tools/testing/selftests/landlock/cap_test.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Landlock tests - Capability restriction
 *
 * Copyright © 2026 Cloudflare, Inc.
 */

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/capability.h>
#include <linux/landlock.h>
#include <sched.h>
#include <stdio.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/wait.h>
#include <sys/xattr.h>
#include <unistd.h>

#include "audit.h"
#include "common.h"
#include "trace.h"

#define TRACE_TASK "cap_test"

static bool list_has_xattr(const char *list, ssize_t len, const char *name)
{
	const char *p;

	for (p = list; p < list + len; p += strlen(p) + 1)
		if (strcmp(p, name) == 0)
			return true;
	return false;
}

static int create_cap_ruleset(void)
{
	const struct landlock_ruleset_attr attr = {
		.handled_permissions = LANDLOCK_PERMISSION_CAPABILITY_USE,
	};

	return landlock_create_ruleset(&attr, sizeof(attr), 0);
}

static int add_cap_rule(int ruleset_fd, __u64 cap)
{
	const struct landlock_capability_attr attr = {
		.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE,
		.allowed_capabilities = (1ULL << cap),
	};

	return landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY, &attr,
				 0);
}

static int add_cap_rule_full(int ruleset_fd, __u64 allowed, __u64 quiet)
{
	const struct landlock_capability_attr attr = {
		.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE,
		.allowed_capabilities = allowed,
		.quiet_capabilities = quiet,
	};

	return landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY, &attr,
				 0);
}

TEST(add_rule_bad_attr)
{
	const struct landlock_ruleset_attr ns_only_attr = {
		.handled_permissions = LANDLOCK_PERMISSION_NAMESPACE_USE,
	};
	int ruleset_fd;
	struct landlock_capability_attr attr = {};

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);

	/* Invalid rule pointer returns EFAULT. */
	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
					NULL, 0));
	ASSERT_EQ(EFAULT, errno);

	/* Empty permissions selector returns ENOMSG. */
	attr.permissions = 0;
	attr.allowed_capabilities = (1ULL << CAP_NET_RAW);
	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
					&attr, 0));
	ASSERT_EQ(ENOMSG, errno);

	/* Useless rule: neither allowed nor quiet capabilities set. */
	attr.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE;
	attr.allowed_capabilities = 0;
	attr.quiet_capabilities = 0;
	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
					&attr, 0));
	ASSERT_EQ(ENOMSG, errno);

	/* Quiet-only rule (empty allowed set) is legal. */
	attr.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE;
	attr.allowed_capabilities = 0;
	attr.quiet_capabilities = (1ULL << CAP_NET_RAW);
	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
				       &attr, 0));

	/* Allow and quiet different members in the same rule. */
	attr.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE;
	attr.allowed_capabilities = (1ULL << CAP_SYS_ADMIN);
	attr.quiet_capabilities = (1ULL << CAP_NET_RAW);
	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
				       &attr, 0));

	/* Valid capability selector plus an extra unhandled selector bit. */
	attr.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE |
			   LANDLOCK_PERMISSION_NAMESPACE_USE;
	attr.allowed_capabilities = (1ULL << CAP_NET_RAW);
	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
					&attr, 0));
	ASSERT_EQ(EINVAL, errno);

	/* permissions with wrong type. */
	attr.permissions = LANDLOCK_PERMISSION_NAMESPACE_USE;
	attr.allowed_capabilities = (1ULL << CAP_NET_RAW);
	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
					&attr, 0));
	ASSERT_EQ(EINVAL, errno);

	/*
	 * Unknown capability bits (e.g. bit 63) are silently accepted for
	 * forward compatibility.  Only known bits are stored.
	 */
	attr.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE;
	attr.allowed_capabilities = 1ULL << 63;
	attr.quiet_capabilities = 0;
	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
				       &attr, 0));

	/*
	 * LANDLOCK_ADD_RULE_QUIET (and any other flag) is filesystem/network
	 * only and must be rejected for capability rules, even when every attr
	 * field is otherwise valid.
	 */
	attr.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE;
	attr.allowed_capabilities = (1ULL << CAP_NET_RAW);
	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
					&attr, LANDLOCK_ADD_RULE_QUIET));
	ASSERT_EQ(EINVAL, errno);

	EXPECT_EQ(0, close(ruleset_fd));

	/*
	 * Ruleset handles LANDLOCK_PERMISSION_NAMESPACE_USE but not
	 * LANDLOCK_PERMISSION_CAPABILITY_USE: adding a capability rule must be
	 * rejected.
	 */
	ruleset_fd =
		landlock_create_ruleset(&ns_only_attr, sizeof(ns_only_attr), 0);
	ASSERT_LE(0, ruleset_fd);
	attr.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE;
	attr.allowed_capabilities = (1ULL << CAP_NET_RAW);
	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
					&attr, 0));
	ASSERT_EQ(EINVAL, errno);
	EXPECT_EQ(0, close(ruleset_fd));
}

/*
 * Unknown capability values above CAP_LAST_CAP are silently accepted
 * (allow-list: they have no effect since the kernel never checks them).
 */
TEST(add_rule_unknown)
{
	int ruleset_fd;
	struct landlock_capability_attr attr = {
		.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE,
	};

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);

	/* Just above CAP_LAST_CAP should succeed. */
	attr.allowed_capabilities = (1ULL << (CAP_LAST_CAP + 1));
	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
				       &attr, 0));

	/* High values (below bit 63) should succeed. */
	attr.allowed_capabilities = (1ULL << 62);
	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
				       &attr, 0));

	EXPECT_EQ(0, close(ruleset_fd));
}

/*
 * A rule that lists only capability bits unknown to the running kernel is
 * accepted by landlock_add_rule() but has no runtime effect: once the domain is
 * enforced, any actual CAP_* capability is still denied by the per-category
 * deny-by-default behaviour.  This documents the forward-compatibility
 * contract: unknown bits are silently accepted so the same policy can be loaded
 * across kernels, but they never grant a capability that the running kernel
 * knows nothing about.
 */
TEST(add_rule_unknown_no_runtime_effect)
{
	const struct landlock_ruleset_attr ruleset_attr = {
		.handled_permissions = LANDLOCK_PERMISSION_CAPABILITY_USE,
	};
	struct landlock_capability_attr attr = {
		.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE,
		/* Only unknown bits above CAP_LAST_CAP. */
		.allowed_capabilities = (1ULL << (CAP_LAST_CAP + 1)) |
					(1ULL << 62),
	};
	int ruleset_fd;

	disable_caps(_metadata);

	ruleset_fd =
		landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
	ASSERT_LE(0, ruleset_fd);

