From patchwork Wed Jul 31 12:14:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13748596 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 1B4601AED43; Wed, 31 Jul 2024 12:19:10 +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=1722428351; cv=none; b=NkYhiQsw1GJ50j61tNg9Z9ewAOqlEJy0uFVr5N2G7mJgiPO4BRmSPzqfQlMu0gGgUXVGf0E5rZ/Hpz5MuPLowimfxhG9GqAf2R1yI/GTLYNeqdaWtlLQnlNB2Hl/jgRvqCfldXZVGeS8tN516P641zeQJwntn5enI3B1BHGItJA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722428351; c=relaxed/simple; bh=FizA8c9Fs3+e20frZgIdFeBpWm1//QTTbE58XxIvdwA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=WLIJ4pitnHivJ7E0/VA/RoeebtiCczpV2TXinnRM4qTMnI2zxx5puWfYfRJ4HV4JIz8ZWmSTP55fvUg7zXS/sM7F+AnIbPTRO7x8DJdaA3QI+GyJ/9kNok+mQ3jytQCmnxCd6sSBSaNQ9F1co6kXFY1ZxN19zkvr3Xl7Ei7H4uA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=F3kh8zFj; 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="F3kh8zFj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40123C4AF09; Wed, 31 Jul 2024 12:19:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722428350; bh=FizA8c9Fs3+e20frZgIdFeBpWm1//QTTbE58XxIvdwA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=F3kh8zFjwH4qQ4/La1f41ikMDz5pGToDA5UrmPEo0IVIgxCMgGPlAnogpeX+CmH/0 k/CcNripPqKhp+6fLiJI8qIO0Ywu4txK7Jr0ysNr8L5iI33PCWh8vA+C9aBpPsA9W0 Wn4447wbO4ml+EWwK4njflYovIZb2AiNXkmenKGMU6Il710zm8i7yIZ6U7oM39Ksln e9WiiACd4aSp6vyhqcvkbOuz0rkX3eA3Tn6xgUSDmMX0jxj47LuSUZm2DNqT5jpCS0 EKIQMecYug7NJmHdjqHokXBZYsS0vHLWU9H9J7fOj+QICeE2xr4UdMxR82RS22l7Zl oLQqP5II8Tnfg== From: Mark Brown Date: Wed, 31 Jul 2024 13:14:07 +0100 Subject: [PATCH RFT v7 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: <20240731-clone3-shadow-stack-v7-1-a9532eebfb1d@kernel.org> References: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@kernel.org> In-Reply-To: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@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 , Daniel Bristot de Oliveira , 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=owGbwMvMwMWocq27KDak/QLjabUkhrRV2quTOH6m32588m6eYmyjYnb9xogqyQdrNhsltApNOPhk Qll5J6MxCwMjF4OsmCLL2mcZq9LDJbbOfzT/FcwgViaQKQxcnAIwkVMX2P97Nc/z+amQNO9XFFf+nJ 8n7Zca3LrEkmxfp/L9kwWvk/KL2ndzoq5/nqSbtaM4vkimr6ee5/2phOVTOETdJBkeVSSmKG7otHlw PLn7vf7s1PV7HVnb19ZLbIqs6hBxvKDZVXLv+NLXC7YwiSapXjd39Yw1/LD+vtrlMPH1IYfFfcw1LX 0lTJ0eRFWal/a1O7EUu5/VZ2SMchTmzZ73lTl5wlw+kWlOm00efOPg+GpbpZN9QtXNIuNOwcmMi+yH 36fPu73H0+XTn71q7GlJrd2TJRftXp/n6esomHNF/vdKie2tSaHc3pVVxf63PI7wqTSwv36TmMOV8X Fr8XrtC85d6dzTuJ5yL+cu5FAAAA== 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 --- 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 Wed Jul 31 12:14:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13748597 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 F38D01AED43; Wed, 31 Jul 2024 12:19:16 +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=1722428357; cv=none; b=TWAQIbx1sgq5SUd4ZceZAeazH3qS9rI2xH4Xe2vh87Fd3WAJwY0DzI1qUFN/jo+OVmfnQYN8iwOwGJB1FwvkB6LjKS8qx7hpcvZGmQDM1FdclntFbvihSQA3kwLSq6jo78wULu4Jw5gElFbAYdVmbAoaiclrteWbQmjttCCmR/4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722428357; 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=FPHYH7pAYMAPTzMUQf7vBFqxTItYmkXvmlNpWdM0C2PTIDmYK1Ll7yhgKRfoEKsdbsZgMWv14O4MAzxrVHXtccs1L4vcBbNnYQS3SdHa8VbCDV0PZ2G53RhmJ1WQfA6SCMN/CfVJa+OKHZ4qFTe3XLuuB9eJWYyF+hrLzb8CFeg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OesBSo9A; 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="OesBSo9A" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1EA0CC116B1; Wed, 31 Jul 2024 12:19:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722428356; bh=vdpMp/+tnPvEc9LtWm/ZG/N3nxsEXfR9pkA/QLvguxA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=OesBSo9AHMTn/v9XY/iVLoA+OS7GdObr7jCMs9akb7TlkAP0T/DyCDEBLKpDCI66t EfoLYynmYTIXL8kfnYocmt2o9ZNE4rxcdrkb51wlEu6grtAOBLALcqVSPX+hKNxYsF qAryRW/BqFdkOnhoQt0qMJRAC7m5yKcC7B/R+pxkHVow5+NUPzsJYA8oiSa9pUTVgv 3OqhsT/+jgemoAhu1hPOBHzgdeCEPfC43sRTuSkItXu9vTdoIcSBzEDHAiquLpSgl5 NFt17cHbbmQ1dTm3U5JUBYeZovKvkPQ6QZNRz7FWk6VG3MV3G8B1KC7N1cBkgxvRv2 s7oxgppGrZ7Xg== From: Mark Brown Date: Wed, 31 Jul 2024 13:14:08 +0100 Subject: [PATCH RFT v7 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: <20240731-clone3-shadow-stack-v7-2-a9532eebfb1d@kernel.org> References: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@kernel.org> In-Reply-To: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@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 , Daniel Bristot de Oliveira , 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/pANAwAKASTWi3JdVIfQAcsmYgBmqiusyzhVnDy2VqHQ8+Yyi5MHGEMWyH8cVVRWIRO0 Ib0o6hKJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZqorrAAKCRAk1otyXVSH0Pi+B/ 44VvjDe+MfQ6/ODA70yfznyRK3SNr98lTr9KR7Oop+QbLlnCrqKZCTQt/53uM7GNzmcuZfYMTKGLVt osTD4gAzhoE7a3t7aKFp8CvwzW5EImJ4XVGIbjIXOK5Uu8jP3yZTehizF/cH9z9/Mi4l29tzN7w0HV BOo6RlfMyMc6OmslWBWk+KkAcwifodPdD793UFlUa/ZAVAxJUPvUBMnQVCH1KJV9Ro+uYNHq0Ua6Hk pJc9bRhk6GWrnOjiC6ibj1YY6QqdRkIxd6W8o6nteEeXg4KX/ogwfI4eeccm+kBYTbtkDj9u9F0gRs 7wcEsTYOg1DkT0LniEL9Q9Dv57U+6j 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 Wed Jul 31 12:14:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13748598 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 009861B0139; Wed, 31 Jul 2024 12:19:22 +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=1722428363; cv=none; b=U4CFinKcxIWX8gZTWlK1diN8ZHs/qMKHkUzqEkcpME/XdJw8jo/R7tgiNGRnzvVHBDZy2KusuWA1F/Hj+v1NFhBizeS29JwA0QWU1+3YjBgoAdej/5n4H70Kv5a5RtgFyueip8Sxi2pCI7v3awFvDjaSs+QcTyNVkpylAWFyYPg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722428363; c=relaxed/simple; bh=+orwRfvizHfGXDNjTwUwjThxjP5rZLiehiVTLaa/d1s=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=qLB2V0nF8JRNLA22IIMRGyiYNIvxuLSLlAK1d+y504LPvb7SLHYr3At1aFY7gtNCi4+8xIT/gfTFNIwo83/4yIp5EDNYNVRF7f6QjGcd/u1C9EApFAv/crviTWeqZ5QkVNH2Fnxl1HpvO6uckvtVJrEiU/gxOtlLEr4aKZVzRrs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bWOs+qlv; 