Annotation of src/usr.bin/ssh/ssh-agent.c, Revision 1.264.4.1
1.264.4.1! deraadt 1: /* $OpenBSD: ssh-agent.c,v 1.264 2020/09/18 08:16:38 djm Exp $ */
1.1 deraadt 2: /*
1.22 deraadt 3: * Author: Tatu Ylonen <ylo@cs.hut.fi>
4: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: * All rights reserved
6: * The authentication agent program.
1.33 markus 7: *
1.35 deraadt 8: * As far as I am concerned, the code I have written for this software
9: * can be used freely for any purpose. Any derived versions of this
10: * software must be clearly marked as such, and if the derived work is
11: * incompatible with the protocol description in the RFC file, it must be
12: * called by a name other than "ssh" or "Secure Shell".
13: *
1.56 markus 14: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.35 deraadt 15: *
16: * Redistribution and use in source and binary forms, with or without
17: * modification, are permitted provided that the following conditions
18: * are met:
19: * 1. Redistributions of source code must retain the above copyright
20: * notice, this list of conditions and the following disclaimer.
21: * 2. Redistributions in binary form must reproduce the above copyright
22: * notice, this list of conditions and the following disclaimer in the
23: * documentation and/or other materials provided with the distribution.
24: *
25: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.22 deraadt 35: */
1.1 deraadt 36:
1.151 deraadt 37: #include <sys/types.h>
1.153 djm 38: #include <sys/time.h>
1.78 provos 39: #include <sys/queue.h>
1.127 stevesk 40: #include <sys/resource.h>
1.141 stevesk 41: #include <sys/socket.h>
1.189 djm 42: #include <sys/stat.h>
1.128 stevesk 43: #include <sys/un.h>
1.238 djm 44: #include <sys/wait.h>
1.126 stevesk 45:
1.185 markus 46: #ifdef WITH_OPENSSL
1.146 stevesk 47: #include <openssl/evp.h>
1.185 markus 48: #endif
1.146 stevesk 49:
1.143 stevesk 50: #include <errno.h>
1.142 stevesk 51: #include <fcntl.h>
1.126 stevesk 52: #include <paths.h>
1.223 djm 53: #include <poll.h>
1.129 stevesk 54: #include <signal.h>
1.149 stevesk 55: #include <stdlib.h>
1.150 stevesk 56: #include <stdio.h>
1.146 stevesk 57: #include <string.h>
1.248 naddy 58: #include <stdarg.h>
1.196 deraadt 59: #include <limits.h>
1.145 stevesk 60: #include <time.h>
1.144 stevesk 61: #include <unistd.h>
1.203 dtucker 62: #include <util.h>
1.194 markus 63:
1.151 deraadt 64: #include "xmalloc.h"
1.1 deraadt 65: #include "ssh.h"
1.258 djm 66: #include "ssh2.h"
1.194 markus 67: #include "sshbuf.h"
68: #include "sshkey.h"
1.32 markus 69: #include "authfd.h"
1.37 markus 70: #include "compat.h"
1.47 markus 71: #include "log.h"
1.107 markus 72: #include "misc.h"
1.182 markus 73: #include "digest.h"
1.194 markus 74: #include "ssherr.h"
1.215 djm 75: #include "match.h"
1.238 djm 76: #include "msg.h"
1.244 djm 77: #include "ssherr.h"
1.238 djm 78: #include "pathnames.h"
1.163 markus 79: #include "ssh-pkcs11.h"
1.251 djm 80: #include "sk-api.h"
1.59 markus 81:
1.262 djm 82: #ifndef DEFAULT_ALLOWED_PROVIDERS
83: # define DEFAULT_ALLOWED_PROVIDERS "/usr/lib*/*,/usr/local/lib*/*"
1.215 djm 84: #endif
85:
1.223 djm 86: /* Maximum accepted message length */
87: #define AGENT_MAX_LEN (256*1024)
1.233 djm 88: /* Maximum bytes to read from client socket */
89: #define AGENT_RBUF_LEN (4096)
1.223 djm 90:
1.73 stevesk 91: typedef enum {
92: AUTH_UNUSED,
93: AUTH_SOCKET,
94: AUTH_CONNECTION
95: } sock_type;
96:
1.21 markus 97: typedef struct {
98: int fd;
1.73 stevesk 99: sock_type type;
1.194 markus 100: struct sshbuf *input;
101: struct sshbuf *output;
102: struct sshbuf *request;
1.1 deraadt 103: } SocketEntry;
104:
1.45 markus 105: u_int sockets_alloc = 0;
1.1 deraadt 106: SocketEntry *sockets = NULL;
107:
1.78 provos 108: typedef struct identity {
109: TAILQ_ENTRY(identity) next;
1.194 markus 110: struct sshkey *key;
1.21 markus 111: char *comment;
1.163 markus 112: char *provider;
1.174 dtucker 113: time_t death;
1.107 markus 114: u_int confirm;
1.238 djm 115: char *sk_provider;
1.1 deraadt 116: } Identity;
117:
1.221 djm 118: struct idtable {
1.33 markus 119: int nentries;
1.78 provos 120: TAILQ_HEAD(idqueue, identity) idlist;
1.221 djm 121: };
1.33 markus 122:
1.221 djm 123: /* private key table */
124: struct idtable *idtab;
1.1 deraadt 125:
126: int max_fd = 0;
127:
1.11 markus 128: /* pid of shell == parent of agent */
1.29 deraadt 129: pid_t parent_pid = -1;
1.176 dtucker 130: time_t parent_alive_interval = 0;
1.10 markus 131:
1.187 djm 132: /* pid of process for which cleanup_socket is applicable */
133: pid_t cleanup_pid = 0;
134:
1.10 markus 135: /* pathname and directory for AUTH_SOCKET */
1.196 deraadt 136: char socket_name[PATH_MAX];
137: char socket_dir[PATH_MAX];
1.10 markus 138:
1.260 djm 139: /* Pattern-list of allowed PKCS#11/Security key paths */
140: static char *allowed_providers;
1.215 djm 141:
1.88 markus 142: /* locking */
1.203 dtucker 143: #define LOCK_SIZE 32
144: #define LOCK_SALT_SIZE 16
145: #define LOCK_ROUNDS 1
1.88 markus 146: int locked = 0;
1.213 djm 147: u_char lock_pwhash[LOCK_SIZE];
148: u_char lock_salt[LOCK_SALT_SIZE];
1.88 markus 149:
1.20 markus 150: extern char *__progname;
151:
1.174 dtucker 152: /* Default lifetime in seconds (0 == forever) */
153: static long lifetime = 0;
1.106 marc 154:
1.192 djm 155: static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
156:
1.258 djm 157: /* Refuse signing of non-SSH messages for web-origin FIDO keys */
158: static int restrict_websafe = 1;
159:
1.55 itojun 160: static void
1.101 stevesk 161: close_socket(SocketEntry *e)
162: {
163: close(e->fd);
164: e->fd = -1;
165: e->type = AUTH_UNUSED;
1.194 markus 166: sshbuf_free(e->input);
167: sshbuf_free(e->output);
168: sshbuf_free(e->request);
1.101 stevesk 169: }
170:
171: static void
1.33 markus 172: idtab_init(void)
1.1 deraadt 173: {
1.221 djm 174: idtab = xcalloc(1, sizeof(*idtab));
175: TAILQ_INIT(&idtab->idlist);
176: idtab->nentries = 0;
1.33 markus 177: }
178:
1.89 markus 179: static void
180: free_identity(Identity *id)
181: {
1.194 markus 182: sshkey_free(id->key);
1.173 djm 183: free(id->provider);
184: free(id->comment);
1.238 djm 185: free(id->sk_provider);
1.173 djm 186: free(id);
1.89 markus 187: }
188:
1.33 markus 189: /* return matching private key for given public key */
1.78 provos 190: static Identity *
1.221 djm 191: lookup_identity(struct sshkey *key)
1.33 markus 192: {
1.78 provos 193: Identity *id;
194:
1.221 djm 195: TAILQ_FOREACH(id, &idtab->idlist, next) {
1.194 markus 196: if (sshkey_equal(key, id->key))
1.78 provos 197: return (id);
1.33 markus 198: }
1.78 provos 199: return (NULL);
200: }
201:
1.107 markus 202: /* Check confirmation of keysign request */
203: static int
204: confirm_key(Identity *id)
205: {
1.122 djm 206: char *p;
1.107 markus 207: int ret = -1;
208:
1.194 markus 209: p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT);
1.197 djm 210: if (p != NULL &&
211: ask_permission("Allow use of key %s?\nKey fingerprint %s.",
1.122 djm 212: id->comment, p))
213: ret = 0;
1.173 djm 214: free(p);
1.122 djm 215:
1.107 markus 216: return (ret);
217: }
218:
1.194 markus 219: static void
220: send_status(SocketEntry *e, int success)
221: {
222: int r;
223:
224: if ((r = sshbuf_put_u32(e->output, 1)) != 0 ||
225: (r = sshbuf_put_u8(e->output, success ?
