openpam_ttyconv.c revision 107937 
1/*-
2 * Copyright (c) 2002 Networks Associates Technology, Inc.
3 * All rights reserved.
4 *
5 * This software was developed for the FreeBSD Project by ThinkSec AS and
6 * Network Associates Laboratories, the Security Research Division of
7 * Network Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
8 * ("CBOSS"), as part of the DARPA CHATS research program.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote
19 *    products derived from this software without specific prior written
20 *    permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $P4: //depot/projects/openpam/lib/openpam_ttyconv.c#14 $
35 */
36
37#include <sys/types.h>
38
39#include <ctype.h>
40#include <setjmp.h>
41#include <signal.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
45#include <termios.h>
46#include <unistd.h>
47
48#include <security/pam_appl.h>
49
50#include "openpam_impl.h"
51
52int openpam_ttyconv_timeout = 0;
53static jmp_buf jmpenv;
54static int timed_out;
55
56static void
57timeout(int sig)
58{
59	timed_out = 1;
60	longjmp(jmpenv, sig);
61}
62
63static char *
64prompt(const char *msg)
65{
66	char buf[PAM_MAX_RESP_SIZE];
67	struct sigaction action, saved_action;
68	sigset_t saved_sigset, sigset;
69	unsigned int saved_alarm;
70	size_t len;
71
72	sigemptyset(&sigset);
73	sigaddset(&sigset, SIGINT);
74	sigaddset(&sigset, SIGTSTP);
75	sigprocmask(SIG_SETMASK, &sigset, &saved_sigset);
76	action.sa_handler = &timeout;
77	action.sa_flags = 0;
78	sigemptyset(&action.sa_mask);
79	sigaction(SIGALRM, &action, &saved_action);
80	fputs(msg, stdout);
81	buf[0] = '\0';
82	timed_out = 0;
83	saved_alarm = alarm(openpam_ttyconv_timeout);
84	if (setjmp(jmpenv) == 0)
85		fgets(buf, sizeof buf, stdin);
86	else
87		fputs(" timeout!\n", stderr);
88	alarm(0);
89	sigaction(SIGALRM, &saved_action, NULL);
90	sigprocmask(SIG_SETMASK, &saved_sigset, NULL);
91	alarm(saved_alarm);
92	if (timed_out || ferror(stdin))
93		return (NULL);
94	/* trim trailing whitespace */
95	for (len = strlen(buf); len > 0; --len)
96		if (!isspace(buf[len - 1]))
97			break;
98	buf[len] = '\0';
99	return (strdup(buf));
100}
101
102static char *
103prompt_echo_off(const char *msg)
104{
105	struct termios tattr;
106	tcflag_t lflag;
107	char *ret;
108	int fd;
109
110	fd = fileno(stdin);
111	if (tcgetattr(fd, &tattr) != 0) {
112		openpam_log(PAM_LOG_ERROR, "tcgetattr(): %m");
113		return (NULL);
114	}
115	lflag = tattr.c_lflag;
116	tattr.c_lflag &= ~ECHO;
117	if (tcsetattr(fd, TCSAFLUSH, &tattr) != 0) {
118		openpam_log(PAM_LOG_ERROR, "tcsetattr(): %m");
119		return (NULL);
120	}
121	ret = prompt(msg);
122	tattr.c_lflag = lflag;
123	(void)tcsetattr(fd, TCSANOW, &tattr);
124	if (ret != NULL)
125		fputs("\n", stdout);
126	return (ret);
127}
128
129/*
130 * OpenPAM extension
131 *
132 * Simple tty-based conversation function
133 */
134
135int
136openpam_ttyconv(int n,
137	 const struct pam_message **msg,
138	 struct pam_response **resp,
139	 void *data)
140{
141	int i;
142
143	ENTER();
144	(void)data;
145	if (n <= 0 || n > PAM_MAX_NUM_MSG)
146		RETURNC(PAM_CONV_ERR);
147	if ((*resp = calloc(n, sizeof **resp)) == NULL)
148		RETURNC(PAM_BUF_ERR);
149	for (i = 0; i < n; ++i) {
150		resp[i]->resp_retcode = 0;
151		resp[i]->resp = NULL;
152		switch (msg[i]->msg_style) {
153		case PAM_PROMPT_ECHO_OFF:
154			resp[i]->resp = prompt_echo_off(msg[i]->msg);
155			if (resp[i]->resp == NULL)
156				goto fail;
157			break;
158		case PAM_PROMPT_ECHO_ON:
159			resp[i]->resp = prompt(msg[i]->msg);
160			if (resp[i]->resp == NULL)
161				goto fail;
162			break;
163		case PAM_ERROR_MSG:
164			fputs(msg[i]->msg, stderr);
165			if (strlen(msg[i]->msg) > 0 &&
166			    msg[i]->msg[strlen(msg[i]->msg) - 1] != '\n')
167				fputc('\n', stderr);
168			break;
169		case PAM_TEXT_INFO:
170			fputs(msg[i]->msg, stdout);
171			if (strlen(msg[i]->msg) > 0 &&
172			    msg[i]->msg[strlen(msg[i]->msg) - 1] != '\n')
173				fputc('\n', stdout);
174			break;
175		default:
176			goto fail;
177		}
178	}
179	RETURNC(PAM_SUCCESS);
180 fail:
181	while (i)
182		free(resp[--i]);
183	free(*resp);
184	*resp = NULL;
185	RETURNC(PAM_CONV_ERR);
186}
187
188/*
189 * NOLIST
190 *
191 * Error codes:
192 *
193 *	PAM_SYSTEM_ERR
194 *	PAM_BUF_ERR
195 *	PAM_CONV_ERR
196 */
197
198/**
199 * The =openpam_ttyconv function is a standard conversation function
200 * suitable for use on TTY devices.  It should be adequate for the needs
201 * of most text-based interactive programs.
202 *
203 * The =openpam_ttyconv function allows the application to specify a
204 * timeout for user input by setting the global variable
205 * :openpam_ttyconv_timeout to the length of the timeout in seconds.
206 *
207 * >openpam_nullconv
208 * >pam_prompt
209 * >pam_vprompt
210 */
211