From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f176.google.com (mail-pg1-f176.google.com [209.85.215.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0F03C47F5D for ; Wed, 14 Aug 2024 06:22:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723616581; cv=none; b=ndII/dNZiM9fZOEG+ZL/nwFXnlKaaUZklATY8ywtcf5VVPa2Z5VCm0svOKpkbJUO4T9U5I4nIKnNdA/X+gwo/MKGMbhYjxbQ+HJbkyqA3CS7RNXIUIlLpJLx+YYMZmp3Ajp1Y+hfEjsglOSjHB+SJARONtOHT686cqzoyRU0u3s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723616581; c=relaxed/simple; bh=zL+qnPL1jO2zhvpEIpxLqlOnW6CEZ9PD7cHRsrI7EA0=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=BUgcyI6Y/Sknt+ktBo+jfDXPv/31ClQ1rUe6bANLFrF9u5ZEGVZ421pTdkbBeonI2jx2arNzjPHdzio7AsyRnyz9uWc7zapp46IYppzQaUduiJ0fF129i/c6SJ4N4vbCii2OxCJxGP/imeyHpA/RxLlcLkf1h+G3kgJrC0Ao478= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=KCOa5BUw; arc=none smtp.client-ip=209.85.215.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KCOa5BUw" Received: by mail-pg1-f176.google.com with SMTP id 41be03b00d2f7-7a1843b4cdbso4327529a12.2 for ; Tue, 13 Aug 2024 23:22:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1723616577; x=1724221377; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=t6qpq46Cmtk8VQ38Im8rdWFCBv9ylccY5eUMWeEbdM0=; b=KCOa5BUwjQsHLH9BogKSqmHTu9QCex2vD4AF30m8xPKEVqlX5vZAbs0+qj/NdfBsMa 7WssQWY3vIC79gWzPBwIwfc9iqPQD9wZJuzMxtUVm+VfUBxx1G0uTw0uHWi1wqRR5OFU mSGy//O061bw96eiHs930HAoizWb7T6iH5lbd/vKOhaosMeUa8flYd8bJb+dpNYc8I+Y QvSrC6R1qxfZHv8pLy2ENz+pEysN8DryndFFsAO38nt4YyavQTAFoMgeBoSf3TFBuq6b jXZ7N9MHboLeDv9MvunnyzXhujkIPatqDqMEkdQ3s6RfdfskYYSc4SAQ3cF2wE0Lus26 KaFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723616577; x=1724221377; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=t6qpq46Cmtk8VQ38Im8rdWFCBv9ylccY5eUMWeEbdM0=; b=Sm0ETMR/wrmvVpeVjHB4pYz2vWg6bHalCrsz9nMKMSxRdz6VOQTlJqLAWMBTzz+vVE VE/vkAdh2EKnfREWJzhaJgkrNMY8v/PKRoj8pLvw6jhYIopjahzJFQXmUeo8MVQ2xqTA o1jx4wGlQ+bLEkvIi4BdmnkKA1ZQc89XccvUG/IN8Rc+/JE6Qak5DIgfYUBLYn/ZzvZ6 cmh+oWvb1jDE8Mwp37exWmzO3dzw24N0HkRYs5fjzr8OCInkigusj5pRr8Yk10HJtx+x unduBq8NjBXTlIrVp5TlInzCr9LKM1/W+o8UDfgi4IF2dBac1MBgCkjThsa17c5QWIbh imlg== X-Gm-Message-State: AOJu0Yyntmf3lzl7HtMNw06FZ7WGsY3DREoX7nIZPXozRhU9fDDkwX+P rSUxzCnHupuqfD4pIDUIg+amQBlGKwICscunJZ8tnhy1GFHmf/O6+7c5OTR8 X-Google-Smtp-Source: AGHT+IEM+cQkNQYxKAzkEIN3SXPl5pEpGF0VS4xS43WkOmnpmzPVe0bsCIM7q1PBWtzTRnWKOVOufQ== X-Received: by 2002:a05:6a21:3a81:b0:1c4:214c:cc0d with SMTP id adf61e73a8af0-1c8eaf80489mr2271288637.36.1723616577336; Tue, 13 Aug 2024 23:22:57 -0700 (PDT) Received: from tahera-OptiPlex-5000.uc.ucalgary.ca ([136.159.49.123]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2d3ac7f2120sm728811a91.31.2024.08.13.23.22.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Aug 2024 23:22:56 -0700 (PDT) From: Tahera Fahimi To: outreachy@lists.linux.dev Cc: mic@digikod.net, gnoack@google.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, bjorn3_gh@protonmail.com, jannh@google.com, netdev@vger.kernel.org, Tahera Fahimi Subject: [PATCH v9 0/5] Landlock: Add abstract unix socket connect restriction Date: Wed, 14 Aug 2024 00:22:18 -0600 Message-Id: X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: outreachy@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch series adds scoping mechanism for abstract unix sockets. Closes: https://github.com/landlock-lsm/linux/issues/7 Problem ======= Abstract unix sockets are used for local inter-process communications independent of the