226: SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
227: fatal("%s: buffer error: %s", __func__, ssh_err(r));
228: }
229:
1.33 markus 230: /* send list of supported public keys to 'client' */
1.55 itojun 231: static void
1.221 djm 232: process_request_identities(SocketEntry *e)
1.33 markus 233: {
1.96 deraadt 234: Identity *id;
1.194 markus 235: struct sshbuf *msg;
236: int r;
1.1 deraadt 237:
1.194 markus 238: if ((msg = sshbuf_new()) == NULL)
239: fatal("%s: sshbuf_new failed", __func__);
1.221 djm 240: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
241: (r = sshbuf_put_u32(msg, idtab->nentries)) != 0)
242: fatal("%s: buffer error: %s", __func__, ssh_err(r));
243: TAILQ_FOREACH(id, &idtab->idlist, next) {
1.228 markus 244: if ((r = sshkey_puts_opts(id->key, msg, SSHKEY_SERIALIZE_INFO))
245: != 0 ||
1.221 djm 246: (r = sshbuf_put_cstring(msg, id->comment)) != 0) {
247: error("%s: put key/comment: %s", __func__,
1.220 djm 248: ssh_err(r));
249: continue;
1.33 markus 250: }
1.21 markus 251: }
1.194 markus 252: if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
253: fatal("%s: buffer error: %s", __func__, ssh_err(r));
254: sshbuf_free(msg);
1.1 deraadt 255: }
256:
1.33 markus 257:
1.208 markus 258: static char *
259: agent_decode_alg(struct sshkey *key, u_int flags)
260: {
261: if (key->type == KEY_RSA) {
262: if (flags & SSH_AGENT_RSA_SHA2_256)
263: return "rsa-sha2-256";
264: else if (flags & SSH_AGENT_RSA_SHA2_512)
265: return "rsa-sha2-512";
1.235 djm 266: } else if (key->type == KEY_RSA_CERT) {
267: if (flags & SSH_AGENT_RSA_SHA2_256)
268: return "rsa-sha2-256-cert-v01@openssh.com";
269: else if (flags & SSH_AGENT_RSA_SHA2_512)
270: return "rsa-sha2-512-cert-v01@openssh.com";
1.208 markus 271: }
272: return NULL;
273: }
274:
1.258 djm 275: /*
276: * This function inspects a message to be signed by a FIDO key that has a
277: * web-like application string (i.e. one that does not begin with "ssh:".
278: * It checks that the message is one of those expected for SSH operations
279: * (pubkey userauth, sshsig, CA key signing) to exclude signing challenges
280: * for the web.
281: */
282: static int
283: check_websafe_message_contents(struct sshkey *key,
284: const u_char *msg, size_t len)
285: {
286: int matched = 0;
287: struct sshbuf *b;
288: u_char m, n;
289: char *cp1 = NULL, *cp2 = NULL;
290: int r;
291: struct sshkey *mkey = NULL;
292:
293: if ((b = sshbuf_from(msg, len)) == NULL)
294: fatal("%s: sshbuf_new", __func__);
295:
296: /* SSH userauth request */
297: if ((r = sshbuf_get_string_direct(b, NULL, NULL)) == 0 && /* sess_id */
298: (r = sshbuf_get_u8(b, &m)) == 0 && /* SSH2_MSG_USERAUTH_REQUEST */
299: (r = sshbuf_get_cstring(b, NULL, NULL)) == 0 && /* server user */
300: (r = sshbuf_get_cstring(b, &cp1, NULL)) == 0 && /* service */
301: (r = sshbuf_get_cstring(b, &cp2, NULL)) == 0 && /* method */
302: (r = sshbuf_get_u8(b, &n)) == 0 && /* sig-follows */
303: (r = sshbuf_get_cstring(b, NULL, NULL)) == 0 && /* alg */
304: (r = sshkey_froms(b, &mkey)) == 0 && /* key */
305: sshbuf_len(b) == 0) {
306: debug("%s: parsed userauth", __func__);
307: if (m == SSH2_MSG_USERAUTH_REQUEST && n == 1 &&
308: strcmp(cp1, "ssh-connection") == 0 &&
309: strcmp(cp2, "publickey") == 0 &&
310: sshkey_equal(key, mkey)) {
311: debug("%s: well formed userauth", __func__);
312: matched = 1;
313: }
314: }
315: free(cp1);
316: free(cp2);
317: sshkey_free(mkey);
318: sshbuf_free(b);
319: if (matched)
320: return 1;
321:
322: if ((b = sshbuf_from(msg, len)) == NULL)
323: fatal("%s: sshbuf_new", __func__);
324: cp1 = cp2 = NULL;
325: mkey = NULL;
326:
327: /* SSHSIG */
328: if ((r = sshbuf_cmp(b, 0, "SSHSIG", 6)) == 0 &&
329: (r = sshbuf_consume(b, 6)) == 0 &&
330: (r = sshbuf_get_cstring(b, NULL, NULL)) == 0 && /* namespace */
331: (r = sshbuf_get_string_direct(b, NULL, NULL)) == 0 && /* reserved */
332: (r = sshbuf_get_cstring(b, NULL, NULL)) == 0 && /* hashalg */
333: (r = sshbuf_get_string_direct(b, NULL, NULL)) == 0 && /* H(msg) */
334: sshbuf_len(b) == 0) {
335: debug("%s: parsed sshsig", __func__);
336: matched = 1;
337: }
338:
339: sshbuf_free(b);
340: if (matched)
341: return 1;
342:
343: /* XXX CA signature operation */
344:
345: error("web-origin key attempting to sign non-SSH message");
346: return 0;
347: }
348:
1.33 markus 349: /* ssh2 only */
1.55 itojun 350: static void
1.33 markus 351: process_sign_request2(SocketEntry *e)
352: {
1.221 djm 353: const u_char *data;
354: u_char *signature = NULL;
355: size_t dlen, slen = 0;
1.194 markus 356: u_int compat = 0, flags;
1.247 djm 357: int r, ok = -1;
1.251 djm 358: char *fp = NULL;
1.194 markus 359: struct sshbuf *msg;
1.221 djm 360: struct sshkey *key = NULL;
1.195 djm 361: struct identity *id;
1.251 djm 362: struct notifier_ctx *notifier = NULL;
1.194 markus 363:
1.195 djm 364: if ((msg = sshbuf_new()) == NULL)
365: fatal("%s: sshbuf_new failed", __func__);
1.221 djm 366: if ((r = sshkey_froms(e->request, &key)) != 0 ||
367: (r = sshbuf_get_string_direct(e->request, &data, &dlen)) != 0 ||
1.225 djm 368: (r = sshbuf_get_u32(e->request, &flags)) != 0) {
369: error("%s: couldn't parse request: %s", __func__, ssh_err(r));
370: goto send;
371: }
372:
1.221 djm 373: if ((id = lookup_identity(key)) == NULL) {
1.195 djm 374: verbose("%s: %s key not found", __func__, sshkey_type(key));
375: goto send;
376: }
377: if (id->confirm && confirm_key(id) != 0) {
378: verbose("%s: user refused key", __func__);
379: goto send;
380: }
1.258 djm 381: if (sshkey_is_sk(id->key)) {
382: if (strncmp(id->key->sk_application, "ssh:", 4) != 0 &&
383: !check_websafe_message_contents(key, data, dlen)) {
384: /* error already logged */
385: goto send;
386: }
387: if ((id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD)) {
388: if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
389: SSH_FP_DEFAULT)) == NULL)
390: fatal("%s: fingerprint failed", __func__);
391: notifier = notify_start(0,
392: "Confirm user presence for key %s %s",
393: sshkey_type(id->key), fp);
394: }
1.251 djm 395: }
1.263 djm 396: /* XXX support PIN required FIDO keys */
1.251 djm 397: if ((r = sshkey_sign(id->key, &signature, &slen,
398: data, dlen, agent_decode_alg(key, flags),
1.263 djm 399: id->sk_provider, NULL, compat)) != 0) {
1.251 djm 400: error("%s: sshkey_sign: %s", __func__, ssh_err(r));
401: goto send;
1.33 markus 402: }
1.195 djm 403: /* Success */
404: ok = 0;
405: send:
1.251 djm 406: notify_complete(notifier);
