From nobody Wed Dec 17 22:40:53 2025 Received: from mail-pf1-f182.google.com (mail-pf1-f182.google.com [209.85.210.182]) (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 BF4CE1474B9 for ; Wed, 1 May 2024 19:37:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714592237; cv=none; b=KvaE4G09Tl7v2Y/fKulugINLJsQx7uhgP8CZUwY6zOkRs0f66VcTEnSlSQX6daSz0DhwZHDTmu1B0zCt6zd0M47pdafptobhJjSVuVutFtVcyjUXoeTzopCVn30+sogIgNaxsU3HJHh2sWptxxYBN1/Jhq4fCi7SD7E8jRklFIE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714592237; c=relaxed/simple; bh=NKsknBWYA84MMDw2XbhVDtmpzCAlaQEA3YQRvQXELjc=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=dO50tSuXT1i/0lYCmXDtACGRw9B2oYfnpTizbUphcvMe6yBgvFjEv36f1MYyyD/xPrFhKJIIvsQs2B0GXmNyGUAEiRl6z2CbTLY4XrZ2NpfROXnenkmocfszv1V8YixLvegAMwz0xUpcsG2y/IBXQ/NZvzw4HKn/E0ZDcq35VDQ= 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=nyA0IR8x; arc=none smtp.client-ip=209.85.210.182 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="nyA0IR8x" Received: by mail-pf1-f182.google.com with SMTP id d2e1a72fcca58-6f4178aec15so1606029b3a.0 for ; Wed, 01 May 2024 12:37:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1714592235; x=1715197035; 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=cvFOg5ZGNpEt6TtWRUDGWd1J8Hf8j/pvcf63R1jFypA=; b=nyA0IR8x2KZ9VqQX6lQKmZR82oaOXsS8OmdT+sDp1mLuHcykoTNmdeuYpv6YonsXOo cGoaGNtn7MgaPmyXYjlBRvKYiFutpQ/PijAKDw0s+Kk7igcX5CbU938p7OivMQq5V+AN DVA4DwYZuim6nYFZJ8ippncnA1BGZbyHTrIyI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714592235; x=1715197035; 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=cvFOg5ZGNpEt6TtWRUDGWd1J8Hf8j/pvcf63R1jFypA=; b=BqrbjRKhMEeg/XLXJipiva+OVNCfzH1JyCSfh362Gb79ABTQNYhf5eI6GvJdzY/QUr p0LaDrqgKYUPkge11okIdv882CWY21urUsO/kASL44twMSviO/T9T6C5jarz7xMYutuh TigCsTPh6Rdiku2tyyVfieGeKeVC9wLeGZN7PxfLft1beasq7dhORgva6YAwnKZQjCoL CxFVg5eGk/B7Myc4b4YNVmSPjMo92gJPLyDstrVtQeV2Svo8bJI1Oo30ai3kKCFn46Xf 3GHes90+DkkUNlVJKIF2aMzclHZNUnPaKQ3A2DIYT5m4JzLgxdP9Wd30skl2AF09VlYi oekw== X-Forwarded-Encrypted: i=1; AJvYcCUTjAtF3hUomSWiC2AOG62tmr+Ovus9I/+4rav92l5U4moWtE4R0h+sPU6vmw6ceJctjxBhSjTWBYKSW2+YiAAjuzusQlINZ6QAz9Ki X-Gm-Message-State: AOJu0Yz04Mb3LDaw75b4WC0hMcUPgMo8NynCQg+nBe+EGzhjjuxBeY2W pjONheiTAN1dDd/vUh87trcAGigvgnfnlJQBmY6J/CdgkSRpCQMTLgtZRuK0iw== X-Google-Smtp-Source: AGHT+IG0ymu3N2wZiVbdkxtYVjzYQ+d8l4Q6OMF22iO5uDx77xWYeuPGSymFUi9RT69ddvd9TyA68w== X-Received: by 2002:aa7:8891:0:b0:6ec:fd67:a27e with SMTP id z17-20020aa78891000000b006ecfd67a27emr3826038pfe.1.1714592234975; Wed, 01 May 2024 12:37:14 -0700 (PDT) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id e15-20020a62aa0f000000b006ece85910edsm23020718pff.152.2024.05.01.12.37.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 May 2024 12:37:14 -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 v3] hardening: Enable KCFI and some other options Date: Wed, 1 May 2024 12:37:12 -0700 Message-Id: <20240501193709.make.982-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=2668; i=keescook@chromium.org; h=from:subject:message-id; bh=NKsknBWYA84MMDw2XbhVDtmpzCAlaQEA3YQRvQXELjc=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBmMpnoXElRy5mtMZ69Kw4EZfui4YPcwQgqNohUb W/mTkIpghGJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZjKZ6AAKCRCJcvTf3G3A JsBnD/0U7s7b3FztnGuIGzP9bQgbSUdqTfM2A0frprWHDhBLVtapVS6/s1+QDaHAcwUVO3Ed91O bhK6QgMIp/BuU8nPESGhEotQjf7KEgj7TeYy9UMR81O1N1aCfJ93m74TGRxM56tf+muQ2h8drgY 82GaBYqsdXAzdDQdmI+wk0XRdCcKdqXhTLxLaEOOa0BGPCJ86G63q9QAqx++NR5UoKBv80qEbKZ OM8A3tQctaM9g2cyn8QL8pyotMmWbuEwTO2NeM6jiOda+B6XaMQq/iXwXgyvhHA5MMGt8IHu//d 9TD5zMGencEKYjk6Ha2PFhL5eo/eWzvdw4qB2eSEQ9FVDO7BO3G7AwszmwW5UwJzn/KmS/O4yTz naP1eVzrFnepZQgMnfB2Q8mZcnrcVG0BjKGk+gJrYpowzFakTHlXk63H3ek1kUHU6RbSyxvsO4p lnG9ygU6y5uFJRPQyH/MkmRBGsCbq8JFI4g/CEaOIteLp1jQibFSuwuUM2Efy08zvnj6vsxmkRQ psMTQkhm3m9nqKLXtPdaxnguKOJkhsRogYcbbRHK0/0YF9K6J2qrySkn0Yat18atruBbAdHb3Bg I7bSpMRDjPi8aIs98dz6FoYoefGQE37GFOzXrS4G9dZTXadE6YGR2ksskT9vZnfsAAqqe+13vbk 3C+OiPU u935fQCw== 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. - CONFIG_PAGE_TABLE_CHECK=3Dy for userspace mapping sanity. Reviewed-by: Nathan Chancellor Signed-off-by: Kees Cook --- v3: we don't want to (and can't) turn off FINEIBT v2: https://lore.kernel.org/lkml/20240430173657.it.699-kees@kernel.org/ v1: https://lore.kernel.org/lkml/20240426222940.work.884-kees@kernel.org/ --- arch/arm64/configs/hardening.config | 1 + arch/x86/configs/hardening.config | 3 +++ kernel/configs/hardening.config | 8 ++++++++ 3 files changed, 12 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..de319852a1e9 100644 --- a/arch/x86/configs/hardening.config +++ b/arch/x86/configs/hardening.config @@ -10,5 +10,8 @@ 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 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