHNO+d8vjFnCUuvbCNoyy2ZkmwoPgW5wodS6dTA2K2pGF4IzTI3 SFvkO4crz3GmQ== From: Mark Brown Date: Thu, 08 Aug 2024 09:15:25 +0100 Subject: [PATCH RFT v8 4/9] fork: Add shadow stack support to clone3() 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-v8-4-0acf37caf14c@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=14277; i=broonie@kernel.org; h=from:subject:message-id; bh=m1OnABhLONczjQkxBBi2It7JqY7+XgeKr6lD4OO/u/8=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmtH7LcdJH8MZVNjq3fYlFc8f+iCmhLc0Yzr6fW Vd3BvaxFPmJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZrR+ywAKCRAk1otyXVSH 0Jg9B/9VS87kdalHif57m6A7b44toTPcl8XmaPDuwGTbTzVWbqoEI+hZG77SP5Ce0pT0K61MoIK iQb6qfYin2RNjo/W2NySj1l6P6SAMLjvS+zkgkLs+C9f+YmKmVp6qb/nQEzBphFd2M9PNugtKAl hZ4aTfvBxAeJmXJX2ulmY7wWEfueN4ad7W0A7LITyvSJK03KUbGWSFuXVHE+z1OInzBDof7e/Vc 32d3Qgo/O/1u5At3+u9BgrcbDbsKwHlBJe6vjEsElLPOvWn16Idhb0ftEq5oGPReai3JM/JJ4d0 e6g4ue6flAKA/kxGZgNaNs4z7phwqwXLVdM04d+WCVbQmfDk X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Unlike with the normal stack there is no API for configuring the the shadow stack for a new thread, instead the kernel will dynamically allocate a new shadow stack with the same size as the normal stack. This appears to be due to the shadow stack series having been in development since before the more extensible clone3() was added rather than anything more deliberate. Add parameters to clone3() specifying the location and size of a shadow stack for the newly created process. If no shadow stack is specified then the existing implicit allocation behaviour is maintained. If a stack is specified then it is required to have an architecture defined token placed on the stack, this will be consumed by the new task. If the token is not provided then this will be reported as a segmentation fault with si_code SEGV_CPERR, as a runtime shadow stack protection error would be. This allows architectures to implement the validation of the token in the child process context. If the architecture does not support shadow stacks the shadow stack parameters must be zero, architectures that do support the feature are expected to enforce the same requirement on individual systems that lack shadow stack support. Update the existing x86 implementation to pay attention to the newly added arguments, in order to maintain compatibility we use the existing behaviour if no shadow stack is specified. Minimal validation is done of the supplied parameters, detailed enforcement is left to when the thread is executed. Since we are now using more fields from the kernel_clone_args we pass that into the shadow stack code rather than individual fields. At present this implementation does not consume the shadow stack token atomically as would be desirable, it uses a separate read and write. Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas --- arch/x86/include/asm/shstk.h | 11 +++-- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/shstk.c | 105 ++++++++++++++++++++++++++++++++++--------- include/linux/sched/task.h | 13 ++++++ include/uapi/linux/sched.h | 13 ++++-- kernel/fork.c | 76 ++++++++++++++++++++++++++----- 6 files changed, 178 insertions(+), 42 deletions(-) diff --git a/arch/x86/include/asm/shstk.h b/arch/x86/include/asm/shstk.h index 4cb77e004615..252feeda6999 100644 --- a/arch/x86/include/asm/shstk.h +++ b/arch/x86/include/asm/shstk.h @@ -6,6 +6,7 @@ #include struct task_struct; +struct kernel_clone_args; struct ksignal; #ifdef CONFIG_X86_USER_SHADOW_STACK @@ -16,8 +17,8 @@ struct thread_shstk { long shstk_prctl(struct task_struct *task, int option, unsigned long arg2); void reset_thread_features(void); -unsigned long shstk_alloc_thread_stack(struct task_struct *p, unsigned long clone_flags, - unsigned long stack_size); +unsigned long shstk_alloc_thread_stack(struct task_struct *p, + const struct kernel_clone_args *args); void shstk_free(struct task_struct *p); int setup_signal_shadow_stack(struct ksignal *ksig); int restore_signal_shadow_stack(void); @@ -28,8 +29,10 @@ static inline long shstk_prctl(struct task_struct *task, int option, unsigned long arg2) { return -EINVAL; } static inline void reset_thread_features(void) {} static inline unsigned long shstk_alloc_thread_stack(struct task_struct *p, - unsigned long clone_flags, - unsigned long stack_size) { return 0; } + const struct kernel_clone_args *args) +{ + return 0; +} static inline void shstk_free(struct task_struct *p) {} static inline int setup_signal_shadow_stack(struct ksignal *ksig) { return 0; } static inline int restore_signal_shadow_stack(void) { return 0; } diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index f63f8fd00a91..59456ab8d93f 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -207,7 +207,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) * is disabled, new_ssp will remain 0, and fpu_clone() will know not to * update it. */ - new_ssp = shstk_alloc_thread_stack(p, clone_flags, args->stack_size); + new_ssp = shstk_alloc_thread_stack(p, args); if (IS_ERR_VALUE(new_ssp)) return PTR_ERR((void *)new_ssp); diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c index 059685612362..d7005974aff5 100644 --- a/arch/x86/kernel/shstk.c +++ b/arch/x86/kernel/shstk.c @@ -191,44 +191,105 @@ void reset_thread_features(void) current->thread.features_locked = 0; } -unsigned long shstk_alloc_thread_stack(struct task_struct *tsk, unsigned long clone_flags, - unsigned long stack_size) +int arch_shstk_post_fork(struct task_struct *t, struct kernel_clone_args *args) +{ + /* + * SSP is aligned, so reserved bits and mode bit are a zero, just mark + * the token 64-bit. + */ + struct mm_struct *mm; + unsigned long addr, ssp; + u64 expected; + u64 val; + int ret = -EINVAL; + + ssp = args->shadow_stack + args->shadow_stack_size; + addr = ssp - SS_FRAME_SIZE; + expected = ssp | BIT(0); + + mm = get_task_mm(t); + if (!mm) + return -EFAULT; + + /* This should really be an atomic cmpxchg. It is not. */ + if (access_remote_vm(mm, addr, &val, sizeof(val), + FOLL_FORCE) != sizeof(val)) + goto out; + + if (val != expected) + goto out; + val = 0; + if (access_remote_vm(mm, addr, &val, sizeof(val), + FOLL_FORCE | FOLL_WRITE) != sizeof(val)) + goto out; + + ret = 0; + +out: + mmput(mm); + return ret; +} + +unsigned long shstk_alloc_thread_stack(struct task_struct *tsk, + const struct kernel_clone_args *args) { struct thread_shstk *shstk = &tsk->thread.shstk; + unsigned long clone_flags = args->flags; unsigned long addr, size; /* * If shadow stack is not enabled on the new thread, skip any - * switch to a new shadow stack. + * implicit switch to a new shadow stack and reject attempts to + * explciitly specify one. */ - if (!features_enabled(ARCH_SHSTK_SHSTK)) + if (!features_enabled(ARCH_SHSTK_SHSTK)) { + if (args->shadow_stack || args->shadow_stack_size) + return (unsigned long)ERR_PTR(-EINVAL); + return 0; + } /* - * For CLONE_VFORK the child will share the parents shadow stack. - * Make sure to clear the internal tracking of the thread shadow - * stack so the freeing logic run for child knows to leave it alone. + * If the user specified a shadow stack then do some basic + * validation and use it, otherwise fall back to a default + * shadow stack size if the clone_flags don't indicate an + * allocation is unneeded. */ - if (clone_flags & CLONE_VFORK) { + if (args->shadow_stack) { + addr = args->shadow_stack; + size = args->shadow_stack_size; shstk->base = 0; shstk->size = 0; - return 0; - } + } else { + /* + * For CLONE_VFORK the child will share the parents + * shadow stack. Make sure to clear the internal + * tracking of the thread shadow stack so the freeing + * logic run for child knows to leave it alone. + */ + if (clone_flags & CLONE_VFORK) { + shstk->base = 0; + shstk->size = 0; + return 0; + } - /* - * For !CLONE_VM the child will use a copy of the parents shadow - * stack. - */ - if (!(clone_flags & CLONE_VM)) - return 0; + /* + * For !CLONE_VM the child will use a copy of the + * parents shadow stack. + */ + if (!(clone_flags & CLONE_VM)) + return 0; - size = adjust_shstk_size(stack_size); - addr = alloc_shstk(0, size, 0, false); - if (IS_ERR_VALUE(addr)) - return addr; + size = args->stack_size; + size = adjust_shstk_size(size); + addr = alloc_shstk(0, size, 0, false); + if (IS_ERR_VALUE(addr)) + return addr; - shstk->base = addr; - shstk->size = size; + /* We allocated the shadow stack, we should deallocate it. */ + shstk->base = addr; + shstk->size = size; + } return addr + size; } diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index d362aacf9f89..56b2013d7fe5 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -43,6 +43,8 @@ struct kernel_clone_args { void *fn_arg; struct cgroup *cgrp; struct css_set *cset; + unsigned long shadow_stack; + unsigned long shadow_stack_size; }; /* @@ -230,4 +232,15 @@ static inline void task_unlock(struct task_struct *p) DEFINE_GUARD(task_lock, struct task_struct *, task_lock(_T), task_unlock(_T)) +#ifdef CONFIG_ARCH_HAS_USER_SHADOW_STACK +int arch_shstk_post_fork(struct task_struct *p, + struct kernel_clone_args *args); +#else +static inline int arch_shstk_post_fork(struct task_struct *p, + struct kernel_clone_args *args) +{ + return 0; +} +#endif + #endif /* _LINUX_SCHED_TASK_H */ diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h index 3bac0a8ceab2..8b7af52548fd 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -84,6 +84,10 @@ * kernel's limit of nested PID namespaces. * @cgroup: If CLONE_INTO_CGROUP is specified set this to * a file descriptor for the cgroup. + * @shadow_stack: Pointer to the memory allocated for the child + * shadow stack. + * @shadow_stack_size: Specify the size of the shadow stack for + * the child process. * * The structure is versioned by size and thus extensible. * New struct members must go at the end of the struct and @@ -101,12 +105,15 @@ struct clone_args { __aligned_u64 set_tid; __aligned_u64 set_tid_size; __aligned_u64 cgroup; + __aligned_u64 shadow_stack; + __aligned_u64 shadow_stack_size; }; #endif -#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */ -#define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */ -#define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */ +#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */ +#define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */ +#define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */ +#define CLONE_ARGS_SIZE_VER3 104 /* sizeof fourth published struct */ /* * Scheduling policies diff --git a/kernel/fork.c b/kernel/fork.c index cc760491f201..18278c72681c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -128,6 +128,11 @@ */ #define MAX_THREADS FUTEX_TID_MASK +/* + * Require that shadow stacks can store at least one element + */ +#define SHADOW_STACK_SIZE_MIN sizeof(void *) + /* * Protected counters by write_lock_irq(&tasklist_lock) */ @@ -2729,6 +2734,19 @@ struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node) return copy_process(NULL, 0, node, &args); } +static void shstk_post_fork(struct task_struct *p, + struct kernel_clone_args *args) +{ + if (!IS_ENABLED(CONFIG_ARCH_HAS_USER_SHADOW_STACK)) + return; + + if (!args->shadow_stack) + return; + + if (arch_shstk_post_fork(p, args) != 0) + force_sig_fault_to_task(SIGSEGV, SEGV_CPERR, NULL, p); +} + /* * Ok, this is the main fork-routine. * @@ -2790,6 +2808,8 @@ pid_t kernel_clone(struct kernel_clone_args *args) */ trace_sched_process_fork(current, p); + shstk_post_fork(p, args); + pid = get_task_pid(p, PIDTYPE_PID); nr = pid_vnr(pid); @@ -2939,7 +2959,9 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, CLONE_ARGS_SIZE_VER1); BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) != CLONE_ARGS_SIZE_VER2); - BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2); + BUILD_BUG_ON(offsetofend(struct clone_args, shadow_stack_size) != + CLONE_ARGS_SIZE_VER3); + BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER3); if (unlikely(usize > PAGE_SIZE)) return -E2BIG; @@ -2972,16 +2994,18 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, return -EINVAL; *kargs = (struct kernel_clone_args){ - .flags = args.flags, - .pidfd = u64_to_user_ptr(args.pidfd), - .child_tid = u64_to_user_ptr(args.child_tid), - .parent_tid = u64_to_user_ptr(args.parent_tid), - .exit_signal = args.exit_signal, - .stack = args.stack, - .stack_size = args.stack_size, - .tls = args.tls, - .set_tid_size = args.set_tid_size, - .cgroup = args.cgroup, + .flags = args.flags, + .pidfd = u64_to_user_ptr(args.pidfd), + .child_tid = u64_to_user_ptr(args.child_tid), + .parent_tid = u64_to_user_ptr(args.parent_tid), + .exit_signal = args.exit_signal, + .stack = args.stack, + .stack_size = args.stack_size, + .tls = args.tls, + .set_tid_size = args.set_tid_size, + .cgroup = args.cgroup, + .shadow_stack = args.shadow_stack, + .shadow_stack_size = args.shadow_stack_size, }; if (args.set_tid && @@ -3022,6 +3046,34 @@ static inline bool clone3_stack_valid(struct kernel_clone_args *kargs) return true; } +/** + * clone3_shadow_stack_valid - check and prepare shadow stack + * @kargs: kernel clone args + * + * Verify that shadow stacks are only enabled if supported. + */ +static inline bool clone3_shadow_stack_valid(struct kernel_clone_args *kargs) +{ + if (kargs->shadow_stack) { + if (!kargs->shadow_stack_size) + return false; + + if (kargs->shadow_stack_size < SHADOW_STACK_SIZE_MIN) + return false; + + if (kargs->shadow_stack_size > rlimit(RLIMIT_STACK)) + return false; + + /* + * The architecture must check support on the specific + * machine. + */ + return IS_ENABLED(CONFIG_ARCH_HAS_USER_SHADOW_STACK); + } else { + return !kargs->shadow_stack_size; + } +} + static bool clone3_args_valid(struct kernel_clone_args *kargs) { /* Verify that no unknown flags are passed along. */ @@ -3044,7 +3096,7 @@ static bool clone3_args_valid(struct kernel_clone_args *kargs) kargs->exit_signal) return false; - if (!clone3_stack_valid(kargs)) + if (!clone3_stack_valid(kargs) || !clone3_shadow_stack_valid(kargs)) return false; return true; From patchwork Thu Aug 8 08:15:26 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 818201 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 8CEFB1891C3; Thu, 8 Aug 2024 08:17:15 +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=1723105035; cv=none; b=FOyv8Y5xEllQK0rtil8b5B+JrmrSPtrnHGb3u9QyR7Taz/4sZh58tu+BHLD24dpyYHo2GENTLyM6gMsJHVTl6ugNvP0OhzidE2rSVguq3amvQPWJCY1UOjvdA2Z+SKKslAFGTaKAt9WMEMrdW8BxTQN5JjxfUsNM6ycBShTc+/0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723105035; c=relaxed/simple; bh=A6PuiVWBdiPH6Nr/YX1UnFJ8RTIAC1FidWNruHY9Zks=; 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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=926; i=broonie@kernel.org; h=from:subject:message-id; bh=A6PuiVWBdiPH6Nr/YX1UnFJ8RTIAC1FidWNruHY9Zks=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmtH7MofVvNn5TwW6oDgCIJDA/rG8resOEgJSiQ x3UDzkReHCJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZrR+zAAKCRAk1otyXVSH 0DhqB/4kV/FvNAFx8tENnuwi8D3w95LyZ5gT0ZMOM2b7QGftmaU3Irdyrvl9EhOk/rmarlkltIq bR6gKXqZjT7JQ0EQby3RNkAWqFU803QJFlmiwzGo7GOyoxDrRgMPJvcGAMtRcO19deAeUR5FO8W