1.195 djm 407: sshkey_free(key);
1.251 djm 408: free(fp);
1.33 markus 409: if (ok == 0) {
1.194 markus 410: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
411: (r = sshbuf_put_string(msg, signature, slen)) != 0)
412: fatal("%s: buffer error: %s", __func__, ssh_err(r));
413: } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
414: fatal("%s: buffer error: %s", __func__, ssh_err(r));
415:
416: if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
417: fatal("%s: buffer error: %s", __func__, ssh_err(r));
418:
419: sshbuf_free(msg);
1.173 djm 420: free(signature);
1.1 deraadt 421: }
422:
1.33 markus 423: /* shared */
1.55 itojun 424: static void
1.221 djm 425: process_remove_identity(SocketEntry *e)
1.1 deraadt 426: {
1.194 markus 427: int r, success = 0;
428: struct sshkey *key = NULL;
1.221 djm 429: Identity *id;
1.21 markus 430:
1.221 djm 431: if ((r = sshkey_froms(e->request, &key)) != 0) {
432: error("%s: get key: %s", __func__, ssh_err(r));
433: goto done;
434: }
435: if ((id = lookup_identity(key)) == NULL) {
436: debug("%s: key not found", __func__);
437: goto done;
438: }
439: /* We have this key, free it. */
440: if (idtab->nentries < 1)
441: fatal("%s: internal error: nentries %d",
442: __func__, idtab->nentries);
443: TAILQ_REMOVE(&idtab->idlist, id, next);
444: free_identity(id);
445: idtab->nentries--;
446: sshkey_free(key);
447: success = 1;
448: done:
1.194 markus 449: send_status(e, success);
1.1 deraadt 450: }
451:
1.55 itojun 452: static void
1.221 djm 453: process_remove_all_identities(SocketEntry *e)
1.1 deraadt 454: {
1.78 provos 455: Identity *id;
1.21 markus 456:
457: /* Loop over all identities and clear the keys. */
1.221 djm 458: for (id = TAILQ_FIRST(&idtab->idlist); id;
459: id = TAILQ_FIRST(&idtab->idlist)) {
460: TAILQ_REMOVE(&idtab->idlist, id, next);
1.78 provos 461: free_identity(id);
1.21 markus 462: }
463:
464: /* Mark that there are no identities. */
1.221 djm 465: idtab->nentries = 0;
1.21 markus 466:
467: /* Send success. */
1.194 markus 468: send_status(e, 1);
1.1 deraadt 469: }
470:
1.155 dtucker 471: /* removes expired keys and returns number of seconds until the next expiry */
1.174 dtucker 472: static time_t
1.89 markus 473: reaper(void)
474: {
1.175 dtucker 475: time_t deadline = 0, now = monotime();
1.89 markus 476: Identity *id, *nxt;
477:
1.221 djm 478: for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
479: nxt = TAILQ_NEXT(id, next);
480: if (id->death == 0)
481: continue;
482: if (now >= id->death) {
483: debug("expiring key '%s'", id->comment);
484: TAILQ_REMOVE(&idtab->idlist, id, next);
485: free_identity(id);
486: idtab->nentries--;
487: } else
488: deadline = (deadline == 0) ? id->death :
489: MINIMUM(deadline, id->death);
1.89 markus 490: }
1.155 dtucker 491: if (deadline == 0 || deadline <= now)
492: return 0;
493: else
494: return (deadline - now);
1.89 markus 495: }
496:
497: static void
1.221 djm 498: process_add_identity(SocketEntry *e)
1.1 deraadt 499: {
1.157 canacar 500: Identity *id;
1.194 markus 501: int success = 0, confirm = 0;
1.257 markus 502: u_int seconds = 0, maxsign;
1.238 djm 503: char *fp, *comment = NULL, *ext_name = NULL, *sk_provider = NULL;
1.254 djm 504: char canonical_provider[PATH_MAX];
1.174 dtucker 505: time_t death = 0;
1.194 markus 506: struct sshkey *k = NULL;
507: u_char ctype;
508: int r = SSH_ERR_INTERNAL_ERROR;
1.33 markus 509:
1.221 djm 510: if ((r = sshkey_private_deserialize(e->request, &k)) != 0 ||
511: k == NULL ||
1.194 markus 512: (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) {
513: error("%s: decode private key: %s", __func__, ssh_err(r));
514: goto err;
515: }
516: while (sshbuf_len(e->request)) {
517: if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) {
518: error("%s: buffer error: %s", __func__, ssh_err(r));
519: goto err;
520: }
521: switch (ctype) {
1.94 markus 522: case SSH_AGENT_CONSTRAIN_LIFETIME:
1.194 markus 523: if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) {
524: error("%s: bad lifetime constraint: %s",
525: __func__, ssh_err(r));
526: goto err;
527: }
528: death = monotime() + seconds;
1.94 markus 529: break;
1.107 markus 530: case SSH_AGENT_CONSTRAIN_CONFIRM:
531: confirm = 1;
532: break;
1.228 markus 533: case SSH_AGENT_CONSTRAIN_MAXSIGN:
534: if ((r = sshbuf_get_u32(e->request, &maxsign)) != 0) {
535: error("%s: bad maxsign constraint: %s",
536: __func__, ssh_err(r));
537: goto err;
538: }
539: if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) {
540: error("%s: cannot enable maxsign: %s",
541: __func__, ssh_err(r));
542: goto err;
543: }
544: break;
1.238 djm 545: case SSH_AGENT_CONSTRAIN_EXTENSION:
546: if ((r = sshbuf_get_cstring(e->request,
547: &ext_name, NULL)) != 0) {
548: error("%s: cannot parse extension: %s",
549: __func__, ssh_err(r));
550: goto err;
551: }
552: debug("%s: constraint ext %s", __func__, ext_name);
553: if (strcmp(ext_name, "sk-provider@openssh.com") == 0) {
554: if (sk_provider != NULL) {
555: error("%s already set", ext_name);
556: goto err;
557: }
558: if ((r = sshbuf_get_cstring(e->request,
559: &sk_provider, NULL)) != 0) {
560: error("%s: cannot parse %s: %s",
561: __func__, ext_name, ssh_err(r));
562: goto err;
563: }
564: } else {
565: error("%s: unsupported constraint \"%s\"",
566: __func__, ext_name);
567: goto err;
568: }
569: free(ext_name);
1.264.4.1! deraadt 570: ext_name = NULL;
1.238 djm 571: break;
1.94 markus 572: default:
1.194 markus 573: error("%s: Unknown constraint %d", __func__, ctype);
574: err:
1.238 djm 575: free(sk_provider);
576: free(ext_name);
1.194 markus 577: sshbuf_reset(e->request);
1.173 djm 578: free(comment);
1.194 markus 579: sshkey_free(k);
1.158 djm 580: goto send;
1.94 markus 581: }
582: }
1.238 djm 583: if (sk_provider != NULL) {
1.240 markus 584: if (!sshkey_is_sk(k)) {
1.255 naddy 585: error("Cannot add provider: %s is not an "
586: "authenticator-hosted key", sshkey_type(k));
1.238 djm 587: free(sk_provider);
588: goto send;
589: }
1.254 djm 590: if (strcasecmp(sk_provider, "internal") == 0) {
1.245 djm 591: debug("%s: internal provider", __func__);
1.254 djm 592: } else {
593: if (realpath(sk_provider, canonical_provider) == NULL) {
594: verbose("failed provider \"%.100s\": "
595: "realpath: %s", sk_provider,
596: strerror(errno));
597: free(sk_provider);
598: goto send;
599: }
1.238 djm 600: free(sk_provider);
1.254 djm 601: sk_provider = xstrdup(canonical_provider);
602: if (match_pattern_list(sk_provider,
