tools/testing/selftests/landlock/audit.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Landlock audit helpers
  *
  * Copyright © 2024-2025 Microsoft Corporation
  */

 #define _GNU_SOURCE
 #include <errno.h>
 #include <linux/audit.h>
 #include <linux/limits.h>
 #include <linux/netlink.h>
 #include <regex.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/time.h>
 #include <unistd.h>

 #include "../kselftest.h"

 #ifndef ARRAY_SIZE
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 #endif

 #define REGEX_LANDLOCK_PREFIX "^audit([0-9.:]\\+): domain=\\([0-9a-f]\\+\\)"

 struct audit_filter {
 	__u32 record_type;
 	size_t exe_len;
 	char exe[PATH_MAX];
 };

 struct audit_message {
 	struct nlmsghdr header;
 	union {
 		struct audit_status status;
 		struct audit_features features;
 		struct audit_rule_data rule;
 		struct nlmsgerr err;
 		char data[PATH_MAX + 200];
 	};
 };

 static const struct timeval audit_tv_dom_drop = {
 	/*
 	 * Because domain deallocation is tied to asynchronous credential
 	 * freeing, receiving such event may take some time.  In practice,
 	 * on a small VM, it should not exceed 100k usec, but let's wait up
 	 * to 1 second to be safe.
 	 */
 	.tv_sec = 1,
 };

 static const struct timeval audit_tv_default = {
 	.tv_usec = 1,
 };

 static int audit_send(const int fd, const struct audit_message *const msg)
 {
 	struct sockaddr_nl addr = {
 		.nl_family = AF_NETLINK,
 	};
 	int ret;

 	do {
 		ret = sendto(fd, msg, msg->header.nlmsg_len, 0,
 			     (struct sockaddr *)&addr, sizeof(addr));
 	} while (ret < 0 && errno == EINTR);

 	if (ret < 0)
 		return -errno;

 	if (ret != msg->header.nlmsg_len)
 		return -E2BIG;

 	return 0;
 }

 static int audit_recv(const int fd, struct audit_message *msg)
 {
 	struct sockaddr_nl addr;
 	socklen_t addrlen = sizeof(addr);
 	struct audit_message msg_tmp;
 	int err;

 	if (!msg)
 		msg = &msg_tmp;

 	do {
 		err = recvfrom(fd, msg, sizeof(*msg), 0,
 			       (struct sockaddr *)&addr, &addrlen);
 	} while (err < 0 && errno == EINTR);

 	if (err < 0)
 		return -errno;

 	if (addrlen != sizeof(addr) || addr.nl_pid != 0)
 		return -EINVAL;

 	/* Checks Netlink error or end of messages. */
 	if (msg->header.nlmsg_type == NLMSG_ERROR)
 		return msg->err.error;

 	return 0;
 }

 static int audit_request(const int fd,
 			 const struct audit_message *const request,
 			 struct audit_message *reply)
 {
 	struct audit_message msg_tmp;
 	bool first_reply = true;
 	int err;

 	err = audit_send(fd, request);
 	if (err)
 		return err;

 	if (!reply)
 		reply = &msg_tmp;

 	do {
 		if (first_reply)
 			first_reply = false;
 		else
 			reply = &msg_tmp;

 		err = audit_recv(fd, reply);
 		if (err)
 			return err;
 	} while (reply->header.nlmsg_type != NLMSG_ERROR &&
 		 reply->err.msg.nlmsg_type != request->header.nlmsg_type);

 	return reply->err.error;
 }

 static int audit_filter_exe(const int audit_fd,
 			    const struct audit_filter *const filter,
 			    const __u16 type)
 {
 	struct audit_message msg = {
 		.header = {
 			.nlmsg_len = NLMSG_SPACE(sizeof(msg.rule)) +
 				     NLMSG_ALIGN(filter->exe_len),
 			.nlmsg_type = type,
 			.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK,
 		},
 		.rule = {
 			.flags = AUDIT_FILTER_EXCLUDE,
 			.action = AUDIT_NEVER,
 			.field_count = 1,
 			.fields[0] = filter->record_type,
 			.fieldflags[0] = AUDIT_NOT_EQUAL,
 			.values[0] = filter->exe_len,
 			.buflen = filter->exe_len,
 		}
 	};

 	if (filter->record_type != AUDIT_EXE)
 		return -EINVAL;

