xref: /illumos-gate/usr/src/lib/pam_modules/dial_auth/dial_auth.c (revision 1a2d662a91cee3bf82f41cd47c7ae6f3825d9db2)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  *
25  * Copyright 2023 OmniOS Community Edition (OmniOSce) Association.
26  */
27 
28 #include <crypt.h>
29 #include <pwd.h>
30 #include <shadow.h>
31 #include <string.h>
32 #include <stdlib.h>
33 #include <syslog.h>
34 #include <security/pam_appl.h>
35 #include <security/pam_modules.h>
36 #include "../../libpam/pam_impl.h"
37 
38 #include <libintl.h>
39 
40 /*
41  * Various useful files and string constants
42  */
43 #define	DIAL_FILE	"/etc/dialups"
44 #define	DPASS_FILE	"/etc/d_passwd"
45 #define	SHELL		"/usr/bin/sh"
46 #define	SCPYN(a, b)	(void) strncpy(a, b, sizeof (a))
47 
48 /*
49  * pam_sm_authenticate	- This is the top level function in the
50  *			module called by pam_auth_port in the framework
51  *			Returns: PAM_AUTH_ERR on failure, 0 on success
52  */
53 int
54 pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv)
55 {
56 	const char *ttyn, *user;
57 	FILE *fp;
58 	char defpass[30];
59 	char line[80];
60 	char *p1 = NULL, *p2 = NULL;
61 	struct passwd pwd;
62 	char pwd_buffer[1024];
63 	char *password = NULL;
64 	int retcode;
65 	int i;
66 	int debug = 0;
67 	int res;
68 
69 	for (i = 0; i < argc; i++) {
70 		if (strcasecmp(argv[i], "debug") == 0)
71 			debug = 1;
72 		else
73 			syslog(LOG_DEBUG, "illegal option %s", argv[i]);
74 	}
75 
76 	if ((retcode = pam_get_user(pamh, &user, NULL))
77 					!= PAM_SUCCESS ||
78 	    (retcode = pam_get_item(pamh, PAM_TTY, (const void **)&ttyn))
79 					!= PAM_SUCCESS)
80 		return (retcode);
81 
82 	if (debug) {
83 		syslog(LOG_DEBUG,
84 			"Dialpass authenticate user = %s, ttyn = %s",
85 			user ? user : "NULL", ttyn ? ttyn : "NULL");
86 	}
87 
88 	if (ttyn == NULL || *ttyn == '\0') {
89 		const char *service;
90 
91 		(void) pam_get_item(pamh, PAM_SERVICE, (const void **)&service);
92 		syslog(LOG_ERR, "pam_dial_auth: terminal-device not specified"
93 		    "by %s, returning %s.", service,
94 		    pam_strerror(pamh, PAM_SERVICE_ERR));
95 		return (PAM_SERVICE_ERR);
96 	}
97 	if (getpwnam_r(user, &pwd, pwd_buffer, sizeof (pwd_buffer)) == NULL)
98 		return (PAM_USER_UNKNOWN);
99 
100 	if ((fp = fopen(DIAL_FILE, "rF")) == NULL)
101 		return (PAM_IGNORE);
102 
103 	while ((p1 = fgets(line, sizeof (line), fp)) != NULL) {
104 		while (*p1 != '\n' && *p1 != ' ' && *p1 != '\t')
105 			p1++;
106 		*p1 = '\0';
107 		if (strcmp(line, ttyn) == 0)
108 			break;
109 	}
110 
111 	(void) fclose(fp);
112 
113 	if ((fp = fopen(DPASS_FILE, "rF")) == NULL) {
114 		syslog(LOG_ERR, "pam_dial_auth: %s without %s, returning %s.",
115 		    DIAL_FILE, DPASS_FILE,
116 		    pam_strerror(pamh, PAM_SYSTEM_ERR));
117 		(void) memset(line, 0, sizeof (line));
118 		return (PAM_SYSTEM_ERR);
119 	}
120 
121 	if (p1 == NULL) {
122 		(void) fclose(fp);
123 		(void) memset(line, 0, sizeof (line));
124 		return (PAM_IGNORE);
125 	}
126 
127 	defpass[0] = '\0';
128 
129 	while ((p1 = fgets(line, sizeof (line)-1, fp)) != NULL) {
130 		while (*p1 && *p1 != ':')
131 			p1++;
132 		*p1++ = '\0';
133 		p2 = p1;
134 		while (*p1 && *p1 != ':')
135 			p1++;
136 		*p1 = '\0';
137 		if (pwd.pw_shell != NULL && strcmp(pwd.pw_shell, line) == 0)
138 			break;
139 
140 		if (strcmp(SHELL, line) == 0)
141 			SCPYN(defpass, p2);
142 		p2 = NULL;
143 	}
144 
145 	(void) memset(line, 0, sizeof (line));
146 	(void) fclose(fp);
147 
148 	if (p2 == NULL)
149 		p2 = defpass;
150 
151 	if (*p2 != '\0') {
152 		res = __pam_get_authtok(pamh, PAM_PROMPT, PAM_AUTHTOK,
153 		    dgettext(TEXT_DOMAIN, "Dialup Password: "), &password);
154 
155 		if (res != PAM_SUCCESS) {
156 			return (res);
157 		}
158 
159 		if (strcmp(crypt(password, p2), p2) != 0) {
160 			(void) memset(password, 0, strlen(password));
161 			free(password);
162 			return (PAM_AUTH_ERR);
163 		}
164 		(void) memset(password, 0, strlen(password));
165 		free(password);
166 	}
167 
168 	return (PAM_SUCCESS);
169 }
170 
171 /*
172  * dummy pam_sm_setcred - does nothing
173  */
174 /*ARGSUSED*/
175 int
176 pam_sm_setcred(pam_handle_t *pamh, int flags, int argc, const char **argv)
177 {
178 	return (PAM_IGNORE);
179 }
180