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f6fdbddf 1/*
2 * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
3 *
4 * Modification and redistribution in source and binary forms is
5 * permitted provided that due credit is given to the author and the
6 * OpenBSD project (for instance by leaving this copyright notice
7 * intact).
8 */
9
10#include "includes.h"
1e3b8b07 11RCSID("$OpenBSD: ssh-keyscan.c,v 1.6 2000/12/19 23:17:58 markus Exp $");
f6fdbddf 12
bf5f69f7 13#ifdef HAVE_SYS_QUEUE_H
f6fdbddf 14#include <sys/queue.h>
bf5f69f7 15#else
16#include "bsd-queue.h"
17#endif
f6fdbddf 18#include <errno.h>
19
20#include <openssl/bn.h>
21#include <openssl/rsa.h>
22#include <openssl/dsa.h>
23
24#include "xmalloc.h"
25#include "ssh.h"
26#include "key.h"
27#include "buffer.h"
28#include "bufaux.h"
29
30static int argno = 1; /* Number of argument currently being parsed */
31
32int family = AF_UNSPEC; /* IPv4, IPv6 or both */
33
34#define PORT 22
35#define MAXMAXFD 256
36
37/* The number of seconds after which to give up on a TCP connection */
38int timeout = 5;
39
40int maxfd;
41#define maxcon (maxfd - 10)
42
1fe6a48f 43#ifdef HAVE___PROGNAME
44extern char *__progname;
45#else
46char *__progname;
47#endif
f6fdbddf 48fd_set read_wait;
49int ncon;
50
51/*
52 * Keep a connection structure for each file descriptor. The state
53 * associated with file descriptor n is held in fdcon[n].
54 */
55typedef struct Connection {
1e3b8b07 56 u_char c_status; /* State of connection on this file desc. */
f6fdbddf 57#define CS_UNUSED 0 /* File descriptor unused */
58#define CS_CON 1 /* Waiting to connect/read greeting */
59#define CS_SIZE 2 /* Waiting to read initial packet size */
60#define CS_KEYS 3 /* Waiting to read public key packet */
61 int c_fd; /* Quick lookup: c->c_fd == c - fdcon */
62 int c_plen; /* Packet length field for ssh packet */
63 int c_len; /* Total bytes which must be read. */
64 int c_off; /* Length of data read so far. */
65 char *c_namebase; /* Address to free for c_name and c_namelist */
66 char *c_name; /* Hostname of connection for errors */
67 char *c_namelist; /* Pointer to other possible addresses */
68 char *c_output_name; /* Hostname of connection for output */
69 char *c_data; /* Data read from this fd */
70 struct timeval c_tv; /* Time at which connection gets aborted */
71 TAILQ_ENTRY(Connection) c_link; /* List of connections in timeout order. */
72} con;
73
74TAILQ_HEAD(conlist, Connection) tq; /* Timeout Queue */
75con *fdcon;
76
77/*
78 * This is just a wrapper around fgets() to make it usable.
79 */
80
81/* Stress-test. Increase this later. */
82#define LINEBUF_SIZE 16
83
84typedef struct {
85 char *buf;
1e3b8b07 86 u_int size;
f6fdbddf 87 int lineno;
88 const char *filename;
89 FILE *stream;
90 void (*errfun) (const char *,...);
91} Linebuf;
92
93static inline Linebuf *
94Linebuf_alloc(const char *filename, void (*errfun) (const char *,...))
