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 31D973B7744; Tue, 8 Sep 2026 20:36:18 +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=1788899779; cv=none; b=oO1dAr+IGdpzO1RqAtw9fgmML05JY5xBxKD1dKMYgzECz4bZ5bmGGtFRtRFMa9widb5/aL6XxG99MFdPj48UxKp2yb2pKuzxXxNNVwuVn93gda1J3aYESnptRQhSPqQRlJ5MftapuQY72Ab1BM5qj8krCd9fuvkILsyl7ntOokQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788899779; c=relaxed/simple; bh=E/wOJJaiN86yA6C+CnI8JxBGKVbnXnR8Q05fxWG5SNY=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=cJaEVg9axTL9yizPD73X31lKCO7x3qTWkdUtWg/eAO82wHDLHqlVS13MXSnFRNPRvDByax8wbGrsG12r54XH7Rf63/Fe3gZ83KD72wLf80a1FMCcfSz+si3BUjBrO2PWwgftIkcE82L63CFZ5/JlsmCjmuNmqUVTaZDY2Nv8vVs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=F+6XI0RL; 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="F+6XI0RL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 397921F00A3A; Tue, 8 Sep 2026 20:36:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788899778; bh=E/wOJJaiN86yA6C+CnI8JxBGKVbnXnR8Q05fxWG5SNY=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=F+6XI0RLwgUtgRuWhZf/pCBWO0VMC6KyA+v47Wtby5K7oj0fOfra4NSugp/25gBj+ J0h+5saCtRVkXQlbg1l6Hhasq83eAChqqN6aADJoSQ6KNNvmhDp9AktWvznNsTTh5x 0nNDewgPoFwHJNZYNEkM4ml0fZsMF3Gs5b21W4pB6PN9k1CR5XEAqzUkyIQY+U4vC7 Hxl4DoIc16Uv+JIHNakHLd/GpMAKlki1GXihpu3ftx9AOw/20ro5Pl2jsy9n+veVzd m/I4i8572VH4N5JnA8fpTmTvBodoXdqnqJ5ohQ9bzw7OjDOnsKdtUNe5rRiOG8603d pB2nPzq+43jbg== From: sashiko-bot@kernel.org Subject: Re: [PATCH 11/39] 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: dri-devel@lists.freedesktop.org, "Alexander Gordeev" , selinux@vger.kernel.org, "Marc Zyngier" , kvm@vger.kernel.org, linux-s390@vger.kernel.org, "Heiko Carstens" , linux-scsi@vger.kernel.org, "Oliver Upton" , linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, kvmarm@lists.linux.dev, "Christian Borntraeger" , "Vasily Gorbik" In-Reply-To: <20260908-b4-mmap-prepare-vma-flag-sanify-v1-11-dacf19cce22b@kernel.org> References: <20260908-b4-mmap-prepare-vma-flag-sanify-v1-0-dacf19cce22b@kernel.org> <20260908-b4-mmap-prepare-vma-flag-sanify-v1-11-dacf19cce22b@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 08 Sep 2026 20:36:16 +0000 Message-Id: <20260908203617.397921F00A3A@smtp.kernel.org> Precedence: bulk X-Mailing-List: kvm@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 > 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/20260908-b4-mmap-pr= epare-vma-flag-sanify-v1-0-dacf19cce22b@kernel.org?part=3D11