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: 815817 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 12:14:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 815816 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 12:14:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 815815 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=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=bllXNNuKyvr/CPxrWt8hntubRonWPLTwEqdMJ29MJdqzTZIyC3Rjd0iNvtD2/ac78Dejw2EMq9WW6RsljlVbD4Xq2GP9Jbm8XGKmyRfTKxwN0mq3dU74E2JUIz7twh2S88MmYzjDAUyxI/zs3jG2FrqFAoy6IPK09BZRvYAeT2o= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aW2HY8+I; 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="aW2HY8+I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D755AC4AF0E; Wed, 31 Jul 2024 12:19:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722428374; bh=A6PuiVWBdiPH6Nr/YX1UnFJ8RTIAC1FidWNruHY9Zks=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=aW2HY8+I0zEnqLmV92KvQNoP+0nx87JB6F3ibWQRE7q0OBFlqhlzKxLHDhUUO8OEb fATyiOXXHOvkhdlzqfDXGdOVUdjYjvmdjx319idtAh5/fEubWbAATi1/hir9GXVQvR MWQJp7Iaexc/pbDxaaE1WgIg+6Ifv9q7MqCzYy5RfwiYFfaUPMK3nRtW8HbOhPuyw6 uHXK6S+LzhkgiiUTnri6eWCa/XScl24lpcxQ/vEdnlR99fBVfMYMS+tkgHvuLBzuji Ka9duASceCDOUCQqM5J9CqlO+gwELEdIzENf14InNeFxR0rE9YlnzMFW+J3TOPurTn cou51WG8/wtcQ== From: Mark Brown Date: Wed, 31 Jul 2024 13:14:11 +0100 Subject: [PATCH RFT v7 5/9] selftests/clone3: Remove redundant flushes of output streams 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-v7-5-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=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 12:14:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 815814 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 12:14:15 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 815813 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) {