pam.c revision 55682 
1/*
2 * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34/* This code is extremely ugly, and would probably be better off
35   beeing completely rewritten */
36
37
38#ifdef HAVE_CONFIG_H
39#include<config.h>
40RCSID("$Id: pam.c,v 1.22 1999/12/02 16:58:37 joda Exp $");
41#endif
42
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <pwd.h>
47#include <unistd.h>
48#include <sys/types.h>
49
50#define PAM_SM_AUTH
51#define PAM_SM_SESSION
52#include <security/pam_appl.h>
53#include <security/pam_modules.h>
54
55#include <netinet/in.h>
56#include <krb.h>
57#include <kafs.h>
58
59static int
60cleanup(pam_handle_t *pamh, void *data, int error_code)
61{
62    if(error_code != PAM_SUCCESS)
63	dest_tkt();
64    free(data);
65    return PAM_SUCCESS;
66}
67
68static int
69doit(pam_handle_t *pamh, char *name, char *inst, char *pwd, char *tkt)
70{
71    char realm[REALM_SZ];
72    int ret;
73
74    pam_set_data(pamh, "KRBTKFILE", strdup(tkt), cleanup);
75    krb_set_tkt_string(tkt);
76
77    krb_get_lrealm(realm, 1);
78    ret = krb_verify_user(name, inst, realm, pwd, KRB_VERIFY_SECURE, NULL);
79    memset(pwd, 0, strlen(pwd));
80    switch(ret){
81    case KSUCCESS:
82	return PAM_SUCCESS;
83    case KDC_PR_UNKNOWN:
84	return PAM_USER_UNKNOWN;
85    case SKDC_CANT:
86    case SKDC_RETRY:
87    case RD_AP_TIME:
88	return PAM_AUTHINFO_UNAVAIL;
89    default:
90	return PAM_AUTH_ERR;
91    }
92}
93
94static int
95auth_login(pam_handle_t *pamh, int flags, char *user, struct pam_conv *conv)
96{
97    int ret;
98    struct pam_message msg, *pmsg;
99    struct pam_response *resp;
100    char prompt[128];
101
102    pmsg = &msg;
103    msg.msg_style = PAM_PROMPT_ECHO_OFF;
104    snprintf(prompt, sizeof(prompt), "%s's Password: ", user);
105    msg.msg = prompt;
106
107    ret = conv->conv(1, (const struct pam_message**)&pmsg,
108		     &resp, conv->appdata_ptr);
109    if(ret != PAM_SUCCESS)
110	return ret;
111
112    {
113	char tkt[1024];
114	struct passwd *pw = getpwnam(user);
115
116	if(pw){
117	    snprintf(tkt, sizeof(tkt),
118		     "%s%u", TKT_ROOT, (unsigned)pw->pw_uid);
119	    ret = doit(pamh, user, "", resp->resp, tkt);
120	    if(ret == PAM_SUCCESS)
121		chown(tkt, pw->pw_uid, pw->pw_gid);
122	}else
123	    ret = PAM_USER_UNKNOWN;
124	memset(resp->resp, 0, strlen(resp->resp));
125	free(resp->resp);
126	free(resp);
127    }
128    return ret;
129}
130
131static int
132auth_su(pam_handle_t *pamh, int flags, char *user, struct pam_conv *conv)
133{
134    int ret;
135    struct passwd *pw;
136    struct pam_message msg, *pmsg;
137    struct pam_response *resp;
138    char prompt[128];
139    krb_principal pr;
140
141    pr.realm[0] = 0;
142    ret = pam_get_user(pamh, &user, "login: ");
143    if(ret != PAM_SUCCESS)
144	return ret;
145
146    pw = getpwuid(getuid());
147    if(strcmp(user, "root") == 0){
148	strlcpy(pr.name, pw->pw_name, sizeof(pr.name));
149	strlcpy(pr.instance, "root", sizeof(pr.instance));
150    }else{
151	strlcpy(pr.name, user, sizeof(pr.name));
152	pr.instance[0] = 0;
153    }
154    pmsg = &msg;
155    msg.msg_style = PAM_PROMPT_ECHO_OFF;
156    snprintf(prompt, sizeof(prompt), "%s's Password: ", krb_unparse_name(&pr));
157    msg.msg = prompt;
158
159    ret = conv->conv(1, (const struct pam_message**)&pmsg,
160		     &resp, conv->appdata_ptr);
161    if(ret != PAM_SUCCESS)
162	return ret;
163
164    {
165	char tkt[1024];
166
167	snprintf(tkt, sizeof(tkt),"%s_%s_to_%s",
168		 TKT_ROOT, pw->pw_name, user);
169	ret = doit(pamh, pr.name, pr.instance, resp->resp, tkt);
170	if(ret == PAM_SUCCESS)
171	    chown(tkt, pw->pw_uid, pw->pw_gid);
172	memset(resp->resp, 0, strlen(resp->resp));
173	free(resp->resp);
174	free(resp);
175    }
176    return ret;
177}
178
179int
180pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv)
181{
182    char *user;
183    int ret;
184    struct pam_conv *conv;
185    ret = pam_get_user(pamh, &user, "login: ");
186    if(ret != PAM_SUCCESS)
187	return ret;
188
189    ret = pam_get_item(pamh, PAM_CONV, (void*)&conv);
190    if(ret != PAM_SUCCESS)
191	return ret;
192
193
194    if(getuid() != geteuid())
195	return auth_su(pamh, flags, user, conv);
196    else
197	return auth_login(pamh, flags, user, conv);
198}
199
200int
201pam_sm_setcred(pam_handle_t *pamh, int flags, int argc, const char **argv)
202{
203    return PAM_SUCCESS;
204}
205
206
207int
208pam_sm_open_session(pam_handle_t *pamh, int flags, int argc, const char **argv)
209{
210    char *tkt, *var;
211    void *user;
212    const char *homedir = NULL;
213
214    if(pam_get_item (pamh, PAM_USER, &user) == PAM_SUCCESS) {
215	struct passwd *pwd;
216
217	pwd = getpwnam ((char *)user);
218	if (pwd != NULL)
219	    homedir = pwd->pw_dir;
220    }
221
222    pam_get_data(pamh, "KRBTKFILE", (const void**)&tkt);
223    var = malloc(strlen("KRBTKFILE=") + strlen(tkt) + 1);
224    strcpy(var, "KRBTKFILE=");
225    strcat(var, tkt);
226    putenv(var);
227    pam_putenv(pamh, var);
228    if(k_hasafs()){
229	k_setpag();
230	krb_afslog_home(0, 0, homedir);
231    }
232    return PAM_SUCCESS;
233}
234
235
236int
237pam_sm_close_session(pam_handle_t *pamh, int flags, int argc, const char **argv)
238{
239    dest_tkt();
240    if(k_hasafs())
241	k_unlog();
242    return PAM_SUCCESS;
243}
244