1.260 djm 603: allowed_providers, 0) != 1) {
1.254 djm 604: error("Refusing add key: "
1.260 djm 605: "provider %s not allowed", sk_provider);
1.254 djm 606: free(sk_provider);
607: goto send;
608: }
1.238 djm 609: }
1.242 markus 610: }
611: if ((r = sshkey_shield_private(k)) != 0) {
612: error("%s: shield private key: %s", __func__, ssh_err(r));
613: goto err;
1.238 djm 614: }
1.194 markus 615:
1.158 djm 616: success = 1;
1.106 marc 617: if (lifetime && !death)
1.175 dtucker 618: death = monotime() + lifetime;
1.221 djm 619: if ((id = lookup_identity(k)) == NULL) {
1.163 markus 620: id = xcalloc(1, sizeof(Identity));
1.221 djm 621: TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
1.33 markus 622: /* Increment the number of identities. */
1.221 djm 623: idtab->nentries++;
1.33 markus 624: } else {
1.228 markus 625: /* key state might have been updated */
626: sshkey_free(id->key);
1.173 djm 627: free(id->comment);
1.238 djm 628: free(id->sk_provider);
1.33 markus 629: }
1.228 markus 630: id->key = k;
1.157 canacar 631: id->comment = comment;
632: id->death = death;
633: id->confirm = confirm;
1.238 djm 634: id->sk_provider = sk_provider;
635:
636: if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT,
637: SSH_FP_DEFAULT)) == NULL)
638: fatal("%s: sshkey_fingerprint failed", __func__);
639: debug("%s: add %s %s \"%.100s\" (life: %u) (confirm: %u) "
640: "(provider: %s)", __func__, sshkey_ssh_name(k), fp, comment,
641: seconds, confirm, sk_provider == NULL ? "none" : sk_provider);
642: free(fp);
1.33 markus 643: send:
1.194 markus 644: send_status(e, success);
1.1 deraadt 645: }
646:
1.88 markus 647: /* XXX todo: encrypt sensitive data with passphrase */
648: static void
649: process_lock_agent(SocketEntry *e, int lock)
650: {
1.203 dtucker 651: int r, success = 0, delay;
1.213 djm 652: char *passwd;
653: u_char passwdhash[LOCK_SIZE];
1.203 dtucker 654: static u_int fail_count = 0;
655: size_t pwlen;
656:
1.226 djm 657: /*
658: * This is deliberately fatal: the user has requested that we lock,
659: * but we can't parse their request properly. The only safe thing to
660: * do is abort.
661: */
1.203 dtucker 662: if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0)
663: fatal("%s: buffer error: %s", __func__, ssh_err(r));
664: if (pwlen == 0) {
665: debug("empty password not supported");
666: } else if (locked && !lock) {
667: if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
668: passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0)
669: fatal("bcrypt_pbkdf");
1.213 djm 670: if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) {
1.203 dtucker 671: debug("agent unlocked");
672: locked = 0;
673: fail_count = 0;
1.213 djm 674: explicit_bzero(lock_pwhash, sizeof(lock_pwhash));
1.203 dtucker 675: success = 1;
676: } else {
677: /* delay in 0.1s increments up to 10s */
678: if (fail_count < 100)
679: fail_count++;
680: delay = 100000 * fail_count;
681: debug("unlock failed, delaying %0.1lf seconds",
682: (double)delay/1000000);
683: usleep(delay);
684: }
685: explicit_bzero(passwdhash, sizeof(passwdhash));
1.88 markus 686: } else if (!locked && lock) {
1.203 dtucker 687: debug("agent locked");
1.88 markus 688: locked = 1;
1.203 dtucker 689: arc4random_buf(lock_salt, sizeof(lock_salt));
690: if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
1.213 djm 691: lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0)
1.203 dtucker 692: fatal("bcrypt_pbkdf");
1.88 markus 693: success = 1;
694: }
1.256 jsg 695: freezero(passwd, pwlen);
1.194 markus 696: send_status(e, success);
1.88 markus 697: }
698:
699: static void
1.221 djm 700: no_identities(SocketEntry *e)
1.88 markus 701: {
1.194 markus 702: struct sshbuf *msg;
703: int r;
1.88 markus 704:
1.194 markus 705: if ((msg = sshbuf_new()) == NULL)
706: fatal("%s: sshbuf_new failed", __func__);
1.221 djm 707: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
1.194 markus 708: (r = sshbuf_put_u32(msg, 0)) != 0 ||
709: (r = sshbuf_put_stringb(e->output, msg)) != 0)
710: fatal("%s: buffer error: %s", __func__, ssh_err(r));
711: sshbuf_free(msg);
1.88 markus 712: }
1.59 markus 713:
1.163 markus 714: #ifdef ENABLE_PKCS11
1.59 markus 715: static void
1.158 djm 716: process_add_smartcard_key(SocketEntry *e)
1.59 markus 717: {
1.226 djm 718: char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
1.253 djm 719: char **comments = NULL;
1.221 djm 720: int r, i, count = 0, success = 0, confirm = 0;
1.194 markus 721: u_int seconds;
1.174 dtucker 722: time_t death = 0;
1.194 markus 723: u_char type;
724: struct sshkey **keys = NULL, *k;
1.84 markus 725: Identity *id;
1.75 deraadt 726:
1.194 markus 727: if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
1.226 djm 728: (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
729: error("%s: buffer error: %s", __func__, ssh_err(r));
730: goto send;
731: }
1.194 markus 732:
733: while (sshbuf_len(e->request)) {
1.226 djm 734: if ((r = sshbuf_get_u8(e->request, &type)) != 0) {
735: error("%s: buffer error: %s", __func__, ssh_err(r));
736: goto send;
737: }
1.194 markus 738: switch (type) {
1.110 djm 739: case SSH_AGENT_CONSTRAIN_LIFETIME:
1.226 djm 740: if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) {
741: error("%s: buffer error: %s",
1.194 markus 742: __func__, ssh_err(r));
1.226 djm 743: goto send;
744: }
1.194 markus 745: death = monotime() + seconds;
1.110 djm 746: break;
747: case SSH_AGENT_CONSTRAIN_CONFIRM:
748: confirm = 1;
749: break;
750: default:
1.221 djm 751: error("%s: Unknown constraint type %d", __func__, type);
1.158 djm 752: goto send;
1.110 djm 753: }
754: }
1.215 djm 755: if (realpath(provider, canonical_provider) == NULL) {
756: verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
757: provider, strerror(errno));
758: goto send;
759: }
1.260 djm 760: if (match_pattern_list(canonical_provider, allowed_providers, 0) != 1) {
1.215 djm 761: verbose("refusing PKCS#11 add of \"%.100s\": "
1.260 djm 762: "provider not allowed", canonical_provider);
1.215 djm 763: goto send;
764: }
765: debug("%s: add %.100s", __func__, canonical_provider);
1.110 djm 766: if (lifetime && !death)
1.175 dtucker 767: death = monotime() + lifetime;
1.110 djm 768:
1.253 djm 769: count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments);
1.163 markus 770: for (i = 0; i < count; i++) {
1.84 markus 771: k = keys[i];
1.221 djm 772: if (lookup_identity(k) == NULL) {
1.163 markus 773: id = xcalloc(1, sizeof(Identity));
1.84 markus 774: id->key = k;