filesystem. Currently, a sandboxed process can connect to a socket outside of the sandboxed environment, since Landlock has no restriction for connecting to an abstract socket address(see more details in [1,2]). Access to such sockets for a sandboxed process should be scoped the same way ptrace is limited. [1] https://lore.kernel.org/all/20231023.ahphah4Wii4v@digikod.net/ [2] https://lore.kernel.org/all/20231102.MaeWaepav8nu@digikod.net/ Solution ======== To solve this issue, we extend the user space interface by adding a new "scoped" field to Landlock ruleset attribute structure. This field can contains different rights to restrict different functionalities. For abstract unix sockets, we introduce "LANDLOCK_SCOPED_ABSTRACT_UNIX_SOCKET" field to specify that a ruleset will deny any connection from within the sandbox domain to its parent (i.e. any parent sandbox or non-sandbox processes). Example ======= Starting a listening socket with socat(1): socat abstract-listen:mysocket - Starting a sandboxed shell from $HOME with samples/landlock/sandboxer: LL_FS_RO=/ LL_FS_RW=. LL_SCOPED="a" ./sandboxer /bin/bash If we try to connect to the listening socket, the connection would be refused. socat - abstract-connect:mysocket --> fails Notes of Implementation ======================= * Using the "scoped" field provides enough compatibility and flexibility to extend the scoping mechanism for other IPCs(e.g. signals). * To access the domain of a socket, we use its credentials of the file's FD which point to the credentials of the process that created the socket. (see more details in [3]). Cases where the process using the socket has a different domain than the process created it are covered in the unix_sock_special_cases test. [3]https://lore.kernel.org/all/20240611.Pi8Iph7ootae@digikod.net/ Previous Versions ================= v8: https://lore.kernel.org/all/cover.1722570749.git.fahimitahera@gmail.com/ v7: https://lore.kernel.org/all/cover.1721269836.git.fahimitahera@gmail.com/ v6: https://lore.kernel.org/all/Zn32CYZiu7pY+rdI@tahera-OptiPlex-5000/ and https://lore.kernel.org/all/Zn32KKIJrY7Zi51K@tahera-OptiPlex-5000/ v5: https://lore.kernel.org/all/ZnSZnhGBiprI6FRk@tahera-OptiPlex-5000/ v4: https://lore.kernel.org/all/ZnNcE3ph2SWi1qmd@tahera-OptiPlex-5000/ v3: https://lore.kernel.org/all/ZmJJ7lZdQuQop7e5@tahera-OptiPlex-5000/ v2: https://lore.kernel.org/all/ZgX5TRTrSDPrJFfF@tahera-OptiPlex-5000/ v1: https://lore.kernel.org/all/ZgXN5fi6A1YQKiAQ@tahera-OptiPlex-5000/ Tahera Fahimi (5): Landlock: Add abstract unix socket connect restriction selftests/Landlock: Abstract unix socket restriction tests selftests/Landlock: Adding pathname Unix socket tests sample/Landlock: Support abstract unix socket restriction Landlock: Document LANDLOCK_SCOPED_ABSTRACT_UNIX_SOCKET and ABI versioning Documentation/userspace-api/landlock.rst | 33 +- include/uapi/linux/landlock.h | 27 + samples/landlock/sandboxer.c | 58 +- security/landlock/limits.h | 3 + security/landlock/ruleset.c | 7 +- security/landlock/ruleset.h | 23 +- security/landlock/syscalls.c | 17 +- security/landlock/task.c | 129 ++ tools/testing/selftests/landlock/base_test.c | 2 +- tools/testing/selftests/landlock/common.h | 38 + tools/testing/selftests/landlock/net_test.c | 31 +- .../landlock/scoped_abstract_unix_test.c | 1146 +++++++++++++++++ 12 files changed, 1469 insertions(+), 45 deletions(-) create mode 100644 tools/testing/selftests/landlock/scoped_abstract_unix_test.c -- 2.34.1