	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
				       &attr, 0));

	/*
	 * Isolate hostname changes and establish a baseline: with CAP_SYS_ADMIN
	 * and absent the domain, sethostname(2) succeeds.  This ensures the
	 * EPERM below is attributable to Landlock rather than to a missing
	 * capability, and fails if the hook always allows.
	 */
	set_cap(_metadata, CAP_SYS_ADMIN);
	ASSERT_EQ(0, unshare(CLONE_NEWUTS));
	ASSERT_EQ(0, sethostname("baseline", 8));
	clear_cap(_metadata, CAP_SYS_ADMIN);

	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	/*
	 * CAP_SYS_ADMIN is a real, known capability but was not authorised by
	 * the rule above; deny-by-default applies.  sethostname(2) requires
	 * CAP_SYS_ADMIN.
	 */
	set_cap(_metadata, CAP_SYS_ADMIN);
	EXPECT_EQ(-1, sethostname("test", 4));
	EXPECT_EQ(EPERM, errno);
	clear_cap(_metadata, CAP_SYS_ADMIN);
}

/* clang-format off */
FIXTURE(cap_enforce) {};
/* clang-format on */

FIXTURE_VARIANT(cap_enforce)
{
	const bool is_sandboxed;
	const bool handle_caps;
	const __u64 allowed_cap;
	const int expected_sysadmin;
	const int expected_chroot;
};

/*
 * Unsandboxed baseline: no Landlock domain is enforced.  Both capabilities
 * should work normally.
 */
/* clang-format off */
FIXTURE_VARIANT_ADD(cap_enforce, unsandboxed) {
	.is_sandboxed = false,
	.handle_caps = false,
	.allowed_cap = 0,
	.expected_sysadmin = 0,
	.expected_chroot = 0,
};
/* clang-format on */

/*
 * Denied: capabilities are handled but no rule allows them.  All capability
 * checks must be denied by Landlock even if the capability is effective.
 */
/* clang-format off */
FIXTURE_VARIANT_ADD(cap_enforce, denied) {
	.is_sandboxed = true,
	.handle_caps = true,
	.allowed_cap = 0,
	.expected_sysadmin = EPERM,
	.expected_chroot = EPERM,
};
/* clang-format on */

/*
 * Allowed: CAP_SYS_ADMIN is allowed by rule, CAP_SYS_CHROOT is not.  Only the
 * explicitly allowed capability should succeed.
 */
/* clang-format off */
FIXTURE_VARIANT_ADD(cap_enforce, allowed) {
	.is_sandboxed = true,
	.handle_caps = true,
	.allowed_cap = CAP_SYS_ADMIN,
	.expected_sysadmin = 0,
	.expected_chroot = EPERM,
};
/* clang-format on */

/*
 * Unhandled: the ruleset does not handle LANDLOCK_PERMISSION_CAPABILITY_USE at
 * all (only handles FS access).  Both capabilities should work since the domain
 * does not restrict them.
 */
/* clang-format off */
FIXTURE_VARIANT_ADD(cap_enforce, unhandled) {
	.is_sandboxed = true,
	.handle_caps = false,
	.allowed_cap = 0,
	.expected_sysadmin = 0,
	.expected_chroot = 0,
};
/* clang-format on */

FIXTURE_SETUP(cap_enforce)
{
	disable_caps(_metadata);
}

FIXTURE_TEARDOWN(cap_enforce)
{
}

/*
 * Capability enforcement: tests the four fundamental enforcement scenarios
 * (unsandboxed baseline, denied, allowed, unhandled) using two independent
 * capability checks (sethostname for CAP_SYS_ADMIN, chroot for CAP_SYS_CHROOT).
 */
TEST_F(cap_enforce, use)
{
	int ruleset_fd;

	/* Isolate hostname changes from other tests. */
	set_cap(_metadata, CAP_SYS_ADMIN);
	ASSERT_EQ(0, unshare(CLONE_NEWUTS));
	clear_cap(_metadata, CAP_SYS_ADMIN);

	if (variant->is_sandboxed) {
		if (variant->handle_caps) {
			ruleset_fd = create_cap_ruleset();
		} else {
			const struct landlock_ruleset_attr attr = {
				.handled_access_fs =
					LANDLOCK_ACCESS_FS_READ_FILE,
			};

			ruleset_fd =
				landlock_create_ruleset(&attr, sizeof(attr), 0);
		}
		ASSERT_LE(0, ruleset_fd);

		if (variant->allowed_cap)
			ASSERT_EQ(0, add_cap_rule(ruleset_fd,
						  variant->allowed_cap));

		enforce_ruleset(_metadata, ruleset_fd);
		EXPECT_EQ(0, close(ruleset_fd));
	}

	/* Test CAP_SYS_ADMIN via sethostname. */
	set_cap(_metadata, CAP_SYS_ADMIN);
	if (variant->expected_sysadmin) {
		EXPECT_EQ(-1, sethostname("test", 4));
		EXPECT_EQ(variant->expected_sysadmin, errno);
	} else {
		EXPECT_EQ(0, sethostname("test", 4));
	}
	clear_cap(_metadata, CAP_SYS_ADMIN);

	/* Test CAP_SYS_CHROOT via chroot. */
	set_cap(_metadata, CAP_SYS_CHROOT);
	if (variant->expected_chroot) {
		EXPECT_EQ(-1, chroot("/"));
		EXPECT_EQ(variant->expected_chroot, errno);
	} else {
		EXPECT_EQ(0, chroot("/"));
	}
	clear_cap(_metadata, CAP_SYS_CHROOT);
}

/*
 * Layer stacking: both layers must allow CAP_SYS_ADMIN for the capability to be
 * exercisable.  Variants cover the three per-layer combinations that exercise
 * distinct walker paths (allow/deny, allow/allow, deny/allow), an unsandboxed
 * baseline, and a mixed-layer case where one layer does not handle
 * LANDLOCK_PERMISSION_CAPABILITY_USE at all.
 */
/* clang-format off */
FIXTURE(cap_stacking) {};
/* clang-format on */