pf+9xNb7kCMdAvs4Wpm0ro7i5QMVtjN6dCc9K5weLAP2LSMAywZAxOaa0ldyO3Av+2WeFnGlU7U K8I1claSdCMXVqzjU3O3bx71634PF+q8HNzaRoh+Q+mHExxXvfWiT8Ea31EupbTKFk1Ewm8hHAW Ua2e94v9igAIe/61CP8qeIbEHozn6m0p0laUZIsHQNynanTH X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Since there were widespread issues with output not being flushed the kselftest framework was modified to explicitly set the output streams unbuffered in commit 58e2847ad2e6 ("selftests: line buffer test program's stdout") so there is no need to explicitly flush in the clone3 tests. Signed-off-by: Mark Brown --- tools/testing/selftests/clone3/clone3_selftests.h | 2 -- 1 file changed, 2 deletions(-) diff --git a/tools/testing/selftests/clone3/clone3_selftests.h b/tools/testing/selftests/clone3/clone3_selftests.h index 3d2663fe50ba..39b5dcba663c 100644 --- a/tools/testing/selftests/clone3/clone3_selftests.h +++ b/tools/testing/selftests/clone3/clone3_selftests.h @@ -35,8 +35,6 @@ struct __clone_args { static pid_t sys_clone3(struct __clone_args *args, size_t size) { - fflush(stdout); - fflush(stderr); return syscall(__NR_clone3, args, size); } From patchwork Thu Aug 8 08:15:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 817817 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 E678A13A257; Thu, 8 Aug 2024 08:17:25 +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=1723105046; cv=none; b=ik9mPatcVglIpRZxtJu0MjwRuUQggpUilFU8kx2S7CLfpt79VZb+T1UpX04tVcCoygv5e/Pv3y99vJH91PYmUIV93ogPmaB47iguWR8RrT7ZkD0DMvnZ7AV5eG0LpIZxhjAvpfbKHhmB9ipoth6DYja2ZxJV5ngK12KOuIXAC/M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723105046; c=relaxed/simple; bh=7/H/C/HH1SlOixEC1xQKfbpAfSVTyHxGoHTFJYjOHFU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=oJXSkGPK3hHCDRVyv+TuUE9MzwtXnkPlE7Gtjx24HSWitHbEjhq+1oeTAAUDEmrpLUW6dbxiUYsnSGfe1ZTaSPr4/mmU3jbUGVynW91ciW/b5NC7oi+eWriZMRhp2CNT8LCGQk8+8tlMdh51yZkUvLxhMKQyolRKK1knQMofVzw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AatM9F6b; 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="AatM9F6b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC00CC4AF0E; Thu, 8 Aug 2024 08:17:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723105045; bh=7/H/C/HH1SlOixEC1xQKfbpAfSVTyHxGoHTFJYjOHFU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=AatM9F6bCADmFPxDYcw3fPa1prj4qk1v31nd9m0WoEBnSPDULGz2JM0GKcupTknaA GwiJi4NW3+gT40+G5PtAtF/T9ZVPmo9JpI42t4mzWyTLsfuEl3akjMCXlQ8gmbUeKN jx/kcOBFXKZ3QH2T7rCPcXPLGGx95ERTma5ND0nn8poJtCyWOaoUkWw6HVgpF5cHxG hNvlSJc20/rLDwqHzdx9gwW9+xnCjF2XqzxEqM6X7rJRM3v8s4OhUFyGCaQZbH7890 T7BvSTccwUpRSPG8weCDwOBzLFgRsGus1t9P/juENW1QI7S4lttS0RLj4wkQjudv8p d3I6SAyHOQGzA== From: Mark Brown Date: Thu, 08 Aug 2024 09:15:27 +0100 Subject: [PATCH RFT v8 6/9] selftests/clone3: Factor more of main loop into test_clone3() 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-v8-6-0acf37caf14c@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=3743; i=broonie@kernel.org; h=from:subject:message-id; bh=7/H/C/HH1SlOixEC1xQKfbpAfSVTyHxGoHTFJYjOHFU=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmtH7OMIOFhZcKbpqWyVPtzy49PCLYFvlCTzKuX SFQ1V7DpHGJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZrR+zgAKCRAk1otyXVSH 0C+IB/95vcpDhMNfYhPu4Jtz5ePuw1yFBHLrvHKojGre7hCSZHKQSitYqpizhcZTZtbDRUnS7dm cROfKCw18JFdQCzINVF7GhF6EJfF/81bQAXhyo4xY2leQ3sE3XxXgXAfksiNJpUsu3icPco038i cTNOlNq7kTSikxuryipDMkAmYBEjuavhgHbpHmjdf0Lw3TqW+vOAcUN0zQKGhi+LAkc4gK+GIWt 5fxLiDrYenqnvNnPVze/OOHYH83DaPsx4yRTpZKT6ZAh6V4TJkYc731ta4TGEZeVekqliz9gtwP mJ11Ze0tXJagBjO4Bn1gV4c3HzpolgEhP06xK+DdNhFfUMRS X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB In order to make it easier to add more configuration for the tests and more support for runtime detection of when tests can be run pass the structure describing the tests into test_clone3() rather than picking the arguments out of it and have that function do all the per-test work. No functional change. Signed-off-by: Mark Brown --- tools/testing/selftests/clone3/clone3.c | 77 ++++++++++++++++----------------- 1 file changed, 37 insertions(+), 40 deletions(-) diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c index e61f07973ce5..e066b201fa64 100644 --- a/tools/testing/selftests/clone3/clone3.c +++ b/tools/testing/selftests/clone3/clone3.c @@ -30,6 +30,19 @@ enum test_mode { CLONE3_ARGS_INVAL_EXIT_SIGNAL_NSIG, }; +typedef bool (*filter_function)(void); +typedef size_t (*size_function)(void); + +struct test { + const char *name; + uint64_t flags; + size_t size; + size_function size_function; + int expected; + enum test_mode test_mode; + filter_function filter; +}; + static int call_clone3(uint64_t flags, size_t size, enum test_mode test_mode) { struct __clone_args args = { @@ -109,30 +122,40 @@ static int call_clone3(uint64_t flags, size_t size, enum test_mode test_mode) return 0; } -static bool test_clone3(uint64_t flags, size_t size, int expected, - enum test_mode test_mode) +static void test_clone3(const struct test *test) { + size_t size; int ret; + if (test->filter && test->filter()) { + ksft_test_result_skip("%s\n", test->name); + return; + } + + if (test->size_function) + size = test->size_function(); + else + size = test->size; + + ksft_print_msg("Running test '%s'\n", test->name); + ksft_print_msg( "[%d] Trying clone3() with flags %#" PRIx64 " (size %zu)\n", - getpid(), flags, size); - ret = call_clone3(flags, size, test_mode); + getpid(), test->flags, size); + ret = call_clone3(test->flags, size, test->test_mode); ksft_print_msg("[%d] clone3() with flags says: %d expected %d\n", - getpid(), ret, expected); - if (ret != expected) { + getpid(), ret, test->expected); + if (ret != test->expected) { ksft_print_msg( "[%d] Result (%d) is different than expected (%d)\n", - getpid(), ret, expected); - return false; + getpid(), ret, test->expected); + ksft_test_result_fail("%s\n", test->name); + return; } - return true; + ksft_test_result_pass("%s\n", test->name); } -typedef bool (*filter_function)(void); -typedef size_t (*size_function)(void); - static bool not_root(void) { if (getuid() != 0) { @@ -160,16 +183,6 @@ static size_t page_size_plus_8(void) return getpagesize() + 8; } -struct test { - const char *name; - uint64_t flags; - size_t size; - size_function size_function; - int expected; - enum test_mode test_mode; - filter_function filter; -}; - static const struct test tests[] = { { .name = "simple clone3()", @@ -319,24 +332,8 @@ int main(int argc, char *argv[]) ksft_set_plan(ARRAY_SIZE(tests)); test_clone3_supported(); - for (i = 0; i < ARRAY_SIZE(tests); i++) { - if (tests[i].filter && tests[i].filter()) { - ksft_test_result_skip("%s\n", tests[i].name); - continue; - } - - if (tests[i].size_function) - size = tests[i].size_function(); - else - size = tests[i].size; - - ksft_print_msg("Running test '%s'\n", tests[i].name); - - ksft_test_result(test_clone3(tests[i].flags, size, - tests[i].expected, - tests[i].test_mode), - "%s\n", tests[i].name); - } + for (i = 0; i < ARRAY_SIZE(tests); i++) + test_clone3(&tests[i]); ksft_finished(); } From patchwork Thu Aug 8 08:15:28 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 818200 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 02E77188CC5; Thu, 8 Aug 2024 08:17:34 +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=1723105055; cv=none; b=K74NBJpM/1sc1PnW/MYfnzhr+j2vChQIfU3lBXXz9QAlatb5dvPSmK11/C+JqG4Rzcz5h9BDItGiLHhSZ0b1+U3YIBsGprmkJyYiRUmnK8W/P7rMYcIfSnM62qTDVzkPVe1+f0NYBuuoc9T7UJmJ7zvpuQUctmQa4wzI2q5U86o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723105055; c=relaxed/simple; bh=Ns+1fxdSm08kdtmE5k60TaoPkn5o0cedh5wov4OMD2s=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=OWsPZ+NDtfqm6jXxuDUDUgAHgQogJiu/OsgOn7z8hVEk4T1n4GpdK8ht+yKjaoYKEdt3rGKu9vxtGLXKhdB4cb7/a5R+0SH1YaddvgKzzpjwD9y1qGmdP/th2VCI33soM0TRTtP83tMXiT7v4FvIrtrVM6omfDYxPovqssARMmE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IBZMaw+q; 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="IBZMaw+q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63484C4AF13; Thu, 8 Aug 2024 08:17:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723105054; bh=Ns+1fxdSm08kdtmE5k60TaoPkn5o0cedh5wov4OMD2s=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=IBZMaw+qQ3UIbw0tHOmQ75l/zS9cgxy0dS/VomfuFsE9NihOtqzzWUinj+v68lsrA ZDMNE/CvsMaycQeKLTCXaayVOPtVDVJqf58qTOtemqUawMDvaS5puqdqGas9TZBLsD w9QWUMHYAOjJpT5SkKE78xKAkngi+8PEUUyZps7u1J3Ozzy44vwp+8kBcVahHg4c9l wrDAwjL3QtOy8qZ6XKk5btm13c6JVklV3aYht/MXN+si51dqtqmTPSTXHdu/mjmPNT tGWfxTAw0seyhEmb0y3BBPJlze6GM2WrFRbvkANXXY+yx0jIVInznvWcpXvMCm53p7 ApK8pCNT6buCQ== From: Mark Brown Date: Thu, 08 Aug 2024 09:15:28 +0100 Subject: [PATCH RFT v8 7/9] selftests/clone3: Explicitly handle child exits due to signals 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-v8-7-0acf37caf14c@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=1097; i=broonie@kernel.org; h=from:subject:message-id; bh=Ns+1fxdSm08kdtmE5k60TaoPkn5o0cedh5wov4OMD2s=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmtH7Pt250n9U88Z0izycnwrJNTy8HRaEsVEjKz ErcU3cXzQiJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZrR+zwAKCRAk1otyXVSH 0LMXB/9yr+1rHyn3A47ReERM2mxpFBh1kzPItdZ1NEsMB0oVm2CJZEjoDd6rnZ+YO8e2lM53QBX Wkx8am19cBrO1sD2+B6STFI5HNcGGEa9DVeX+SE4X2BiEGidFOV/7Kfh7ED3W6oz1sNFzh0is5X XLHugTDQE+I4Ce3uBAiSQ7fc9fdTAU6dKYSNquskuZSfP6IE9JfcsT9O63aHhB3bwFu4O792Mp7 X8LozPalk9chxwlLrZvDWtQ0oA+lobpkRdwEGRpD/zH4s7IqlT3/PH+YaEx5Xjb66ohTGffx6Hg zmeLt6T6dfKOxK1xfk0Wj4cTtD0BLV1BR2bveF6kwXoKslsw X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB In order to improve diagnostics and allow tests to explicitly look for signals check to see if the child exited due to a signal and if it did print the code and return it as a positive value, distinct from the negative errnos currently returned. Signed-off-by: Mark Brown --- tools/testing/selftests/clone3/clone3.