95{
96 Linebuf *lb;
97
98 if (!(lb = malloc(sizeof(*lb)))) {
99 if (errfun)
100 (*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
101 return (NULL);
102 }
103 if (filename) {
104 lb->filename = filename;
105 if (!(lb->stream = fopen(filename, "r"))) {
106 free(lb);
107 if (errfun)
108 (*errfun) ("%s: %s\n", filename, strerror(errno));
109 return (NULL);
110 }
111 } else {
112 lb->filename = "(stdin)";
113 lb->stream = stdin;
114 }
115
116 if (!(lb->buf = malloc(lb->size = LINEBUF_SIZE))) {
117 if (errfun)
118 (*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
119 free(lb);
120 return (NULL);
121 }
122 lb->errfun = errfun;
123 lb->lineno = 0;
124 return (lb);
125}
126
127static inline void
128Linebuf_free(Linebuf * lb)
129{
130 fclose(lb->stream);
131 free(lb->buf);
132 free(lb);
133}
134
135static inline void
136Linebuf_restart(Linebuf * lb)
137{
138 clearerr(lb->stream);
139 rewind(lb->stream);
140 lb->lineno = 0;
141}
142
143static inline int
144Linebuf_lineno(Linebuf * lb)
145{
146 return (lb->lineno);
147}
148
149static inline char *
150getline(Linebuf * lb)
151{
152 int n = 0;
153
154 lb->lineno++;
155 for (;;) {
156 /* Read a line */
157 if (!fgets(&lb->buf[n], lb->size - n, lb->stream)) {
158 if (ferror(lb->stream) && lb->errfun)
159 (*lb->errfun) ("%s: %s\n", lb->filename, strerror(errno));
160 return (NULL);
161 }
162 n = strlen(lb->buf);
163
164 /* Return it or an error if it fits */
165 if (n > 0 && lb->buf[n - 1] == '\n') {
166 lb->buf[n - 1] = '\0';
167 return (lb->buf);
168 }
169 if (n != lb->size - 1) {
170 if (lb->errfun)
171 (*lb->errfun) ("%s: skipping incomplete last line\n", lb->filename);
172 return (NULL);
173 }
174 /* Double the buffer if we need more space */
175 if (!(lb->buf = realloc(lb->buf, (lb->size *= 2)))) {
176 if (lb->errfun)
177 (*lb->errfun) ("linebuf (%s): realloc failed\n", lb->filename);
178 return (NULL);
179 }
180 }
181}
182
183static int
184fdlim_get(int hard)
185{
186 struct rlimit rlfd;
187 if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
188 return (-1);
189 if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
190 return 10000;
191 else
192 return hard ? rlfd.rlim_max : rlfd.rlim_cur;
193}
194
195static int
196fdlim_set(int lim)
197{
198 struct rlimit rlfd;
199 if (lim <= 0)
200 return (-1);
201 if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
202 return (-1);
203 rlfd.rlim_cur = lim;
204 if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
205 return (-1);
206 return (0);
207}
208
209/*
210 * This is an strsep function that returns a null field for adjacent
211 * separators. This is the same as the 4.4BSD strsep, but different from the
212 * one in the GNU libc.
213 */
214inline char *
215xstrsep(char **str, const char *delim)
216{
217 char *s, *e;
218
219 if (!**str)
220 return (NULL);
221
222 s = *str;
223 e = s + strcspn(s, delim);
224
225 if (*e != '\0')
226 *e++ = '\0';
227 *str = e;
228
229 return (s);
230}
231
232/*
233 * Get the next non-null token (like GNU strsep). Strsep() will return a
234 * null token for two adjacent separators, so we may have to loop.
235 */
236char *
237strnnsep(char **stringp, char *delim)
238{
239 char *tok;
240
241 do {
242 tok = xstrsep(stringp, delim);
243 } while (tok && *tok == '\0');
244 return (tok);
245}
246
247void
248keyprint(char *host, char *output_name, char *kd, int len)
249{
250 static Key *rsa;
251 static Buffer msg;
252
253 if (rsa == NULL) {
254 buffer_init(&msg);
255 rsa = key_new(KEY_RSA1);
256 }
257 buffer_append(&msg, kd, len);
258 buffer_consume(&msg, 8 - (len & 7)); /* padding */
259 if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
260 error("%s: invalid packet type", host);
261 buffer_clear(&msg);
262 return;
263 }
264 buffer_consume(&msg, 8); /* cookie */
265
266 /* server key */
267 (void) buffer_get_int(&msg);
268 buffer_get_bignum(&msg, rsa->rsa->e);
269 buffer_get_bignum(&msg, rsa->rsa->n);
270
271 /* host key */