FIXTURE_VARIANT(cap_stacking)
{
	const bool is_sandboxed;
	const bool first_layer_allows;
	const bool second_layer_allows;
	const bool second_layer_is_fs_only;
	const int expected_sysadmin;
	const int expected_chroot;
};

/*
 * Unsandboxed baseline: no Landlock layers are stacked.  Both capabilities
 * should work normally.
 */
/* clang-format off */
FIXTURE_VARIANT_ADD(cap_stacking, unsandboxed) {
	.is_sandboxed = false,
	.first_layer_allows = false,
	.second_layer_allows = false,
	.expected_sysadmin = 0,
	.expected_chroot = 0,
};
/* clang-format on */

/* Layer 1 allows CAP_SYS_ADMIN, layer 2 denies -> denied. */
/* clang-format off */
FIXTURE_VARIANT_ADD(cap_stacking, deny) {
	.is_sandboxed = true,
	.first_layer_allows = true,
	.second_layer_allows = false,
	.expected_sysadmin = EPERM,
	.expected_chroot = EPERM,
};
/* clang-format on */

/* Both layers allow CAP_SYS_ADMIN -> sysadmin succeeds, chroot still denied. */
/* clang-format off */
FIXTURE_VARIANT_ADD(cap_stacking, allow) {
	.is_sandboxed = true,
	.first_layer_allows = true,
	.second_layer_allows = true,
	.expected_sysadmin = 0,
	.expected_chroot = EPERM,
};
/* clang-format on */

/*
 * Layer 1 denies CAP_SYS_ADMIN, layer 2 allows -> still denied: a child layer
 * cannot grant what an ancestor layer withheld.  Complements the
 * parent-allows/child-denies variant; together they verify the walker checks
 * both layers and accepts only the (allow, allow) cell.
 */
/* clang-format off */
FIXTURE_VARIANT_ADD(cap_stacking, parent_denies) {
	.is_sandboxed = true,
	.first_layer_allows = false,
	.second_layer_allows = true,
	.expected_sysadmin = EPERM,
	.expected_chroot = EPERM,
};
/* clang-format on */

/*
 * Mixed layers: first layer handles LANDLOCK_PERMISSION_CAPABILITY_USE (denies
 * all caps), second layer is FS-only (does not handle it).  The permission
 * walker iterates from youngest (layer 1) to oldest (layer 0) and must skip the
 * FS-only layer to find the denying layer beneath.
 */
/* clang-format off */
FIXTURE_VARIANT_ADD(cap_stacking, mixed_layers) {
	/* clang-format on */
	.is_sandboxed = true,
	.first_layer_allows = false,
	.second_layer_is_fs_only = true,
	.expected_sysadmin = EPERM,
	.expected_chroot = EPERM,
};

FIXTURE_SETUP(cap_stacking)
{
	disable_caps(_metadata);

	/* Isolate every successful sethostname() from the other tests. */
	set_cap(_metadata, CAP_SYS_ADMIN);
	ASSERT_EQ(0, unshare(CLONE_NEWUTS));
	clear_cap(_metadata, CAP_SYS_ADMIN);
}

FIXTURE_TEARDOWN(cap_stacking)
{
}

TEST_F(cap_stacking, two_layers)
{
	int ruleset_fd;

	if (variant->is_sandboxed) {
		/*
		 * First layer: handles LANDLOCK_PERMISSION_CAPABILITY_USE; rule
		 * added per variant.
		 */
		ruleset_fd = create_cap_ruleset();
		ASSERT_LE(0, ruleset_fd);
		if (variant->first_layer_allows)
			ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_SYS_ADMIN));

		enforce_ruleset(_metadata, ruleset_fd);
		EXPECT_EQ(0, close(ruleset_fd));

		if (variant->second_layer_is_fs_only) {
			/*
			 * Second layer: FS-only (does not handle
			 * LANDLOCK_PERMISSION_CAPABILITY_USE).  The permission
			 * walker must skip this layer.
			 */
			const struct landlock_ruleset_attr fs_attr = {
				.handled_access_fs =
					LANDLOCK_ACCESS_FS_READ_FILE,
			};

			ruleset_fd = landlock_create_ruleset(
				&fs_attr, sizeof(fs_attr), 0);
		} else {
			/* Second layer: cap allow or deny. */
			ruleset_fd = create_cap_ruleset();
			if (variant->second_layer_allows)
				ASSERT_EQ(0, add_cap_rule(ruleset_fd,
							  CAP_SYS_ADMIN));
		}
		ASSERT_LE(0, ruleset_fd);
		enforce_ruleset(_metadata, ruleset_fd);
		EXPECT_EQ(0, close(ruleset_fd));
	}

	/* Test CAP_SYS_ADMIN via sethostname. */
	set_cap(_metadata, CAP_SYS_ADMIN);
	if (variant->expected_sysadmin) {
		EXPECT_EQ(-1, sethostname("test", 4));
		EXPECT_EQ(variant->expected_sysadmin, errno);
	} else {
		EXPECT_EQ(0, sethostname("test", 4));
	}
	clear_cap(_metadata, CAP_SYS_ADMIN);

	/* Test CAP_SYS_CHROOT via chroot. */
	set_cap(_metadata, CAP_SYS_CHROOT);
	if (variant->expected_chroot) {
		EXPECT_EQ(-1, chroot("/"));
		EXPECT_EQ(variant->expected_chroot, errno);
	} else {
		EXPECT_EQ(0, chroot("/"));
	}
	clear_cap(_metadata, CAP_SYS_CHROOT);
}

/*
 * Verify that LANDLOCK_PERMISSION_CAPABILITY_USE enforces when the domain is
 * applied without no_new_privs, using CAP_SYS_ADMIN for
 * landlock_restrict_self() authorization instead.  Privileged processes (e.g.
 * container managers) can sandbox themselves this way.
 */
TEST(cap_without_nnp)
{
	int ruleset_fd;

	disable_caps(_metadata);

	/* Isolate an unexpected successful sethostname(). */
	set_cap(_metadata, CAP_SYS_ADMIN);
	ASSERT_EQ(0, unshare(CLONE_NEWUTS));
	clear_cap(_metadata, CAP_SYS_ADMIN);

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);

	/* Allow CAP_SYS_CHROOT but not CAP_SYS_ADMIN. */
	ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_SYS_CHROOT));

