From nobody Thu Dec 18 07:09:38 2025 Received: from mail-pl1-f182.google.com (mail-pl1-f182.google.com [209.85.214.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D7F7B1802B5 for ; Tue, 30 Apr 2024 17:37:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714498627; cv=none; b=U0IkUd3OZryiX+YelVcoQ8FOXHRhLSimL6wf7HPHnJzL1SpCu7bPsK7qEWDcUSAv5ZkB3ioMoBw8jtl1Vi0s9nZD7UhaFbiPCv91P/dRnTEOKZPfGEhVcQOPzJocgF/evOnZnlDkvGxKQku5E6uHefxaDydbJpbeOfGxOrOkWfw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714498627; c=relaxed/simple; bh=HwleHbMmvyClSw2hkCjqzzitfJIFUgKSvCPPJPbOXUI=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=JyDJ1GjaPhYo+wZf8EuhuZR+80mLy+G3BkPP/LJOLPTvhYtX4+lSmdUHivVtmUDsrWWMciASXa3JOWSNG9Q0+r5YzvQt54l/RgS4tIRGhuYA8Cl4+QEF0t5pNUjq/qNYfaaUIxaZBncCQM/eZsARaW4svSWS4rPO4/zWQpR+FWU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=ftHtMFai; arc=none smtp.client-ip=209.85.214.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="ftHtMFai" Received: by mail-pl1-f182.google.com with SMTP id d9443c01a7336-1eab16dcfd8so51869985ad.0 for ; Tue, 30 Apr 2024 10:37:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1714498624; x=1715103424; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=H7TCEkmJU5v9XbqMkMv7vhbRAU+5JxBsl8E5GjM9uj8=; b=ftHtMFaipxj1hya2+OVkgdkd2QSO3ryMoAfBnkywgVaRrfaqGZL08O474COmBBxSWC mbqrsACYOo7wb81W8kMSBXyqih1lnGo7UHAR+hJhXVyxTqTtf7E1v9xNUwlMG+XHeYY0 b7Udlsl8Wzmvg8yzMJs/DckhvgShi1agj9Iw4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714498624; x=1715103424; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=H7TCEkmJU5v9XbqMkMv7vhbRAU+5JxBsl8E5GjM9uj8=; b=Q/0ZT1MJR/08DPXCcMWIiZlyLmI1TJW+oMA8WJBFCSsezR6uCxBJcKNLoCzcntbp2j rGhjl8orflPkcA5gB9BKoBgDdrmBv5ChWQsgQcGwVu4j81jUXvodycPibNXeiWhn7m2H PxOwqSV9knJmd2TjNJee3Gty5IYGi1jP7fPYzHdXja3NJl0J9RZsVIig+CcbyvOIYhrB zsFtxbnZIXv2gTkvfyUcN8du0A8W23R0dqtoPwhjmmUfBoigaRXgqskXRWwT0wbjHayD kfYPmDzrwkrI+1FajdtEKmx9unnsZj7unrfXXourunzMhoEAxXzj2/pg3nEwol9hhs4L pFrg== X-Forwarded-Encrypted: i=1; AJvYcCUVnwMevuquzkJ1vCwPXcxvzEIbtCggMgW+xzr9Yi2Te6Kxb+TCDmj19jmQEJ3f/hRQZ0YHd4Dmeg/41GWkfzZbu9gIX88nbyUbi5WS X-Gm-Message-State: AOJu0YwTljSdCyMNRUvX/R1Hos3mGpzs0bQWvgGxjZwdtydTIYDNiqBW hsD+EBmDm/UQ4RqqNf78l7fIoBc5lCxRYdzOPvlhsTmzdhtNn5zwPHIf7q/41g== X-Google-Smtp-Source: AGHT+IEgJyBdK8IaFbZBEcXMW5JQxffHszntW2uwXu4E0cAx4+VHUvWNNAEX/51rVj/TOrVaFr9SYA== X-Received: by 2002:a17:902:eac4:b0:1ec:76a6:ea9 with SMTP id p4-20020a170902eac400b001ec76a60ea9mr98049pld.26.1714498624229; Tue, 30 Apr 2024 10:37:04 -0700 (PDT) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id i12-20020a17090320cc00b001eab1258197sm10400741plb.144.2024.04.30.10.37.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Apr 2024 10:37:03 -0700 (PDT) From: Kees Cook To: Nathan Chancellor Cc: Kees Cook , "Gustavo A. R. Silva" , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Nick Desaulniers , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org, x86@kernel.org, linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev Subject: [PATCH v2] hardening: Enable KCFI and some other options Date: Tue, 30 Apr 2024 10:37:00 -0700 Message-Id: <20240430173657.it.699-kees@kernel.org> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2768; i=keescook@chromium.org; h=from:subject:message-id; bh=HwleHbMmvyClSw2hkCjqzzitfJIFUgKSvCPPJPbOXUI=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBmMSw8JAuEaLHzrMs+I0z2zE2/9ONfTrWuUhxfB nUIns+oImyJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZjEsPAAKCRCJcvTf3G3A