Annotation of src/usr.bin/ssh/ssh-agent.c, Revision 1.278
1.278 ! djm 1: /* $OpenBSD: ssh-agent.c,v 1.277 2021/02/12 03:14:18 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 {
1.275 djm 92: AUTH_UNUSED = 0,
93: AUTH_SOCKET = 1,
94: AUTH_CONNECTION = 2,
1.73 stevesk 95: } sock_type;
96:
1.274 djm 97: typedef struct socket_entry {
1.21 markus 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) */
1.268 dtucker 153: static int 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);
1.194 markus 164: sshbuf_free(e->input);
165: sshbuf_free(e->output);
166: sshbuf_free(e->request);
1.269 djm 167: memset(e, '\0', sizeof(*e));
168: e->fd = -1;
169: e->type = AUTH_UNUSED;
1.101 stevesk 170: }
171:
172: static void
1.33 markus 173: idtab_init(void)
1.1 deraadt 174: {
1.221 djm 175: idtab = xcalloc(1, sizeof(*idtab));
176: TAILQ_INIT(&idtab->idlist);
177: idtab->nentries = 0;
1.33 markus 178: }
179:
1.89 markus 180: static void
181: free_identity(Identity *id)
182: {
1.194 markus 183: sshkey_free(id->key);
1.173 djm 184: free(id->provider);
185: free(id->comment);
1.238 djm 186: free(id->sk_provider);
1.173 djm 187: free(id);
1.89 markus 188: }
189:
1.33 markus 190: /* return matching private key for given public key */
1.78 provos 191: static Identity *
1.221 djm 192: lookup_identity(struct sshkey *key)
1.33 markus 193: {
1.78 provos 194: Identity *id;
195:
1.221 djm 196: TAILQ_FOREACH(id, &idtab->idlist, next) {
1.194 markus 197: if (sshkey_equal(key, id->key))
1.78 provos 198: return (id);
1.33 markus 199: }
1.78 provos 200: return (NULL);
201: }
202:
1.107 markus 203: /* Check confirmation of keysign request */
204: static int
1.270 djm 205: confirm_key(Identity *id, const char *extra)
1.107 markus 206: {
1.122 djm 207: char *p;
1.107 markus 208: int ret = -1;
209:
1.194 markus 210: p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT);
1.197 djm 211: if (p != NULL &&
1.270 djm 212: ask_permission("Allow use of key %s?\nKey fingerprint %s.%s%s",
213: id->comment, p,
214: extra == NULL ? "" : "\n", extra == NULL ? "" : extra))
1.122 djm 215: ret = 0;
1.173 djm 216: free(p);
1.122 djm 217:
1.107 markus 218: return (ret);
219: }
220:
1.194 markus 221: static void
222: send_status(SocketEntry *e, int success)
223: {
224: int r;
225:
226: if ((r = sshbuf_put_u32(e->output, 1)) != 0 ||
227: (r = sshbuf_put_u8(e->output, success ?
228: SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
1.266 djm 229: fatal_fr(r, "compose");
1.194 markus 230: }
231:
1.33 markus 232: /* send list of supported public keys to 'client' */
1.55 itojun 233: static void
1.221 djm 234: process_request_identities(SocketEntry *e)
1.33 markus 235: {
1.96 deraadt 236: Identity *id;
1.194 markus 237: struct sshbuf *msg;
238: int r;
1.1 deraadt 239:
1.269 djm 240: debug2_f("entering");
241:
1.194 markus 242: if ((msg = sshbuf_new()) == NULL)
1.266 djm 243: fatal_f("sshbuf_new failed");
1.221 djm 244: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
245: (r = sshbuf_put_u32(msg, idtab->nentries)) != 0)
1.266 djm 246: fatal_fr(r, "compose");
1.221 djm 247: TAILQ_FOREACH(id, &idtab->idlist, next) {
1.278 ! djm 248: if ((r = sshkey_puts_opts(id->key, msg,
! 249: SSHKEY_SERIALIZE_INFO)) != 0 ||
1.221 djm 250: (r = sshbuf_put_cstring(msg, id->comment)) != 0) {
1.266 djm 251: error_fr(r, "compose key/comment");
1.220 djm 252: continue;
1.33 markus 253: }
1.21 markus 254: }
1.194 markus 255: if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
1.266 djm 256: fatal_fr(r, "enqueue");
1.194 markus 257: sshbuf_free(msg);
1.1 deraadt 258: }
259:
1.33 markus 260:
1.208 markus 261: static char *
262: agent_decode_alg(struct sshkey *key, u_int flags)
263: {
264: if (key->type == KEY_RSA) {
265: if (flags & SSH_AGENT_RSA_SHA2_256)
266: return "rsa-sha2-256";
267: else if (flags & SSH_AGENT_RSA_SHA2_512)
268: return "rsa-sha2-512";
1.235 djm 269: } else if (key->type == KEY_RSA_CERT) {
270: if (flags & SSH_AGENT_RSA_SHA2_256)
271: return "rsa-sha2-256-cert-v01@openssh.com";
272: else if (flags & SSH_AGENT_RSA_SHA2_512)
273: return "rsa-sha2-512-cert-v01@openssh.com";
1.208 markus 274: }
275: return NULL;
276: }
277:
1.258 djm 278: /*
1.270 djm 279: * Attempt to parse the contents of a buffer as a SSH publickey userauth
280: * request, checking its contents for consistency and matching the embedded
281: * key against the one that is being used for signing.