	/*
	 * Enforce WITHOUT NNP: landlock_restrict_self() succeeds when the
	 * caller has CAP_SYS_ADMIN (checked before the new domain takes
	 * effect).
	 */
	set_cap(_metadata, CAP_SYS_ADMIN);
	ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0));
	EXPECT_EQ(0, close(ruleset_fd));

	/*
	 * CAP_SYS_ADMIN is still in effective set but Landlock denies it:
	 * cap_capable() returns 0, then hook_capable() returns -EPERM.
	 */
	EXPECT_EQ(-1, sethostname("test", 4));
	EXPECT_EQ(EPERM, errno);
	clear_cap(_metadata, CAP_SYS_ADMIN);

	/* CAP_SYS_CHROOT is allowed by the rule. */
	set_cap(_metadata, CAP_SYS_CHROOT);
	EXPECT_EQ(0, chroot("/"));
	clear_cap(_metadata, CAP_SYS_CHROOT);
}

/*
 * Verify that capabilities gained through user namespace ownership are still
 * restricted by LANDLOCK_PERMISSION_CAPABILITY_USE.  When a process creates a
 * user namespace, the kernel grants CAP_FULL_SET in the new namespace via
 * cap_capable_helper()'s ownership bypass.  Landlock's hook_capable() must
 * still deny capabilities not in the allowed set, ensuring that user namespace
 * creation cannot be used to escape capability restrictions.
 */
TEST(cap_userns_ownership_bypass)
{
	pid_t child;
	int status;

	child = fork();
	ASSERT_LE(0, child);
	if (child == 0) {
		int ruleset_fd;

		disable_caps(_metadata);

		ruleset_fd = create_cap_ruleset();
		ASSERT_LE(0, ruleset_fd);

		/* Allow CAP_SYS_ADMIN only. */
		ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_SYS_ADMIN));
		enforce_ruleset(_metadata, ruleset_fd);
		EXPECT_EQ(0, close(ruleset_fd));

		/*
		 * Create a user namespace.  This is unprivileged and does not
		 * require capabilities.  LANDLOCK_PERMISSION_NAMESPACE_USE is
		 * not handled so namespace creation is unrestricted.
		 */
		ASSERT_EQ(0, unshare(CLONE_NEWUSER));

		/*
		 * After unshare(CLONE_NEWUSER), the kernel set cap_effective =
		 * CAP_FULL_SET in the new namespace.  Create a UTS namespace
		 * (requires CAP_SYS_ADMIN in the new user NS).  Landlock allows
		 * CAP_SYS_ADMIN.
		 */
		ASSERT_EQ(0, unshare(CLONE_NEWUTS))
		{
			TH_LOG("unshare(CLONE_NEWUTS): %s", strerror(errno));
		}

		/*
		 * sethostname checks against uts_ns->user_ns, which is now the
		 * new user NS.  CAP_SYS_ADMIN is allowed.
		 */
		EXPECT_EQ(0, sethostname("test", 4));

		/*
		 * chroot checks against current_user_ns(), which is the new
		 * user NS.  The process has CAP_SYS_CHROOT in cap_effective
		 * (from user NS creation), so cap_capable() returns 0.  But
		 * Landlock denies because no rule allows CAP_SYS_CHROOT.
		 */
		EXPECT_EQ(-1, chroot("/"));
		EXPECT_EQ(EPERM, errno);

		_exit(_metadata->exit_code);
		return;
	}

	ASSERT_EQ(child, waitpid(child, &status, 0));
	if (WIFSIGNALED(status) || !WIFEXITED(status) ||
	    WEXITSTATUS(status) != EXIT_SUCCESS)
		_metadata->exit_code = KSFT_FAIL;
}

/*
 * Verify that capability restrictions do not depend on which user namespace the
 * kernel checks.  An actor in the initial user namespace can enter a descendant
 * user namespace with CAP_SYS_ADMIN.  With the same Linux capability state,
 * handling capability use without an allow rule must deny that target-namespace
 * check even though the target differs from current_user_ns().
 */
TEST(cap_target_userns_independent)
{
	int sockets[2], status, target_userns_fd;
	pid_t actor, target;

	disable_caps(_metadata);
	ASSERT_EQ(0,
		  socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, sockets));

	target = fork();
	ASSERT_LE(0, target);
	if (target == 0) {
		int fd;

		close(sockets[0]);
		if (unshare(CLONE_NEWUSER))
			_exit(255);
		fd = open("/proc/self/ns/user", O_RDONLY | O_CLOEXEC);
		if (fd < 0 || send_fd(sockets[1], fd))
			_exit(255);
		close(fd);
		close(sockets[1]);
		_exit(EXIT_SUCCESS);
	}

	close(sockets[1]);
	target_userns_fd = recv_fd(sockets[0]);
	ASSERT_LE(0, target_userns_fd);
	EXPECT_EQ(0, close(sockets[0]));
	ASSERT_EQ(target, waitpid(target, &status, 0));
	ASSERT_TRUE(WIFEXITED(status));
	ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));

	set_cap(_metadata, CAP_SYS_ADMIN);
	for (int sandboxed = 0; sandboxed <= 1; sandboxed++) {
		actor = fork();
		ASSERT_LE(0, actor);
		if (actor == 0) {
			int ret, saved_errno;

			if (sandboxed) {
				int ruleset_fd = create_cap_ruleset();

				if (ruleset_fd < 0 ||
				    prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) ||
				    landlock_restrict_self(ruleset_fd, 0) ||
				    close(ruleset_fd))
					_exit(255);
			}

			ret = setns(target_userns_fd, CLONE_NEWUSER);
			saved_errno = errno;
			_exit(ret ? saved_errno : EXIT_SUCCESS);
		}

		ASSERT_EQ(actor, waitpid(actor, &status, 0));
		ASSERT_TRUE(WIFEXITED(status));
		EXPECT_EQ(sandboxed ? EPERM : EXIT_SUCCESS,
			  WEXITSTATUS(status));
	}
	clear_cap(_metadata, CAP_SYS_ADMIN);
	EXPECT_EQ(0, close(target_userns_fd));
}

