Initial revision

1 files changed, 220 insertions, 0 deletions

diff --git a/modules/pam_unix/pam_unix_auth.c b/modules/pam_unix/pam_unix_auth.c
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+/*
+ * Copyright Alexander O. Yuriev, 1996.  All rights reserved.
+ * NIS+ support by Thorsten Kukuk <kukuk@weber.uni-paderborn.de>
+ * Copyright Jan Rêkorajski, 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