From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f176.google.com (mail-pf1-f176.google.com [209.85.210.176]) (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 8CD5438B for ; Thu, 5 Sep 2024 00:14:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725495263; cv=none; b=Tha1SFcxe+42LOxtnJoA2y8C8MntPgn84sl5iODk93wAM0W8RhDa9g5rqhbAgcvhWwwKOtz8ezpQB1rjcjZiWg7SdNzGc/KXnHQd7x1ANSqr5Sc8U4UY/abt5C1sjfMVaWcARarur8rRWBahgHlRW8bVS2wmOTszM1UR4LdVzmY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725495263; c=relaxed/simple; bh=qhfENanhYlqO+Tb9devw7AVXsZcEt1vJt7XKABJZUp8=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=I8JIfHBPwDrJ08JAdQ44y+3hu0CMcN6cmjIyQZ0r1OYMgjZ9PAAxCLoMDKjQJUNNh8kq5k1JQdudRHejYVPpzNVz1Cs60Iusu/XLQ/lfLXkp4nenVRRKvuYkktdA6Lmvq9h35pHjPgSGMv8qvud2Ge3rSarCXNBCX1iTpixOHpc= 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=D3m8SivF; arc=none smtp.client-ip=209.85.210.176 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="D3m8SivF" Received: by mail-pf1-f176.google.com with SMTP id d2e1a72fcca58-717877183a2so154535b3a.1 for ; Wed, 04 Sep 2024 17:14:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1725495260; x=1726100060; 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=oAeF4Hyg0coER913U25Eksuz8dAnYzaOfEwRiEEL0qE=; b=D3m8SivFSgWUp2j72x9I8WkQAvGynh0Swt+71rcX0TshtiYwzOF+h6ZlAgWE344ziI KBD5a7BWJC0Gnm7v/4yu0rWcEeiaUanKbzUMTfPd94DCTKVtdYTPhqZX7ygzZmuqnODh SykwYr8r7UciG53iIESNGwimDu0O0wXHGGgCeD7pb0xzUHi8JuIjr2zKosVBkcLG2ZdH 8+7Ri/bxe41glBx4ZqK7qwTbUeruQRlsnxF5+fpCp1jJKwQuJONzOPwqQxFLsatAsl0V XSOrN3z0WHKmITqKC9nFdvTkPv5c+X4bwVKij4qIROpW0Z+IFZPi3fxeYvJQq4AWi8cu H1Xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1725495260; x=1726100060; 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=oAeF4Hyg0coER913U25Eksuz8dAnYzaOfEwRiEEL0qE=; b=H/8U0ruDcQtPfG9pwr87J41YTR6MefDUGvo+Y3WCpJQdhUq1M/HJL9HMlmzRc54Ixs c4L0mqK6C2DnEXpoP1ZKugrjsW0EaA/peoIoCxfn7erwGDSDlb01Dw6nonYPzQmW+o9z Wraa05ddESPiTXU6yoMm+mKlaj0ZNw3FnJ/VyZHAPUVJaj32/PYJhh9k75eLJWSh1Wup q0Y69VIwwRq1Ev+lXYrwZsLgNs6FeOCU+4boZ/3BmcM7o4u6IGtSPbsuZuDSBb1+iR6c GbMB7BvQpiqXSM+irCM+IWBDlvd3MQoC+2+kjHCLNv6Ox76RDCFmEdiMMFQFUo2LA1jE i+2Q== X-Gm-Message-State: AOJu0YzanubNh5r/gQiW11Nc0iQhEkyjFlkS8FLd7ikGXNPmq29lEHSs ae2kglxlTZMsHDEzpJ4J6eOKmfsNrxeTUDmqDIJo3n5shK0ilr6ROAlaJNHe X-Google-Smtp-Source: AGHT+IHyfjWhUvFw1Huv+dk80Us3saRElnhLngJ5hOHA40vi4UsdUdntl8ZeyERi10edcXy4+Dwz1w== X-Received: by 2002:a05:6a00:2d07:b0:717:87d6:fdd2 with SMTP id d2e1a72fcca58-71787d6ffe0mr2767467b3a.4.1725495259874; Wed, 04 Sep 2024 17:14:19 -0700 (PDT) Received: from tahera-OptiPlex-5000.tail3bf47f.ts.net ([136.159.49.123]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-71778534921sm2159781b3a.76.2024.09.04.17.14.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Sep 2024 17:14:19 -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 v11 0/8] Landlock: Add abstract UNIX socket restriction Date: Wed, 4 Sep 2024 18:13:54 -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 gets 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 "outside_socket" test. [3]https://lore.kernel.org/all/20240611.Pi8Iph7ootae@digikod.net/ Previous Versions ================= v10:https://lore.kernel.org/all/cover.1724125513.git.fahimitahera@gmail.com/ v9: https://lore.kernel.org/all/cover.1723615689.git.fahimitahera@gmail.com/ 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 (8): Landlock: Add abstract UNIX socket restriction selftests/landlock: Add test for handling unknown scope selftests/landlock: Add abstract UNIX socket restriction tests selftests/landlock: Add tests for UNIX sockets with any address formats selftests/landlock: Test connected vs non-connected datagram UNIX socket selftests/landlock: Restrict inherited datagram UNIX socket to connect sample/landlock: Add support abstract UNIX socket restriction Landlock: Document LANDLOCK_SCOPED_ABSTRACT_UNIX_SOCKET and ABI version Documentation/userspace-api/landlock.rst | 45 +- include/uapi/linux/landlock.h | 28 + samples/landlock/sandboxer.c | 61 +- security/landlock/limits.h | 3 + security/landlock/ruleset.c | 7 +- security/landlock/ruleset.h | 24 +- security/landlock/syscalls.c | 17 +- security/landlock/task.c | 136 +++ 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 | 993 ++++++++++++++++++ .../selftests/landlock/scoped_base_variants.h | 154 +++ .../selftests/landlock/scoped_common.h | 28 + .../scoped_multiple_domain_variants.h | 154 +++ .../testing/selftests/landlock/scoped_test.c | 33 + 16 files changed, 1709 insertions(+), 45 deletions(-) create mode 100644 tools/testing/selftests/landlock/scoped_abstract_unix_test.c create mode 100644 tools/testing/selftests/landlock/scoped_base_variants.h create mode 100644 tools/testing/selftests/landlock/scoped_common.h create mode 100644 tools/testing/selftests/landlock/scoped_multiple_domain_variants.h create mode 100644 tools/testing/selftests/landlock/scoped_test.c -- 2.34.1