linux_audit.c   [plain text]

/*
 * Copyright (c) 2010 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <config.h>

#include <sys/types.h>
#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
#  include <stdlib.h>
# endif
#endif /* STDC_HEADERS */
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <libaudit.h>

#include "missing.h"
#include "error.h"
#include "alloc.h"
#include "linux_audit.h"

/*
 * Open audit connection if possible.
 * Returns audit fd on success and -1 on failure.
 */
static int
linux_audit_open(void)
{
    static int au_fd = -1;

    if (au_fd != -1)
	return au_fd;
    au_fd = audit_open();
    if (au_fd == -1) {
	/* Kernel may not have audit support. */
	if (errno != EINVAL && errno != EPROTONOSUPPORT && errno != EAFNOSUPPORT)
	    error(1, "unable to open audit system");
    } else {
	(void)fcntl(au_fd, F_SETFD, FD_CLOEXEC);
    }
    return au_fd;
}

int
linux_audit_command(char *argv[], int result)
{
    int au_fd, rc;
    char *command, *cp, **av;
    size_t size, n;

    if ((au_fd = linux_audit_open()) == -1)
	return -1;

    /* Convert argv to a flat string. */
    for (size = 0, av = argv; *av != NULL; av++)
	size += strlen(*av) + 1;
    command = cp = emalloc(size);
    for (av = argv; *av != NULL; av++) {
	n = strlcpy(cp, *av, size - (cp - command));
	if (n >= size - (cp - command))
	    errorx(1, "internal error, linux_audit_command() overflow");
	cp += n;
	*cp++ = ' ';
    }
    *--cp = '\0';

    /* Log command, ignoring ECONNREFUSED on error. */
    rc = audit_log_user_command(au_fd, AUDIT_USER_CMD, command, NULL, result);
    if (rc <= 0 && errno != ECONNREFUSED)
	warning("unable to send audit message");

    efree(command);

    return rc;
}

#ifdef HAVE_SELINUX
int
linux_audit_role_change(const char *old_context,
    const char *new_context, const char *ttyn)
{
    int au_fd, rc;
    char *message;

    if ((au_fd = linux_audit_open()) == -1)
	return -1;

    /* audit role change using the same format as newrole(1) */
    easprintf(&message, "newrole: old-context=%s new-context=%s",
	old_context, new_context);
    rc = audit_log_user_message(au_fd, AUDIT_USER_ROLE_CHANGE,
	message, NULL, NULL, ttyn, 1);
    if (rc <= 0)
	warning("unable to send audit message");

    efree(message);

    return rc;
}
#endif /* HAVE_SELINUX */