/* Audit tests */

static int matches_log_cap(int audit_fd, int cap_number)
{
	static const char log_template[] = REGEX_LANDLOCK_PREFIX
		" blockers=capability\\.use capability=%d $";
	char log_match[sizeof(log_template) + 10];
	int log_match_len;

	log_match_len = snprintf(log_match, sizeof(log_match), log_template,
				 cap_number);
	if (log_match_len >= sizeof(log_match))
		return -E2BIG;

	return audit_match_record(audit_fd, AUDIT_LANDLOCK_ACCESS, log_match,
				  NULL);
}

FIXTURE(cap_audit)
{
	struct audit_filter audit_filter;
	int audit_fd;
};

FIXTURE_SETUP(cap_audit)
{
	ASSERT_TRUE(is_in_init_user_ns());

	disable_caps(_metadata);

	/* Isolate successful sethostname() calls. */
	set_cap(_metadata, CAP_SYS_ADMIN);
	ASSERT_EQ(0, unshare(CLONE_NEWUTS));
	clear_cap(_metadata, CAP_SYS_ADMIN);

	set_cap(_metadata, CAP_AUDIT_CONTROL);
	self->audit_fd = audit_init_with_exe_filter(&self->audit_filter);
	EXPECT_LE(0, self->audit_fd);
	clear_cap(_metadata, CAP_AUDIT_CONTROL);
}

FIXTURE_TEARDOWN(cap_audit)
{
	set_cap(_metadata, CAP_AUDIT_CONTROL);
	EXPECT_EQ(0, audit_cleanup(self->audit_fd, &self->audit_filter));
	clear_cap(_metadata, CAP_AUDIT_CONTROL);
}

/*
 * Verifies that a denied capability produces the expected audit record with the
 * correct capability number and blocker string.
 */
TEST_F(cap_audit, denied)
{
	struct audit_records records = {};
	int ruleset_fd;
	__u64 domain_id;

	/* Baseline: chroot works before Landlock. */
	set_cap(_metadata, CAP_SYS_CHROOT);
	ASSERT_EQ(0, chroot("/"));
	clear_cap(_metadata, CAP_SYS_CHROOT);

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	/* Allow CAP_AUDIT_CONTROL for child-side audit cleanup. */
	ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_AUDIT_CONTROL));
	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	/* Deny CAP_SYS_CHROOT (no allow rule). */
	set_cap(_metadata, CAP_SYS_CHROOT);
	EXPECT_EQ(-1, chroot("/"));
	EXPECT_EQ(EPERM, errno);
	clear_cap(_metadata, CAP_SYS_CHROOT);

	EXPECT_EQ(0, matches_log_cap(self->audit_fd, CAP_SYS_CHROOT));

	/*
	 * The domain allocation record is emitted in the same event as the
	 * first denial; anchor its status=allocated and enforcing pid.  Both
	 * access and domain records are now consumed, so none remain.
	 */
	EXPECT_EQ(0, matches_log_domain_allocated(self->audit_fd, getpid(),
						  &domain_id));
	EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
	EXPECT_EQ(0, records.access);
	EXPECT_EQ(0, records.domain);
}

TEST_F(cap_audit, allowed)
{
	struct audit_records records = {};
	int ruleset_fd;

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_SYS_ADMIN));
	/* Allow CAP_AUDIT_CONTROL for child-side audit cleanup. */
	ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_AUDIT_CONTROL));
	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	set_cap(_metadata, CAP_SYS_ADMIN);
	EXPECT_EQ(0, sethostname("test", 4));
	clear_cap(_metadata, CAP_SYS_ADMIN);

	/* No records: allowed operations never trigger audit logging. */
	EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
	EXPECT_EQ(0, records.access);
}

/* An allowed capability remains allowed when the same rule also quiets it. */
TEST_F(cap_audit, allow_and_quiet_same_member)
{
	struct audit_records records = {};
	int ruleset_fd;

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	ASSERT_EQ(0, add_cap_rule_full(ruleset_fd,
				       (1ULL << CAP_SYS_ADMIN) |
					       (1ULL << CAP_AUDIT_CONTROL),
				       1ULL << CAP_SYS_ADMIN));
	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	set_cap(_metadata, CAP_SYS_ADMIN);
	EXPECT_EQ(0, sethostname("test", 4));
	clear_cap(_metadata, CAP_SYS_ADMIN);

	/*
	 * Quiet is inert for the allowed member: nothing is denied or logged.
	 */
	EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
	EXPECT_EQ(0, records.access);
}

/*
 * A quieted capability denial is still denied (EPERM); only its audit record is
 * suppressed.  Quiet-only rule (empty allowed set).
 */
TEST_F(cap_audit, quieted)
{
	struct audit_records records = {};
	int ruleset_fd;
	__u64 domain_id;

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	/* Allow CAP_AUDIT_CONTROL for child-side audit cleanup. */
	ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_AUDIT_CONTROL));
	ASSERT_EQ(0,
		  add_cap_rule_full(ruleset_fd, 0, (1ULL << CAP_SYS_CHROOT)));
	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	set_cap(_metadata, CAP_SYS_CHROOT);
	EXPECT_EQ(-1, chroot("/"));
	EXPECT_EQ(EPERM, errno);
	clear_cap(_metadata, CAP_SYS_CHROOT);

	/*
	 * Positive control: CAP_SYS_ADMIN is denied but not quieted, so its
	 * denial IS logged.  This proves quieting is per-member, not global.
	 */
	set_cap(_metadata, CAP_SYS_ADMIN);
	EXPECT_EQ(-1, sethostname("test", 4));
	EXPECT_EQ(EPERM, errno);
	clear_cap(_metadata, CAP_SYS_ADMIN);

	/*
	 * The quieted CAP_SYS_CHROOT denial is suppressed; the CAP_SYS_ADMIN
	 * denial is logged.
	 */
	EXPECT_EQ(0, matches_log_cap(self->audit_fd, CAP_SYS_ADMIN));
	EXPECT_EQ(0, matches_log_domain_allocated(self->audit_fd, getpid(),
						  &domain_id));
	EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
	EXPECT_EQ(0, records.access);
	EXPECT_EQ(0, records.domain);
}

/*
 * Only the youngest denying layer decides quieting: a parent cannot silence a
 * denial by a deeper layer that handles but does not quiet the capability.
 */
TEST_F(cap_audit, quiet_youngest_layer_wins)
{
	struct audit_records records = {};
	int ruleset_fd;
	__u64 domain_id;