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="bWOs+qlv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1A27C4AF13; Wed, 31 Jul 2024 12:19:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722428362; bh=+orwRfvizHfGXDNjTwUwjThxjP5rZLiehiVTLaa/d1s=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=bWOs+qlv4epwrENJqKaeWdap3YUIqdJACjgPkfeNIjyzZRd36GEAl5uaQNKXtW43F 2ezXPVtPp/7MRuJ9J7KdTRvaNuLnSg398DYW9CGY4N+h5ULtndjhwV0gIzM85xwDZh jueBKxZDxpao7NZgu4FPF+UqeHVg1EGAFG7nfDFYdkRTOzzFYIDYZxd0ERBBHpjDvX GHbBM7Ig8gWREsFGHB/pSQNiot+y0oQwqKlAgtwft/UuiRFVzUj4hWRHEsFFG3K/74 ss6D4S2HIcVVrqqNJLpqsOS6Lr8RuwAY2ThY65Xaw22zHGWfq8Miq24Go3JEN00wX6 JCaOjir12V6UA== From: Mark Brown Date: Wed, 31 Jul 2024 13:14:09 +0100 Subject: [PATCH RFT v7 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: <20240731-clone3-shadow-stack-v7-3-a9532eebfb1d@kernel.org> References: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@kernel.org> In-Reply-To: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@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 , Daniel Bristot de Oliveira , 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/pANAwAKASTWi3JdVIfQAcsmYgBmqiutmyS6KTfVaKVigjkcIuwaZLNIiG+JN6PPqQ/s xUOeyxaJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZqorrQAKCRAk1otyXVSH0Bm4CA CCun+l32pjSurBbTGV9CwVflFXomBm+PLhUX3xQqbnFO4r7Ri/kFkaynaqnhWQwUNPuZDbJKnfkvpJ e7ZdrZSa+pNCYjLQZ3SHMoN9q0dJ6L6yvjqaoEGXEY3x2xh+gW087xJDgfq5bczoUn9OMdbWsmofs8 QEWE9kqlYyejLuEfpF2DR9E4ZqJtZ+PAEr8l9ZkfVh8q+ObCJyCVC86HuVVTC2SqKP0U2yNBZeUpkU KzyJa+8qy6lCtw7XLKkRaAnRty3ofxk0nBUb5vzYlmrBuYzzPrIL3Zg4Sofktw5SdoQogisuy4OnzT 3Li1xi1aOx/lujfdw3JdUGzC5KwIyz 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 --- 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 Wed Jul 31 12:14:10 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13748599 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 E26CF1B151C; Wed, 31 Jul 2024 12:19:28 +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=1722428369; cv=none; b=GF2BjoUhp0eWJJMKp31l+Mzf/50lug9Ud93cDA1dCibRvxnVN0g1+QHD3HdfJH2FTyYuYoJ5wIFXLOBpx0p5zl1EIFUvpDAW66pAMXyDsL0teAtqrLad9XUGgJIvk6BbJ1nguS2KTOQbEv93b/YednY6gkQCf+Vzasdn58wTT1I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722428369; c=relaxed/simple; bh=x56zzA6iyEl4hYlVsxr4pVDsnY2Epg1Ay/M+axG7wxA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=DWOBc1aJEakEyoe2R27mVw4vSnP+jS7kNHoiOionxw4BcKRwa71oOP6WUJViSi9zgQvpCcEteWZ/WUVP3+EPitUMgX4AkUHCVLTsRZbHPCsJlQZH6rIey4TUqyKkZeFqZFIJXDY/l9h0TztRgrY5iVhJmYzEXS6xDk/mAmqq9Dc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Y1V7E7tS; 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="Y1V7E7tS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0818DC116B1; Wed, 31 Jul 2024 