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c index e066b201fa64..3b3a08e6a34d 100644 --- a/tools/testing/selftests/clone3/clone3.c +++ b/tools/testing/selftests/clone3/clone3.c @@ -111,6 +111,13 @@ static int call_clone3(uint64_t flags, size_t size, enum test_mode test_mode) ksft_print_msg("waitpid() returned %s\n", strerror(errno)); return -errno; } + + if (WIFSIGNALED(status)) { + ksft_print_msg("Child exited with signal %d\n", + WTERMSIG(status)); + return WTERMSIG(status); + } + if (!WIFEXITED(status)) { ksft_print_msg("Child did not exit normally, status 0x%x\n", status); From patchwork Thu Aug 8 08:15:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 817816 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 81C59188CA4; Thu, 8 Aug 2024 08:17:44 +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=1723105064; cv=none; b=Nyr0Eu8Ivbg4F0w+lnZhi2rfyEv0GW8HpMkJKydaTY5PpJEUkdOUIfJJ1/8qY8rHy1ioGLlUKMC/kK7kFnRk8yuuz8mflbD5ZJZyut8vQhnGmyOn0g2V3KP7DkyC+7cxgkBj5WsXVma94EHfRkAshvMRcPrxBFmZmg0BoHYsUbk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723105064; c=relaxed/simple; bh=OrLlJZLIdpu8469ekNLVgxT7+eFxGI9yqTN5LZeTdZg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ah1F+O+HjTCPWecTQlwdm+7frdJDgYdi2yMLnQiEHljXM+shDfiT6UTzXEOqeMjnkgUIKjgJjBJpc+1v1jjlIlma0bemVX4rSa54UYCvOkuUQZ4P5pEmsyyU1VLSiMVOuXec0rJZkFFkEXwIVlBHGxp2EeQbNIkPaTym18dD2rY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ioxw37Oi; 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="Ioxw37Oi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82CCCC4AF16; Thu, 8 Aug 2024 08:17:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723105064; bh=OrLlJZLIdpu8469ekNLVgxT7+eFxGI9yqTN5LZeTdZg=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Ioxw37Oima6PVBah/shmp5Ter51Q/TISbJaYTLYUASaTIgzJBlo7dhI/v6psdMgSI MyqkYhE5WLwbj1iOUxpWxDrDD1OBiR6QvzdoJRgZQB7UND7omn0dfxEJcU+PYrYtjt V73qb2Z4dGXvtvO/rk/l6bklY+qkWSiRLbAe41EVnMj/kOjyBBr0Thq5de+OCys3d7 NcvZ4QciF/viz2orK3T+0lvdS9FQ8ixl6cy7xLta+Hg29+GXTtktnlr9lflDJ3SJiH N560rbGY7rKu2amZQUwXQhvOeSDuPigVzhumlCHLYg9gvzkEGEBpWbVVaw8pQuBoO9 iHsLISpy+eiDQ== From: Mark Brown Date: Thu, 08 Aug 2024 09:15:29 +0100 Subject: [PATCH RFT v8 8/9] selftests/clone3: Allow tests to flag if -E2BIG is a valid error code 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-v8-8-0acf37caf14c@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=1887; i=broonie@kernel.org; h=from:subject:message-id; bh=OrLlJZLIdpu8469ekNLVgxT7+eFxGI9yqTN5LZeTdZg=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmtH7PF8qRF2BJmh32y0RmrHBzpwv8UR9FcqUq4 jSMVpDSLRWJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZrR+zwAKCRAk1otyXVSH 0C5XB/0cRSLnJkkl/RUdqEyjK4e+rrlHnGZ3l1sf7QgUfhJAfjRIjUcNwvf0eV0+QBsa+kIIglQ 348zMED92ZaZ+qQbrlbDtdl7vKd+B5QYU2u4RR1pHr2yc7ZJ1vB5Ts0WSnw/OkRyuH73CuNZ6X7 lDjHb0h21KhsspDThWrU2dWOpKHCceJWkYmY+A+wBuL1H2O2WZ2bxg9h49ia1ukFE2U0izn8Qf9 yn/a5tA2PXWGGNYwrm/CtB9l/ATWbWy9c1UGF2qL5SS6k3qXHaNNcM2OErisBRJvQMhqgJMp/d/ MfgG8xekX8ppkSlVEad5S4Y3rRg+FKbmbZYNreOrrsYt+LYq X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB The clone_args structure is extensible, with the syscall passing in the length of the structure. Inside the kernel we use copy_struct_from_user() to read the struct but this has the unfortunate side effect of silently accepting some overrun in the structure size providing the extra data is all zeros. This means that we can't discover the clone3() features that the running kernel supports by simply probing with various struct sizes. We need to check this for the benefit of test systems which run newer kselftests on old kernels. Add a flag which can be set on a test to indicate that clone3() may return -E2BIG due to the use of newer struct versions. Currently no tests need this but it will become an issue for testing clone3() support for shadow stacks, the support for shadow stacks is already present on x86. Signed-off-by: Mark Brown --- tools/testing/selftests/clone3/clone3.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c index 3b3a08e6a34d..26221661e9ae 100644 --- a/tools/testing/selftests/clone3/clone3.c +++ b/tools/testing/selftests/clone3/clone3.c @@ -39,6 +39,7 @@ struct test { size_t size; size_function size_function; int expected; + bool e2big_valid; enum test_mode test_mode; filter_function filter; }; @@ -153,6 +154,11 @@ static void test_clone3(const struct test *test) ksft_print_msg("[%d] clone3() with flags says: %d expected %d\n", getpid(), ret, test->expected); if (ret != test->expected) { + if (test->e2big_valid && ret == -E2BIG) { + ksft_print_msg("Test reported -E2BIG\n"); + ksft_test_result_skip("%s\n", test->name); + return; + } ksft_print_msg( "[%d] Result (%d) is different than expected (%d)\n", getpid(), ret, test->expected); From patchwork Thu Aug 8 08:15:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 818199 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 E280C1898ED; Thu, 8 Aug 2024 08:17:53 +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=1723105074; cv=none; b=l5K/7b7t7o8WwDwZcb1hH5ombw+XL4wkfCknCb07Cm1SzfwUXyzfN7IZ6fjCVchNgJwOZIeKPUXQ+Zo1E30zKL5Mc47yWdUwjV/v9qgwWkAFrm/Bd5DP1FDCpu4AEeh3fpjS6LcE8TXGBuEBrtncmud0lwWzrUf8hMN16x4Tc7Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723105074; c=relaxed/simple; bh=ePficpvEcImrfJYxAgXbKEtc0fEAKvtwRYbBp5UBY5U=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=RDpypQjZskx/mN/9m+RUAtJ4gY1pIAZ0fmfZmQefFxeVxaPnYCZjPAiq2qyad/jo8f9y2YHHD9ILfJmmhShdPpbXJdTpRdOhUcUuVqGlU2/Q5iNY1yQcLIK/tA+3UFgAL3vDZCvnf87JM16du6h9pWmDp+48KhYTYNIUns08Pls= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uslPJluZ; 