282: * Note: does not modify msg buffer.
283: * Optionally extract the username and session ID from the request.
1.258 djm 284: */
285: static int
1.270 djm 286: parse_userauth_request(struct sshbuf *msg, const struct sshkey *expected_key,
287: char **userp, struct sshbuf **sess_idp)
1.258 djm 288: {
1.270 djm 289: struct sshbuf *b = NULL, *sess_id = NULL;
290: char *user = NULL, *service = NULL, *method = NULL, *pkalg = NULL;
1.258 djm 291: int r;
1.270 djm 292: u_char t, sig_follows;
1.258 djm 293: struct sshkey *mkey = NULL;
294:
1.270 djm 295: if (userp != NULL)
296: *userp = NULL;
297: if (sess_idp != NULL)
298: *sess_idp = NULL;
299: if ((b = sshbuf_fromb(msg)) == NULL)
300: fatal_f("sshbuf_fromb");
1.258 djm 301:
302: /* SSH userauth request */
1.270 djm 303: if ((r = sshbuf_froms(b, &sess_id)) != 0)
304: goto out;
305: if (sshbuf_len(sess_id) == 0) {
306: r = SSH_ERR_INVALID_FORMAT;
307: goto out;
308: }
309: if ((r = sshbuf_get_u8(b, &t)) != 0 || /* SSH2_MSG_USERAUTH_REQUEST */
310: (r = sshbuf_get_cstring(b, &user, NULL)) != 0 || /* server user */
311: (r = sshbuf_get_cstring(b, &service, NULL)) != 0 || /* service */
312: (r = sshbuf_get_cstring(b, &method, NULL)) != 0 || /* method */
313: (r = sshbuf_get_u8(b, &sig_follows)) != 0 || /* sig-follows */
314: (r = sshbuf_get_cstring(b, &pkalg, NULL)) != 0 || /* alg */
315: (r = sshkey_froms(b, &mkey)) != 0) /* key */
316: goto out;
317: if (t != SSH2_MSG_USERAUTH_REQUEST ||
318: sig_follows != 1 ||
319: strcmp(service, "ssh-connection") != 0 ||
320: !sshkey_equal(expected_key, mkey) ||
321: sshkey_type_from_name(pkalg) != expected_key->type) {
322: r = SSH_ERR_INVALID_FORMAT;
323: goto out;
324: }
325: if (strcmp(method, "publickey") != 0) {
326: r = SSH_ERR_INVALID_FORMAT;
327: goto out;
328: }
329: if (sshbuf_len(b) != 0) {
330: r = SSH_ERR_INVALID_FORMAT;
331: goto out;
332: }
333: /* success */
334: r = 0;
335: debug3_f("well formed userauth");
336: if (userp != NULL) {
337: *userp = user;
338: user = NULL;
339: }
340: if (sess_idp != NULL) {
341: *sess_idp = sess_id;
342: sess_id = NULL;
1.258 djm 343: }
1.270 djm 344: out:
345: sshbuf_free(b);
346: sshbuf_free(sess_id);
347: free(user);
348: free(service);
349: free(method);
350: free(pkalg);
1.258 djm 351: sshkey_free(mkey);
1.270 djm 352: return r;
353: }
354:
355: /*
356: * Attempt to parse the contents of a buffer as a SSHSIG signature request.
357: * Note: does not modify buffer.