12:19:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722428368; bh=x56zzA6iyEl4hYlVsxr4pVDsnY2Epg1Ay/M+axG7wxA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Y1V7E7tSE58NuZBzQ65h8W/2ESLa8rcUSzqP3NnCrrYajot5hjHaVY3jC1XCn8IA3 7fsfm1mjQPpcWFzk3LI1v7amGPawhAulf9KCH5YRuhGREneQ5tH7h7dxHK62pAGla6 vB+pcdI34zU6i29KSgh4i/ONTqh7rS1fI88u2qF8zk5FUulzkyvTziVoqJ2sc9AVt+ bRRvAjjDZXiPXzxwQGDSK8Fwv38RYQC2EvzD8gb9qNeTZ9m5LhXVWM8RVDrgw28dkq OUm1wNSYy3L4s/UdsReuNsgymqYtWurvF6+nUMDTiXuR5B/pRYUPAYy0bsaaEOZlSN A7YqRmbCRNdBg== From: Mark Brown Date: Wed, 31 Jul 2024 13:14:10 +0100 Subject: [PATCH RFT v7 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: <20240731-clone3-shadow-stack-v7-4-a9532eebfb1d@kernel.org> References: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@kernel.org> In-Reply-To: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@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 , Daniel Bristot de Oliveira , 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=14271; i=broonie@kernel.org; h=from:subject:message-id; bh=x56zzA6iyEl4hYlVsxr4pVDsnY2Epg1Ay/M+axG7wxA=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmqiuuY9ajMjER9WiNW+tbe1HvU4h+9UYrwco04tK6 H4kLPlGJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZqorrgAKCRAk1otyXVSH0EzeCA CDg9vUtgRuW1eZ3HcZUHCiQpJ9rGPEmP8zIrzl+qxwf79RKXUfnZv8vCa1Z9O10uhDbE9F1wWt3ZK7 Wnhi6blrLP5gyixmWXbCZra/NgcTnZr5+e22r+2JUsAfELYs7zMZEQGwK849navDctQdmr0YNoayKV n0ishdWvtajiR/1ZFSNmrgnOKFU3UelJuGpz0gzI9KYQDqtU1QELpIpoC7jlcWkoUcgNxFiiWbRZzV wOpDcayRvMM3ZXjSuIY51rRdBUO6LW2iUTc25T67ulkswTGux50uOTzw0r1b7oNlqdnO6g/LUEhnHs aeyW0y0oKOG0MDGpv7SRqM45F48EV0 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 --- arch/x86/include/asm/shstk.h | 11 +++-- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/shstk.c | 104 +++++++++++++++++++++++++++++++++---------- include/linux/sched/task.h | 13 ++++++ include/uapi/linux/sched.h | 13 ++++-- kernel/fork.c | 76 ++++++++++++++++++++++++++----- 6 files changed, 176 insertions(+), 43 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..1755fa21e6fb 100644 --- a/arch/x86/kernel/shstk.c +++ b/arch/x86/kernel/shstk.c @@ -191,44 +191,102 @@ 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; + u64 expected; + u64 val; + int ret = -EINVAL;; + + addr = args->shadow_stack + args->shadow_stack_size - sizeof(u64); + expected = (addr - SS_FRAME_SIZE) | 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)) - return 0; + if (!features_enabled(ARCH_SHSTK_SHSTK)) { + if (args->shadow_stack || args->shadow_stack_size) + return (unsigned long)ERR_PTR(-EINVAL); - /* - * 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 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_VM)) - return 0; + if (args->shadow_stack) { + addr = args->shadow_stack; + size = args->shadow_stack_size; + } 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; + } - size = adjust_shstk_size(stack_size); - addr = alloc_shstk(0, size, 0, false); - if (IS_ERR_VALUE(addr)) - return addr; + /* + * For !CLONE_VM the child will use a copy of the + * parents shadow stack. + */ + if (!