/*-
* Copyright (c) 2002-2003 Networks Associates Technology, Inc.
* Copyright (c) 2004-2011 Dag-Erling Smørgrav
* All rights reserved.
*
* This software was developed for the FreeBSD Project by ThinkSec AS and
* Network Associates Laboratories, the Security Research Division of
* Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
* ("CBOSS"), as part of the DARPA CHATS research program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $OpenPAM: openpam_dynamic.c 938 2017-04-30 21:34:42Z des $
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <sys/param.h>
#include <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <security/pam_appl.h>
#include "openpam_impl.h"
#include "openpam_asprintf.h"
#include "openpam_ctype.h"
#include "openpam_dlfunc.h"
#ifndef RTLD_NOW
#define RTLD_NOW RTLD_LAZY
#endif
/*
* OpenPAM internal
*
* Perform sanity checks and attempt to load a module
*/
#ifdef HAVE_FDLOPEN
static void *
try_dlopen(const char *modfn)
{
void *dlh;
int fd;
openpam_log(PAM_LOG_LIBDEBUG, "dlopen(%s)", modfn);
if ((fd = open(modfn, O_RDONLY)) < 0) {
if (errno != ENOENT)
openpam_log(PAM_LOG_ERROR, "%s: %m", modfn);
return (NULL);
}
if (OPENPAM_FEATURE(VERIFY_MODULE_FILE) &&
openpam_check_desc_owner_perms(modfn, fd) != 0) {
close(fd);
return (NULL);
}
if ((dlh = fdlopen(fd, RTLD_NOW)) == NULL) {
openpam_log(PAM_LOG_ERROR, "%s: %s", modfn, dlerror());
close(fd);
errno = 0;
return (NULL);
}
close(fd);
return (dlh);
}
#else
static void *
try_dlopen(const char *modfn)
{
int check_module_file;
void *dlh;
openpam_log(PAM_LOG_LIBDEBUG, "dlopen(%s)", modfn);
openpam_get_feature(OPENPAM_VERIFY_MODULE_FILE,
&check_module_file);
if (check_module_file &&
openpam_check_path_owner_perms(modfn) != 0)
return (NULL);
if ((dlh = dlopen(modfn, RTLD_NOW)) == NULL) {
openpam_log(PAM_LOG_ERROR, "%s: %s", modfn, dlerror());
errno = 0;
return (NULL);
}
return (dlh);
}
#endif
/*
* Try to load a module from the suggested location.
*/
static pam_module_t *
try_module(const char *modpath)
{
const pam_module_t *dlmodule;
pam_module_t *module;
int i, serrno;
if ((module = calloc(1, sizeof *module)) == NULL ||
(module->path = strdup(modpath)) == NULL ||
(module->dlh = try_dlopen(modpath)) == NULL)
goto err;
dlmodule = dlsym(module->dlh, "_pam_module");
for (i = 0; i < PAM_NUM_PRIMITIVES; ++i) {
if (dlmodule) {
module->func[i] = dlmodule->func[i];
} else {
module->func[i] = (pam_func_t)dlfunc(module->dlh,
pam_sm_func_name[i]);
/*
* This openpam_log() call is a major source of
* log spam, and the cases that matter are caught
* and logged in openpam_dispatch(). This would
* be less problematic if dlerror() returned an
* error code so we could log an error only when
* dlfunc() failed for a reason other than "no
* such symbol".
*/
#if 0
if (module->func[i] == NULL)
openpam_log(PAM_LOG_LIBDEBUG, "%s: %s(): %s",
modpath, pam_sm_func_name[i], dlerror());
#endif
}
}
return (module);
err:
serrno = errno;
if (module != NULL) {
if (module->dlh != NULL)
dlclose(module->dlh);
if (module->path != NULL)
FREE(module->path);
FREE(module);
}
errno = serrno;
if (serrno != 0 && serrno != ENOENT)
openpam_log(PAM_LOG_ERROR, "%s: %m", modpath);
errno = serrno;
return (NULL);
}
/*
* OpenPAM internal
*
* Locate a dynamically linked module
*/
pam_module_t *
openpam_dynamic(const char *modname)
{
pam_module_t *module;
char modpath[PATH_MAX];
const char **path, *p;
int has_so, has_ver;
int dot, len;
/*
* Simple case: module name contains path separator(s)
*/
if (strchr(modname, '/') != NULL) {
/*
* Absolute paths are not allowed if RESTRICT_MODULE_NAME
* is in effect (default off). Relative paths are never
* allowed.
*/
if (OPENPAM_FEATURE(RESTRICT_MODULE_NAME) ||
modname[0] != '/') {
openpam_log(PAM_LOG_ERROR,
"invalid module name: %s", modname);
return (NULL);
}
return (try_module(modname));
}
/*
* Check for .so and version sufixes
*/
p = strchr(modname, '\0');
has_ver = has_so = 0;
while (is_digit(*p))
--p;
if (*p == '.' && *++p != '\0') {
/* found a numeric suffix */
has_ver = 1;
/* assume that .so is either present or unneeded */
has_so = 1;
} else if (*p == '\0' && p >= modname + sizeof PAM_SOEXT &&
strcmp(p - sizeof PAM_SOEXT + 1, PAM_SOEXT) == 0) {
/* found .so suffix */
has_so = 1;
}
/*
* Complicated case: search for the module in the usual places.
*/
for (path = openpam_module_path; *path != NULL; ++path) {
/*
* Assemble the full path, including the version suffix. Take
* note of where the suffix begins so we can cut it off later.
*/
if (has_ver)
len = snprintf(modpath, sizeof modpath, "%s/%s%n",
*path, modname, &dot);
else if (has_so)
len = snprintf(modpath, sizeof modpath, "%s/%s%n.%d",
*path, modname, &dot, LIB_MAJ);
else
len = snprintf(modpath, sizeof modpath, "%s/%s%s%n.%d",
*path, modname, PAM_SOEXT, &dot, LIB_MAJ);
/* check for overflow */
if (len < 0 || (unsigned int)len >= sizeof modpath) {
errno = ENOENT;
continue;
}
/* try the versioned path */
if ((module = try_module(modpath)) != NULL)
return (module);
if (errno == ENOENT && modpath[dot] != '\0') {
/* no luck, try the unversioned path */
modpath[dot] = '\0';
if ((module = try_module(modpath)) != NULL)
return (module);
}
}
/* :( */
return (NULL);
}
/*
* NOPARSE
*/