ct.c, ct.h: New constant-time operations.
[u/mdw/catacomb] / pixie-common.c
1 /* -*-c-*-
2 *
3 * $Id$
4 *
5 * Common code for Pixie client and server (Unix-specific)
6 *
7 * (c) 1999 Straylight/Edgeware
8 */
9
10 /*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of Catacomb.
13 *
14 * Catacomb is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
18 *
19 * Catacomb is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
25 * License along with Catacomb; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
27 * MA 02111-1307, USA.
28 */
29
30 /*----- Header files ------------------------------------------------------*/
31
32 #include <errno.h>
33 #include <stddef.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37
38 #include <sys/types.h>
39 #include <unistd.h>
40 #include <fcntl.h>
41 #include <termios.h>
42 #include <pwd.h>
43
44 #include <sys/socket.h>
45 #include <sys/un.h>
46
47 #include <mLib/alloc.h>
48 #include <mLib/dstr.h>
49 #include <mLib/str.h>
50
51 #include "pixie.h"
52
53 /*----- Main code ---------------------------------------------------------*/
54
55 /* --- @pixie_address@ --- *
56 *
57 * Arguments: @const char *sock@ = pointer to socket name
58 * @size_t *psz@ = where to write the address size
59 *
60 * Returns: Pointer to filled-in Unix-domain socket address.
61 *
62 * Use: Returns a Unix-domain socket address to use to find the
63 * passphrase pixie.
64 */
65
66 struct sockaddr_un *pixie_address(const char *sock, size_t *psz)
67 {
68 dstr d = DSTR_INIT;
69
70 /* --- Get the default socket path if none specified --- */
71
72 if (!sock)
73 sock = getenv("CATACOMB_PIXIE_SOCKET");
74 if (!sock)
75 sock = "%h/.catacomb/pixie";
76
77 /* --- Substitute interesting sequences in the path --- */
78
79 {
80 const char *q, *qq;
81
82 q = sock;
83 for (;;) {
84 qq = strchr(q, '%');
85 if (!qq || !qq[1]) {
86 DPUTS(&d, q);
87 break;
88 }
89 DPUTM(&d, q, qq - q);
90 q = qq + 1;
91 switch (*q) {
92 case 'u':
93 qq = getenv("USER");
94 if (!qq)
95 qq = getenv("LOGNAME");
96 if (!qq) {
97 struct passwd *pw = getpwuid(getuid());
98 if (pw)
99 qq = pw->pw_name;
100 else
101 qq = "<unknown>";
102 }
103 DPUTS(&d, qq);
104 break;
105 case 'h':
106 qq = getenv("HOME");
107 if (!qq) {
108 struct passwd *pw = getpwuid(getuid());
109 if (pw)
110 qq = pw->pw_dir;
111 else
112 qq = "<unknown>";
113 }
114 DPUTS(&d, qq);
115 break;
116 default:
117 DPUTC(&d, '%');
118 DPUTC(&d, *q);
119 break;
120 }
121 q++;
122 }
123 DPUTZ(&d);
124 }
125
126 /* --- Allocate and initialize the socket address --- */
127
128 {
129 struct sockaddr_un *sun;
130 size_t bsz = offsetof(struct sockaddr_un, sun_path);
131 *psz = bsz + d.len + 1;
132 sun = xmalloc(bsz + d.len + 1);
133 memset(sun, 0, bsz);
134 sun->sun_family = AF_UNIX;
135 memcpy(sun->sun_path, d.buf, d.len + 1);
136 dstr_destroy(&d);
137 return (sun);
138 }
139 }
140
141 /* --- @pixie_fdline@ --- *
142 *
143 * Arguments: @int fd@ = file descriptor to read from
144 * @char *buf@ = pointer to buffer
145 * @size_t sz@ = size of buffer
146 *
147 * Returns: ---
148 *
149 * Use: Reads a line from a file descriptor. The read is done one
150 * character at a time. If the entire line won't fit, the end
151 * is truncated. The line is null terminated.
152 */
153
154 void pixie_fdline(int fd, char *buf, size_t sz)
155 {
156 char *p = buf;
157 char *q = p + sz - 1;
158
159 for (;;) {
160 char c;
161 if (read(fd, &c, 1) < 1)
162 break;
163 if (c == '\n')
164 break;
165 if (p < q)
166 *p++ = c;
167 }
168 *p = 0;
169 }
170
171 /* --- @pixie_getpass@ --- *
172 *
173 * Arguments: @const char *prompt@ = pointer to prompt string
174 * @char *buf@ = pointer to buffer
175 * @size_t sz@ = size of buffer
176 *
177 * Returns: Zero if it worked OK, nonzero otherwise.
178 *
179 * Use: Reads a passphrase from the terminal or some other requested
180 * source.