(clone_flags & CLONE_VM)) + return 0; - shstk->base = addr; - shstk->size = size; + size = args->stack_size; + size = adjust_shstk_size(size); + addr = alloc_shstk(0, size, 0, false); + if (IS_ERR_VALUE(addr)) + return addr; + + /* 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 Wed Jul 31 12:14:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13748600 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 B15F61B29DA; Wed, 31 Jul 2024 12:19:34 +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=1722428374; cv=none; b=UurbHIWTXblweaekVM2WxMGrodYr7uIHR3a9bkmpysN8k6yRAGa/UxMrHCxthaNa6NkzUCiDTpSRuTH6rQ2icQIf04JUVbLsfha1KsyhMJIQxteEmWAlNmAgdlMVvr2P45LFlokRgeUV4cYB8MVyBh8zah8BGQZZ2c+b5I9dk8k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722428374; 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 , Daniel Bristot de Oliveira , 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/pANAwAKASTWi3JdVIfQAcsmYgBmqiuv9nAXNTzad6mi6/LJyQNW3JnA0igS4K4G/Mxf bbfpB0aJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZqorrwAKCRAk1otyXVSH0GuCB/ 9j9XiiEOtEOi1/O4et0H9uIvHoYKcdjA6c8FWg4z3Z5keZPVszhDrao7xk2OdU4HLA3qsx2GQ0We/J nzqkAP8kpaD7vkiyM/CQ1tMOXYy1uFh6/oa8raLaKBz+g0ZpjeIVvHyu8g7yCDTi0PzEBhDvGQMzY8 FFQbAsCPBfuRbxuN3bW+hDsv6AOT8+n0SmptxAOupN9j7i17vytPbToPD+r5lIhSN8r6lXyxNbrkMP AZwIX0iVfhyIAyalVH0PN0vQcUCez31iwV7K3D5PhDG+ZlZXN6YPFCg2vbbjfOFaJDPMFZ03O93Cmn fswDLwnpkonYgiDlWCkey3U7kujBhb 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 Wed Jul 31 12:14:12 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13748601 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 826A11B1415; Wed, 31 Jul 2024 12:19:40 +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=1722428380; cv=none; b=G6b3yz+63Wn8ymoixSffIwU0nQDR1560IQhSiJm/YHC5DjGG5SdQr8nXrc7n7xp7c8/vTlL+EELkozG/Bkap9G65BHNSbalyKdl9pynDVLX3xc6mikR2x6I3zebXv+D0WFRtppEVisJrkIlcJcJq8ozrm4VvxS8VXLZffTu4vEs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722428380; 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=U0n8ablWGEXehek6aqiSadbb2C/KvCjtzOfu8isCLbubn9B2gQRt7wn3go6t+Peh4IMZMV4rEq8IChU/TBMCOSgCj8j9KTyBIgyumPDhh+X1p0IzuTAv6++78aw3O+wMe6VVH1iAeidzmuQBV7HxBI4NrDfHphNu9TrAKEviA5k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hznVxISx; 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="hznVxISx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0D61C116B1; Wed, 31 Jul 2024 12:19:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722428380; bh=7/H/C/HH1SlOixEC1xQKfbpAfSVTyHxGoHTFJYjOHFU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=hznVxISxqWW13+0irAYMoUjwm1sLRSt42tudUkBu2fsofwAtZ4KLaXXfyRQdIjH/g f04bc+u6nddj8IcHdFgBs08LMFvF1IbBJl2+SLH9QRAgHfKwnfyOIrTKU0Fbtw2g/W /QZE/2z2hUYfIfmi94EK7oTE0CYX3iwecC0OWyoc/rkFWPY36PejU+VPBKZHqq43Ai B5FWEUog3UMvwRBLQbEtvUvsb2E1YJU2FVNCNgalrAzqOvEhtg+ON9QFynvY26Krn9 