 	memcpy(msg.rule.buf, filter->exe, filter->exe_len);
 	return audit_request(audit_fd, &msg, NULL);
 }

 static int audit_filter_drop(const int audit_fd, const __u16 type)
 {
 	struct audit_message msg = {
 		.header = {
 			.nlmsg_len = NLMSG_SPACE(sizeof(msg.rule)),
 			.nlmsg_type = type,
 			.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK,
 		},
 		.rule = {
 			.flags = AUDIT_FILTER_EXCLUDE,
 			.action = AUDIT_NEVER,
 			.field_count = 1,
 			.fields[0] = AUDIT_MSGTYPE,
 			.fieldflags[0] = AUDIT_NOT_EQUAL,
 			.values[0] = AUDIT_LANDLOCK_DOMAIN,
 		}
 	};

 	return audit_request(audit_fd, &msg, NULL);
 }

 static int audit_set_status(int fd, __u32 key, __u32 val)
 {
 	const struct audit_message msg = {
 		.header = {
 			.nlmsg_len = NLMSG_SPACE(sizeof(msg.status)),
 			.nlmsg_type = AUDIT_SET,
 			.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK,
 		},
 		.status = {
 			.mask = key,
 			.enabled = key == AUDIT_STATUS_ENABLED ? val : 0,
 			.pid = key == AUDIT_STATUS_PID ? val : 0,
 		}
 	};

 	return audit_request(fd, &msg, NULL);
 }

 /* Returns a pointer to the last filled character of @dst, which is `\0`.  */
 static __maybe_unused char *regex_escape(const char *const src, char *dst,
 					 size_t dst_size)
 {
 	char *d = dst;

 	for (const char *s = src; *s; s++) {
 		switch (*s) {
 		case '$':
 		case '*':
 		case '.':
 		case '[':
 		case '\\':
 		case ']':
 		case '^':
 			if (d >= dst + dst_size - 2)
 				return (char *)-ENOMEM;

 			*d++ = '\\';
 			*d++ = *s;
 			break;
 		default:
 			if (d >= dst + dst_size - 1)
 				return (char *)-ENOMEM;

 			*d++ = *s;
 		}
 	}
 	if (d >= dst + dst_size - 1)
 		return (char *)-ENOMEM;

 	*d = '\0';
 	return d;
 }

 /*
  * @domain_id: The domain ID extracted from the audit message (if the first part
  * of @pattern is REGEX_LANDLOCK_PREFIX).  It is set to 0 if the domain ID is
  * not found.
  */
 static int audit_match_record(int audit_fd, const __u16 type,
 			      const char *const pattern, __u64 *domain_id)
 {
 	struct audit_message msg;
 	int ret, err = 0;
 	bool matches_record = !type;
 	regmatch_t matches[2];
 	regex_t regex;

 	ret = regcomp(&regex, pattern, 0);
 	if (ret)
 		return -EINVAL;

 	do {
 		memset(&msg, 0, sizeof(msg));
 		err = audit_recv(audit_fd, &msg);
 		if (err)
 			goto out;

 		if (msg.header.nlmsg_type == type)
 			matches_record = true;
 	} while (!matches_record);

 	ret = regexec(&regex, msg.data, ARRAY_SIZE(matches), matches, 0);
 	if (ret) {
 		printf("DATA: %s\n", msg.data);
 		printf("ERROR: no match for pattern: %s\n", pattern);
 		err = -ENOENT;
 	}

 	if (domain_id) {
 		*domain_id = 0;
 		if (matches[1].rm_so != -1) {
 			int match_len = matches[1].rm_eo - matches[1].rm_so;
 			/* The maximal characters of a 2^64 hexadecimal number is 17. */
 			char dom_id[18];

 			if (match_len > 0 && match_len < sizeof(dom_id)) {
 				memcpy(dom_id, msg.data + matches[1].rm_so,
 				       match_len);
 				dom_id[match_len] = '\0';
 				if (domain_id)
 					*domain_id = strtoull(dom_id, NULL, 16);
 			}
 		}
 	}

 out:
 	regfree(&regex);
 	return err;
 }

 static int __maybe_unused matches_log_domain_allocated(int audit_fd, pid_t pid,
 						       __u64 *domain_id)
 {
 	static const char log_template[] = REGEX_LANDLOCK_PREFIX
 		" status=allocated mode=enforcing pid=%d uid=[0-9]\\+"
 		" exe=\"[^\"]\\+\" comm=\".*_test\"$";
 	char log_match[sizeof(log_template) + 10];
 	int log_match_len;

