From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 7C1CB4F4740; Fri, 9 Oct 2026 18:26:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791570413; cv=none; b=Z4oDmK61VMxZ/Mdb8wzZS3tsTrADPMZtGZTPlzK2ovUdxWf/yedxj2I7yz1Mz7vtPbQLXwuR3DvO7IFt+16wUDhPCvkrhR6ra+axekyVA/wlz6HkU7wVEABdgPQnCoIfN5wiEIXZvyshXyoNMRBoApkzcm7BDfeI1SuelJvFNJQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791570413; c=relaxed/simple; bh=hCYG4mb6Y3+WHTuTX+96FEwLU/wi/dMPvdqqRXrtajA=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=i+zz6k1Z3+9kBVib7Ht2CCnjoCJndcuMaaF8uCoCfvjnLhUNyzwxq9bt5zxQ809EmL/F+KpghjUeUMX+pSQBtpntSFwwEngVZLSW+th3AuhYSBsKEDtqyNRUi0QqyyMGH9rXFXIViT4oi9GDlOORZ82U2fzoLn4aqzPXb8tSBOA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eAQlCbpA; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eAQlCbpA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E4421F000FF; Fri, 9 Oct 2026 18:26:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791570411; bh=hCYG4mb6Y3+WHTuTX+96FEwLU/wi/dMPvdqqRXrtajA=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=eAQlCbpAS96MLx70Tc9gifLpJ5iahGMxgYJh0/bJ0pS63IADsDEnPq08vLVgceN7Q o9yN87ptROgczUv2QkI5s4xXnMLel6q3WkGRlF4nOflAQvE1YxUzixs5Y657eC53km Tg/sapcML71/94YFP3oYNnbU8cuCD0rflyPoxGcNdbcN9QJWYNTl7kVG4gvkHdIOJ3 QV8tfjm2kH/Id98OADQPdImQSdpjAKFj20c6ppcmWjlHynqdK00ix1ERAu6MeyZPLU V9vAG6OOJoBUd/iq6r3SOLKCZbD+E1zb+9b1gCvKqRwVANvSJqF1yo1nlZscL2V70A 58qv+8XpuYRiw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v5 11/38] selinux: reject writable opens of policy file, drop mmap shared/write check Reply-To: sashiko-reviews@lists.linux.dev To: =?utf-8?b?TG9yZW56byBTdG9ha2VzIChBUk0p?= Cc: "Alexander Gordeev" , linux-scsi@vger.kernel.org, "Marc Zyngier" , linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, "Christian Borntraeger" , linux-s390@vger.kernel.org, linux-usb@vger.kernel.org, "Heiko Carstens" , "Vasily Gorbik" , kvmarm@lists.linux.dev, selinux@vger.kernel.org, "Oliver Upton" , linux-rdma@vger.kernel.org, dri-devel@lists.freedesktop.org, kvm@vger.kernel.org, bpf@vger.kernel.org In-Reply-To: <20261009-b4-mmap-prepare-vma-flag-sanify-v5-11-923b70125b1e@kernel.org> References: <20261009-b4-mmap-prepare-vma-flag-sanify-v5-0-923b70125b1e@kernel.org> <20261009-b4-mmap-prepare-vma-flag-sanify-v5-11-923b70125b1e@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 09 Oct 2026 18:26:50 +0000 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > The policy file has no write method and is exposed read-only (S_IRUGO in > selinux_files[]), yet sel_open_policy() performs no open mode check, so a > CAP_DAC_OVERRIDE caller can open it O_RDWR. Reject FMODE_WRITE at open, as > kernfs does. >=20 > The file can then never be mapped with FMODE_WRITE, so do_mmap() always > clears VM_MAYWRITE and VM_SHARED for MAP_SHARED mappings and the VM_SHARED > check in sel_mmap_policy() cannot be reached. Remove it. >=20 > This also stops sel_mmap_policy() clearing VM_MAYWRITE on a mapping that = is > neither a PFN map nor a mixed map, ahead of the core enforcing that only > such mappings may do so. >=20 > Acked-by: Stephen Smalley > Reviewed-by: Jann Horn > Acked-by: Paul Moore > Reviewed-by: Suren Baghdasaryan > Signed-off-by: Lorenzo Stoakes (ARM) Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261009-b4-mmap-pr= epare-vma-flag-sanify-v5-0-923b70125b1e@kernel.org?part=3D11