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="uslPJluZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E02CC32782; Thu, 8 Aug 2024 08:17:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723105073; bh=ePficpvEcImrfJYxAgXbKEtc0fEAKvtwRYbBp5UBY5U=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=uslPJluZIk7AoZ+52rhqYv4bldYUW3R0nKjbrDQWd9DLnQxPyY+D21h3DycL6nfDq Z8PrE82ZlKJ60OhXeoHSQCTqtAxlj1Qxl2vomnb50a9mZuELDjo7WqX8x064ISxdVB Mo3IGDSMBqhyJeTTpU88MHBaBbHpax3ojat/36GCsZYu31ewK9oM2d9Ueo0HczsVNr Wv3vrTppQpbHt2ISffVR5auspKuaNAUyrad8yGLeI4VHGmgJYXT0xFRQ3o9fDuNMIk cKHuHmlfxKZA+9ICqQklcnwyCw77hO15UAfuvDUrSBH/PQq+J9aECIchpylH1VCa97 n+rh92ksfgajA== From: Mark Brown Date: Thu, 08 Aug 2024 09:15:30 +0100 Subject: [PATCH RFT v8 9/9] selftests/clone3: Test shadow stack support 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-v8-9-0acf37caf14c@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=9005; i=broonie@kernel.org; h=from:subject:message-id; bh=ePficpvEcImrfJYxAgXbKEtc0fEAKvtwRYbBp5UBY5U=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmtH7QOIgKQXc8zuHRze2x7rw75u/L6H5dHcUNY lXRNQsbv/2JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZrR+0AAKCRAk1otyXVSH 0CIKB/0VKXyXqakZmhYnnqalOHv07rQ74Uvhm4l74xcz+j+Yo75WQGDcfh455QWu3BJGkePXpIz V93iEBcr3GNXEKqsrboeLVcU6SDD3gscaVhd+Z321LF0w4o3WSmTeH8h9jdxb1uv8UXD9yTZq2D MD/7NudOi4lh0kErU9FCq7IsE2pGERLQuMkC24jrhW+uUAFRvmg0dVWDEMhiuVahFFeqkHknH1j XIoWwJ3+OCdZtb/Y4fYpy5mSvgAvjKP/kh9SV2nwZkuZ5a6C3lHB9g+3suB0FLrAjklRxf9/HKI eXpkw1kJgjrUurgaU1q5gEniorykgM+vDqWzP1GawgxrGs5Q X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Add basic test coverage for specifying the shadow stack for a newly created thread via clone3(), including coverage of the newly extended argument structure. We check that a user specified shadow stack can be provided, and that invalid combinations of parameters are rejected. In order to facilitate testing on systems without userspace shadow stack support we manually enable shadow stacks on startup, this is architecture specific due to the use of an arch_prctl() on x86. Due to interactions with potential userspace locking of features we actually detect support for shadow stacks on the running system by attempting to allocate a shadow stack page during initialisation using map_shadow_stack(), warning if this succeeds when the enable failed. In order to allow testing of user configured shadow stacks on architectures with that feature we need to ensure that we do not return from the function where the clone3() syscall is called in the child process, doing so would trigger a shadow stack underflow. To do this we use inline assembly rather than the standard syscall wrapper to call clone3(). In order to avoid surprises we also use a syscall rather than the libc exit() function., this should be overly cautious. Signed-off-by: Mark Brown --- tools/testing/selftests/clone3/clone3.c | 134 +++++++++++++++++++++- tools/testing/selftests/clone3/clone3_selftests.h | 38 ++++++ 2 files changed, 171 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c index 26221661e9ae..81c2e8648e8b 100644 --- a/tools/testing/selftests/clone3/clone3.c +++ b/tools/testing/selftests/clone3/clone3.c @@ -3,6 +3,7 @@ /* Based on Christian Brauner's clone3() example */ #define _GNU_SOURCE +#include #include #include #include @@ -11,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -19,8 +21,12 @@ #include #include "../kselftest.h" +#include "../ksft_shstk.h" #include "clone3_selftests.h" +static bool shadow_stack_supported; +static size_t max_supported_args_size; + enum test_mode { CLONE3_ARGS_NO_TEST, CLONE3_ARGS_ALL_0, @@ -28,6 +34,10 @@ enum test_mode { CLONE3_ARGS_INVAL_EXIT_SIGNAL_NEG, CLONE3_ARGS_INVAL_EXIT_SIGNAL_CSIG, CLONE3_ARGS_INVAL_EXIT_SIGNAL_NSIG, + CLONE3_ARGS_SHADOW_STACK, + CLONE3_ARGS_SHADOW_STACK_NO_SIZE, + CLONE3_ARGS_SHADOW_STACK_NO_POINTER, + CLONE3_ARGS_SHADOW_STACK_NO_TOKEN, }; typedef bool (*filter_function)(void); @@ -44,6 +54,44 @@ struct test { filter_function filter; }; + +/* + * We check for shadow stack support by attempting to use + * map_shadow_stack() since features may have been locked by the + * dynamic linker resulting in spurious errors when we attempt to + * enable on startup. We warn if the enable failed. + */ +static void test_shadow_stack_supported(void) +{ + long ret; + + ret = syscall(__NR_map_shadow_stack, 0, getpagesize(), 0); + if (ret == -1) { + ksft_print_msg("map_shadow_stack() not supported\n"); + } else if ((void *)ret == MAP_FAILED) { + ksft_print_msg("Failed to map shadow stack\n"); + } else { + ksft_print_msg("Shadow stack supportd\n"); + shadow_stack_supported = true; + + if (!shadow_stack_enabled) + ksft_print_msg("Mapped but did not enable shadow stack\n"); + } +} + +static unsigned