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

 	return audit_match_record(audit_fd, AUDIT_LANDLOCK_DOMAIN, log_match,
 				  domain_id);
 }

 static int __maybe_unused matches_log_domain_deallocated(
 	int audit_fd, unsigned int num_denials, __u64 *domain_id)
 {
 	static const char log_template[] = REGEX_LANDLOCK_PREFIX
 		" status=deallocated denials=%u$";
 	char log_match[sizeof(log_template) + 10];
 	int log_match_len;

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

 	return audit_match_record(audit_fd, AUDIT_LANDLOCK_DOMAIN, log_match,
 				  domain_id);
 }

 struct audit_records {
 	size_t access;
 	size_t domain;
 };

 static int audit_count_records(int audit_fd, struct audit_records *records)
 {
 	struct audit_message msg;
 	int err;

 	records->access = 0;
 	records->domain = 0;

 	do {
 		memset(&msg, 0, sizeof(msg));
 		err = audit_recv(audit_fd, &msg);
 		if (err) {
 			if (err == -EAGAIN)
 				return 0;
 			else
 				return err;
 		}

 		switch (msg.header.nlmsg_type) {
 		case AUDIT_LANDLOCK_ACCESS:
 			records->access++;
 			break;
 		case AUDIT_LANDLOCK_DOMAIN:
 			records->domain++;
 			break;
 		}
 	} while (true);

 	return 0;
 }

 static int audit_init(void)
 {
 	int fd, err;

 	fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_AUDIT);
 	if (fd < 0)
 		return -errno;

 	err = audit_set_status(fd, AUDIT_STATUS_ENABLED, 1);
 	if (err)
 		return err;

 	err = audit_set_status(fd, AUDIT_STATUS_PID, getpid());
 	if (err)
 		return err;

 	/* Sets a timeout for negative tests. */
 	err = setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &audit_tv_default,
 			 sizeof(audit_tv_default));
 	if (err)
 		return -errno;

 	return fd;
 }

 static int audit_init_filter_exe(struct audit_filter *filter, const char *path)
 {
 	char *absolute_path = NULL;

 	/* It is assume that there is not already filtering rules. */
 	filter->record_type = AUDIT_EXE;
 	if (!path) {
 		int ret = readlink("/proc/self/exe", filter->exe,
 				   sizeof(filter->exe) - 1);
 		if (ret < 0)
 			return -errno;

 		filter->exe_len = ret;
 		return 0;
 	}

 	absolute_path = realpath(path, NULL);
 	if (!absolute_path)
 		return -errno;

 	/* No need for the terminating NULL byte. */
 	filter->exe_len = strlen(absolute_path);
 	if (filter->exe_len > sizeof(filter->exe))
 		return -E2BIG;

 	memcpy(filter->exe, absolute_path, filter->exe_len);
 	free(absolute_path);
 	return 0;
 }

 static int audit_cleanup(int audit_fd, struct audit_filter *filter)
 {
 	struct audit_filter new_filter;

 	if (audit_fd < 0 || !filter) {
 		int err;

 		/*
 		 * Simulates audit_init_with_exe_filter() when called from
 		 * FIXTURE_TEARDOWN_PARENT().
 		 */
 		audit_fd = audit_init();
 		if (audit_fd < 0)
 			return audit_fd;

 		filter = &new_filter;
 		err = audit_init_filter_exe(filter, NULL);
 		if (err)
 			return err;
 	}

 	/* Filters might not be in place. */
 	audit_filter_exe(audit_fd, filter, AUDIT_DEL_RULE);
 	audit_filter_drop(audit_fd, AUDIT_DEL_RULE);

 	/*
 	 * Because audit_cleanup() might not be called by the test auditd
 	 * process, it might not be possible to explicitly set it.  Anyway,
 	 * AUDIT_STATUS_ENABLED will implicitly be set to 0 when the auditd
 	 * process will exit.
 	 */
 	return close(audit_fd);
 }

 static int audit_init_with_exe_filter(struct audit_filter *filter)
 {
 	int fd, err;

 	fd = audit_init();
 	if (fd < 0)
 		return fd;

 	err = audit_init_filter_exe(filter, NULL);
 	if (err)
 		return err;

 	err = audit_filter_exe(fd, filter, AUDIT_ADD_RULE);
 	if (err)
 		return err;

 	return fd;
 }
	/* SPDX-License-Identifier: GPL-2.0 */
	/*
	* Landlock audit helpers
	*
	* Copyright © 2024-2025 Microsoft Corporation
	*/

