sudo/goodpath.c

/*
 * Copyright (c) 1996, 1998, 1999, 2001
 *	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.
 *
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */

#include <config.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <stdio.h>
#ifdef HAVE_STRING_H
# include <string.h>
#else
# ifdef HAVE_STRINGS_H
#  include <strings.h>
# endif
#endif /* HAVE_STRING_H */
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include <errno.h>

#include "sudo.h"

#ifndef lint
static const char rcsid[] = "$Sudo$";
#endif /* lint */

/*
 * Verify that path is a normal file and executable by root.
 */
char *
sudo_goodpath(path, sbp)
    const char *path;
    struct stat *sbp;
{
    struct stat sb;

    /* Check for brain damage */
    if (path == NULL || path[0] == '\0')
	return(NULL);

    if (stat(path, &sb))
	return(NULL);

    /* Make sure path describes an executable regular file. */
    if (!S_ISREG(sb.st_mode) || !(sb.st_mode & 0000111)) {
	errno = EACCES;
	return(NULL);
    }

    if (sbp != NULL)
	(void) memcpy(sbp, &sb, sizeof(struct stat));
    return((char *)path);
}