1 /*-
2 * Copyright (c) 2002-2003 Networks Associates Technology, Inc.
3 * Copyright (c) 2004-2017 Dag-Erling Smørgrav
4 * All rights reserved.
5 *
6 * This software was developed for the FreeBSD Project by ThinkSec AS and
7 * Network Associates Laboratories, the Security Research Division of
8 * Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
9 * ("CBOSS"), as part of the DARPA CHATS research program.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. The name of the author may not be used to endorse or promote
20 * products derived from this software without specific prior written
21 * permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #ifdef HAVE_CONFIG_H
37 # include "config.h"
38 #endif
39
40 #include <sys/param.h>
41
42 #include <stdlib.h>
43
44 #include <security/pam_appl.h>
45 #include <security/openpam.h>
46
47 #include "openpam_impl.h"
48
49 static const char user_prompt[] = "Login:";
50
51 /*
52 * XSSO 4.2.1
53 * XSSO 6 page 52
54 *
55 * Retrieve user name
56 */
57
58 int
pam_get_user(pam_handle_t * pamh,const char ** user,const char * prompt)59 pam_get_user(pam_handle_t *pamh,
60 const char **user,
61 const char *prompt)
62 {
63 char prompt_buf[1024];
64 size_t prompt_size;
65 const void *promptp;
66 char *resp;
67 int r;
68
69 ENTER();
70 r = pam_get_item(pamh, PAM_USER, (const void **)user);
71 if (r == PAM_SUCCESS && *user != NULL)
72 RETURNC(PAM_SUCCESS);
73 /* pam policy overrides the module's choice */
74 if ((promptp = openpam_get_option(pamh, "user_prompt")) != NULL)
75 prompt = promptp;
76 /* no prompt provided, see if there is one tucked away somewhere */
77 if (prompt == NULL) {
78 r = pam_get_item(pamh, PAM_USER_PROMPT, &promptp);
79 if (r == PAM_SUCCESS && promptp != NULL)
80 prompt = promptp;
81 }
82 /* fall back to hardcoded default */
83 if (prompt == NULL)
84 prompt = user_prompt;
85 /* expand */
86 prompt_size = sizeof prompt_buf;
87 r = openpam_subst(pamh, prompt_buf, &prompt_size, prompt);
88 if (r == PAM_SUCCESS && prompt_size <= sizeof prompt_buf)
89 prompt = prompt_buf;
90 r = pam_prompt(pamh, PAM_PROMPT_ECHO_ON, &resp, "%s", prompt);
91 if (r != PAM_SUCCESS)
92 RETURNC(r);
93 r = pam_set_item(pamh, PAM_USER, resp);
94 FREE(resp);
95 if (r != PAM_SUCCESS)
96 RETURNC(r);
97 r = pam_get_item(pamh, PAM_USER, (const void **)user);
98 RETURNC(r);
99 }
100
101 /*
102 * Error codes:
103 *
104 * =pam_get_item
105 * =pam_prompt
106 * =pam_set_item
107 * !PAM_SYMBOL_ERR
108 */
109
110 /**
111 * The =pam_get_user function returns the name of the target user, as
112 * specified to =pam_start.
113 * If no user was specified, nor set using =pam_set_item, =pam_get_user
114 * will prompt for a user name.
115 * Either way, a pointer to the user name is stored in the location
116 * pointed to by the =user argument, and the corresponding PAM item is
117 * updated.
118 *
119 * The =prompt argument specifies a prompt to use if no user name is
120 * cached.
121 * If it is =NULL, the =PAM_USER_PROMPT item will be used.
122 * If that item is also =NULL, a hardcoded default prompt will be used.
123 * Additionally, when =pam_get_user is called from a service module, the
124 * prompt may be affected by module options as described below.
125 * The prompt is then expanded using =openpam_subst before it is passed to
126 * the conversation function.
127 *
128 * MODULE OPTIONS
129 *
130 * When called by a service module, =pam_get_user will recognize the
131 * following module options:
132 *
133 * ;user_prompt:
134 * Prompt to use when asking for the user name.
135 * This option overrides both the =prompt argument and the
136 * =PAM_USER_PROMPT item.
137 *
138 * >pam_conv
139 * >pam_get_item
140 * >pam_get_authtok
141 * >openpam_get_option
142 * >openpam_subst
143 */
144