1.253 djm 775: keys[i] = NULL; /* transferred */
1.215 djm 776: id->provider = xstrdup(canonical_provider);
1.253 djm 777: if (*comments[i] != '\0') {
778: id->comment = comments[i];
779: comments[i] = NULL; /* transferred */
780: } else {
781: id->comment = xstrdup(canonical_provider);
782: }
1.110 djm 783: id->death = death;
784: id->confirm = confirm;
1.221 djm 785: TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
786: idtab->nentries++;
1.84 markus 787: success = 1;
788: }
1.253 djm 789: sshkey_free(keys[i]);
790: free(comments[i]);
1.59 markus 791: }
792: send:
1.173 djm 793: free(pin);
794: free(provider);
795: free(keys);
1.253 djm 796: free(comments);
1.194 markus 797: send_status(e, success);
1.59 markus 798: }
799:
800: static void
801: process_remove_smartcard_key(SocketEntry *e)
802: {
1.217 djm 803: char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
1.221 djm 804: int r, success = 0;
1.163 markus 805: Identity *id, *nxt;
1.59 markus 806:
1.194 markus 807: if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
1.226 djm 808: (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
809: error("%s: buffer error: %s", __func__, ssh_err(r));
810: goto send;
811: }
1.173 djm 812: free(pin);
1.59 markus 813:
1.217 djm 814: if (realpath(provider, canonical_provider) == NULL) {
815: verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
816: provider, strerror(errno));
817: goto send;
818: }
819:
820: debug("%s: remove %.100s", __func__, canonical_provider);
1.221 djm 821: for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
822: nxt = TAILQ_NEXT(id, next);
823: /* Skip file--based keys */
824: if (id->provider == NULL)
825: continue;
826: if (!strcmp(canonical_provider, id->provider)) {
827: TAILQ_REMOVE(&idtab->idlist, id, next);
828: free_identity(id);
829: idtab->nentries--;
1.59 markus 830: }
831: }
1.217 djm 832: if (pkcs11_del_provider(canonical_provider) == 0)
1.163 markus 833: success = 1;
834: else
1.221 djm 835: error("%s: pkcs11_del_provider failed", __func__);
1.218 deraadt 836: send:
1.173 djm 837: free(provider);
1.194 markus 838: send_status(e, success);
1.59 markus 839: }
1.163 markus 840: #endif /* ENABLE_PKCS11 */
1.59 markus 841:
1.264 djm 842: /*
843: * dispatch incoming message.
844: * returns 1 on success, 0 for incomplete messages or -1 on error.
845: */
1.223 djm 846: static int
847: process_message(u_int socknum)
1.1 deraadt 848: {
1.194 markus 849: u_int msg_len;
850: u_char type;
851: const u_char *cp;
852: int r;
1.223 djm 853: SocketEntry *e;
854:
855: if (socknum >= sockets_alloc) {
856: fatal("%s: socket number %u >= allocated %u",
857: __func__, socknum, sockets_alloc);
858: }
859: e = &sockets[socknum];
1.89 markus 860:
1.194 markus 861: if (sshbuf_len(e->input) < 5)
1.223 djm 862: return 0; /* Incomplete message header. */
1.194 markus 863: cp = sshbuf_ptr(e->input);
864: msg_len = PEEK_U32(cp);
1.223 djm 865: if (msg_len > AGENT_MAX_LEN) {
866: debug("%s: socket %u (fd=%d) message too long %u > %u",
867: __func__, socknum, e->fd, msg_len, AGENT_MAX_LEN);
868: return -1;
1.21 markus 869: }
1.194 markus 870: if (sshbuf_len(e->input) < msg_len + 4)
1.223 djm 871: return 0; /* Incomplete message body. */
1.87 markus 872:
873: /* move the current input to e->request */
1.194 markus 874: sshbuf_reset(e->request);
875: if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 ||
1.223 djm 876: (r = sshbuf_get_u8(e->request, &type)) != 0) {
877: if (r == SSH_ERR_MESSAGE_INCOMPLETE ||
878: r == SSH_ERR_STRING_TOO_LARGE) {
879: debug("%s: buffer error: %s", __func__, ssh_err(r));
880: return -1;
881: }
1.194 markus 882: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.223 djm 883: }
884:
885: debug("%s: socket %u (fd=%d) type %d", __func__, socknum, e->fd, type);
1.21 markus 886:
1.230 djm 887: /* check whether agent is locked */
1.88 markus 888: if (locked && type != SSH_AGENTC_UNLOCK) {
1.194 markus 889: sshbuf_reset(e->request);
1.88 markus 890: switch (type) {
891: case SSH2_AGENTC_REQUEST_IDENTITIES:
892: /* send empty lists */
1.221 djm 893: no_identities(e);
1.88 markus 894: break;
895: default:
896: /* send a fail message for all other request types */
1.194 markus 897: send_status(e, 0);
1.88 markus 898: }
1.264 djm 899: return 1;
1.88 markus 900: }
901:
1.21 markus 902: switch (type) {
1.88 markus 903: case SSH_AGENTC_LOCK:
904: case SSH_AGENTC_UNLOCK:
905: process_lock_agent(e, type == SSH_AGENTC_LOCK);
906: break;
1.21 markus 907: case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
1.221 djm 908: process_remove_all_identities(e); /* safe for !WITH_SSH1 */
1.33 markus 909: break;
910: /* ssh2 */
911: case SSH2_AGENTC_SIGN_REQUEST:
912: process_sign_request2(e);
913: break;
914: case SSH2_AGENTC_REQUEST_IDENTITIES:
1.221 djm 915: process_request_identities(e);
1.33 markus 916: break;
917: case SSH2_AGENTC_ADD_IDENTITY:
1.94 markus 918: case SSH2_AGENTC_ADD_ID_CONSTRAINED:
1.221 djm 919: process_add_identity(e);
1.33 markus 920: break;
921: case SSH2_AGENTC_REMOVE_IDENTITY:
1.221 djm 922: process_remove_identity(e);
1.33 markus 923: break;
924: case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
1.221 djm 925: process_remove_all_identities(e);
1.21 markus 926: break;
1.163 markus 927: #ifdef ENABLE_PKCS11
1.59 markus 928: case SSH_AGENTC_ADD_SMARTCARD_KEY:
1.110 djm 929: case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
1.59 markus 930: process_add_smartcard_key(e);
1.75 deraadt 931: break;
1.59 markus 932: case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
933: process_remove_smartcard_key(e);
1.75 deraadt 934: break;
1.163 markus 935: #endif /* ENABLE_PKCS11 */
1.21 markus 936: default:
937: /* Unknown message. Respond with failure. */
938: error("Unknown message %d", type);
1.194 markus 939: sshbuf_reset(e->request);
940: send_status(e, 0);
1.21 markus 941: break;
942: }
1.264 djm 943: return 1;
1.1 deraadt 944: }
945:
1.55 itojun 946: static void
1.73 stevesk 947: new_socket(sock_type type, int fd)
1.1 deraadt 948: {
1.112 markus 949: u_int i, old_alloc, new_alloc;
1.96 deraadt 950:
1.119 djm 951: set_nonblock(fd);
1.21 markus 952:
953: if (fd > max_fd)
954: max_fd = fd;
955:
956: for (i = 0; i < sockets_alloc; i++)
957: if (sockets[i].type == AUTH_UNUSED) {
958: sockets[i].fd = fd;
1.194 markus 959: if ((sockets[i].input = sshbuf_new()) == NULL)
960: fatal("%s: sshbuf_new failed", __func__);
961: if ((sockets[i].output = sshbuf_new()) == NULL)
962: fatal("%s: sshbuf_new failed", __func__);
