263 lines
6.9 KiB
C
263 lines
6.9 KiB
C
/*-
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* Copyright (c) 2002-2003 Networks Associates Technology, Inc.
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* Copyright (c) 2004-2011 Dag-Erling Smørgrav
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* All rights reserved.
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*
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* This software was developed for the FreeBSD Project by ThinkSec AS and
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* Network Associates Laboratories, the Security Research Division of
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* Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
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* ("CBOSS"), as part of the DARPA CHATS research program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: openpam_dynamic.c 683 2013-04-14 14:49:59Z des $
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <sys/param.h>
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#include <dlfcn.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <security/pam_appl.h>
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#include "openpam_impl.h"
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#include "openpam_asprintf.h"
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#include "openpam_ctype.h"
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#include "openpam_dlfunc.h"
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#ifndef RTLD_NOW
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#define RTLD_NOW RTLD_LAZY
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#endif
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/*
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* OpenPAM internal
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*
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* Perform sanity checks and attempt to load a module
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*/
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#ifdef HAVE_FDLOPEN
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static void *
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try_dlopen(const char *modfn)
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{
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void *dlh;
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int fd;
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openpam_log(PAM_LOG_LIBDEBUG, "dlopen(%s)", modfn);
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if ((fd = open(modfn, O_RDONLY)) < 0) {
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if (errno != ENOENT)
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openpam_log(PAM_LOG_ERROR, "%s: %m", modfn);
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return (NULL);
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}
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if (OPENPAM_FEATURE(VERIFY_MODULE_FILE) &&
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openpam_check_desc_owner_perms(modfn, fd) != 0) {
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close(fd);
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return (NULL);
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}
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if ((dlh = fdlopen(fd, RTLD_NOW)) == NULL) {
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openpam_log(PAM_LOG_ERROR, "%s: %s", modfn, dlerror());
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close(fd);
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errno = 0;
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return (NULL);
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}
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close(fd);
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return (dlh);
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}
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#else
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static void *
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try_dlopen(const char *modfn)
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{
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int check_module_file;
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void *dlh;
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openpam_log(PAM_LOG_LIBDEBUG, "dlopen(%s)", modfn);
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openpam_get_feature(OPENPAM_VERIFY_MODULE_FILE,
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&check_module_file);
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if (check_module_file &&
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openpam_check_path_owner_perms(modfn) != 0)
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return (NULL);
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if ((dlh = dlopen(modfn, RTLD_NOW)) == NULL) {
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openpam_log(PAM_LOG_ERROR, "%s: %s", modfn, dlerror());
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errno = 0;
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return (NULL);
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}
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return (dlh);
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}
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#endif
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/*
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* Try to load a module from the suggested location.
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*/
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static pam_module_t *
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try_module(const char *modpath)
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{
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const pam_module_t *dlmodule;
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pam_module_t *module;
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int i, serrno;
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if ((module = calloc(1, sizeof *module)) == NULL ||
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(module->path = strdup(modpath)) == NULL ||
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(module->dlh = try_dlopen(modpath)) == NULL)
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goto err;
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dlmodule = dlsym(module->dlh, "_pam_module");
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for (i = 0; i < PAM_NUM_PRIMITIVES; ++i) {
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if (dlmodule) {
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module->func[i] = dlmodule->func[i];
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} else {
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module->func[i] = (pam_func_t)dlfunc(module->dlh,
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pam_sm_func_name[i]);
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/*
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* This openpam_log() call is a major source of
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* log spam, and the cases that matter are caught
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* and logged in openpam_dispatch(). This would
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* be less problematic if dlerror() returned an
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* error code so we could log an error only when
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* dlfunc() failed for a reason other than "no
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* such symbol".
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*/
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#if 0
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if (module->func[i] == NULL)
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openpam_log(PAM_LOG_LIBDEBUG, "%s: %s(): %s",
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modpath, pam_sm_func_name[i], dlerror());
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#endif
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}
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}
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return (module);
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err:
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serrno = errno;
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if (module != NULL) {
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if (module->dlh != NULL)
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dlclose(module->dlh);
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if (module->path != NULL)
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FREE(module->path);
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FREE(module);
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}
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errno = serrno;
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if (serrno != 0 && serrno != ENOENT)
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openpam_log(PAM_LOG_ERROR, "%s: %m", modpath);
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errno = serrno;
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return (NULL);
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}
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/*
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* OpenPAM internal
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*
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* Locate a dynamically linked module
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*/
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pam_module_t *
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openpam_dynamic(const char *modname)
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{
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pam_module_t *module;
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char modpath[PATH_MAX];
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const char **path, *p;
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int has_so, has_ver;
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int dot, len;
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/*
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* Simple case: module name contains path separator(s)
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*/
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if (strchr(modname, '/') != NULL) {
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/*
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* Absolute paths are not allowed if RESTRICT_MODULE_NAME
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* is in effect (default off). Relative paths are never
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* allowed.
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*/
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if (OPENPAM_FEATURE(RESTRICT_MODULE_NAME) ||
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modname[0] != '/') {
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openpam_log(PAM_LOG_ERROR,
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"invalid module name: %s", modname);
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return (NULL);
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}
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return (try_module(modname));
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}
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/*
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* Check for .so and version sufixes
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*/
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p = strchr(modname, '\0');
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has_ver = has_so = 0;
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while (is_digit(*p))
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--p;
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if (*p == '.' && *++p != '\0') {
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/* found a numeric suffix */
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has_ver = 1;
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/* assume that .so is either present or unneeded */
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has_so = 1;
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} else if (*p == '\0' && p >= modname + sizeof PAM_SOEXT &&
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strcmp(p - sizeof PAM_SOEXT + 1, PAM_SOEXT) == 0) {
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/* found .so suffix */
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has_so = 1;
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}
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/*
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* Complicated case: search for the module in the usual places.
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*/
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for (path = openpam_module_path; *path != NULL; ++path) {
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/*
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* Assemble the full path, including the version suffix. Take
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* note of where the suffix begins so we can cut it off later.
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*/
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if (has_ver)
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len = snprintf(modpath, sizeof modpath, "%s/%s%n",
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*path, modname, &dot);
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else if (has_so)
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len = snprintf(modpath, sizeof modpath, "%s/%s%n.%d",
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*path, modname, &dot, LIB_MAJ);
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else
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len = snprintf(modpath, sizeof modpath, "%s/%s%s%n.%d",
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*path, modname, PAM_SOEXT, &dot, LIB_MAJ);
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/* check for overflow */
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if (len < 0 || (unsigned int)len >= sizeof modpath) {
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errno = ENOENT;
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continue;
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}
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/* try the versioned path */
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if ((module = try_module(modpath)) != NULL)
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return (module);
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if (errno == ENOENT && modpath[dot] != '\0') {
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/* no luck, try the unversioned path */
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modpath[dot] = '\0';
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if ((module = try_module(modpath)) != NULL)
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return (module);
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}
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}
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/* :( */
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return (NULL);
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}
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/*
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* NOPARSE
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*/
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