JhTEEACOGEhRbFkij9Hg8wOi94RhI/kWW1frkUHlY6k9hvRUHCG4HdzS1hJHcBlfpZuXkJ8j3ub qAINSRxOpsnxez1sFGK5iy91hNbeRGXyJ5znmwbewZssGCdDyRs99mhcp2+zJJgcOGltMW5q44d C1e3GA22dEyNX7IKQneeJpm5SaZbKusp72+3dNQcpkQOc4stcvPbT+b28JZdM+gnuryWpkgwhuS ozeSggCI0N6FD0P0HXnFp0tQKEDDINxCW0wIyg07WLruf+R5CRt5jLkZFPN46KcygR5668GeDzS ToWYc44Tk88mmSaxTKzPN0afz12vfTuPkrf1+Z6QjOagPIWLEvWW0JtqXVjiw3Tc9qphdzOah/k /SQY3iG3kgMJ7y8oh4dPMutI5Ustzk8Vj0rmka0bFaM78u+LC9Ha5grFnsvD17eh9mLFPtn8K75 YJi9wR7tyyCpnFjSUr/5231n8Y9Q9u+K2TalZMppSa1E2QaDg6giY4ZK3LKPsbDCfPkjyggWTR4 kHXXHnz9MGksi/hKRITQ/Aq3qpVYyKOBChuMppK9xOqjLZRs/gosEDqtYVjN3nsbGcxnKyOgE+L wLHf2ApifK8pF64VYy9at8D0ixOjL8IoywKA39+LMBkzyfENJD+IN+4MRqcigX77oUDCIuuYgtI ySSnPDH nd/DoKkA== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add some stuff that got missed along the way: - CONFIG_UNWIND_PATCH_PAC_INTO_SCS=3Dy so SCS vs PAC is hardware selectable. - CONFIG_X86_KERNEL_IBT=3Dy while a default, just be sure. - CONFIG_CFI_CLANG=3Dy globally. (And disable FINEIBT since it isn't as secure as straight KCFI.) - CONFIG_PAGE_TABLE_CHECK=3Dy for userspace mapping sanity. Reviewed-by: Nathan Chancellor Signed-off-by: Kees Cook --- v2: move CONFIG_CFI_CLANG=3Dy to global config v1: https://lore.kernel.org/all/20240426222940.work.884-kees@kernel.org/ --- arch/arm64/configs/hardening.config | 1 + arch/x86/configs/hardening.config | 6 ++++++ kernel/configs/hardening.config | 8 ++++++++ 3 files changed, 15 insertions(+) diff --git a/arch/arm64/configs/hardening.config b/arch/arm64/configs/harde= ning.config index b0e795208998..24179722927e 100644 --- a/arch/arm64/configs/hardening.config +++ b/arch/arm64/configs/hardening.config @@ -5,6 +5,7 @@ CONFIG_ARM64_SW_TTBR0_PAN=3Dy =20 # Software Shadow Stack or PAC CONFIG_SHADOW_CALL_STACK=3Dy +CONFIG_UNWIND_PATCH_PAC_INTO_SCS=3Dy =20 # Pointer authentication (ARMv8.3 and later). If hardware actually supports # it, one can turn off CONFIG_STACKPROTECTOR_STRONG with this enabled. diff --git a/arch/x86/configs/hardening.config b/arch/x86/configs/hardening= .config index 7b497f3b7bc3..bf3d31618e12 100644 --- a/arch/x86/configs/hardening.config +++ b/arch/x86/configs/hardening.config @@ -10,5 +10,11 @@ CONFIG_INTEL_IOMMU_DEFAULT_ON=3Dy CONFIG_INTEL_IOMMU_SVM=3Dy CONFIG_AMD_IOMMU=3Dy =20 +# Enforce CET Indirect Branch Tracking in the kernel. +CONFIG_X86_KERNEL_IBT=3Dy + # Enable CET Shadow Stack for userspace. CONFIG_X86_USER_SHADOW_STACK=3Dy + +# When CONFIG_CFI_CLANG is enabled, disable weaker FINEIBT landing pads. +# CONFIG_FINEIBT is not set diff --git a/kernel/configs/hardening.config b/kernel/configs/hardening.con= fig index 7a5bbfc024b7..47e6564129c3 100644 --- a/kernel/configs/hardening.config +++ b/kernel/configs/hardening.config @@ -23,6 +23,10 @@ CONFIG_SLAB_FREELIST_HARDENED=3Dy CONFIG_SHUFFLE_PAGE_ALLOCATOR=3Dy CONFIG_RANDOM_KMALLOC_CACHES=3Dy =20 +# Sanity check userspace page table mappings. +CONFIG_PAGE_TABLE_CHECK=3Dy +CONFIG_PAGE_TABLE_CHECK_ENFORCED=3Dy + # Randomize kernel stack offset on syscall entry. CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=3Dy =20 @@ -81,6 +85,10 @@ CONFIG_SECCOMP_FILTER=3Dy # Provides some protections against SYN flooding. CONFIG_SYN_COOKIES=3Dy =20 +# Enable Kernel Control Flow Integrity (currently Clang only). +CONFIG_CFI_CLANG=3Dy +# CONFIG_CFI_PERMISSIVE is not set + # Attack surface reduction: do not autoload TTY line disciplines. # CONFIG_LDISC_AUTOLOAD is not set =20 --=20 2.34.1