358: */
359: static int
360: parse_sshsig_request(struct sshbuf *msg)
361: {
362: int r;
363: struct sshbuf *b;
364:
365: if ((b = sshbuf_fromb(msg)) == NULL)
366: fatal_f("sshbuf_fromb");
367:
368: if ((r = sshbuf_cmp(b, 0, "SSHSIG", 6)) != 0 ||
369: (r = sshbuf_consume(b, 6)) != 0 ||
370: (r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* namespace */
371: (r = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || /* reserved */
372: (r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* hashalg */
373: (r = sshbuf_get_string_direct(b, NULL, NULL)) != 0) /* H(msg) */
374: goto out;
375: if (sshbuf_len(b) != 0) {
376: r = SSH_ERR_INVALID_FORMAT;
377: goto out;
378: }
379: /* success */
380: r = 0;
381: out:
1.258 djm 382: sshbuf_free(b);
1.270 djm 383: return r;
384: }
385:
386: /*
387: * This function inspects a message to be signed by a FIDO key that has a
388: * web-like application string (i.e. one that does not begin with "ssh:".
389: * It checks that the message is one of those expected for SSH operations
390: * (pubkey userauth, sshsig, CA key signing) to exclude signing challenges
391: * for the web.
392: */
393: static int
394: check_websafe_message_contents(struct sshkey *key, struct sshbuf *data)
395: {
396: if (parse_userauth_request(data, key, NULL, NULL) == 0) {
397: debug_f("signed data matches public key userauth request");
1.258 djm 398: return 1;
399: }
1.270 djm 400: if (parse_sshsig_request(data) == 0) {
401: debug_f("signed data matches SSHSIG signature request");
1.258 djm 402: return 1;
1.270 djm 403: }
1.258 djm 404:
1.270 djm 405: /* XXX check CA signature operation */
1.258 djm 406:
407: error("web-origin key attempting to sign non-SSH message");
408: return 0;
409: }
410:
1.33 markus 411: /* ssh2 only */
1.55 itojun 412: static void
1.33 markus 413: process_sign_request2(SocketEntry *e)
414: {
1.221 djm 415: u_char *signature = NULL;
1.272 dtucker 416: size_t slen = 0;
1.194 markus 417: u_int compat = 0, flags;
1.247 djm 418: int r, ok = -1;
1.251 djm 419: char *fp = NULL;
1.270 djm 420: struct sshbuf *msg = NULL, *data = NULL;
1.221 djm 421: struct sshkey *key = NULL;
1.195 djm 422: struct identity *id;
1.251 djm 423: struct notifier_ctx *notifier = NULL;
1.194 markus 424:
1.270 djm 425: debug_f("entering");
426:
1.273 dtucker 427: if ((msg = sshbuf_new()) == NULL || (data = sshbuf_new()) == NULL)
1.266 djm 428: fatal_f("sshbuf_new failed");
1.221 djm 429: if ((r = sshkey_froms(e->request, &key)) != 0 ||
1.270 djm 430: (r = sshbuf_get_stringb(e->request, data)) != 0 ||
1.225 djm 431: (r = sshbuf_get_u32(e->request, &flags)) != 0) {
1.266 djm 432: error_fr(r, "parse");
1.225 djm 433: goto send;
434: }
435:
1.221 djm 436: if ((id = lookup_identity(key)) == NULL) {
1.266 djm 437: verbose_f("%s key not found", sshkey_type(key));
1.195 djm 438: goto send;
439: }
1.270 djm 440: if (id->confirm && confirm_key(id, NULL) != 0) {
1.266 djm 441: verbose_f("user refused key");
1.195 djm 442: goto send;
443: }
1.258 djm 444: if (sshkey_is_sk(id->key)) {
445: if (strncmp(id->key->sk_application, "ssh:", 4) != 0 &&
1.270 djm 446: !check_websafe_message_contents(key, data)) {
1.258 djm 447: /* error already logged */
448: goto send;
449: }
450: if ((id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD)) {
451: if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
452: SSH_FP_DEFAULT)) == NULL)
1.266 djm 453: fatal_f("fingerprint failed");
1.258 djm 454: notifier = notify_start(0,
455: "Confirm user presence for key %s %s",
456: sshkey_type(id->key), fp);
457: }
1.251 djm 458: }
1.263 djm 459: /* XXX support PIN required FIDO keys */