	#define _GNU_SOURCE
	#include <errno.h>
	#include <linux/audit.h>
	#include <linux/limits.h>
	#include <linux/netlink.h>
	#include <regex.h>
	#include <stdbool.h>
	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/socket.h>
	#include <sys/time.h>
	#include <unistd.h>

	#include "../kselftest.h"

	#ifndef ARRAY_SIZE
	#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
	#endif

	#define REGEX_LANDLOCK_PREFIX "^audit([0-9.:]\\+): domain=\\([0-9a-f]\\+\\)"

	struct audit_filter {
	__u32 record_type;
	size_t exe_len;
	char exe[PATH_MAX];
	};

	struct audit_message {
	struct nlmsghdr header;
	union {
	struct audit_status status;
	struct audit_features features;
	struct audit_rule_data rule;
	struct nlmsgerr err;
	char data[PATH_MAX + 200];
	};
	};

	static const struct timeval audit_tv_dom_drop = {
	/*
	* Because domain deallocation is tied to asynchronous credential
	* freeing, receiving such event may take some time. In practice,
	* on a small VM, it should not exceed 100k usec, but let's wait up
	* to 1 second to be safe.
	*/
	.tv_sec = 1,
	};

	static const struct timeval audit_tv_default = {
	.tv_usec = 1,
	};

	static int audit_send(const int fd, const struct audit_message *const msg)
	{
	struct sockaddr_nl addr = {
	.nl_family = AF_NETLINK,
	};
	int ret;

	do {
	ret = sendto(fd, msg, msg->header.nlmsg_len, 0,
	(struct sockaddr *)&addr, sizeof(addr));
	} while (ret < 0 && errno == EINTR);

	if (ret < 0)
	return -errno;

	if (ret != msg->header.nlmsg_len)
	return -E2BIG;

	return 0;
	}

	static int audit_recv(const int fd, struct audit_message *msg)
	{
	struct sockaddr_nl addr;
	socklen_t addrlen = sizeof(addr);
	struct audit_message msg_tmp;
	int err;

	if (!msg)
	msg = &msg_tmp;

	do {
	err = recvfrom(fd, msg, sizeof(*msg), 0,
	(struct sockaddr *)&addr, &addrlen);
	} while (err < 0 && errno == EINTR);

	if (err < 0)
	return -errno;

	if (addrlen != sizeof(addr) \|\| addr.nl_pid != 0)
	return -EINVAL;

	/* Checks Netlink error or end of messages. */
	if (msg->header.nlmsg_type == NLMSG_ERROR)
	return msg->err.error;

	return 0;
	}

	static int audit_request(const int fd,
	const struct audit_message *const request,
	struct audit_message *reply)
	{
	struct audit_message msg_tmp;
	bool first_reply = true;
	int err;

	err = audit_send(fd, request);
	if (err)
	return err;

	if (!reply)
	reply = &msg_tmp;

	do {
	if (first_reply)
	first_reply = false;
	else
	reply = &msg_tmp;

	err = audit_recv(fd, reply);
	if (err)
	return err;
	} while (reply->header.nlmsg_type != NLMSG_ERROR &&
	reply->err.msg.nlmsg_type != request->header.nlmsg_type);

	return reply->err.error;
	}

	static int audit_filter_exe(const int audit_fd,
	const struct audit_filter *const filter,
	const __u16 type)
	{
	struct audit_message msg = {
	.header = {
	.nlmsg_len = NLMSG_SPACE(sizeof(msg.rule)) +
	NLMSG_ALIGN(filter->exe_len),
	.nlmsg_type = type,
	.nlmsg_flags = NLM_F_REQUEST \| NLM_F_ACK,
	},
	.rule = {
	.flags = AUDIT_FILTER_EXCLUDE,
	.action = AUDIT_NEVER,
	.field_count = 1,
	.fields[0] = filter->record_type,
	.fieldflags[0] = AUDIT_NOT_EQUAL,
	.values[0] = filter->exe_len,
	.buflen = filter->exe_len,
	}
	};