963: if ((sockets[i].request = sshbuf_new()) == NULL)
964: fatal("%s: sshbuf_new failed", __func__);
1.112 markus 965: sockets[i].type = type;
1.21 markus 966: return;
967: }
968: old_alloc = sockets_alloc;
1.112 markus 969: new_alloc = sockets_alloc + 10;
1.200 deraadt 970: sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0]));
1.112 markus 971: for (i = old_alloc; i < new_alloc; i++)
1.21 markus 972: sockets[i].type = AUTH_UNUSED;
1.112 markus 973: sockets_alloc = new_alloc;
1.21 markus 974: sockets[old_alloc].fd = fd;
1.194 markus 975: if ((sockets[old_alloc].input = sshbuf_new()) == NULL)
976: fatal("%s: sshbuf_new failed", __func__);
977: if ((sockets[old_alloc].output = sshbuf_new()) == NULL)
978: fatal("%s: sshbuf_new failed", __func__);
979: if ((sockets[old_alloc].request = sshbuf_new()) == NULL)
980: fatal("%s: sshbuf_new failed", __func__);
1.112 markus 981: sockets[old_alloc].type = type;
1.1 deraadt 982: }
983:
1.55 itojun 984: static int
1.223 djm 985: handle_socket_read(u_int socknum)
1.1 deraadt 986: {
1.223 djm 987: struct sockaddr_un sunaddr;
988: socklen_t slen;
989: uid_t euid;
990: gid_t egid;
991: int fd;
992:
993: slen = sizeof(sunaddr);
994: fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen);
1.237 deraadt 995: if (fd == -1) {
1.223 djm 996: error("accept from AUTH_SOCKET: %s", strerror(errno));
997: return -1;
998: }
1.237 deraadt 999: if (getpeereid(fd, &euid, &egid) == -1) {
1.223 djm 1000: error("getpeereid %d failed: %s", fd, strerror(errno));
1001: close(fd);
1002: return -1;
1003: }
1004: if ((euid != 0) && (getuid() != euid)) {
1005: error("uid mismatch: peer euid %u != uid %u",
1006: (u_int) euid, (u_int) getuid());
1007: close(fd);
1008: return -1;
1009: }
1010: new_socket(AUTH_CONNECTION, fd);
1011: return 0;
1012: }
1013:
1014: static int
1015: handle_conn_read(u_int socknum)
1016: {
1.233 djm 1017: char buf[AGENT_RBUF_LEN];
1.223 djm 1018: ssize_t len;
1019: int r;
1020:
1021: if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) {
1022: if (len == -1) {
1023: if (errno == EAGAIN || errno == EINTR)
1024: return 0;
1025: error("%s: read error on socket %u (fd %d): %s",
1026: __func__, socknum, sockets[socknum].fd,
1027: strerror(errno));
1028: }
1029: return -1;
1030: }
1031: if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0)
1032: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1033: explicit_bzero(buf, sizeof(buf));
1.264 djm 1034: for (;;) {
1035: if ((r = process_message(socknum)) == -1)
1036: return -1;
1037: else if (r == 0)
1038: break;
1039: }
1.223 djm 1040: return 0;
1041: }
1042:
1043: static int
1044: handle_conn_write(u_int socknum)
1045: {
1046: ssize_t len;
1047: int r;
1048:
1049: if (sshbuf_len(sockets[socknum].output) == 0)
1050: return 0; /* shouldn't happen */
1051: if ((len = write(sockets[socknum].fd,
1052: sshbuf_ptr(sockets[socknum].output),
1053: sshbuf_len(sockets[socknum].output))) <= 0) {
1054: if (len == -1) {
1055: if (errno == EAGAIN || errno == EINTR)
1056: return 0;
1057: error("%s: read error on socket %u (fd %d): %s",
1058: __func__, socknum, sockets[socknum].fd,
1059: strerror(errno));
1060: }
1061: return -1;
1062: }
1063: if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0)
1064: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1065: return 0;
1066: }
1067:
1068: static void
1.231 djm 1069: after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds)
1.223 djm 1070: {
1071: size_t i;
1.231 djm 1072: u_int socknum, activefds = npfd;
1.223 djm 1073:
1074: for (i = 0; i < npfd; i++) {
1075: if (pfd[i].revents == 0)
1076: continue;
1077: /* Find sockets entry */
1078: for (socknum = 0; socknum < sockets_alloc; socknum++) {
1079: if (sockets[socknum].type != AUTH_SOCKET &&
1080: sockets[socknum].type != AUTH_CONNECTION)
1081: continue;
1082: if (pfd[i].fd == sockets[socknum].fd)
1083: break;
1084: }
1085: if (socknum >= sockets_alloc) {
1086: error("%s: no socket for fd %d", __func__, pfd[i].fd);
1087: continue;
1088: }
1089: /* Process events */
1090: switch (sockets[socknum].type) {
1091: case AUTH_SOCKET:
1.231 djm 1092: if ((pfd[i].revents & (POLLIN|POLLERR)) == 0)
1093: break;
1094: if (npfd > maxfds) {
1095: debug3("out of fds (active %u >= limit %u); "
1096: "skipping accept", activefds, maxfds);
1097: break;
1098: }
1099: if (handle_socket_read(socknum) == 0)
1100: activefds++;
1.223 djm 1101: break;
1102: case AUTH_CONNECTION:
1103: if ((pfd[i].revents & (POLLIN|POLLERR)) != 0 &&
1104: handle_conn_read(socknum) != 0) {
1.231 djm 1105: goto close_sock;
1106: }
1107: if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 &&
1108: handle_conn_write(socknum) != 0) {
1109: close_sock:
1110: if (activefds == 0)
1111: fatal("activefds == 0 at close_sock");
1.223 djm 1112: close_socket(&sockets[socknum]);
1.231 djm 1113: activefds--;
1.223 djm 1114: break;
1115: }
1116: break;
1117: default:
1118: break;
1119: }
1120: }
1121: }
1122:
1123: static int
1.231 djm 1124: prepare_poll(struct pollfd **pfdp, size_t *npfdp, int *timeoutp, u_int maxfds)
1.223 djm 1125: {
1126: struct pollfd *pfd = *pfdp;
1127: size_t i, j, npfd = 0;
1.174 dtucker 1128: time_t deadline;
1.233 djm 1129: int r;
1.46 markus 1130:
1.223 djm 1131: /* Count active sockets */
1.46 markus 1132: for (i = 0; i < sockets_alloc; i++) {
1.21 markus 1133: switch (sockets[i].type) {
1134: case AUTH_SOCKET:
1135: case AUTH_CONNECTION:
1.223 djm 1136: npfd++;
1.21 markus 1137: break;
1138: case AUTH_UNUSED:
1139: break;
1140: default:
1141: fatal("Unknown socket type %d", sockets[i].type);
1142: break;
1143: }
1.46 markus 1144: }
1.223 djm 1145: if (npfd != *npfdp &&
1146: (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL)
1147: fatal("%s: recallocarray failed", __func__);
1148: *pfdp = pfd;
1149: *npfdp = npfd;
1.46 markus 1150:
1.223 djm 1151: for (i = j = 0; i < sockets_alloc; i++) {
1.46 markus 1152: switch (sockets[i].type) {
1153: case AUTH_SOCKET:
1.231 djm 1154: if (npfd > maxfds) {
1155: debug3("out of fds (active %zu >= limit %u); "
1156: "skipping arming listener", npfd, maxfds);
1157: break;
1158: }
1159: pfd[j].fd = sockets[i].fd;
1160: pfd[j].revents = 0;
1161: pfd[j].events = POLLIN;
1162: j++;
1163: break;
1.46 markus 1164: case AUTH_CONNECTION:
1.223 djm 1165: pfd[j].fd = sockets[i].fd;
1166: pfd[j].revents = 0;
1.233 djm 1167: /*
1168: * Only prepare to read if we can handle a full-size
1169: * input read buffer and enqueue a max size reply..
