openpam_ttyconv.c revision 99158 
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#12 $
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#include <security/openpam.h>
50
51int openpam_ttyconv_timeout = 0;
52static jmp_buf jmpenv;
53static int timed_out;
54
55static void
56timeout(int sig)
57{
58	timed_out = 1;
59	longjmp(jmpenv, sig);
60}
61
62static char *
63prompt(const char *msg)
64{
65	char buf[PAM_MAX_RESP_SIZE];
66	struct sigaction action, saved_action;
67	sigset_t saved_sigset, sigset;
68	unsigned int saved_alarm;
69	size_t len;
70
71	sigemptyset(&sigset);
72	sigaddset(&sigset, SIGINT);
73	sigaddset(&sigset, SIGTSTP);
74	sigprocmask(SIG_SETMASK, &sigset, &saved_sigset);
75	action.sa_handler = &timeout;
76	action.sa_flags = 0;
77	sigemptyset(&action.sa_mask);
78	sigaction(SIGALRM, &action, &saved_action);
79	fputs(msg, stderr);
80	buf[0] = '\0';
81	timed_out = 0;
82	saved_alarm = alarm(openpam_ttyconv_timeout);
83	if (setjmp(jmpenv) == 0)
84		fgets(buf, sizeof buf, stdin);
85	else
86		fputs(" timeout!\n", stderr);
87	alarm(0);
88	sigaction(SIGALRM, &saved_action, NULL);
89	sigprocmask(SIG_SETMASK, &saved_sigset, NULL);
90	alarm(saved_alarm);
91	if (timed_out || ferror(stdin))
92		return (NULL);
93	/* trim trailing whitespace */
94	for (len = strlen(buf); len > 0; --len)
95		if (!isspace(buf[len - 1]))
96			break;
97	buf[len] = '\0';
98	return (strdup(buf));
99}
100
101static char *
102prompt_echo_off(const char *msg)
103{
104	struct termios tattr;
105	tcflag_t lflag;
106	char *ret;
107	int fd;
108
109	fd = fileno(stdin);
110	if (tcgetattr(fd, &tattr) != 0) {
111		openpam_log(PAM_LOG_ERROR, "tcgetattr(): %m");
112		return (NULL);
113	}
114	lflag = tattr.c_lflag;
115	tattr.c_lflag &= ~ECHO;
116	if (tcsetattr(fd, TCSAFLUSH, &tattr) != 0) {
117		openpam_log(PAM_LOG_ERROR, "tcsetattr(): %m");
118		return (NULL);
119	}
120	ret = prompt(msg);
121	tattr.c_lflag = lflag;
122	(void)tcsetattr(fd, TCSANOW, &tattr);
123	if (ret != NULL)
124		fputs("\n", stdout);
125	return (ret);
126}
127
128/*
129 * OpenPAM extension
130 *
131 * Simple tty-based conversation function
132 */
133
134int
135openpam_ttyconv(int n,
136	 const struct pam_message **msg,
137	 struct pam_response **resp,
138	 void *data)
139{
140	int i;
141
142	data = data;
143	if (n <= 0 || n > PAM_MAX_NUM_MSG)
144		return (PAM_CONV_ERR);
145	if ((*resp = calloc(n, sizeof **resp)) == NULL)
146		return (PAM_BUF_ERR);
147	for (i = 0; i < n; ++i) {
148		resp[i]->resp_retcode = 0;
149		resp[i]->resp = NULL;
150		switch (msg[i]->msg_style) {
151		case PAM_PROMPT_ECHO_OFF:
152			resp[i]->resp = prompt_echo_off(msg[i]->msg);
153			if (resp[i]->resp == NULL)
154				goto fail;
155			break;
156		case PAM_PROMPT_ECHO_ON:
157			resp[i]->resp = prompt(msg[i]->msg);
158			if (resp[i]->resp == NULL)
159				goto fail;
160			break;
161		case PAM_ERROR_MSG:
162			fputs(msg[i]->msg, stderr);
163			if (strlen(msg[i]->msg) > 0 &&
164			    msg[i]->msg[strlen(msg[i]->msg) - 1] != '\n')
165				fputc('\n', stderr);
166			break;
167		case PAM_TEXT_INFO:
168			fputs(msg[i]->msg, stdout);
169			if (strlen(msg[i]->msg) > 0 &&
170			    msg[i]->msg[strlen(msg[i]->msg) - 1] != '\n')
171				fputc('\n', stdout);
172			break;
173		default:
174			goto fail;
175		}
176	}
177	return (PAM_SUCCESS);
178 fail:
179	while (i)
180		free(resp[--i]);
181	free(*resp);
182	*resp = NULL;
183	return (PAM_CONV_ERR);
184}
185
186/*
187 * NOLIST
188 *
189 * Error codes:
190 *
191 *	PAM_SYSTEM_ERR
192 *	PAM_BUF_ERR
193 *	PAM_CONV_ERR
194 */
195
196/**
197 * The =openpam_ttyconv function is a standard conversation function
198 * suitable for use on TTY devices.  It should be adequate for the needs
199 * of most text-based interactive programs.
200 *
201 * The =openpam_ttyconv function allows the application to specify a
202 * timeout for user input by setting the global variable
203 * :openpam_ttyconv_timeout to the length of the timeout in seconds.
204 *
205 * >openpam_nullconv
206 * >pam_prompt
207 * >pam_vprompt
208 */
209