	if (filter->record_type != AUDIT_EXE)
	return -EINVAL;

	memcpy(msg.rule.buf, filter->exe, filter->exe_len);
	return audit_request(audit_fd, &msg, NULL);
	}

	static int audit_filter_drop(const int audit_fd, const __u16 type)
	{
	struct audit_message msg = {
	.header = {
	.nlmsg_len = NLMSG_SPACE(sizeof(msg.rule)),
	.nlmsg_type = type,
	.nlmsg_flags = NLM_F_REQUEST \| NLM_F_ACK,
	},
	.rule = {
	.flags = AUDIT_FILTER_EXCLUDE,
	.action = AUDIT_NEVER,
	.field_count = 1,
	.fields[0] = AUDIT_MSGTYPE,
	.fieldflags[0] = AUDIT_NOT_EQUAL,
	.values[0] = AUDIT_LANDLOCK_DOMAIN,
	}
	};

	return audit_request(audit_fd, &msg, NULL);
	}

	static int audit_set_status(int fd, __u32 key, __u32 val)
	{
	const struct audit_message msg = {
	.header = {
	.nlmsg_len = NLMSG_SPACE(sizeof(msg.status)),
	.nlmsg_type = AUDIT_SET,
	.nlmsg_flags = NLM_F_REQUEST \| NLM_F_ACK,
	},
	.status = {
	.mask = key,
	.enabled = key == AUDIT_STATUS_ENABLED ? val : 0,
	.pid = key == AUDIT_STATUS_PID ? val : 0,
	}
	};

	return audit_request(fd, &msg, NULL);
	}

	/* Returns a pointer to the last filled character of @dst, which is `\0`. */
	static __maybe_unused char regex_escape(const char const src, char *dst,
	size_t dst_size)
	{
	char *d = dst;

	for (const char s = src; s; s++) {
	switch (*s) {
	case '$':
	case '*':
	case '.':
	case '[':
	case '\\':
	case ']':
	case '^':
	if (d >= dst + dst_size - 2)
	return (char *)-ENOMEM;

	*d++ = '\\';
	d++ = s;
	break;
	default:
	if (d >= dst + dst_size - 1)
	return (char *)-ENOMEM;

	d++ = s;
	}
	}
	if (d >= dst + dst_size - 1)
	return (char *)-ENOMEM;

	*d = '\0';
	return d;
	}

	/*
	* @domain_id: The domain ID extracted from the audit message (if the first part
	* of @pattern is REGEX_LANDLOCK_PREFIX). It is set to 0 if the domain ID is
	* not found.
	*/
	static int audit_match_record(int audit_fd, const __u16 type,
	const char const pattern, __u64 domain_id)
	{
	struct audit_message msg;
	int ret, err = 0;
	bool matches_record = !type;
	regmatch_t matches[2];
	regex_t regex;

	ret = regcomp(&regex, pattern, 0);
	if (ret)
	return -EINVAL;

	do {
	memset(&msg, 0, sizeof(msg));
	err = audit_recv(audit_fd, &msg);
	if (err)
	goto out;

	if (msg.header.nlmsg_type == type)
	matches_record = true;
	} while (!matches_record);

	ret = regexec(&regex, msg.data, ARRAY_SIZE(matches), matches, 0);
	if (ret) {
	printf("DATA: %s\n", msg.data);
	printf("ERROR: no match for pattern: %s\n", pattern);
	err = -ENOENT;
	}

	if (domain_id) {
	*domain_id = 0;
	if (matches[1].rm_so != -1) {
	int match_len = matches[1].rm_eo - matches[1].rm_so;
	/* The maximal characters of a 2^64 hexadecimal number is 17. */
	char dom_id[18];

	if (match_len > 0 && match_len < sizeof(dom_id)) {
	memcpy(dom_id, msg.data + matches[1].rm_so,
	match_len);
	dom_id[match_len] = '\0';
	if (domain_id)
	*domain_id = strtoull(dom_id, NULL, 16);
	}
	}
	}

	out:
	regfree(&regex);
	return err;
	}

	static int __maybe_unused matches_log_domain_allocated(int audit_fd, pid_t pid,
	__u64 *domain_id)
	{
	static const char log_template[] = REGEX_LANDLOCK_PREFIX
	" status=allocated mode=enforcing pid=%d uid=[0-9]\\+"
	" exe=\"[^\"]\\+\" comm=\".*_test\"$";
	char log_match[sizeof(log_template) + 10];
	int log_match_len;