272 (void) buffer_get_int(&msg);
273 buffer_get_bignum(&msg, rsa->rsa->e);
274 buffer_get_bignum(&msg, rsa->rsa->n);
275 buffer_clear(&msg);
276
277 fprintf(stdout, "%s ", output_name ? output_name : host);
278 key_write(rsa, stdout);
279 fputs("\n", stdout);
280}
281
282int
283tcpconnect(char *host)
284{
285 struct addrinfo hints, *ai, *aitop;
286 char strport[NI_MAXSERV];
287 int gaierr, s = -1;
288
289 snprintf(strport, sizeof strport, "%d", PORT);
290 memset(&hints, 0, sizeof(hints));
291 hints.ai_family = family;
292 hints.ai_socktype = SOCK_STREAM;
293 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
294 fatal("getaddrinfo %s: %s", host, gai_strerror(gaierr));
295 for (ai = aitop; ai; ai = ai->ai_next) {
296 s = socket(ai->ai_family, SOCK_STREAM, 0);
297 if (s < 0) {
298 error("socket: %s", strerror(errno));
299 continue;
300 }
301 if (fcntl(s, F_SETFL, O_NDELAY) < 0)
302 fatal("F_SETFL: %s", strerror(errno));
303 if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
304 errno != EINPROGRESS)
305 error("connect (`%s'): %s", host, strerror(errno));
306 else
307 break;
308 close(s);
309 s = -1;
310 }
311 freeaddrinfo(aitop);
312 return s;
313}
314
315int
316conalloc(char *iname, char *oname)
317{
318 int s;
319 char *namebase, *name, *namelist;
320
321 namebase = namelist = xstrdup(iname);
322
323 do {
324 name = xstrsep(&namelist, ",");
325 if (!name) {
326 free(namebase);
327 return (-1);
328 }
329 } while ((s = tcpconnect(name)) < 0);
330
331 if (s >= maxfd)
227e8e86 332 fatal("conalloc: fdno %d too high", s);
f6fdbddf 333 if (fdcon[s].c_status)
227e8e86 334 fatal("conalloc: attempt to reuse fdno %d", s);
f6fdbddf 335
336 fdcon[s].c_fd = s;
337 fdcon[s].c_status = CS_CON;
338 fdcon[s].c_namebase = namebase;
339 fdcon[s].c_name = name;
340 fdcon[s].c_namelist = namelist;
341 fdcon[s].c_output_name = xstrdup(oname);
342 fdcon[s].c_data = (char *) &fdcon[s].c_plen;
343 fdcon[s].c_len = 4;
344 fdcon[s].c_off = 0;
345 gettimeofday(&fdcon[s].c_tv, NULL);
346 fdcon[s].c_tv.tv_sec += timeout;
347 TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
348 FD_SET(s, &read_wait);
349 ncon++;
350 return (s);
351}
352
353void
354confree(int s)
355{
356 close(s);
357 if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
227e8e86 358 fatal("confree: attempt to free bad fdno %d", s);
f6fdbddf 359 free(fdcon[s].c_namebase);
360 free(fdcon[s].c_output_name);
361 if (fdcon[s].c_status == CS_KEYS)
362 free(fdcon[s].c_data);
363 fdcon[s].c_status = CS_UNUSED;
364 TAILQ_REMOVE(&tq, &fdcon[s], c_link);
365 FD_CLR(s, &read_wait);
366 ncon--;
367}
368
369void
370contouch(int s)
371{
372 TAILQ_REMOVE(&tq, &fdcon[s], c_link);
373 gettimeofday(&fdcon[s].c_tv, NULL);
374 fdcon[s].c_tv.tv_sec += timeout;
375 TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
376}
377
378int
379conrecycle(int s)
380{
381 int ret;
382 con *c = &fdcon[s];
383 char *iname, *oname;
384
385 iname = xstrdup(c->c_namelist);
386 oname = c->c_output_name;
387 c->c_output_name = NULL;/* prevent it from being freed */
388 confree(s);
389 ret = conalloc(iname, oname);
390 free(iname);
391 return (ret);
392}
393
394void
395congreet(int s)
396{
397 char buf[80];
398 int n;
399 con *c = &fdcon[s];
400
401 n = read(s, buf, sizeof(buf));
402 if (n < 0) {
403 if (errno != ECONNREFUSED)
404 error("read (%s): %s", c->c_name, strerror(errno));
405 conrecycle(s);
406 return;
407 }
408 if (buf[n - 1] != '\n') {
409 error("%s: bad greeting", c->c_name);
410 confree(s);
411 return;
412 }
413 buf[n - 1] = '\0';
414 fprintf(stderr, "# %s %s\n", c->c_name, buf);
415 n = snprintf(buf, sizeof buf, "SSH-1.5-OpenSSH-keyscan\r\n");
416 if (write(s, buf, n) != n) {
417 error("write (%s): %s", c->c_name, strerror(errno));
418 confree(s);
419 return;
420 }
421 c->c_status = CS_SIZE;
422 contouch(s);
423}
424
425void
426conread(int s)
427{
428 int n;
429 con *c = &fdcon[s];
430
431 if (c->c_status == CS_CON) {
432 congreet(s);
