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/*
* Copyright (c) 1996, 1998-2005, 2010-2015
* Todd C. Miller <Todd.Miller@sudo.ws>
*
* 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.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_STRING_H
# include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif /* HAVE_STRINGS_H */
#include <unistd.h>
#include <errno.h>
#include "sudoers.h"
/*
* Check the given command against the specified whitelist (NULL-terminated).
* On success, rewrites cmnd based on the whitelist and returns true.
* On failure, returns false.
*/
static bool
cmnd_allowed(char *cmnd, size_t cmnd_size, struct stat *cmnd_sbp,
char * const *whitelist)
{
const char *cmnd_base;
char * const *wl;
debug_decl(cmnd_allowed, SUDOERS_DEBUG_UTIL)
if (!sudo_goodpath(cmnd, cmnd_sbp))
debug_return_bool(false);
if (whitelist == NULL)
debug_return_bool(true); /* nothing to check */
/* We compare the base names to avoid excessive stat()ing. */
if ((cmnd_base = strrchr(cmnd, '/')) == NULL)
debug_return_bool(false); /* can't happen */
cmnd_base++;
for (wl = whitelist; *wl != NULL; wl++) {
struct stat sb;
const char *base;
if ((base = strrchr(*wl, '/')) == NULL)
continue; /* XXX - warn? */
base++;
if (strcmp(cmnd_base, base) != 0)
continue;
if (sudo_goodpath(*wl, &sb) &&
sb.st_dev == cmnd_sbp->st_dev && sb.st_ino == cmnd_sbp->st_ino) {
/* Overwrite cmnd with safe version from whitelist. */
if (strlcpy(cmnd, *wl, cmnd_size) < cmnd_size)
return true;
debug_return_bool(true);
}
}
debug_return_bool(false);
}
/*
* This function finds the full pathname for a command and
* stores it in a statically allocated array, filling in a pointer
* to the array. Returns FOUND if the command was found, NOT_FOUND
* if it was not found, or NOT_FOUND_DOT if it would have been found
* but it is in '.' and IGNORE_DOT is set.
* The caller is responsible for freeing the output file.
*/
int
find_path(const char *infile, char **outfile, struct stat *sbp,
const char *path, int ignore_dot, char * const *whitelist)
{
char command[PATH_MAX];
const char *cp, *ep, *pathend;
bool found = false;
bool checkdot = false;
int len;
debug_decl(find_path, SUDOERS_DEBUG_UTIL)
/*
* If we were given a fully qualified or relative path
* there is no need to look at $PATH.
*/
if (strchr(infile, '/') != NULL) {
if (strlcpy(command, infile, sizeof(command)) >= sizeof(command)) {
errno = ENAMETOOLONG;
debug_return_int(NOT_FOUND_ERROR);
}
found = cmnd_allowed(command, sizeof(command), sbp, whitelist);
goto done;
}
if (path == NULL)
debug_return_int(NOT_FOUND);
pathend = path + strlen(path);
for (cp = sudo_strsplit(path, pathend, ":", &ep); cp != NULL;
cp = sudo_strsplit(NULL, pathend, ":", &ep)) {
/*
* Search current dir last if it is in PATH.
* This will miss sneaky things like using './' or './/' (XXX)
*/
if (cp == ep || (*cp == '.' && cp + 1 == ep)) {
checkdot = 1;
continue;
}
/*
* Resolve the path and exit the loop if found.
*/
len = snprintf(command, sizeof(command), "%.*s/%s",
(int)(ep - cp), cp, infile);
if (len <= 0 || (size_t)len >= sizeof(command)) {
errno = ENAMETOOLONG;
debug_return_int(NOT_FOUND_ERROR);
}
found = cmnd_allowed(command, sizeof(command), sbp, whitelist);
if (found)
break;
}
/*
* Check current dir if dot was in the PATH
*/
if (!found && checkdot) {
len = snprintf(command, sizeof(command), "./%s", infile);
if (len <= 0 || (size_t)len >= sizeof(command)) {
errno = ENAMETOOLONG;
debug_return_int(NOT_FOUND_ERROR);
}
found = cmnd_allowed(command, sizeof(command), sbp, whitelist);
if (found && ignore_dot)
debug_return_int(NOT_FOUND_DOT);
}
done:
if (found) {
if ((*outfile = strdup(command)) == NULL)
debug_return_int(NOT_FOUND_ERROR);
debug_return_int(FOUND);
}
debug_return_int(NOT_FOUND);
}
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