	/* Baseline: commoncap allows chroot before Landlock. */
	set_cap(_metadata, CAP_SYS_CHROOT);
	ASSERT_EQ(0, chroot("/"));
	clear_cap(_metadata, CAP_SYS_CHROOT);

	/* Parent layer: denies and quiets CAP_SYS_CHROOT. */
	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	ASSERT_EQ(0, add_cap_rule_full(ruleset_fd, 1ULL << CAP_AUDIT_CONTROL,
				       1ULL << CAP_SYS_CHROOT));
	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	/* Child layer: denies CAP_SYS_CHROOT without quieting it. */
	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_AUDIT_CONTROL));
	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	set_cap(_metadata, CAP_SYS_CHROOT);
	EXPECT_EQ(-1, chroot("/"));
	EXPECT_EQ(EPERM, errno);
	clear_cap(_metadata, CAP_SYS_CHROOT);

	/*
	 * The child is the youngest denier and does not quiet: log the denial.
	 */
	EXPECT_EQ(0, matches_log_cap(self->audit_fd, CAP_SYS_CHROOT));
	EXPECT_EQ(0, matches_log_domain_allocated(self->audit_fd, getpid(),
						  &domain_id));
	EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
	EXPECT_EQ(0, records.access);
	EXPECT_EQ(0, records.domain);
}

/*
 * Quieting an unknown capability bit has no effect: a rule that quiets only a
 * bit above CAP_LAST_CAP still logs the denial of a known capability.
 */
TEST_F(cap_audit, quiet_unknown_bit_no_effect)
{
	struct audit_records records = {};
	int ruleset_fd;
	__u64 domain_id;

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_AUDIT_CONTROL));
	/* Quiet only an unknown bit (bit 63 is above CAP_LAST_CAP). */
	ASSERT_EQ(0, add_cap_rule_full(ruleset_fd, 0, (1ULL << 63)));
	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	set_cap(_metadata, CAP_SYS_CHROOT);
	EXPECT_EQ(-1, chroot("/"));
	EXPECT_EQ(EPERM, errno);
	clear_cap(_metadata, CAP_SYS_CHROOT);

	/* The unknown quiet bit does not suppress the known denial. */
	EXPECT_EQ(0, matches_log_cap(self->audit_fd, CAP_SYS_CHROOT));
	EXPECT_EQ(0, matches_log_domain_allocated(self->audit_fd, getpid(),
						  &domain_id));
	EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
	EXPECT_EQ(0, records.access);
	EXPECT_EQ(0, records.domain);
}

/*
 * A capability check made with CAP_OPT_NOAUDIT is denied by Landlock but not
 * logged: hook_capable() emits no Landlock audit record when the caller passes
 * CAP_OPT_NOAUDIT, so the denial is silent here even though CAP_SYS_ADMIN is
 * neither allowed nor quieted.  The probe is the
 * ns_capable_noaudit(CAP_SYS_ADMIN) call in simple_xattr_list(), reached
 * through tmpfs, which decides whether trusted.* xattrs are visible to
 * listxattr(2).
 */
TEST_F(cap_audit, noaudit_probe_not_logged)
{
	struct audit_records records = {};
	int ruleset_fd, fd;
	__u64 domain_id;
	char list[256];
	ssize_t len;

	/*
	 * Private tmpfs holding a trusted.* xattr so its listxattr(2)
	 * visibility depends only on the CAP_SYS_ADMIN noaudit probe.
	 */
	set_cap(_metadata, CAP_SYS_ADMIN);
	ASSERT_EQ(0, unshare(CLONE_NEWNS));
	ASSERT_EQ(0, mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL));
	ASSERT_EQ(0, mount("test", "/tmp", "tmpfs", 0, NULL));
	fd = open("/tmp/f", O_CREAT | O_RDWR | O_CLOEXEC, 0600);
	ASSERT_LE(0, fd);
	ASSERT_EQ(0, fsetxattr(fd, "trusted.landlock_test", "x", 1, 0));

	/* Baseline: with CAP_SYS_ADMIN, the trusted xattr is listed. */
	len = flistxattr(fd, list, sizeof(list));
	ASSERT_LE(0, len);
	ASSERT_TRUE(list_has_xattr(list, len, "trusted.landlock_test"));

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	/* Allow CAP_AUDIT_CONTROL for child-side audit cleanup. */
	ASSERT_EQ(0, add_cap_rule(ruleset_fd, CAP_AUDIT_CONTROL));
	/* CAP_SYS_ADMIN is neither allowed nor quieted. */
	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	/*
	 * CAP_SYS_ADMIN is still effective, but Landlock denies the noaudit
	 * probe, so the trusted.* xattr is filtered out of the listing.
	 */
	len = flistxattr(fd, list, sizeof(list));
	ASSERT_LE(0, len);
	EXPECT_FALSE(list_has_xattr(list, len, "trusted.landlock_test"));
	EXPECT_EQ(0, close(fd));

	/* The denied noaudit probe leaves no audit record nor denial. */
	EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
	EXPECT_EQ(0, records.access);

	/*
	 * Positive control: a normal (audited) CAP_SYS_ADMIN denial in the same
	 * domain IS logged.  This proves the empty record set above is caused
	 * by CAP_OPT_NOAUDIT, not by an always-allow or always-silent bug.
	 */
	EXPECT_EQ(-1, sethostname("test", 4));
	EXPECT_EQ(EPERM, errno);
	clear_cap(_metadata, CAP_SYS_ADMIN);

	EXPECT_EQ(0, matches_log_cap(self->audit_fd, CAP_SYS_ADMIN));
	EXPECT_EQ(0, matches_log_domain_allocated(self->audit_fd, getpid(),
						  &domain_id));
	EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
	EXPECT_EQ(0, records.access);
	EXPECT_EQ(0, records.domain);
}

/* Trace tests */

/* clang-format off */
FIXTURE(cap_trace) {
	/* clang-format on */
	int tracefs_ok;
};

FIXTURE_SETUP(cap_trace)
{
	int ret;

	set_cap(_metadata, CAP_SYS_ADMIN);
	ASSERT_EQ(0, unshare(CLONE_NEWNS));
	ASSERT_EQ(0, mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL));

	ret = tracefs_fixture_setup();
	if (ret) {
		clear_cap(_metadata, CAP_SYS_ADMIN);
		self->tracefs_ok = 0;
		SKIP(return, "tracefs not available");
	}
	self->tracefs_ok = 1;