qNuvRrcjbLGLVNmL5s+PsebEENUKbfAHNHq4fVQDcxL3P7ROwDznBWNybbvGHcXVFu 4/vBzfX5G3xqw== From: Mark Brown Date: Wed, 31 Jul 2024 13:14:12 +0100 Subject: [PATCH RFT v7 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: <20240731-clone3-shadow-stack-v7-6-a9532eebfb1d@kernel.org> References: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@kernel.org> In-Reply-To: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@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 , Daniel Bristot de Oliveira , 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=owGbwMvMwMWocq27KDak/QLjabUkhrRV2utLpdJ6Nz63cZ/UGP2aOf5oxZEELnbZlNTnL9w5rsvs teLrZDRmYWDkYpAVU2RZ+yxjVXq4xNb5j+a/ghnEygQyhYGLUwAmMrmM/a+4bKRorkhj8QaBl49fFS 1NXh318KPkNxXJajMWPbkUPp+Nagsvv6uZ8bFx+65m3hjedRs+qe0xXVOUJjv74OrnvcIq125KTjE5 6XaI77Uk+3WTTP8u9U2GipfDlHO8zRWtejymSNoXHbmrcEpHgu/xvZlLLRmX1LCIdzh0mWWdn7pT7z rfrcNSrSxrond9C+njCjs8d7uWQlK07v9djt9XftJd/7xy5lOdvB/evGu+LPQTLa+yuKe+qX773cD8 aBeJd7JXhcL/lItaZGwK9KmUFlcJOOPTopcTFTlPklFG9ZHcvx2PXQ/EMb4trZF8dGud7M+etYZ/mW xLK7S3OjUpBNxSWV+30M7veMwjAA== 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 Wed Jul 31 12:14:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13748602 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 7211D1B010D; Wed, 31 Jul 2024 12:19:46 +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=1722428386; cv=none; b=K3YLwJSLy4pRBKvMHtoj8SMkt8mZzAsoHXZjdn+3xDLfhS/VJpLsbAmyR7ExfR183tvOtQ/8Gvki/uxNT4f1y7VjZpGqkMd6Jgm6lcuVyNYmgemIwYL7q1ns78/cFv8W9QvCD2o6sTLmnW9hwBtEUbjPT3Ou8JNHfzL+uc3TupA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722428386; c=relaxed/simple; bh=Ns+1fxdSm08kdtmE5k60TaoPkn5o0cedh5wov4OMD2s=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=VtlhCjiYFdA+KPdtZniOL/TTd/9gc1DHyUG9ESElGjxecFmkH/BJ+AP0rah3hCUKdm8p27MVTvTzybA2Lsnw2BsE8sXzZejI+5+NrG0KxKT87bXm8m8grxFGIB/bCCk1PAMmvW47+lF031EXDQoih6bRgqlzuv+bD9QcCCpBNvk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ht8q6aAY; 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="ht8q6aAY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DCE0C4AF0C; Wed, 31 Jul 2024 12:19:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722428386; bh=Ns+1fxdSm08kdtmE5k60TaoPkn5o0cedh5wov4OMD2s=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=ht8q6aAYkmsoxJWrvp9DVOsvJNMUeaUQYvmi1zNQm9HZf+iO9FL8mW3fWpfmkqtLj gSX58F7+JZ1teV5C5A4X1FhoJ08iwztwP+UkEc6iFS/0QNIEWw8xJguQrZFKY96oDT 0ln0u+o1diDHV31vAkwd00JUStGjZ4cRC5ALZTqIy46ilRjP79Bffpz0LCSrpCE1vQ bu8lq814gDACrI7wvvwG14vw9wMCzh83CT4WvqPGsUqBWQ71RJO8WGDj6r4wF4Fy6G KFzZRWm00lk3t1JVnllNraQqPiFh7ivqZuSx+V88aP7JVfn92nMWAfLCFho2lpTp+o 63x0Wi7qds+TA== From: Mark Brown Date: Wed, 31 Jul 2024 13:14:13 +0100 Subject: [PATCH RFT v7 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: <20240731-clone3-shadow-stack-v7-7-a9532eebfb1d@kernel.org> References: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@kernel.org> In-Reply-To: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@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 , Daniel Bristot de Oliveira , 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/pANAwAKASTWi3JdVIfQAcsmYgBmqiuwbcO9UTdUesirwLQsw94zrJDokDcQEQcmEH9b Qqiy90KJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZqorsAAKCRAk1otyXVSH0PcdB/ 0f+JoYeSHm2g+j+gFYmG6VcSGazpUHB49Dyho4aDTQtJyufbHcP9xIKuK/Lj2BNApVkHbpDpZ6NSUo fWjsOzSTmJYXo4tpllISxzZDvIb0LsHVu+IcZ2jrk350lhimnJ0stdumPhBHUaEb5LXUV0ZoN+viia YVcWnZfGDq24L1sUguNdo04C2FKqW5V16qkIuLKSt7ZP0tLB2grNxPE3UUjZTVJF/84y4RYvtzWp44 MoUOZvWbE0dxn0Ug2qbpSLYjkn5DQxcgkVfOFaASX/qHqnc4lzO9/AwBK3m+FjBW97jqTkH1k3heuH e0Rlk9HWFAouPIVDwI0s8lRJb3zU6U 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 Wed Jul 31 12:14:14 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13748603 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 69E2D1AE853; Wed, 31 Jul 2024 12:19:52 +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=1722428392; cv=none; b=b/vF3l8hVkETVce5cMR6c7PiehENd3rjroiSuSp1YGZe+X8JAHeUHje2wOfU8aFRTiWlgDia68wchOH6dhKYNsIDA3pA1tmTTK60Pde56mLWtGZyM4pxY2hswub7WInZ6OZomLCPkGu1d+m+lSPh39NIDXmJvht4yqA1MEDzTD4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722428392; c=relaxed/simple; bh=OrLlJZLIdpu8469ekNLVgxT7+eFxGI9yqTN5LZeTdZg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Sv6vx91AO1kyiBYIJ82JHAibYGVrLjCkNns6EiM49i3eqQaJnydZ7YJ/FfZVc8CCoinBrNw/nJ0/UNsiPrPvLllUdr2fHuDEn1yjo0Lk8fD2Jckp3U8xFR83q+jHdcUuvuGkcFHyG9p9eEBLZ4dM2aYrBW9EwTHi0iL4UL/+6Ns= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jOFFvtqM; 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="jOFFvtqM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76FC3C4AF0E; Wed, 31 Jul 2024 12:19:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722428391; bh=OrLlJZLIdpu8469ekNLVgxT7+eFxGI9yqTN5LZeTdZg=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=jOFFvtqMOGTGoUH5asW8YOPnPFK/+M3cMtk5WN2yWsB7hVmcUrsyYQtza0vG+0FFA c+Ru4JhfFyQpZSmYibj0EATrJ/eM0sgoYOkqh+HHtp0Ekk7ZOCds6hMY5DTdP0D5xr Eco0kR1Ebsvi/8m/S92+2Oz5REP0qn0b30B22FfBUK6NzDDTRtLUIFicLGgLm8NGaE 57pUX9EdMWxPpR2p/Cipp5xgsF3hZfCKYocrmkd0vuaUb7TgIs3HhRvHzRe0LoqIAo y6aOETfc01ZYRgbNCGJNLiOHg+0dInUZe5FSnarbPre/hUAyyAg/MrU/6SzjdvJRiv Wg9RwXht2V3ZA== From: Mark Brown Date: Wed, 31 Jul 2024 13:14:14 +0100 Subject: [PATCH RFT v7 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: <20240731-clone3-shadow-stack-v7-8-a9532eebfb1d@kernel.org> References: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@kernel.org> In-Reply-To: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@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 , Daniel Bristot de Oliveira , 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/pANAwAKASTWi3JdVIfQAcsmYgBmqiuxOoTUUwb/oJnYCd+qB32Ynk8XPuZ3cOEJ8w6u uABPoKSJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZqorsQAKCRAk1otyXVSH0BEnB/ 