From mboxrd@z Thu Jan 1 00:00:00 1970 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 EBF8017798F; Mon, 29 Apr 2024 22:16:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714429014; cv=none; b=rCucBmI1BRERp1V7Yl0ZKORdv7/4LSCSEjXb7OtWvgsHLtrtsHF64h4BOtf5allvqdKGi9c3GPIohkZ4x1rKAP/xwPPkVM2cGT7iuLT3Ynz0QPtlo8hKmpTc+BDkjSCv+dgBAK81vhQVJzXJrqAzcqJCIv98GBqTmbGH/UHQVj4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714429014; c=relaxed/simple; bh=sM12wNpxyClzIujECU2Q2Xq0Fp03wR6ElrAkPU8LTJE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=k0EPSmQ5BpBtQg1zoVNxP6H1v6ZDa7yKS8SALHqOWc/IqySRPRKReQcUYWOP6knpfm9m9pRlaf25CoLHEjjnlAh1Z6qXbYRhkPQ1N+fi7OCKMm18pxkZJTW8oIjtpgdpxIL/ymneR/L92M1tOolKwMYyecX6gxj1zkuMWPI8/Uo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AE1ScLev; 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="AE1ScLev" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DF9AC113CD; Mon, 29 Apr 2024 22:16:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714429013; bh=sM12wNpxyClzIujECU2Q2Xq0Fp03wR6ElrAkPU8LTJE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AE1ScLevghQRxQ4qCrFsi9uVrMVHe0DLu4Fi/opB2QweZCJaOCcNoj2YYHHt9thz9 OcNY7C5Z3n0iQWyNGzwz56muSCRYaNXZ8oBvZSXpMnzO+MgjyRx2jIF2hB5Y/cmyTo m/wpaUuexq+73sniwy1mApDi33fXdLHpVnz03b44dFGEr9mNhZTSv7PDS69z9ySIDh jP3ikArks0EEvjdH8fM536Qivg8+lYUYPQXlFc8MlpW2w9VAKb+9rbjeSryEb4prFF PxAA0zNei5LqRS91RkxXZJGXGOUVPG4obGjO1WWzq1ErlpDec91w5ye2wl5xuAn1PH 2PKJqWxdYTT4g== Date: Mon, 29 Apr 2024 15:16:50 -0700 From: Nathan Chancellor To: Kees Cook Cc: "Gustavo A. R. Silva" , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Nick Desaulniers , Bill Wendling , Justin Stitt , linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] hardening: Refresh KCFI options, add some more Message-ID: <20240429221650.GA3666021@dev-arch.thelio-3990X> References: <20240426222940.work.884-kees@kernel.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240426222940.work.884-kees@kernel.org> On Fri, Apr 26, 2024 at 03:29:44PM -0700, Kees Cook wrote: > Add some stuff that got missed along the way: > > - CONFIG_UNWIND_PATCH_PAC_INTO_SCS=y so SCS vs PAC is hardware > selectable. > > - CONFIG_X86_KERNEL_IBT=y while a default, just be sure. > > - CONFIG_CFI_CLANG=y for x86 and arm64. (And disable FINEIBT since > it isn't as secure as straight KCFI.) > > - CONFIG_PAGE_TABLE_CHECK=y for userspace mapping sanity. > > Signed-off-by: Kees Cook Seems reasonable to me. Reviewed-by: Nathan Chancellor One comment below. > --- > Cc: "Gustavo A. R. Silva" > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Borislav Petkov > Cc: Dave Hansen > Cc: x86@kernel.org > Cc: "H. Peter Anvin" > Cc: Nathan Chancellor > Cc: Nick Desaulniers > Cc: Bill Wendling > Cc: Justin Stitt > Cc: linux-hardening@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: llvm@lists.linux.dev > --- > arch/arm64/configs/hardening.config | 5 +++++ > arch/x86/configs/hardening.config | 9 +++++++++ > kernel/configs/hardening.config | 4 ++++ > 3 files changed, 18 insertions(+) > > diff --git a/arch/arm64/configs/hardening.config b/arch/arm64/configs/hardening.config > index b0e795208998..e8a18fec7a3e 100644 > --- a/arch/arm64/configs/hardening.config > +++ b/arch/arm64/configs/hardening.config > @@ -5,6 +5,7 @@ CONFIG_ARM64_SW_TTBR0_PAN=y > > # Software Shadow Stack or PAC > CONFIG_SHADOW_CALL_STACK=y > +CONFIG_UNWIND_PATCH_PAC_INTO_SCS=y > > # Pointer authentication (ARMv8.3 and later). If hardware actually supports > # it, one can turn off CONFIG_STACKPROTECTOR_STRONG with this enabled. > @@ -20,3 +21,7 @@ CONFIG_ARM64_E0PD=y > > # Available in ARMv8.7 and later. > CONFIG_ARM64_EPAN=y > + > +# Enable Kernel Control Flow Integrity (currently Clang only). > +CONFIG_CFI_CLANG=y > +# CONFIG_CFI_PERMISSIVE is not set Should this be a part of kernel/configs/hardening.config because RISC-V supports it (and 32-bit ARM will soon too)? > diff --git a/arch/x86/configs/hardening.config b/arch/x86/configs/hardening.config > index 7b497f3b7bc3..b47e5f411dd3 100644 > --- a/arch/x86/configs/hardening.config > +++ b/arch/x86/configs/hardening.config > @@ -10,5 +10,14 @@ CONFIG_INTEL_IOMMU_DEFAULT_ON=y > CONFIG_INTEL_IOMMU_SVM=y > CONFIG_AMD_IOMMU=y > > +# Enforce CET Indirect Branch Tracking in the kernel. > +CONFIG_X86_KERNEL_IBT=y > + > +# Enable Kernel Control Flow Integrity (currently Clang only), but disable > +# weaker FINEIBT landing pads. > +CONFIG_CFI_CLANG=y > +# CONFIG_CFI_PERMISSIVE is not set > +# CONFIG_FINEIBT is not set > + > # Enable CET Shadow Stack for userspace. > CONFIG_X86_USER_SHADOW_STACK=y > diff --git a/kernel/configs/hardening.config b/kernel/configs/hardening.config > index 7a5bbfc024b7..4be0de1f085c 100644 > --- a/kernel/configs/hardening.config > +++ b/kernel/configs/hardening.config > @@ -23,6 +23,10 @@ CONFIG_SLAB_FREELIST_HARDENED=y > CONFIG_SHUFFLE_PAGE_ALLOCATOR=y > CONFIG_RANDOM_KMALLOC_CACHES=y > > +# Sanity check userspace page table mappings. > +CONFIG_PAGE_TABLE_CHECK=y > +CONFIG_PAGE_TABLE_CHECK_ENFORCED=y > + > # Randomize kernel stack offset on syscall entry. > CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y > > -- > 2.34.1 >