1.251 djm 460: if ((r = sshkey_sign(id->key, &signature, &slen,
1.270 djm 461: sshbuf_ptr(data), sshbuf_len(data), agent_decode_alg(key, flags),
1.263 djm 462: id->sk_provider, NULL, compat)) != 0) {
1.266 djm 463: error_fr(r, "sshkey_sign");
1.251 djm 464: goto send;
1.33 markus 465: }
1.195 djm 466: /* Success */
467: ok = 0;
468: send:
1.267 djm 469: notify_complete(notifier, "User presence confirmed");
1.270 djm 470:
1.33 markus 471: if (ok == 0) {
1.194 markus 472: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
473: (r = sshbuf_put_string(msg, signature, slen)) != 0)
1.266 djm 474: fatal_fr(r, "compose");
1.194 markus 475: } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
1.266 djm 476: fatal_fr(r, "compose failure");
1.194 markus 477:
478: if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
1.266 djm 479: fatal_fr(r, "enqueue");
1.194 markus 480:
1.270 djm 481: sshbuf_free(data);
1.194 markus 482: sshbuf_free(msg);
1.270 djm 483: sshkey_free(key);
484: free(fp);
1.173 djm 485: free(signature);
1.1 deraadt 486: }
487:
1.33 markus 488: /* shared */
1.55 itojun 489: static void
1.221 djm 490: process_remove_identity(SocketEntry *e)
1.1 deraadt 491: {
1.194 markus 492: int r, success = 0;
493: struct sshkey *key = NULL;
1.221 djm 494: Identity *id;
1.21 markus 495:
1.269 djm 496: debug2_f("entering");
1.221 djm 497: if ((r = sshkey_froms(e->request, &key)) != 0) {
1.266 djm 498: error_fr(r, "parse key");
1.221 djm 499: goto done;
500: }
501: if ((id = lookup_identity(key)) == NULL) {
1.266 djm 502: debug_f("key not found");
1.221 djm 503: goto done;
504: }
505: /* We have this key, free it. */
506: if (idtab->nentries < 1)
1.266 djm 507: fatal_f("internal error: nentries %d", idtab->nentries);
1.221 djm 508: TAILQ_REMOVE(&idtab->idlist, id, next);
509: free_identity(id);
510: idtab->nentries--;
511: success = 1;
512: done:
1.276 djm 513: sshkey_free(key);
1.194 markus 514: send_status(e, success);
1.1 deraadt 515: }
516:
1.55 itojun 517: static void
1.221 djm 518: process_remove_all_identities(SocketEntry *e)
1.1 deraadt 519: {
1.78 provos 520: Identity *id;
1.21 markus 521:
1.269 djm 522: debug2_f("entering");
1.21 markus 523: /* Loop over all identities and clear the keys. */
1.221 djm 524: for (id = TAILQ_FIRST(&idtab->idlist); id;
525: id = TAILQ_FIRST(&idtab->idlist)) {
526: TAILQ_REMOVE(&idtab->idlist, id, next);
1.78 provos 527: free_identity(id);
1.21 markus 528: }
529:
530: /* Mark that there are no identities. */
1.221 djm 531: idtab->nentries = 0;
1.21 markus 532:
533: /* Send success. */
1.194 markus 534: send_status(e, 1);
1.1 deraadt 535: }
536:
1.155 dtucker 537: /* removes expired keys and returns number of seconds until the next expiry */
1.174 dtucker 538: static time_t
1.89 markus 539: reaper(void)
540: {
1.175 dtucker 541: time_t deadline = 0, now = monotime();
1.89 markus 542: Identity *id, *nxt;
543:
1.221 djm 544: for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
545: nxt = TAILQ_NEXT(id, next);
546: if (id->death == 0)
547: continue;
548: if (now >= id->death) {
549: debug("expiring key '%s'", id->comment);
550: TAILQ_REMOVE(&idtab->idlist, id, next);
551: free_identity(id);
552: idtab->nentries--;
553: } else
554: deadline = (deadline == 0) ? id->death :
555: MINIMUM(deadline, id->death);
1.89 markus 556: }
1.155 dtucker 557: if (deadline == 0 || deadline <= now)
558: return 0;
559: else
560: return (deadline - now);
1.89 markus 561: }
562:
1.271 djm 563: static int
1.277 djm 564: parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp)
565: {
566: char *ext_name = NULL;
567: int r;
568:
569: if ((r = sshbuf_get_cstring(m, &ext_name, NULL)) != 0) {