	ASSERT_EQ(0, tracefs_enable_event(TRACEFS_CREATE_RULESET_ENABLE, true));
	ASSERT_EQ(0, tracefs_enable_event(TRACEFS_ADD_RULE_CAPABILITY_ENABLE,
					  true));
	ASSERT_EQ(0, tracefs_enable_event(
			     TRACEFS_DENY_PERMISSION_CAPABILITY_ENABLE, true));
	ASSERT_EQ(0, tracefs_clear());
	clear_cap(_metadata, CAP_SYS_ADMIN);
}

FIXTURE_TEARDOWN(cap_trace)
{
	if (!self->tracefs_ok)
		return;

	set_cap(_metadata, CAP_SYS_ADMIN);
	tracefs_enable_event(TRACEFS_CREATE_RULESET_ENABLE, false);
	tracefs_enable_event(TRACEFS_ADD_RULE_CAPABILITY_ENABLE, false);
	tracefs_enable_event(TRACEFS_DENY_PERMISSION_CAPABILITY_ENABLE, false);
	tracefs_fixture_teardown();
	clear_cap(_metadata, CAP_SYS_ADMIN);
}

/*
 * Check the permission fields and version history, including two rejected calls
 * and two successful calls that do not extend the effective policy: a repeated
 * rule and an unknown-only rule.
 */
TEST_F(cap_trace, rule_events)
{
	const char *const version_1 =
		REGEX_ADD_RULE_CAPABILITY_VERSION(TRACE_TASK, "1");
	const char *const version_2 =
		REGEX_ADD_RULE_CAPABILITY_VERSION(TRACE_TASK, "2");
	const char *const version_3 =
		REGEX_ADD_RULE_CAPABILITY_VERSION(TRACE_TASK, "3");
	const struct landlock_capability_attr valid_attr = {
		.permissions = LANDLOCK_PERMISSION_CAPABILITY_USE,
		.allowed_capabilities = 1ULL << CAP_SYS_ADMIN,
		.quiet_capabilities = 1ULL << CAP_SYS_CHROOT,
	};
	const struct landlock_capability_attr invalid_attr = {
		.permissions = LANDLOCK_PERMISSION_NAMESPACE_USE,
		.allowed_capabilities = 1ULL << CAP_SYS_ADMIN,
	};
	char expected[32], field[64];
	char *buf;
	int ruleset_fd;

	if (!self->tracefs_ok)
		SKIP(return, "tracefs not available");

	ASSERT_EQ(0, tracefs_clear_buf());

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	ASSERT_EQ(0, add_cap_rule_full(ruleset_fd, 1ULL << CAP_SYS_ADMIN,
				       1ULL << CAP_SYS_CHROOT));
	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
					&invalid_attr, 0));
	ASSERT_EQ(EINVAL, errno);
	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_CAPABILITY,
					&valid_attr, LANDLOCK_ADD_RULE_QUIET));
	ASSERT_EQ(EINVAL, errno);
	ASSERT_EQ(0, add_cap_rule_full(ruleset_fd, 1ULL << CAP_SYS_ADMIN,
				       1ULL << CAP_SYS_CHROOT));
	ASSERT_EQ(0, add_cap_rule(ruleset_fd, 63));
	EXPECT_EQ(0, close(ruleset_fd));

	buf = tracefs_read_buf();
	ASSERT_NE(NULL, buf);

	ASSERT_EQ(1,
		  tracefs_count_matches(buf, REGEX_CREATE_RULESET(TRACE_TASK)));
	ASSERT_EQ(0, tracefs_extract_field(
			     buf, REGEX_CREATE_RULESET(TRACE_TASK),
			     "handled_permissions", field, sizeof(field)));
	EXPECT_STREQ("capability.use", field);

	ASSERT_EQ(3,
		  tracefs_count_matches(buf, "landlock_add_rule_capability: "));
	ASSERT_EQ(3, tracefs_count_matches(
			     buf, REGEX_ADD_RULE_CAPABILITY(TRACE_TASK)));
	EXPECT_EQ(1, tracefs_count_matches(buf, version_1));
	EXPECT_EQ(1, tracefs_count_matches(buf, version_2));
	EXPECT_EQ(1, tracefs_count_matches(buf, version_3));

	ASSERT_EQ(0, tracefs_extract_field(buf, version_1, "permissions", field,
					   sizeof(field)));
	EXPECT_STREQ("capability.use", field);
	ASSERT_EQ(0,
		  tracefs_extract_field(buf, version_1, "allowed_capabilities",
					field, sizeof(field)));
	snprintf(expected, sizeof(expected), "0x%llx", 1ULL << CAP_SYS_ADMIN);
	EXPECT_STREQ(expected, field);
	ASSERT_EQ(0, tracefs_extract_field(buf, version_1, "quiet_capabilities",
					   field, sizeof(field)));
	snprintf(expected, sizeof(expected), "0x%llx", 1ULL << CAP_SYS_CHROOT);
	EXPECT_STREQ(expected, field);

	/* The rejected calls emit no event and do not consume version 2. */
	ASSERT_EQ(0, tracefs_extract_field(buf, version_2, "permissions", field,
					   sizeof(field)));
	EXPECT_STREQ("capability.use", field);
	ASSERT_EQ(0,
		  tracefs_extract_field(buf, version_2, "allowed_capabilities",
					field, sizeof(field)));
	snprintf(expected, sizeof(expected), "0x%llx", 1ULL << CAP_SYS_ADMIN);
	EXPECT_STREQ(expected, field);
	ASSERT_EQ(0, tracefs_extract_field(buf, version_2, "quiet_capabilities",
					   field, sizeof(field)));
	snprintf(expected, sizeof(expected), "0x%llx", 1ULL << CAP_SYS_CHROOT);
	EXPECT_STREQ(expected, field);

