1/*
2 * Dropbear SSH
3 *
4 * Copyright (c) 2005 Matt Johnston
5 * All rights reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23 * SOFTWARE. */
24
25#include "includes.h"
26#include "buffer.h"
27#include "dbutil.h"
28#include "session.h"
29#include "ssh.h"
30#include "runopts.h"
31
32#ifdef ENABLE_CLI_INTERACT_AUTH
33
34static unsigned char* get_response(unsigned char* prompt)
35{
36	FILE* tty = NULL;
37	unsigned char* response = NULL;
38	/* not a password, but a reasonable limit */
39	char buf[DROPBEAR_MAX_CLI_PASS];
40	char* ret = NULL;
41
42	fprintf(stderr, "%s", prompt);
43
44	tty = fopen(_PATH_TTY, "r");
45	if (tty) {
46		ret = fgets(buf, sizeof(buf), tty);
47		fclose(tty);
48	} else {
49		ret = fgets(buf, sizeof(buf), stdin);
50	}
51
52	if (ret == NULL) {
53		response = (unsigned char*)m_strdup("");
54	} else {
55		unsigned int buflen = strlen(buf);
56		/* fgets includes newlines */
57		if (buflen > 0 && buf[buflen-1] == '\n')
58			buf[buflen-1] = '\0';
59		response = (unsigned char*)m_strdup(buf);
60	}
61
62	m_burn(buf, sizeof(buf));
63
64	return response;
65}
66
67void recv_msg_userauth_info_request() {
68
69	unsigned char *name = NULL;
70	unsigned char *instruction = NULL;
71	unsigned int num_prompts = 0;
72	unsigned int i;
73
74	unsigned char *prompt = NULL;
75	unsigned int echo = 0;
76	unsigned char *response = NULL;
77
78	TRACE(("enter recv_msg_recv_userauth_info_request"))
79
80	cli_ses.interact_request_received = 1;
81
82	name = buf_getstring(ses.payload, NULL);
83	instruction = buf_getstring(ses.payload, NULL);
84
85	/* language tag */
86	buf_eatstring(ses.payload);
87
88	num_prompts = buf_getint(ses.payload);
89
90	if (num_prompts >= DROPBEAR_MAX_CLI_INTERACT_PROMPTS) {
91		dropbear_exit("Too many prompts received for keyboard-interactive");
92	}
93
94	/* we'll build the response as we go */
95	CHECKCLEARTOWRITE();
96	buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_INFO_RESPONSE);
97	buf_putint(ses.writepayload, num_prompts);
98
99	if (strlen(name) > 0) {
100		cleantext(name);
101		fprintf(stderr, "%s", name);
102	}
103	m_free(name);
104
105	if (strlen(instruction) > 0) {
106		cleantext(instruction);
107		fprintf(stderr, "%s", instruction);
108	}
109	m_free(instruction);
110
111	for (i = 0; i < num_prompts; i++) {
112		unsigned int response_len = 0;
113		prompt = buf_getstring(ses.payload, NULL);
114		cleantext(prompt);
115
116		echo = buf_getbool(ses.payload);
117
118		if (!echo) {
119			unsigned char* p = getpass_or_cancel(prompt);
120			response = m_strdup(p);
121			m_burn(p, strlen(p));
122		} else {
123			response = get_response(prompt);
124		}
125
126		response_len = strlen(response);
127		buf_putstring(ses.writepayload, response, response_len);
128		m_burn(response, response_len);
129		m_free(response);
130	}
131
132	encrypt_packet();
133
134
135	TRACE(("leave recv_msg_recv_userauth_info_request"))
136}
137
138void cli_auth_interactive() {
139
140	TRACE(("enter cli_auth_interactive"))
141	CHECKCLEARTOWRITE();
142
143	buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_REQUEST);
144
145	/* username */
146	buf_putstring(ses.writepayload, cli_opts.username,
147			strlen(cli_opts.username));
148
149	/* service name */
150	buf_putstring(ses.writepayload, SSH_SERVICE_CONNECTION,
151			SSH_SERVICE_CONNECTION_LEN);
152
153	/* method */
154	buf_putstring(ses.writepayload, AUTH_METHOD_INTERACT,
155			AUTH_METHOD_INTERACT_LEN);
156
157	/* empty language tag */
158	buf_putstring(ses.writepayload, "", 0);
159
160	/* empty submethods */
161	buf_putstring(ses.writepayload, "", 0);
162
163	encrypt_packet();
164	cli_ses.interact_request_received = 0;
165
166	TRACE(("leave cli_auth_interactive"))
167
168}
169#endif	/* ENABLE_CLI_INTERACT_AUTH */
170