1170: */
1171: if ((r = sshbuf_check_reserve(sockets[i].input,
1172: AGENT_RBUF_LEN)) == 0 &&
1173: (r = sshbuf_check_reserve(sockets[i].output,
1174: AGENT_MAX_LEN)) == 0)
1175: pfd[j].events = POLLIN;
1176: else if (r != SSH_ERR_NO_BUFFER_SPACE) {
1177: fatal("%s: buffer error: %s",
1178: __func__, ssh_err(r));
1179: }
1.194 markus 1180: if (sshbuf_len(sockets[i].output) > 0)
1.223 djm 1181: pfd[j].events |= POLLOUT;
1182: j++;
1.46 markus 1183: break;
1184: default:
1185: break;
1186: }
1187: }
1.155 dtucker 1188: deadline = reaper();
1189: if (parent_alive_interval != 0)
1190: deadline = (deadline == 0) ? parent_alive_interval :
1.214 deraadt 1191: MINIMUM(deadline, parent_alive_interval);
1.155 dtucker 1192: if (deadline == 0) {
1.224 djm 1193: *timeoutp = -1; /* INFTIM */
1.155 dtucker 1194: } else {
1.223 djm 1195: if (deadline > INT_MAX / 1000)
1196: *timeoutp = INT_MAX / 1000;
1197: else
1198: *timeoutp = deadline * 1000;
1.155 dtucker 1199: }
1.46 markus 1200: return (1);
1.21 markus 1201: }
1202:
1.55 itojun 1203: static void
1.113 markus 1204: cleanup_socket(void)
1.15 markus 1205: {
1.187 djm 1206: if (cleanup_pid != 0 && getpid() != cleanup_pid)
1207: return;
1208: debug("%s: cleanup", __func__);
1.48 deraadt 1209: if (socket_name[0])
1210: unlink(socket_name);
1211: if (socket_dir[0])
1212: rmdir(socket_dir);
1.10 markus 1213: }
1214:
1.114 markus 1215: void
1.15 markus 1216: cleanup_exit(int i)
1217: {
1.113 markus 1218: cleanup_socket();
1219: _exit(i);
1.15 markus 1220: }
1221:
1.135 deraadt 1222: /*ARGSUSED*/
1.55 itojun 1223: static void
1.48 deraadt 1224: cleanup_handler(int sig)
1225: {
1.113 markus 1226: cleanup_socket();
1.163 markus 1227: #ifdef ENABLE_PKCS11
1228: pkcs11_terminate();
1229: #endif
1.48 deraadt 1230: _exit(2);
1.113 markus 1231: }
1232:
1.68 markus 1233: static void
1.155 dtucker 1234: check_parent_exists(void)
1.68 markus 1235: {
1.172 dtucker 1236: /*
1237: * If our parent has exited then getppid() will return (pid_t)1,
1238: * so testing for that should be safe.
1239: */
1240: if (parent_pid != -1 && getppid() != parent_pid) {
1.68 markus 1241: /* printf("Parent has died - Authentication agent exiting.\n"); */
1.155 dtucker 1242: cleanup_socket();
1243: _exit(2);
1.68 markus 1244: }
1.48 deraadt 1245: }
1246:
1.55 itojun 1247: static void
1.50 itojun 1248: usage(void)
1.15 markus 1249: {
1.184 deraadt 1250: fprintf(stderr,
1.250 jmc 1251: "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n"
1.261 jmc 1252: " [-P allowed_providers] [-t life]\n"
1.260 djm 1253: " ssh-agent [-a bind_address] [-E fingerprint_hash] [-P allowed_providers]\n"
1.259 dtucker 1254: " [-t life] command [arg ...]\n"
1.250 jmc 1255: " ssh-agent [-c | -s] -k\n");
1.21 markus 1256: exit(1);
1.15 markus 1257: }
1258:
1.2 provos 1259: int
1260: main(int ac, char **av)
1.1 deraadt 1261: {
1.201 djm 1262: int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0;
1.154 dtucker 1263: int sock, fd, ch, result, saved_errno;
1.96 deraadt 1264: char *shell, *format, *pidstr, *agentsocket = NULL;
1.41 markus 1265: struct rlimit rlim;
1.96 deraadt 1266: extern int optind;
1.98 stevesk 1267: extern char *optarg;
1.21 markus 1268: pid_t pid;
1.96 deraadt 1269: char pidstrbuf[1 + 3 * sizeof pid];
1.161 tobias 1270: size_t len;
1.189 djm 1271: mode_t prev_mask;
1.224 djm 1272: int timeout = -1; /* INFTIM */
1.223 djm 1273: struct pollfd *pfd = NULL;
1274: size_t npfd = 0;
1.231 djm 1275: u_int maxfds;
1.123 djm 1276:
1277: /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1278: sanitise_stdfd();
1.99 markus 1279:
1280: /* drop */
1281: setegid(getgid());
1282: setgid(getgid());
1.53 markus 1283:
1.231 djm 1284: if (getrlimit(RLIMIT_NOFILE, &rlim) == -1)
1285: fatal("%s: getrlimit: %s", __progname, strerror(errno));
1286:
1.185 markus 1287: #ifdef WITH_OPENSSL
1.170 djm 1288: OpenSSL_add_all_algorithms();
1.185 markus 1289: #endif
1.21 markus 1290:
1.258 djm 1291: while ((ch = getopt(ac, av, "cDdksE:a:O:P:t:")) != -1) {
1.21 markus 1292: switch (ch) {
1.192 djm 1293: case 'E':
1294: fingerprint_hash = ssh_digest_alg_by_name(optarg);
1295: if (fingerprint_hash == -1)
1296: fatal("Invalid hash algorithm \"%s\"", optarg);
1297: break;
1.21 markus 1298: case 'c':
1299: if (s_flag)
1300: usage();
1301: c_flag++;
1302: break;
1303: case 'k':
1304: k_flag++;
1.258 djm 1305: break;
1306: case 'O':
1307: if (strcmp(optarg, "no-restrict-websafe") == 0)
1308: restrict_websafe = 0;
1309: else
1310: fatal("Unknown -O option");
1.21 markus 1311: break;
1.215 djm 1312: case 'P':
1.260 djm 1313: if (allowed_providers != NULL)
1.215 djm 1314: fatal("-P option already specified");
1.260 djm 1315: allowed_providers = xstrdup(optarg);
1.215 djm 1316: break;
1.21 markus 1317: case 's':
1318: if (c_flag)
1319: usage();
1320: s_flag++;
1321: break;
1.57 markus 1322: case 'd':
1.201 djm 1323: if (d_flag || D_flag)
1.57 markus 1324: usage();
1325: d_flag++;
1326: break;
1.201 djm 1327: case 'D':
1328: if (d_flag || D_flag)
1329: usage();
1330: D_flag++;
1331: break;
1.86 markus 1332: case 'a':
1333: agentsocket = optarg;
1.106 marc 1334: break;
1335: case 't':
1336: if ((lifetime = convtime(optarg)) == -1) {
1337: fprintf(stderr, "Invalid lifetime\n");
1338: usage();
1339: }
1.86 markus 1340: break;
1.21 markus 1341: default:
1342: usage();
1343: }
1344: }
1345: ac -= optind;
1346: av += optind;
1347:
1.201 djm 1348: if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag))
1.21 markus 1349: usage();
1350:
1.260 djm 1351: if (allowed_providers == NULL)
1.262 djm 1352: allowed_providers = xstrdup(DEFAULT_ALLOWED_PROVIDERS);
1.215 djm 1353:
1.85 markus 1354: if (ac == 0 && !c_flag && !s_flag) {
1.21 markus 1355: shell = getenv("SHELL");
1.161 tobias 1356: if (shell != NULL && (len = strlen(shell)) > 2 &&
1357: strncmp(shell + len - 3, "csh", 3) == 0)
1.21 markus 1358: c_flag = 1;
1359: }
1360: if (k_flag) {
1.136 deraadt 1361: const char *errstr = NULL;
1362:
1.21 markus 1363: pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1364: if (pidstr == NULL) {
1365: fprintf(stderr, "%s not set, cannot kill agent\n",
1.46 markus 1366: SSH_AGENTPID_ENV_NAME);
1.21 markus 1367: exit(1);
1368: }
1.136 deraadt 1369: pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1370: if (errstr) {
1371: fprintf(stderr,
1372: "%s=\"%s\", which is not a good PID: %s\n",
1373: SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1.21 markus 1374: exit(1);
1375: }
1376: if (kill(pid, SIGTERM) == -1) {
1377: perror("kill");
1378: exit(1);
1379: }
1380: format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1.140 djm 1381: printf(format, SSH_AUTHSOCKET_ENV_NAME);
1382: printf(format, SSH_AGENTPID_ENV_NAME);
1.91 mpech 1383: printf("echo Agent pid %ld killed;\n", (long)pid);
1.21 markus 1384: exit(0);
1385: }
1.231 djm 1386:
1387: /*
1388: * Minimum file descriptors:
1389: * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) +
1390: * a few spare for libc / stack protectors / sanitisers, etc.