	/* The unknown-only call succeeds but contributes no effective bits. */
	ASSERT_EQ(0, tracefs_extract_field(buf, version_3, "permissions", field,
					   sizeof(field)));
	EXPECT_STREQ("capability.use", field);
	ASSERT_EQ(0,
		  tracefs_extract_field(buf, version_3, "allowed_capabilities",
					field, sizeof(field)));
	EXPECT_STREQ("0x0", field);
	ASSERT_EQ(0, tracefs_extract_field(buf, version_3, "quiet_capabilities",
					   field, sizeof(field)));
	EXPECT_STREQ("0x0", field);

	free(buf);
}

enum cap_trace_denial_kind {
	CAP_TRACE_DENY,
	CAP_TRACE_DENY_QUIET,
	CAP_TRACE_DENY_NOAUDIT,
};

static void exercise_cap_trace_denial(struct __test_metadata *const _metadata,
				      const enum cap_trace_denial_kind kind)
{
	int ruleset_fd, fd = -1;
	char list[256];
	ssize_t len;

	disable_caps(_metadata);

	if (kind == CAP_TRACE_DENY_NOAUDIT) {
		set_cap(_metadata, CAP_SYS_ADMIN);
		set_cap(_metadata, CAP_SYS_CHROOT);
		ASSERT_EQ(0, mount("test", "/tmp", "tmpfs", 0, NULL));
		fd = open("/tmp/f", O_CREAT | O_RDWR | O_CLOEXEC, 0600);
		ASSERT_LE(0, fd);
		ASSERT_EQ(0, fsetxattr(fd, "trusted.landlock_test", "x", 1, 0));

		/* Baseline: CAP_SYS_ADMIN exposes the trusted xattr. */
		len = flistxattr(fd, list, sizeof(list));
		ASSERT_LE(0, len);
		ASSERT_TRUE(list_has_xattr(list, len, "trusted.landlock_test"));
	} else {
		set_cap(_metadata, CAP_SYS_CHROOT);
	}

	ruleset_fd = create_cap_ruleset();
	ASSERT_LE(0, ruleset_fd);
	if (kind == CAP_TRACE_DENY_QUIET)
		ASSERT_EQ(0, add_cap_rule_full(ruleset_fd, 0,
					       1ULL << CAP_SYS_CHROOT));
	enforce_ruleset(_metadata, ruleset_fd);
	EXPECT_EQ(0, close(ruleset_fd));

	if (kind == CAP_TRACE_DENY_NOAUDIT) {
		/* Probe CAP_SYS_ADMIN with CAP_OPT_NOAUDIT. */
		len = flistxattr(fd, list, sizeof(list));
		ASSERT_LE(0, len);
		EXPECT_FALSE(
			list_has_xattr(list, len, "trusted.landlock_test"));
		EXPECT_EQ(0, close(fd));

		/* Control: an ordinary denial in the same domain is traced. */
		EXPECT_EQ(-1, chroot("/"));
		EXPECT_EQ(EPERM, errno);
		clear_cap(_metadata, CAP_SYS_ADMIN);
		clear_cap(_metadata, CAP_SYS_CHROOT);
	} else {
		EXPECT_EQ(-1, chroot("/"));
		EXPECT_EQ(EPERM, errno);
		clear_cap(_metadata, CAP_SYS_CHROOT);
	}
}

static void test_cap_trace_denial(struct __test_metadata *const _metadata,
				  const enum cap_trace_denial_kind kind,
				  const int expected_capability,
				  const char *const expected_logged)
{
	char expected[16], field[64];
	int status;
	char *buf;
	pid_t child;

	ASSERT_EQ(0, tracefs_clear_buf());

	child = fork();
	ASSERT_LE(0, child);
	if (child == 0) {
		exercise_cap_trace_denial(_metadata, kind);
		_exit(_metadata->exit_code);
	}

	ASSERT_EQ(child, waitpid(child, &status, 0));
	ASSERT_TRUE(WIFEXITED(status));
	ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));

	buf = tracefs_read_buf();
	ASSERT_NE(NULL, buf);
	ASSERT_EQ(1, tracefs_count_matches(
			     buf, REGEX_DENY_PERMISSION_CAPABILITY(TRACE_TASK)))
	{
		TH_LOG("Expected one capability denial event\n%s", buf);
	}

	ASSERT_EQ(0, tracefs_extract_field(
			     buf, REGEX_DENY_PERMISSION_CAPABILITY(TRACE_TASK),
			     "domain", field, sizeof(field)));
	EXPECT_STRNE("0", field);
	ASSERT_EQ(0, tracefs_extract_field(
			     buf, REGEX_DENY_PERMISSION_CAPABILITY(TRACE_TASK),
			     "same_exec", field, sizeof(field)));
	EXPECT_STREQ("1", field);
	ASSERT_EQ(0, tracefs_extract_field(
			     buf, REGEX_DENY_PERMISSION_CAPABILITY(TRACE_TASK),
			     "logged", field, sizeof(field)));
	EXPECT_STREQ(expected_logged, field);
	ASSERT_EQ(0, tracefs_extract_field(
			     buf, REGEX_DENY_PERMISSION_CAPABILITY(TRACE_TASK),
			     "blockers", field, sizeof(field)));
	EXPECT_STREQ("use", field);
	ASSERT_EQ(0, tracefs_extract_field(
			     buf, REGEX_DENY_PERMISSION_CAPABILITY(TRACE_TASK),
			     "capability", field, sizeof(field)));
	snprintf(expected, sizeof(expected), "%d", expected_capability);
	EXPECT_STREQ(expected, field);

	free(buf);
}

TEST_F(cap_trace, deny)
{
	if (!self->tracefs_ok)
		SKIP(return, "tracefs not available");
	test_cap_trace_denial(_metadata, CAP_TRACE_DENY, CAP_SYS_CHROOT, "1");
}

TEST_F(cap_trace, deny_quiet)
{
	if (!self->tracefs_ok)
		SKIP(return, "tracefs not available");
	test_cap_trace_denial(_metadata, CAP_TRACE_DENY_QUIET, CAP_SYS_CHROOT,
			      "0");
}

/*
 * A CAP_OPT_NOAUDIT probe is denied without any record.  The audit counterpart
 * checks the missing audit record; this one checks that the CAP_SYS_ADMIN probe
 * emits no trace event, while the CAP_SYS_CHROOT denial that follows it in the
 * same domain still does.
 */
TEST_F(cap_trace, noaudit_probe_not_traced)
{
	if (!self->tracefs_ok)
		SKIP(return, "tracefs not available");
	test_cap_trace_denial(_metadata, CAP_TRACE_DENY_NOAUDIT, CAP_SYS_CHROOT,
			      "1");
}

TEST_HARNESS_MAIN