570: error_fr(r, "parse constraint extension");
571: goto out;
572: }
573: debug_f("constraint ext %s", ext_name);
574: if (strcmp(ext_name, "sk-provider@openssh.com") == 0) {
575: if (sk_providerp == NULL) {
576: error_f("%s not valid here", ext_name);
577: r = SSH_ERR_INVALID_FORMAT;
578: goto out;
579: }
580: if (*sk_providerp != NULL) {
581: error_f("%s already set", ext_name);
582: r = SSH_ERR_INVALID_FORMAT;
583: goto out;
584: }
585: if ((r = sshbuf_get_cstring(m, sk_providerp, NULL)) != 0) {
586: error_fr(r, "parse %s", ext_name);
587: goto out;
588: }
589: } else {
590: error_f("unsupported constraint \"%s\"", ext_name);
591: r = SSH_ERR_FEATURE_UNSUPPORTED;
592: goto out;
593: }
594: /* success */
595: r = 0;
596: out:
597: free(ext_name);
598: return r;
599: }
600:
601: static int
1.271 djm 602: parse_key_constraints(struct sshbuf *m, struct sshkey *k, time_t *deathp,
603: u_int *secondsp, int *confirmp, char **sk_providerp)
1.1 deraadt 604: {
1.194 markus 605: u_char ctype;
1.271 djm 606: int r;
607: u_int seconds, maxsign = 0;
1.33 markus 608:
1.271 djm 609: while (sshbuf_len(m)) {
610: if ((r = sshbuf_get_u8(m, &ctype)) != 0) {
1.266 djm 611: error_fr(r, "parse constraint type");
1.277 djm 612: goto out;
1.194 markus 613: }
614: switch (ctype) {
1.94 markus 615: case SSH_AGENT_CONSTRAIN_LIFETIME:
1.271 djm 616: if (*deathp != 0) {
617: error_f("lifetime already set");
1.277 djm 618: r = SSH_ERR_INVALID_FORMAT;
619: goto out;
1.271 djm 620: }
621: if ((r = sshbuf_get_u32(m, &seconds)) != 0) {
1.266 djm 622: error_fr(r, "parse lifetime constraint");
1.277 djm 623: goto out;
1.194 markus 624: }
1.271 djm 625: *deathp = monotime() + seconds;
626: *secondsp = seconds;
1.94 markus 627: break;
1.107 markus 628: case SSH_AGENT_CONSTRAIN_CONFIRM:
1.271 djm 629: if (*confirmp != 0) {
630: error_f("confirm already set");
1.277 djm 631: r = SSH_ERR_INVALID_FORMAT;
632: goto out;
1.271 djm 633: }
634: *confirmp = 1;
1.107 markus 635: break;
1.228 markus 636: case SSH_AGENT_CONSTRAIN_MAXSIGN:
1.271 djm 637: if (k == NULL) {
638: error_f("maxsign not valid here");
1.277 djm 639: r = SSH_ERR_INVALID_FORMAT;
640: goto out;
1.271 djm 641: }
642: if (maxsign != 0) {
643: error_f("maxsign already set");
1.277 djm 644: r = SSH_ERR_INVALID_FORMAT;
645: goto out;
1.271 djm 646: }
647: if ((r = sshbuf_get_u32(m, &maxsign)) != 0) {
1.266 djm 648: error_fr(r, "parse maxsign constraint");
1.277 djm 649: goto out;
1.228 markus 650: }
651: if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) {
1.266 djm 652: error_fr(r, "enable maxsign");
1.277 djm 653: goto out;
1.228 markus 654: }
655: break;
1.238 djm 656: case SSH_AGENT_CONSTRAIN_EXTENSION:
1.277 djm 657: if ((r = parse_key_constraint_extension(m,
658: sk_providerp)) != 0)
659: goto out; /* error already logged */
1.238 djm 660: break;
1.94 markus 661: default:
1.266 djm 662: error_f("Unknown constraint %d", ctype);
1.277 djm 663: r = SSH_ERR_FEATURE_UNSUPPORTED;
664: goto out;
1.94 markus 665: }
666: }
1.271 djm 667: /* success */
1.277 djm 668: r = 0;
669: out:
670: return r;
1.271 djm 671: }
672:
673: static void
674: process_add_identity(SocketEntry *e)
675: {
676: Identity *id;
677: int success = 0, confirm = 0;
1.272 dtucker 678: char *fp, *comment = NULL, *sk_provider = NULL;
1.271 djm 679: char canonical_provider[PATH_MAX];
680: time_t death = 0;
681: u_int seconds = 0;
682: struct sshkey *k = NULL;
683: int r = SSH_ERR_INTERNAL_ERROR;
684:
685: debug2_f("entering");
686: if ((r = sshkey_private_deserialize(e->request, &k)) != 0 ||
687: k == NULL ||
688: (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) {