433 return;
434 }
435 n = read(s, c->c_data + c->c_off, c->c_len - c->c_off);
436 if (n < 0) {
437 error("read (%s): %s", c->c_name, strerror(errno));
438 confree(s);
439 return;
440 }
441 c->c_off += n;
442
443 if (c->c_off == c->c_len)
444 switch (c->c_status) {
445 case CS_SIZE:
446 c->c_plen = htonl(c->c_plen);
447 c->c_len = c->c_plen + 8 - (c->c_plen & 7);
448 c->c_off = 0;
449 c->c_data = xmalloc(c->c_len);
450 c->c_status = CS_KEYS;
451 break;
452 case CS_KEYS:
453 keyprint(c->c_name, c->c_output_name, c->c_data, c->c_plen);
454 confree(s);
455 return;
456 break;
457 default:
227e8e86 458 fatal("conread: invalid status %d", c->c_status);
f6fdbddf 459 break;
460 }
461
462 contouch(s);
463}
464
465void
466conloop(void)
467{
468 fd_set r, e;
469 struct timeval seltime, now;
470 int i;
471 con *c;
472
473 gettimeofday(&now, NULL);
474 c = tq.tqh_first;
475
476 if (c &&
477 (c->c_tv.tv_sec > now.tv_sec ||
478 (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
479 seltime = c->c_tv;
480 seltime.tv_sec -= now.tv_sec;
481 seltime.tv_usec -= now.tv_usec;
482 if ((int) seltime.tv_usec < 0) {
483 seltime.tv_usec += 1000000;
484 seltime.tv_sec--;
485 }
486 } else
487 seltime.tv_sec = seltime.tv_usec = 0;
488
489 r = e = read_wait;
490 select(maxfd, &r, NULL, &e, &seltime);
491 for (i = 0; i < maxfd; i++)
492 if (FD_ISSET(i, &e)) {
493 error("%s: exception!", fdcon[i].c_name);
494 confree(i);
495 } else if (FD_ISSET(i, &r))
496 conread(i);
497
498 c = tq.tqh_first;
499 while (c &&
500 (c->c_tv.tv_sec < now.tv_sec ||
501 (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
502 int s = c->c_fd;
503 c = c->c_link.tqe_next;
504 conrecycle(s);
505 }
506}
507
508char *
509nexthost(int argc, char **argv)
510{
511 static Linebuf *lb;
512
513 for (;;) {
514 if (!lb) {
515 if (argno >= argc)
516 return (NULL);
517 if (argv[argno][0] != '-')
518 return (argv[argno++]);
519 if (!strcmp(argv[argno], "--")) {
520 if (++argno >= argc)
521 return (NULL);
522 return (argv[argno++]);
523 } else if (!strncmp(argv[argno], "-f", 2)) {
524 char *fname;
525 if (argv[argno][2])
526 fname = &argv[argno++][2];
527 else if (++argno >= argc) {
528 error("missing filename for `-f'");
529 return (NULL);
530 } else
531 fname = argv[argno++];
532 if (!strcmp(fname, "-"))
533 fname = NULL;
f20255cb 534 lb = Linebuf_alloc(fname, error);
f6fdbddf 535 } else
536 error("ignoring invalid/misplaced option `%s'", argv[argno++]);
537 } else {
538 char *line;
539 line = getline(lb);
540 if (line)
541 return (line);
542 Linebuf_free(lb);
543 lb = NULL;
544 }
545 }
546}
547
548static void
549usage(void)
550{
227e8e86 551 fatal("usage: %s [-t timeout] { [--] host | -f file } ...", __progname);
f6fdbddf 552 return;
553}
554
555int
556main(int argc, char **argv)
557{
558 char *host = NULL;
559
1fe6a48f 560 __progname = get_progname(argv[0]);
f6fdbddf 561 TAILQ_INIT(&tq);
562
f6fdbddf 563 if (argc <= argno)
564 usage();
565
566 if (argv[1][0] == '-' && argv[1][1] == 't') {
567 argno++;
568 if (argv[1][2])
569 timeout = atoi(&argv[1][2]);
570 else {
571 if (argno >= argc)
572 usage();
573 timeout = atoi(argv[argno++]);
574 }
575 if (timeout <= 0)
576 usage();
577 }
578 if (argc <= argno)
579 usage();
580
581 maxfd = fdlim_get(1);
582 if (maxfd < 0)
227e8e86 583 fatal("%s: fdlim_get: bad value", __progname);
f6fdbddf 584 if (maxfd > MAXMAXFD)
585 maxfd = MAXMAXFD;
586 if (maxcon <= 0)
227e8e86 587 fatal("%s: not enough file descriptors", __progname);
f6fdbddf 588 if (maxfd > fdlim_get(0))
589 fdlim_set(maxfd);
590 fdcon = xmalloc(maxfd * sizeof(con));
591
592 do {
593 while (ncon < maxcon) {
594 char *name;
595
596 host = nexthost(argc, argv);
597 if (host == NULL)
598 break;
599 name = strnnsep(&host, " \t\n");
600 conalloc(name, *host ? host : name);
601 }
602 conloop();
603 } while (host);
604 while (ncon > 0)
605 conloop();
606
607 return (0);
608}
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