From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793312306; b=jkqgLTXXYoY9oVtaNpxKK9VHKOHSt/ew8y39BjkD+KwKsZEHOoFWtsikBEwh2MuMYaaq Nypyh0LfxcV74nzoyo/zUHTjzx+RO6CvPplrxF98xI4o7ANYoqU9H5qdA9EwdXO8U/9B/ UVxsmdzSmX23t9IZH5CttzYZQBWCrQVneB2EWyIKXBfDVNmGGCI8gS2UO83c7VvotOQEz tKq3q093BiEt0cXbIr9Fzx7jfZPdxL+ffSa+RatbHyZ315A6wqSfRKp5u9tzKGGD+itLd /OILm7ZNEN/m/I9yX92vgsPJHUqd4A9XalzA/Xfs5TZ9h3uyZKk5WPjlzs2iC2ZgPSw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793312306; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=v5YPM49aNTe7a9LI7foYC+81vU3NuvTOzVPNOmQHTFM=; b=NjF6qAD4YkYePlQcaFBuEHY1vPj+f9vAFPNZzX/GSCiPhfI9dYWx/YtiM4odfU4OtElW oQ4o2f1WzbfjjJ+6zMyWt7qJqdcZkdxF6KJJ21Ebh9IUcXYbaW6w9f/I0axvFb0sVL+d2 M9LB7aOcY0UHQr7J9RgwvWtNhZut2OnScgCGPKXGGoRXWrPGGOaXK1bAoWdZ3Te1dZtde hs6pN8J/VZVMKJlxb2UZEkNMfXOLg2S1uF4jzAYesh0I8vYY+mAB9A/G86o5IY/TaAcop SBFnPU9BPi3xHrY6C8NRDyZv5MKpNp/lhfFbdxc0yA7XO9lU4gIkEl0O0zxJVNHqzkQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XdoNRlAZ; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4E22A606A31A for ; Thu, 29 Oct 2026 22:18:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XdoNRlAZ Received: by smtp.kernel.org (Postfix) with ESMTPSA id BFFF31F01816 for ; Thu, 29 Oct 2026 22:18:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793312305; bh=v5YPM49aNTe7a9LI7foYC+81vU3NuvTOzVPNOmQHTFM=; h=From:Subject:Reply-To:Cc:In-Reply-To:References:Date; b=XdoNRlAZA2ZFil1sOlGOIGFuiQey3krmq/h68uH9RcrwRL7hAn/OSCq3dtnTMtueV 7lCNqok+S2FPVQt63OigmLYz5n+A7bWkT4UfrfBBz8jriYRvDoMQG8B+MB1cVmnbDn hXDpzNPa2BRpijNWTdDzXkEon0XcmS40hAdLNOquJ868abHkoLcwBwbPJp8tO+a79Z IZKb60qI2k55ENE9zdYU+F5lruXJao/IHeB/5C+xF8MWV2c3CKYy06TfhtTvT06FG3 8WAi+NAZEP3de/iuTzP4vHDDnI9kg2BtyU7wWx+tehoQk+D2qODFDlD0YInxI1GU6v GehfSQY9d380w== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 1/8] net: introduce CLONE_NEWNET_LOOPBACK to auto-enable loopback Reply-To: sashiko-reviews@lists.linux.dev Cc: linux-security-module@vger.kernel.org In-Reply-To: <20261028221705.3915340-2-halg@google.com> References: <20261028221705.3915340-1-halg@google.com> <20261028221705.3915340-2-halg@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 29 Oct 2026 22:18:25 +0000 X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > New network namespaces start with the loopback interface DOWN by > default, requiring CAP_NET_ADMIN over the owning user namespace to > bring it up. >=20 > To block external network access while preserving the localhost > networking that many applications expect, sandboxes (such as bwrap, > nsjail and minijail) commonly create an isolated network namespace > with only the loopback interface enabled. >=20 > However, requiring a sandbox to hold CAP_NET_ADMIN in a new user > namespace solely to bring loopback up conflicts with reducing the > CAP_NET_ADMIN attack surface. >=20 > Today, an unprivileged sandbox or sandbox manager must start with > CAP_NET_ADMIN in its user namespace to be able to bring up loopback, > [ ... ] > semantics while allowing unprivileged sandboxes to create an isolated > network namespace with functional localhost networking without ever > holding CAP_NET_ADMIN. >=20 > Signed-off-by: Hallgrimur H. Gunnarsson Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261028221705.3915= 340-1-halg@google.com?part=3D1