181 */
182
183 int pixie_getpass(const char *prompt, char *buf, size_t sz)
184 {
185 const char *pfd = getenv("CATACOMB_PASSPHRASE_FD");
186 int fd = 0;
187
188 /* --- See whether a terminal is what's wanted --- */
189
190 if (pfd) {
191 fd = atoi(pfd);
192 pixie_fdline(fd, buf, sz);
193 } else {
194 struct termios ta;
195 struct termios ota;
196 char nl = '\n';
197
198 if ((fd = open("/dev/tty", O_RDWR)) < 0)
199 goto fail_0;
200 if (tcgetattr(fd, &ta) < 0)
201 goto fail_1;
202 ota = ta;
203 ta.c_lflag &= ~(ECHO | ISIG);
204 if (tcsetattr(fd, TCSAFLUSH, &ta))
205 goto fail_1;
206 write(fd, prompt, strlen(prompt));
207 pixie_fdline(fd, buf, sz);
208 tcsetattr(fd, TCSAFLUSH, &ota);
209 write(fd, &nl, 1);
210 close(fd);
211 }
212 return (0);
213
214 /* --- Tidy up if things went wrong --- */
215
216 fail_1:
217 close(fd);
218 fail_0:
219 return (-1);
220 }
221
222 /* --- @pixie_open@ --- *
223 *
224 * Arguments: @const char *sock@ = path to pixie socket
225 *
226 * Returns: Less than zero if it failed, or file descriptor.
227 *
228 * Use: Opens a connection to a passphrase pixie.
229 */
230
231 int pixie_open(const char *sock)
232 {
233 struct sockaddr_un *sun;
234 size_t sz;
235 int fd;
236
237 /* --- Open the connection --- */
238
239 if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
240 goto fail_0;
241 sun = pixie_address(sock, &sz);
242 if (connect(fd, (struct sockaddr *)sun, sz))
243 goto fail_1;
244 xfree(sun);
245 return (fd);
246
247 /* --- Tidy up if things went wrong --- */
248
249 fail_1:
250 xfree(sun);
251 close(fd);
252 fail_0:
253 return (-1);
254 }
255
256 /* --- @pixie_read@ --- *
257 *
258 * Arguments: @int fd@ = connection to passphrase pixie
259 * @const char *tag@ = pointer to tag string
260 * @unsigned mode@ = reading mode
261 * @char *buf@ = pointer to destination buffer
262 * @size_t sz@ = size of the buffer
263 *
264 * Returns: Zero if all went well, @-1@ if the read fails, @+1@ to
265 * request the passphrase from the user.
266 *
267 * Use: Reads a passphrase from the pixie.
268 */
269
270 int pixie_read(int fd, const char *tag, unsigned mode, char *buf, size_t sz)
271 {
272 dstr d = DSTR_INIT;
273 char *p, *q;
274
275 /* --- Send the request --- */
276
277 dstr_putf(&d, "%s %s\n", mode == PMODE_READ ? "PASS" : "VERIFY", tag);
278 write(fd, d.buf, d.len);
279 dstr_destroy(&d);
280
281 /* --- Sort out the result --- */
282
283 again:
284 pixie_fdline(fd, buf, sz);
285 p = buf;
286 if ((q = str_getword(&p)) == 0)
287 return (-1);
288 if (strcmp(q, "INFO") == 0)
289 goto again;
290 else if (strcmp(q, "MISSING") == 0)
291 return (+1);
292 else if (strcmp(q, "OK") != 0)
293 return (-1);
294
295 /* --- Return the final answer --- */
296
297 if (p)
298 memmove(buf, p, strlen(p) + 1);
299 else
300 *buf = 0;
301 return (0);
302 }
303
304 /* --- @pixie_set@ --- *
305 *
306 * Arguments: @int fd@ = pixie file descriptor
307 * @const char *tag@ = pointer to tag string
308 * @const char *phrase@ = pointer to passphrase string
309 *
310 * Returns: ---
311 *
312 * Use: Sends a passphrase to the passphrase pixie.
313 */
314
315 void pixie_set(int fd, const char *tag, const char *phrase)
316 {
317 dstr d = DSTR_INIT;
318 char buf[16];
319 size_t sz = strlen(phrase);
320 char nl = '\n';
321 char *p, *q;
322
323 /* --- Send the request --- *
324 *
325 * I didn't want to copy it out of the caller's buffer. @writev@ may
326 * produce a copy, too, so I didn't do that either.
327 */
328
329 dstr_putf(&d, "SET %s -- ", tag);
330 write(fd, d.buf, d.len);
331 write(fd, phrase, sz);
332 write(fd, &nl, 1);
333 dstr_destroy(&d);
334
335 /* --- Pick up the pieces --- */
336
337 again:
338 pixie_fdline(fd, buf, sizeof(buf));
339 p = buf;
340 if ((q = str_getword(&p)) != 0 && strcmp(q, "INFO") == 0)
341 goto again;
342 }
343
344 /* --- @pixie_cancel@ --- *
345 *
346 * Arguments: @int fd@ = pixie file descriptor
347 * @const char *tag@ = pointer to tag string
348 *
349 * Returns: ---
350 *
351 * Use: Cancels a passphrase if it turns out to be bogus.
352 */
353
354 void pixie_cancel(int fd, const char *tag)
355 {
356 dstr d = DSTR_INIT;
357 char buf[16];
358 char *p, *q;
359
360 /* --- Send the request --- */
361
362 dstr_putf(&d, "FLUSH %s\n", tag);
363 write(fd, d.buf, d.len);
364 dstr_destroy(&d);
365
366 /* --- Sort out the result --- */
367
368 again:
369 pixie_fdline(fd, buf, sizeof(buf));
370 p = buf;
371 if ((q = str_getword(&p)) != 0 && strcmp(q, "INFO") == 0)
372 goto again;
373 }
374
375 /*----- That's all, folks -------------------------------------------------*/
376