From patchwork Mon Apr 8 09:47:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikhail Ivanov X-Patchwork-Id: 13620920 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (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 7347739FDD; Mon, 8 Apr 2024 09:48:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.188 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712569728; cv=none; b=IXnPPq7zPIIZAdMLwFW9BPcf6XqlwIODtWrmx7A0Xa4Otkaau5ahN3CCdWPGhosnlmIKgCzrn9LhPZ/BLnRs9dv2SNNPhT3ZxxnRBGyOVC0oNmj+BF4j/Tzrh1XMe8jHVBrpXc7O0Gm+K8QFk6AEzk2fkhQufSnCDBuf7IcjlN0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712569728; c=relaxed/simple; bh=kX09jP7Qd17zNz9DPXQK9L+bUAc//Zw+me8sdEYNyMw=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=UF/JC0sFyGkykWaQz4eMoHzJaNsZ4ztAPduc2nMgfTec/ejM1WR0lIgl2ajQcK4q7fC8N0xMNX6vBJ7tPoZHm0oIfqSk5dMnoIWiRltoLJHn/NeElxm66ixtq0mrVqQuRhTqL8mdwOUoNv4+QyZnfI4e6wL211dJa/2UoufLNDQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei-partners.com; spf=pass smtp.mailfrom=huawei-partners.com; arc=none smtp.client-ip=45.249.212.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei-partners.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei-partners.com Received: from mail.maildlp.com (unknown [172.19.163.48]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4VCkjZ6ZHbzXjB3; Mon, 8 Apr 2024 17:45:38 +0800 (CST) Received: from dggpemm500020.china.huawei.com (unknown [7.185.36.49]) by mail.maildlp.com (Postfix) with ESMTPS id 18DF818007B; Mon, 8 Apr 2024 17:48:44 +0800 (CST) Received: from mscphis02103.huawei.com (10.123.65.215) by dggpemm500020.china.huawei.com (7.185.36.49) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Mon, 8 Apr 2024 17:48:42 +0800 From: Ivanov Mikhail To: CC: , , , , , , , Subject: [PATCH 0/2] Forbid illegitimate binding via listen(2) Date: Mon, 8 Apr 2024 17:47:45 +0800 Message-ID: <20240408094747.1761850-1-ivanov.mikhail1@huawei-partners.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: mscpeml100003.china.huawei.com (10.199.174.67) To dggpemm500020.china.huawei.com (7.185.36.49) listen(2) can be called without explicit bind(2) call. For a TCP socket it would result in assigning random port(in some range) to this socket by the kernel. If Landlock sandbox supports LANDLOCK_ACCESS_NET_BIND_TCP, this may lead to implicit access to a prohibited (by Landlock sandbox) port. Malicious sandboxed process can accidentally impersonate a legitimate server process (if listen(2) assigns it a server port number). Patch adds hook on socket_listen() that prevents such scenario by checking LANDLOCK_ACCESS_NET_BIND_TCP access for port 0. Few tests were added to cover this case. Code coverage(gcov): * security/landlock: lines......: 94.5% (745 of 788 lines) functions..: 97.1% (100 of 103 functions) Ivanov Mikhail (2): landlock: Add hook on socket_listen() selftests/landlock: Create 'listen_zero', 'deny_listen_zero' tests security/landlock/net.c | 104 +++++++++++++++++--- tools/testing/selftests/landlock/net_test.c | 89 +++++++++++++++++ 2 files changed, 177 insertions(+), 16 deletions(-)