1391: */
1392: #define SSH_AGENT_MIN_FDS (3+1+1+1+4)
1393: if (rlim.rlim_cur < SSH_AGENT_MIN_FDS)
1.232 djm 1394: fatal("%s: file descriptor rlimit %lld too low (minimum %u)",
1.231 djm 1395: __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS);
1396: maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS;
1397:
1.21 markus 1398: parent_pid = getpid();
1399:
1.86 markus 1400: if (agentsocket == NULL) {
1401: /* Create private directory for agent socket */
1.171 djm 1402: mktemp_proto(socket_dir, sizeof(socket_dir));
1.86 markus 1403: if (mkdtemp(socket_dir) == NULL) {
1404: perror("mkdtemp: private socket dir");
1405: exit(1);
1406: }
1.91 mpech 1407: snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1408: (long)parent_pid);
1.86 markus 1409: } else {
1410: /* Try to use specified agent socket */
1411: socket_dir[0] = '\0';
1412: strlcpy(socket_name, agentsocket, sizeof socket_name);
1.21 markus 1413: }
1414:
1.23 markus 1415: /*
1416: * Create socket early so it will exist before command gets run from
1417: * the parent.
1418: */
1.189 djm 1419: prev_mask = umask(0177);
1.188 millert 1420: sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0);
1.21 markus 1421: if (sock < 0) {
1.188 millert 1422: /* XXX - unix_listener() calls error() not perror() */
1.121 djm 1423: *socket_name = '\0'; /* Don't unlink any existing file */
1.21 markus 1424: cleanup_exit(1);
1425: }
1.189 djm 1426: umask(prev_mask);
1.46 markus 1427:
1.23 markus 1428: /*
1429: * Fork, and have the parent execute the command, if any, or present
1430: * the socket data. The child continues as the authentication agent.
1431: */
1.201 djm 1432: if (D_flag || d_flag) {
1433: log_init(__progname,
1434: d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO,
1435: SYSLOG_FACILITY_AUTH, 1);
1.57 markus 1436: format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1437: printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1438: SSH_AUTHSOCKET_ENV_NAME);
1.91 mpech 1439: printf("echo Agent pid %ld;\n", (long)parent_pid);
1.210 dtucker 1440: fflush(stdout);
1.57 markus 1441: goto skip;
1442: }
1.21 markus 1443: pid = fork();
1444: if (pid == -1) {
1445: perror("fork");
1.81 stevesk 1446: cleanup_exit(1);
1.21 markus 1447: }
1448: if (pid != 0) { /* Parent - execute the given command. */
1449: close(sock);
1.91 mpech 1450: snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1.21 markus 1451: if (ac == 0) {
1452: format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1453: printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1.46 markus 1454: SSH_AUTHSOCKET_ENV_NAME);
1.21 markus 1455: printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1.46 markus 1456: SSH_AGENTPID_ENV_NAME);
1.91 mpech 1457: printf("echo Agent pid %ld;\n", (long)pid);
1.21 markus 1458: exit(0);
1459: }
1.36 deraadt 1460: if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1461: setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1462: perror("setenv");
1463: exit(1);
1464: }
1.21 markus 1465: execvp(av[0], av);
1466: perror(av[0]);
1467: exit(1);
1468: }
1.81 stevesk 1469: /* child */
1470: log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1.67 stevesk 1471:
1472: if (setsid() == -1) {
1.81 stevesk 1473: error("setsid: %s", strerror(errno));
1.67 stevesk 1474: cleanup_exit(1);
1475: }
1476:
1477: (void)chdir("/");
1.107 markus 1478: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1479: /* XXX might close listen socket */
1480: (void)dup2(fd, STDIN_FILENO);
1481: (void)dup2(fd, STDOUT_FILENO);
1482: (void)dup2(fd, STDERR_FILENO);
1483: if (fd > 2)
1484: close(fd);
1485: }
1.21 markus 1486:
1.41 markus 1487: /* deny core dumps, since memory contains unencrypted private keys */
1488: rlim.rlim_cur = rlim.rlim_max = 0;
1.237 deraadt 1489: if (setrlimit(RLIMIT_CORE, &rlim) == -1) {
1.81 stevesk 1490: error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1.21 markus 1491: cleanup_exit(1);
1492: }
1.57 markus 1493:
1494: skip:
1.187 djm 1495:
1496: cleanup_pid = getpid();
1.163 markus 1497:
1498: #ifdef ENABLE_PKCS11
1499: pkcs11_init(0);
1500: #endif
1.21 markus 1501: new_socket(AUTH_SOCKET, sock);
1.155 dtucker 1502: if (ac > 0)
1503: parent_alive_interval = 10;
1.33 markus 1504: idtab_init();
1.252 dtucker 1505: ssh_signal(SIGPIPE, SIG_IGN);
1506: ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN);
1507: ssh_signal(SIGHUP, cleanup_handler);
1508: ssh_signal(SIGTERM, cleanup_handler);
1.205 djm 1509:
1.215 djm 1510: if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1)
1.205 djm 1511: fatal("%s: pledge: %s", __progname, strerror(errno));
1.66 markus 1512:
1.21 markus 1513: while (1) {
1.231 djm 1514: prepare_poll(&pfd, &npfd, &timeout, maxfds);
1.223 djm 1515: result = poll(pfd, npfd, timeout);
1.154 dtucker 1516: saved_errno = errno;
1.155 dtucker 1517: if (parent_alive_interval != 0)
1518: check_parent_exists();
1519: (void) reaper(); /* remove expired keys */
1.237 deraadt 1520: if (result == -1) {
1.154 dtucker 1521: if (saved_errno == EINTR)
1.21 markus 1522: continue;
1.223 djm 1523: fatal("poll: %s", strerror(saved_errno));
1.154 dtucker 1524: } else if (result > 0)
1.231 djm 1525: after_poll(pfd, npfd, maxfds);
1.15 markus 1526: }
1.21 markus 1527: /* NOTREACHED */
1.1 deraadt 1528: }
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