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 E28243A6F0B; Sat, 3 Oct 2026 17:56:40 +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=1791050202; cv=none; b=j1QTaYzzYNZbdiHYmNy47N3cSDaADowaXBr4xsdnDqMVhlRpBy+uwLeeUTPSqr/0lAH3EGcW1PhQxb3I0Iyf8yjABBAW5oxAiuprecGVi4H4cvLmYXwEHkbmJK3hykf1VzvNYf8KY+Lox0zQtVJZa1DedoEDNlYrsfxoOo/CDqY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791050202; c=relaxed/simple; bh=We9SPyjRDJvyFxiU73xJrKbNsJY8jWQtDNcOJSCIRZE=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=haHPh4hdWcNiKUtnlPC4crbthj8UvwpsUobN1wR851IQ5imT4TRkiO7DahU6rYbHj73y6saIUNZX3m0XBB/uEULRRw6cQ1pYZsdGigJ3YdgL7myzxgno2+gcWQYMIp8mX7w/Vnl9+jXBTHu2lLH01RXlrEWiyJVkTim75nv7hDw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E+sMmNlc; 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="E+sMmNlc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 041461F0089E; Sat, 3 Oct 2026 17:56:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791050200; bh=We9SPyjRDJvyFxiU73xJrKbNsJY8jWQtDNcOJSCIRZE=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=E+sMmNlcwWMdOivJYnnKbEA/WJgQE7x7RnJNKHzxmBmif0O9Kb9/6K9UDgx8WPC45 yWy3qtW6fW7eWrBWWLH2cRsoq6UEsK8M+957iQxzLZrHHKiCM8nl75ga9PW6kbRc41 paqUVUe+twpgQZ4Uv2lqv1ZbNjbnT05/iVbKs4encEJs8sxRu+A0aC7wxaHty5KVK4 oMvPxd/ZIQWOM+4wbvRtfcZsycJ196lj1ealjtFDg3pws3fnXygg32raO1poNF03IP N3NOOzpYXdRT5knlSOqXIa+csOyEnGgIaIWT4fubtAYNFhzVy1rD87d4NuzJusfquN QFZERzH4uG++g== From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 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-perf-users@vger.kernel.org, linux-scsi@vger.kernel.org, kvm@vger.kernel.org, linux-trace-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, "Heiko Carstens" , "Christian Borntraeger" , selinux@vger.kernel.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, kvmarm@lists.linux.dev, "Oliver Upton" , "Marc Zyngier" , linux-s390@vger.kernel.org, "Vasily Gorbik" In-Reply-To: <20261003-b4-mmap-prepare-vma-flag-sanify-v4-11-a1f052500fd7@kernel.org> References: <20261003-b4-mmap-prepare-vma-flag-sanify-v4-0-a1f052500fd7@kernel.org> <20261003-b4-mmap-prepare-vma-flag-sanify-v4-11-a1f052500fd7@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 03 Oct 2026 17:56:39 +0000 Message-Id: <20261003175640.041461F0089E@smtp.kernel.org> Precedence: bulk X-Mailing-List: bpf@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 > 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/20261003-b4-mmap-pr= epare-vma-flag-sanify-v4-0-a1f052500fd7@kernel.org?part=3D11