9vHf4XSsUVnoB83DVXXn5TSfUE8u8e7JrkManpAIL7gqJCGOQMDhTxxn2z2Oc4/DXUyFWcu4wCXuOz FJoX6XVItKjUCUpjNZGmWX8A6ZqID0txxaJcOjVqe+21cpHITZiaV0ofT0SGhRiMYxj4qod+FT6gsp 53og5bZYZBkq43TWWyQfywZNU4coMpRByxDJF2DVFDADAQznMooGuVyR2noV7aMVtUlozit0Oq3I6a QvwFmMj/RiJaV8wtZ5HI50QnyZZT8vjqLSnDD8Ejs9xzZdyw0b8uU0CKEDLcYV82TmW3WATQUIdWe7 WuD6ahBlfs31DoXwJtMQyDzVDlODpt 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 Wed Jul 31 12:14:15 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13748604 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 5E0312E40E; Wed, 31 Jul 2024 12:19:57 +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=1722428398; cv=none; b=V6Q+yyf9NW/r2y9QC/O7Dr+/5G6qt/jVWTSNl1rc40I5+t9MhfLVsDdT8uxYCllkU/P0vxguMHJnKCXq8QpY41GD8bZdgJ+WGuMhIG+yRQfikDa/qtATYWyuI7krSpCroep63FcFm8Qhb5X0A/YMJcG6CfvNFBIXmY27VCtLkbY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722428398; c=relaxed/simple; bh=ePficpvEcImrfJYxAgXbKEtc0fEAKvtwRYbBp5UBY5U=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=psLeIQtS5CE17txm+XOpubE/2dFpMlkM3VXFiuQ3Kl8fS5Mrc+8iIvqLUqfsxRiCDSIxu+VlrngeE8QwJ/I7ok/sFWmy6dGedmrKioyxlAxvOTVDQ+OUSIX9IC+SdCHW29FXvXoHC1t9MtkVvdef4QKIF/CXQtl3RXEG3Q0T01c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=N5z4LPHT; 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="N5z4LPHT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BDE8C4AF10; Wed, 31 Jul 2024 12:19:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722428397; bh=ePficpvEcImrfJYxAgXbKEtc0fEAKvtwRYbBp5UBY5U=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=N5z4LPHTw2OgDbdtQeBybzS6XIwOGL1fjR7KFUik5rxyoEBjxaQ3W3drlCakhlZUU kUlRwucPRuSOirr0e76ZTYIXP5pbKtL4n04J0BrBcMtNHhCRxJHLEBLKHtSBI7jchV aSdf6/dyLyREZfeQrxyL3caZS11DCrzu1GOUFdOluidelvyqy1JIh0LzqkuYUgtvni 3R4rXU1pRokjBLJ0y6zEvXOuCEseqRnzCighZTdsG0fZRNuCsrv9iXY1Ci1RtN/mPn flgV9vKEi4QOf+jtQYlEnqoYd76C9KZRg+FGJdQTxBF2q1Y/h3fPBrFsr0MBi4bZsV P3hhoPeWU+lOw== From: Mark Brown Date: Wed, 31 Jul 2024 13:14:15 +0100 Subject: [PATCH RFT v7 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: <20240731-clone3-shadow-stack-v7-9-a9532eebfb1d@kernel.org> References: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@kernel.org> In-Reply-To: <20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@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 , Daniel Bristot de Oliveira , 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/pANAwAKASTWi3JdVIfQAcsmYgBmqiuyYPhBHao4vXI4T/9r+3pdRhGkDCR1z5IJffA7 XKBMIBCJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZqorsgAKCRAk1otyXVSH0M2bB/ 9qTutRPtqwO+Sjefyr7BuGVaNCBNpazam00SDX9Wa6x44sUVX5MESm/Mqs9iYAKE3u6NJXkod3gsbl vQp/k2ie3jsOa7BMDxbo+gl7RWEZn9GqrfCWtQsKzvh8Rlj5YXpjQWcOKVxYGctLpvYaH/rNEHkBGK TUQ/bWlQkwgt7l9LvVkaU2QOYTKc/h4osnWTHmbI6sd9mgspinThJG7DKYHeguNq+ECbvMJipAt1L9 59Zl62XFqjmEPjsnEDPiXIr7hFH+fWsXPhLR7FKGVmWtZ3UKLQD2UdkMWniYweuwUwlPYMU+K3Rnx9 Sqbu/hHkM+pjZLAtCBJ4XYDRNL68XQ 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) {