From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f175.google.com (mail-pl1-f175.google.com [209.85.214.175]) (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 6DECE12C49B for ; Tue, 6 Aug 2024 18:11:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722967879; cv=none; b=rNQ17VeUWq9RIwmxKZqhEGjEYr+d0jmnmtxykPx7l4vQFpweH5nzOgH3LT8ecLQQTFLpmfeJfvjbBV2TrW+Of4yOyHS+Zd0QrQpW5GVA2JWguvGi6/4icmj9PwQcNUP/43WP0JiE50jhihYtZ+iR+zuRcdFLgPC2z/iacvQubLk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722967879; c=relaxed/simple; bh=0ewYccFC+gUsRirqVBgroPLIdoo7vvA0gP/+dnGxjmI=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=uVJwcU0gNnMXh+GYxxnQDcWH86lIxbDCAi6ETgqekD+Q08/S2xQQFFghB+jNI1TtgCR3PZp7wRakPR3vLvbFOchAS/GOCHYn+OOwUDfFrHo0DXJFumNL+PLHmTBcMEF+UMLitOsF4D597aoaoLS/UBg2/foSA60ZU4cM/KfV5yk= 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=gqOlv75H; arc=none smtp.client-ip=209.85.214.175 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="gqOlv75H" Received: by mail-pl1-f175.google.com with SMTP id d9443c01a7336-1fc49c0aaffso8042815ad.3 for ; Tue, 06 Aug 2024 11:11:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722967877; x=1723572677; 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=0RBuTc6tLdIB/+vTHorcWL7vaqZKWklEKUMNzfbf8ug=; b=gqOlv75HJLftmcEI2zIqtzIN8SARvqEGflR86XwnuBFs4+DeuyiQro3PlgyC3W5uT2 iUAzmh2xmAivB0G3OXZNDI+YwiG3ZwtqzQO3sRwkJQyBzHnDmKVsjSuVEaavxuI7o7IT yjTBmAGUb7PB7gzHZCy/VcA9mV8lvsJLLwxq4puan0aqf7GKSdyRoi8H6gDou2WQ6uX+ +7vOQnLfn42AeCmpNCT0CoYbWaDYUEr7v5ez/gzMcMjnJS+B86YxG7xEa7Gyk9C0J+lX hP5srhpsdLhj8HVQZUXumz6G3PreCYkJbo2/NKtbXfcFnk6ire44WO4HS3MuzFYHrycX Lrww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722967877; x=1723572677; 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=0RBuTc6tLdIB/+vTHorcWL7vaqZKWklEKUMNzfbf8ug=; b=Z7CoKgZKr33ZGeBVnrv6Wm62yoziT9z+dwSZ9TWLGT1FO4a+587KsiNF/9qFsrDdYS vv2YuEqofxH6YA39zCLlw/FhQEJ8XoRc+5WzDs6+8bMrqDxLGcSC6hfmMcmCa8V8vMQP vEpzqT8UaEAUokUUoNyYd9Ahpp/5G6MqvqNahwGia5ljIwXMcdt8KzKuAJCVXGKqaHXM LGjULlOz9l54XbWVwszXbp9xaqFjX03BJQePUKT8dsH3SSmjZlqf1GLzBhFimsBZxE7Y cVq9u85IATnnVFyt3RzRdje5RQD5lyzmJUUzG3x4nMbmdoY6ByrL9PyC9wkTb9UTrfQd rQfw== X-Gm-Message-State: AOJu0YyOpzGAMt+T4EvLQWETkHYqqY9wdYF7hw3UW16m2CPKCs/W56TA vl0GIJhO/5h1cEqe1Xya5dZsHZkIwqtXzsqPu+pJ01dIUdBBmjtspkMmJXfB X-Google-Smtp-Source: AGHT+IEMFDWxG3XriWekADN9wxkPJTTGnTZ26Onx658MWf6fTZ3OlRburIFFPLH7N2CuvRHyAkCeBA== X-Received: by 2002:a17:902:d501:b0:1fd:9105:7dd3 with SMTP id d9443c01a7336-1ff5750acd3mr176378275ad.64.1722967877035; Tue, 06 Aug 2024 11:11:17 -0700 (PDT) Received: from tahera-OptiPlex-5000.tail3bf47f.ts.net ([136.159.49.123]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2cfdc45b51esm12829504a91.32.2024.08.06.11.11.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Aug 2024 11:11:16 -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 v2 0/4] Landlock: Signal Scoping Support Date: Tue, 6 Aug 2024 12:10:39 -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-Transfer-Encoding: 8bit This patch series adds scoping mechanism for signals. Closes: https://github.com/landlock-lsm/linux/issues/8 Problem ======= A sandboxed process is currently not restricted from sending signals (e.g. SIGKILL) to processes outside the sandbox since Landlock has no restriction on signals(see more details in [1]). A simple way to apply this restriction would be to scope signals the same way abstract unix sockets are restricted. [1]https://lore.kernel.org/all/20231023.ahphah4Wii4v@digikod.net/ Solution ======== To solve this issue, we extend the "scoped" field in the Landlock ruleset attribute structure by introducing "LANDLOCK_SCOPED_SIGNAL" field to specify that a ruleset will deny sending any signals from within the sandbox domain to its parent(i.e. any parent sandbox or non-sandbox processes). Example ======= Create a sansboxed shell and pass the character "s" to LL_SCOPED: LL_FD_RO=/ LL_FS_RW=. LL_SCOPED="s" ./sandboxer /bin/bash Try to send a signal(like SIGTRAP) to a process ID through: kill -SIGTRAP The sandboxed process should not be able to send the signal. Tahera Fahimi (4): Landlock: Add signal control selftest/Landlock: Signal restriction tests sample/Landlock: Support signal scoping restriction Landlock: Document LANDLOCK_SCOPED_SIGNAL Documentation/userspace-api/landlock.rst | 27 +- include/uapi/linux/landlock.h | 3 + samples/landlock/sandboxer.c | 13 +- security/landlock/limits.h | 2 +- security/landlock/task.c | 43 +++ tools/testing/selftests/landlock/base_test.c | 2 +- .../selftests/landlock/scoped_signal_test.c | 303 ++++++++++++++++++ 7 files changed, 376 insertions(+), 17 deletions(-) create mode 100644 tools/testing/selftests/landlock/scoped_signal_test.c -- 2.34.1