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AJvYcCUM0LNHcxOlm3NeWQ3DOro+iJilpAaNm4rhD92F7Qi1KsAHlTgRNRPRVu01Jn7bikwokdfhoecp@vger.kernel.org, AJvYcCVchMor3sgDrQrrmiRsb6yISn4WVH3RAWyVIJJCMi7dE7Hxs7oRBabMbdij55IwCYTP2IpP7N32D4dJMz8=@vger.kernel.org, AJvYcCXT8z+2mIa9MSQNC2sUDxoS81ZWJohu6cDz+zYM/ejB7hL3rXBCdj1qTsbUVVn/YrwcAcEZRIVH1MYVbIgTgP8fy0wj3wml@vger.kernel.org X-Gm-Message-State: AOJu0Yyuoccu5I5sXwdl9u5vH37u65zNo20N3N2RD9DRkLRtHxLgxxBE 66Zp+0vgWJWxEOb0ZkbIQeUUL4Y6hT0qc8CDULAGSrkUNJSw4Yiu X-Google-Smtp-Source: AGHT+IEAx3eAq13eKvyQi76A8rHmXhmvNa2y+UtFzSmr+VF8ucB8ZCth/llQ5TrkB5fficwGiAOAxQ== X-Received: by 2002:a05:6a21:2d86:b0:1c4:9100:6a1b with SMTP id adf61e73a8af0-1c904fca42bmr648447637.30.1723746584960; Thu, 15 Aug 2024 11:29:44 -0700 (PDT) Received: from tahera-OptiPlex-5000.uc.ucalgary.ca ([136.159.49.123]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-7c6b6356c76sm1431683a12.62.2024.08.15.11.29.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Aug 2024 11:29:44 -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 v3 3/6] selftest/Landlock: Signal restriction tests Date: Thu, 15 Aug 2024 12:29:22 -0600 Message-Id: <82b0d2103013397d8b46de9fc7c8c78456055299.1723680305.git.fahimitahera@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This patch expands Landlock ABI version 6 by providing tests for signal scoping mechanism. Base on kill(2), if the signal is 0, no signal will be sent, but the permission of a process to send a signal will be checked. Likewise, this test consider one signal for each signal category. Signed-off-by: Tahera Fahimi --- Chnages in versions: V2: * Moving tests from ptrace_test.c to scoped_signal_test.c * Remove debugging statements. * Covering all basic restriction scenarios by sending 0 as signal V1: * Expanding Landlock ABI version 6 by providing basic tests for four signals to test signal scoping mechanism. --- .../selftests/landlock/scoped_signal_test.c | 302 ++++++++++++++++++ 1 file changed, 302 insertions(+) create mode 100644 tools/testing/selftests/landlock/scoped_signal_test.c diff --git a/tools/testing/selftests/landlock/scoped_signal_test.c b/tools/testing/selftests/landlock/scoped_signal_test.c new file mode 100644 index 000000000000..92958c6266ca --- /dev/null +++ b/tools/testing/selftests/landlock/scoped_signal_test.c @@ -0,0 +1,302 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Landlock tests - Signal Scoping + * + * Copyright © 2017-2020 Mickaël Salaün + * Copyright © 2019-2020 ANSSI + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include + +#include "common.h" + +static sig_atomic_t signaled; + +static void create_signal_domain(struct __test_metadata *const _metadata) +{ + int ruleset_fd; + const struct landlock_ruleset_attr ruleset_attr = { + .scoped = LANDLOCK_SCOPED_SIGNAL, + }; + + ruleset_fd = + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); + EXPECT_LE(0, ruleset_fd) + { + TH_LOG("Failed to create a ruleset: %s", strerror(errno)); + } + enforce_ruleset(_metadata, ruleset_fd); + EXPECT_EQ(0, close(ruleset_fd)); +} + +static void scope_signal_handler(int sig, siginfo_t *info, void *ucontext) +{ + if (sig == SIGHUP || sig == SIGURG || sig == SIGTSTP || + sig == SIGTRAP || sig == SIGUSR1) { + signaled = 1; + } +} + +/* clang-format off */ +FIXTURE(signal_scoping) {}; +/* clang-format on */ + +FIXTURE_VARIANT(signal_scoping) +{ + const int sig; + const bool domain_both; + const bool domain_parent; + const bool domain_child; +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, allow_without_domain) { + /* clang-format on */ + .sig = 0, + .domain_both = false, + .domain_parent = false, + .domain_child = false, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, deny_with_child_domain) { + /* clang-format on */ + .sig = 0, + .domain_both = false, + .domain_parent = false, + .domain_child = true, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, allow_with_parent_domain) { + /* clang-format on */ + .sig = 0, + .domain_both = false, + .domain_parent = true, + .domain_child = false, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, deny_with_sibling_domain) { + /* clang-format on */ + .sig = 0, + .domain_both = false, + .domain_parent = true, + .domain_child = true, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, allow_sibling_domain) { + /* clang-format on */ + .sig = 0, + .domain_both = true, + .domain_parent = false, + .domain_child = false, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, deny_with_nested_domain) { + /* clang-format on */ + .sig = 0, + .domain_both = true, + .domain_parent = false, + .domain_child = true, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, allow_with_nested_and_parent_domain) { + /* clang-format on */ + .sig = 0, + .domain_both = true, + .domain_parent = true, + .domain_child = false, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, deny_with_forked_domain) { + /* clang-format on */ + .sig = 0, + .domain_both = true, + .domain_parent = true, + .domain_child = true, +}; + +/* Default Action: Terminate*/ +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, deny_with_forked_domain_SIGHUP) { + /* clang-format on */ + .sig = SIGHUP, + .domain_both = true, + .domain_parent = true, + .domain_child = true, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, allow_with_forked_domain_SIGHUP) { + /* clang-format on */ + .sig = SIGHUP, + .domain_both = false, + .domain_parent = true, + .domain_child = false, +}; + +/* Default Action: Ignore*/ +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, deny_with_forked_domain_SIGURG) { + /* clang-format on */ + .sig = SIGURG, + .domain_both = true, + .domain_parent = true, + .domain_child = true, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, allow_with_forked_domain_SIGURG) { + /* clang-format on */ + .sig = SIGURG, + .domain_both = false, + .domain_parent = true, + .domain_child = false, +}; + +/* Default Action: Stop*/ +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, deny_with_forked_domain_SIGTSTP) { + /* clang-format on */ + .sig = SIGTSTP, + .domain_both = true, + .domain_parent = true, + .domain_child = true, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, allow_with_forked_domain_SIGTSTP) { + /* clang-format on */ + .sig = SIGTSTP, + .domain_both = false, + .domain_parent = true, + .domain_child = false, +}; + +/* Default Action: Coredump*/ +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, deny_with_forked_domain_SIGTRAP) { + /* clang-format on */ + .sig = SIGTRAP, + .domain_both = true, + .domain_parent = true, + .domain_child = true, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, allow_with_forked_domain_SIGTRAP) { + /* clang-format on */ + .sig = SIGTRAP, + .domain_both = false, + .domain_parent = true, + .domain_child = false, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(signal_scoping, deny_with_forked_domain_SIGUSR1) { + /* clang-format on */ + .sig = SIGUSR1, + .domain_both = true, + .domain_parent = true, + .domain_child = true, +}; + +FIXTURE_SETUP(signal_scoping) +{ +} + +FIXTURE_TEARDOWN(signal_scoping) +{ +} + +TEST_F(signal_scoping, test_signal) +{ + pid_t child; + pid_t parent = getpid(); + int status; + bool can_signal; + int pipe_parent[2]; + struct sigaction action = { + .sa_sigaction = scope_signal_handler, + .sa_flags = SA_SIGINFO, + + }; + + can_signal = !variant->domain_child; + + if (variant->sig > 0) + ASSERT_LE(0, sigaction(variant->sig, &action, NULL)); + + if (variant->domain_both) { + create_signal_domain(_metadata); + if (!__test_passed(_metadata)) + /* Aborts before forking. */ + return; + } + ASSERT_EQ(0, pipe2(pipe_parent, O_CLOEXEC)); + + child = fork(); + ASSERT_LE(0, child); + if (child == 0) { + char buf_child; + int err; + + ASSERT_EQ(0, close(pipe_parent[1])); + if (variant->domain_child) + create_signal_domain(_metadata); + + /* Waits for the parent to be in a domain, if any. */ + ASSERT_EQ(1, read(pipe_parent[0], &buf_child, 1)); + + err = kill(parent, variant->sig); + if (can_signal) { + ASSERT_EQ(0, err); + } else { + ASSERT_EQ(-1, err); + ASSERT_EQ(EPERM, errno); + } + /* no matter of the domain, a process should be able to send + * a signal to itself. + */ + ASSERT_EQ(0, raise(variant->sig)); + if (variant->sig > 0) + ASSERT_EQ(1, signaled); + _exit(_metadata->exit_code); + return; + } + ASSERT_EQ(0, close(pipe_parent[0])); + if (variant->domain_parent) + create_signal_domain(_metadata); + + /* Signals that the parent is in a domain, if any. */ + ASSERT_EQ(1, write(pipe_parent[1], ".", 1)); + + if (can_signal && variant->sig > 0) { + ASSERT_EQ(-1, pause()); + ASSERT_EQ(EINTR, errno); + ASSERT_EQ(1, signaled); + } else { + ASSERT_EQ(0, signaled); + } + + ASSERT_EQ(child, waitpid(child, &status, 0)); + + if (WIFSIGNALED(status) || !WIFEXITED(status) || + WEXITSTATUS(status) != EXIT_SUCCESS) + _metadata->exit_code = KSFT_FAIL; +} + +TEST_HARNESS_MAIN