long long get_shadow_stack_page(unsigned long flags) +{ + unsigned long long page; + + page = syscall(__NR_map_shadow_stack, 0, getpagesize(), flags); + if ((void *)page == MAP_FAILED) { + ksft_print_msg("map_shadow_stack() failed: %d\n", errno); + return 0; + } + + return page; +} + static int call_clone3(uint64_t flags, size_t size, enum test_mode test_mode) { struct __clone_args args = { @@ -89,6 +137,21 @@ static int call_clone3(uint64_t flags, size_t size, enum test_mode test_mode) case CLONE3_ARGS_INVAL_EXIT_SIGNAL_NSIG: args.exit_signal = 0x00000000000000f0ULL; break; + case CLONE3_ARGS_SHADOW_STACK: + /* We need to specify a normal stack too to avoid corruption */ + args.shadow_stack = get_shadow_stack_page(SHADOW_STACK_SET_TOKEN); + args.shadow_stack_size = getpagesize(); + break; + case CLONE3_ARGS_SHADOW_STACK_NO_POINTER: + args.shadow_stack_size = getpagesize(); + break; + case CLONE3_ARGS_SHADOW_STACK_NO_SIZE: + args.shadow_stack = get_shadow_stack_page(SHADOW_STACK_SET_TOKEN); + break; + case CLONE3_ARGS_SHADOW_STACK_NO_TOKEN: + args.shadow_stack = get_shadow_stack_page(0); + args.shadow_stack_size = getpagesize(); + break; } memcpy(&args_ext.args, &args, sizeof(struct __clone_args)); @@ -102,7 +165,12 @@ static int call_clone3(uint64_t flags, size_t size, enum test_mode test_mode) if (pid == 0) { ksft_print_msg("I am the child, my PID is %d\n", getpid()); - _exit(EXIT_SUCCESS); + /* + * Use a raw syscall to ensure we don't get issues + * with manually specified shadow stack and exit handlers. + */ + syscall(__NR_exit, EXIT_SUCCESS); + ksft_print_msg("CHILD FAILED TO EXIT PID is %d\n", getpid()); } ksft_print_msg("I am the parent (%d). My child's pid is %d\n", @@ -191,6 +259,26 @@ static bool no_timenamespace(void) return true; } +static bool have_shadow_stack(void) +{ + if (shadow_stack_supported) { + ksft_print_msg("Shadow stack supported\n"); + return true; + } + + return false; +} + +static bool no_shadow_stack(void) +{ + if (!shadow_stack_supported) { + ksft_print_msg("Shadow stack not supported\n"); + return true; + } + + return false; +} + static size_t page_size_plus_8(void) { return getpagesize() + 8; @@ -334,6 +422,47 @@ static const struct test tests[] = { .expected = -EINVAL, .test_mode = CLONE3_ARGS_NO_TEST, }, + { + .name = "Shadow stack on system with shadow stack", + .size = 0, + .expected = 0, + .e2big_valid = true, + .test_mode = CLONE3_ARGS_SHADOW_STACK, + .filter = no_shadow_stack, + }, + { + .name = "Shadow stack with no pointer", + .size = 0, + .expected = -EINVAL, + .e2big_valid = true, + .test_mode = CLONE3_ARGS_SHADOW_STACK_NO_POINTER, + }, + { + .name = "Shadow stack with no size", + .size = 0, + .expected = -EINVAL, + .e2big_valid = true, + .test_mode = CLONE3_ARGS_SHADOW_STACK_NO_SIZE, + .filter = no_shadow_stack, + }, + { + .name = "Shadow stack with no token", + .flags = CLONE_VM, + .size = 0, + .expected = SIGSEGV, + .e2big_valid = true, + .test_mode = CLONE3_ARGS_SHADOW_STACK_NO_TOKEN, + .filter = no_shadow_stack, + }, + { + .name = "Shadow stack on system without shadow stack", + .flags = CLONE_VM, + .size = 0, + .expected = -EINVAL, + .e2big_valid = true, + .test_mode = CLONE3_ARGS_SHADOW_STACK, + .filter = have_shadow_stack, + }, }; int main(int argc, char *argv[]) @@ -341,9 +470,12 @@ int main(int argc, char *argv[]) size_t size; int i; + enable_shadow_stack(); + ksft_print_header(); ksft_set_plan(ARRAY_SIZE(tests)); test_clone3_supported(); + test_shadow_stack_supported(); for (i = 0; i < ARRAY_SIZE(tests); i++) test_clone3(&tests[i]); diff --git a/tools/testing/selftests/clone3/clone3_selftests.h b/tools/testing/selftests/clone3/clone3_selftests.h index 39b5dcba663c..38d82934668a 100644 --- a/tools/testing/selftests/clone3/clone3_selftests.h +++ b/tools/testing/selftests/clone3/clone3_selftests.h @@ -31,12 +31,50 @@ struct __clone_args { __aligned_u64 set_tid; __aligned_u64 set_tid_size; __aligned_u64 cgroup; +#ifndef CLONE_ARGS_SIZE_VER2 +#define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */ +#endif + __aligned_u64 shadow_stack; + __aligned_u64 shadow_stack_size; +#ifndef CLONE_ARGS_SIZE_VER3 +#define CLONE_ARGS_SIZE_VER3 104 /* sizeof fourth published struct */ +#endif }; +/* + * For architectures with shadow stack support we need to be + * absolutely sure that the clone3() syscall will be inline and not a + * function call so we open code. + */ +#ifdef __x86_64__ +static pid_t __always_inline sys_clone3(struct __clone_args *args, size_t size) +{ + long ret; + register long _num __asm__ ("rax") = __NR_clone3; + register long _args __asm__ ("rdi") = (long)(args); + register long _size __asm__ ("rsi") = (long)(size); + + __asm__ volatile ( + "syscall\n" + : "=a"(ret) + : "r"(_args), "r"(_size), + "0"(_num) + : "rcx", "r11", "memory", "cc" + ); + + if (ret < 0) { + errno = -ret; + return -1; + } + + return ret; +} +#else static pid_t sys_clone3(struct __clone_args *args, size_t size) { return syscall(__NR_clone3, args, size); } +#endif static inline void test_clone3_supported(void) {