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

	return audit_match_record(audit_fd, AUDIT_LANDLOCK_DOMAIN, log_match,
	domain_id);
	}

	static int __maybe_unused matches_log_domain_deallocated(
	int audit_fd, unsigned int num_denials, __u64 *domain_id)
	{
	static const char log_template[] = REGEX_LANDLOCK_PREFIX
	" status=deallocated denials=%u$";
	char log_match[sizeof(log_template) + 10];
	int log_match_len;

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

	return audit_match_record(audit_fd, AUDIT_LANDLOCK_DOMAIN, log_match,
	domain_id);
	}

	struct audit_records {
	size_t access;
	size_t domain;
	};

	static int audit_count_records(int audit_fd, struct audit_records *records)
	{
	struct audit_message msg;
	int err;

	records->access = 0;
	records->domain = 0;

	do {
	memset(&msg, 0, sizeof(msg));
	err = audit_recv(audit_fd, &msg);
	if (err) {
	if (err == -EAGAIN)
	return 0;
	else
	return err;
	}

	switch (msg.header.nlmsg_type) {
	case AUDIT_LANDLOCK_ACCESS:
	records->access++;
	break;
	case AUDIT_LANDLOCK_DOMAIN:
	records->domain++;
	break;
	}
	} while (true);

	return 0;
	}

	static int audit_init(void)
	{
	int fd, err;

	fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_AUDIT);
	if (fd < 0)
	return -errno;

	err = audit_set_status(fd, AUDIT_STATUS_ENABLED, 1);
	if (err)
	return err;

	err = audit_set_status(fd, AUDIT_STATUS_PID, getpid());
	if (err)
	return err;

	/* Sets a timeout for negative tests. */
	err = setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &audit_tv_default,
	sizeof(audit_tv_default));
	if (err)
	return -errno;

	return fd;
	}

	static int audit_init_filter_exe(struct audit_filter filter, const char path)
	{
	char *absolute_path = NULL;

	/* It is assume that there is not already filtering rules. */
	filter->record_type = AUDIT_EXE;
	if (!path) {
	int ret = readlink("/proc/self/exe", filter->exe,
	sizeof(filter->exe) - 1);
	if (ret < 0)
	return -errno;

	filter->exe_len = ret;
	return 0;
	}

	absolute_path = realpath(path, NULL);
	if (!absolute_path)
	return -errno;

	/* No need for the terminating NULL byte. */
	filter->exe_len = strlen(absolute_path);
	if (filter->exe_len > sizeof(filter->exe))
	return -E2BIG;

	memcpy(filter->exe, absolute_path, filter->exe_len);
	free(absolute_path);
	return 0;
	}

	static int audit_cleanup(int audit_fd, struct audit_filter *filter)
	{
	struct audit_filter new_filter;

	if (audit_fd < 0 \|\| !filter) {
	int err;

	/*
	* Simulates audit_init_with_exe_filter() when called from
	* FIXTURE_TEARDOWN_PARENT().
	*/
	audit_fd = audit_init();
	if (audit_fd < 0)
	return audit_fd;

	filter = &new_filter;
	err = audit_init_filter_exe(filter, NULL);
	if (err)
	return err;
	}

	/* Filters might not be in place. */
	audit_filter_exe(audit_fd, filter, AUDIT_DEL_RULE);
	audit_filter_drop(audit_fd, AUDIT_DEL_RULE);

	/*
	* Because audit_cleanup() might not be called by the test auditd
	* process, it might not be possible to explicitly set it. Anyway,
	* AUDIT_STATUS_ENABLED will implicitly be set to 0 when the auditd
	* process will exit.
	*/
	return close(audit_fd);
	}

	static int audit_init_with_exe_filter(struct audit_filter *filter)
	{
	int fd, err;

	fd = audit_init();
	if (fd < 0)
	return fd;

	err = audit_init_filter_exe(filter, NULL);
	if (err)
	return err;

	err = audit_filter_exe(fd, filter, AUDIT_ADD_RULE);
	if (err)
	return err;

	return fd;
	}