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+/*
+ * Copyright Alexander O. Yuriev, 1996. All rights reserved.
+ * NIS+ support by Thorsten Kukuk <kukuk@weber.uni-paderborn.de>
+ * Copyright Jan RÍkorajski, 1999. All rights reserved.
+ *
+ * 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, and the entire permission notice in its entirety,
+ * including the disclaimer of warranties.
+ * 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.
+ *
+ * ALTERNATIVELY, this product may be distributed under the terms of
+ * the GNU Public License, in which case the provisions of the GPL are
+ * required INSTEAD OF the above restrictions. (This clause is
+ * necessary due to a potential bad interaction between the GPL and
+ * the restrictions contained in a BSD-style copyright.)
+ *
+ * THIS SOFTWARE IS PROVIDED ``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 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.
+ */
+
+/* #define DEBUG */
+
+#ifdef linux
+#define _GNU_SOURCE
+#include <features.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+/* indicate the following groups are defined */
+
+#define PAM_SM_AUTH
+
+#define _PAM_EXTERN_FUNCTIONS
+#include <security/_pam_macros.h>
+#include <security/pam_modules.h>
+
+#ifndef LINUX_PAM
+#include <security/pam_appl.h>
+#endif /* LINUX_PAM */
+
+#include "support.h"
+
+/*
+ * PAM framework looks for these entry-points to pass control to the
+ * authentication module.
+ */
+
+/* Fun starts here :)
+
+ * pam_sm_authenticate() performs UNIX/shadow authentication
+ *
+ * First, if shadow support is available, attempt to perform
+ * authentication using shadow passwords. If shadow is not
+ * available, or user does not have a shadow password, fallback
+ * onto a normal UNIX authentication
+ */
+
+#define _UNIX_AUTHTOK "-UN*X-PASS"
+
+#define AUTH_RETURN \
+{ \
+ if (on(UNIX_LIKE_AUTH, ctrl)) { \
+ D(("recording return code for next time [%d]", \
+ retval)); \
+ pam_set_data(pamh, "unix_setcred_return", \
+ (void *) &retval, NULL); \
+ } \
+ D(("done. [%s]", pam_strerror(pamh, retval))); \
+ return retval; \
+}
+
+PAM_EXTERN int pam_sm_authenticate(pam_handle_t * pamh, int flags
+ ,int argc, const char **argv)
+{
+ unsigned int ctrl;
+ int retval;
+ const char *name, *p;
+
+ D(("called."));
+
+ ctrl = _set_ctrl(flags, NULL, argc, argv);
+
+ /* get the user'name' */
+
+ retval = pam_get_user(pamh, &name, "login: ");
+ if (retval == PAM_SUCCESS) {
+ /*
+ * Various libraries at various times have had bugs related to
+ * '+' or '-' as the first character of a user name. Don't take
+ * any chances here. Require that the username starts with an
+ * alphanumeric character.
+ */
+ if (name == NULL || !isalnum(*name)) {
+ _log_err(LOG_ERR, "bad username [%s]", name);
+ retval = PAM_USER_UNKNOWN;
+ AUTH_RETURN
+ }
+ if (retval == PAM_SUCCESS && on(UNIX_DEBUG, ctrl))
+ D(("username [%s] obtained", name));
+ } else {
+ D(("trouble reading username"));
+ if (retval == PAM_CONV_AGAIN) {
+ D(("pam_get_user/conv() function is not ready yet"));
+ /* it is safe to resume this function so we translate this
+ * retval to the value that indicates we're happy to resume.
+ */
+ retval = PAM_INCOMPLETE;
+ }
+ AUTH_RETURN
+ }
+
+ /* if this user does not have a password... */
+
+ if (_unix_blankpasswd(ctrl, name)) {
+ D(("user '%s' has blank passwd", name));
+ name = NULL;
+ retval = PAM_SUCCESS;
+ AUTH_RETURN
+ }
+ /* get this user's authentication token */
+
+ retval = _unix_read_password(pamh, ctrl, NULL, "Password: ", NULL
+ ,_UNIX_AUTHTOK, &p);
+ if (retval != PAM_SUCCESS) {
+ if (retval != PAM_CONV_AGAIN) {
+ _log_err(LOG_CRIT, "auth could not identify password for [%s]"
+ ,name);
+ } else {
+ D(("conversation function is not ready yet"));
+ /*
+ * it is safe to resume this function so we translate this
+ * retval to the value that indicates we're happy to resume.
+ */
+ retval = PAM_INCOMPLETE;
+ }
+ name = NULL;
+ AUTH_RETURN
+ }
+ D(("user=%s, password=[%s]", name, p));
+
+ /* verify the password of this user */
+ retval = _unix_verify_password(pamh, name, p, ctrl);
+ name = p = NULL;
+
+ AUTH_RETURN
+}
+
+
+/*
+ * The only thing _pam_set_credentials_unix() does is initialization of
+ * UNIX group IDs.
+ *
+ * Well, everybody but me on linux-pam is convinced that it should not
+ * initialize group IDs, so I am not doing it but don't say that I haven't
+ * warned you. -- AOY
+ */
+
+PAM_EXTERN int pam_sm_setcred(pam_handle_t * pamh, int flags
+ ,int argc, const char **argv)
+{
+ unsigned int ctrl;
+ int retval;
+
+ D(("called."));
+
+ /* FIXME: it shouldn't be necessary to parse the arguments again. The
+ only argument we need is UNIX_LIKE_AUTH: if it was set,
+ pam_get_data will succeed. If it wasn't, it will fail, and we
+ return PAM_SUCCESS. -SRL */
+ ctrl = _set_ctrl(flags, NULL, argc, argv);
+ retval = PAM_SUCCESS;
+
+ if (on(UNIX_LIKE_AUTH, ctrl)) {
+ int *pretval = &retval;
+
+ D(("recovering return code from auth call"));
+ pam_get_data(pamh, "unix_setcred_return", (const void **) &pretval);
+ pam_set_data(pamh, "unix_setcred_return", NULL, NULL);
+ D(("recovered data indicates that old retval was %d", retval));
+ }
+ return retval;
+}
+
+#ifdef PAM_STATIC
+struct pam_module _pam_unix_auth_modstruct = {
+ "pam_unix_auth",
+ pam_sm_authenticate,
+ pam_sm_setcred,
+ NULL,
+ NULL,
+ NULL,
+ NULL,
+};
+#endif