689: error_fr(r, "parse");
690: goto out;
691: }
692: if (parse_key_constraints(e->request, k, &death, &seconds, &confirm,
693: &sk_provider) != 0) {
694: error_f("failed to parse constraints");
695: sshbuf_reset(e->request);
696: goto out;
697: }
698:
1.238 djm 699: if (sk_provider != NULL) {
1.240 markus 700: if (!sshkey_is_sk(k)) {
1.255 naddy 701: error("Cannot add provider: %s is not an "
702: "authenticator-hosted key", sshkey_type(k));
1.271 djm 703: goto out;
1.238 djm 704: }
1.254 djm 705: if (strcasecmp(sk_provider, "internal") == 0) {
1.266 djm 706: debug_f("internal provider");
1.254 djm 707: } else {
708: if (realpath(sk_provider, canonical_provider) == NULL) {
709: verbose("failed provider \"%.100s\": "
710: "realpath: %s", sk_provider,
711: strerror(errno));
1.271 djm 712: goto out;
1.254 djm 713: }
1.238 djm 714: free(sk_provider);
1.254 djm 715: sk_provider = xstrdup(canonical_provider);
716: if (match_pattern_list(sk_provider,
1.260 djm 717: allowed_providers, 0) != 1) {
1.254 djm 718: error("Refusing add key: "
1.260 djm 719: "provider %s not allowed", sk_provider);
1.271 djm 720: goto out;
1.254 djm 721: }
1.238 djm 722: }
1.242 markus 723: }
724: if ((r = sshkey_shield_private(k)) != 0) {
1.266 djm 725: error_fr(r, "shield private");
1.271 djm 726: goto out;
1.238 djm 727: }
1.106 marc 728: if (lifetime && !death)
1.175 dtucker 729: death = monotime() + lifetime;
1.221 djm 730: if ((id = lookup_identity(k)) == NULL) {
1.163 markus 731: id = xcalloc(1, sizeof(Identity));
1.221 djm 732: TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
1.33 markus 733: /* Increment the number of identities. */
1.221 djm 734: idtab->nentries++;
1.33 markus 735: } else {
1.228 markus 736: /* key state might have been updated */
737: sshkey_free(id->key);
1.173 djm 738: free(id->comment);
1.238 djm 739: free(id->sk_provider);
1.33 markus 740: }
1.271 djm 741: /* success */
1.228 markus 742: id->key = k;
1.157 canacar 743: id->comment = comment;
744: id->death = death;
745: id->confirm = confirm;
1.238 djm 746: id->sk_provider = sk_provider;
747:
748: if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT,
749: SSH_FP_DEFAULT)) == NULL)
1.266 djm 750: fatal_f("sshkey_fingerprint failed");
751: debug_f("add %s %s \"%.100s\" (life: %u) (confirm: %u) "
1.271 djm 752: "(provider: %s)", sshkey_ssh_name(k), fp, comment, seconds,
753: confirm, sk_provider == NULL ? "none" : sk_provider);
1.238 djm 754: free(fp);
1.271 djm 755: /* transferred */
756: k = NULL;
757: comment = NULL;
758: sk_provider = NULL;
759: success = 1;
760: out:
761: free(sk_provider);
762: free(comment);
763: sshkey_free(k);
1.194 markus 764: send_status(e, success);
1.1 deraadt 765: }
766:
1.88 markus 767: /* XXX todo: encrypt sensitive data with passphrase */
768: static void
769: process_lock_agent(SocketEntry *e, int lock)
770: {
1.203 dtucker 771: int r, success = 0, delay;
1.213 djm 772: char *passwd;
773: u_char passwdhash[LOCK_SIZE];
1.203 dtucker 774: static u_int fail_count = 0;
775: size_t pwlen;
776:
1.269 djm 777: debug2_f("entering");
1.226 djm 778: /*
779: * This is deliberately fatal: the user has requested that we lock,
780: * but we can't parse their request properly. The only safe thing to
781: * do is abort.
782: */
1.203 dtucker 783: if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0)
1.266 djm 784: fatal_fr(r, "parse");
1.203 dtucker 785: if (pwlen == 0) {
786: debug("empty password not supported");
787: } else if (locked && !lock) {
788: if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
789: passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0)
790: fatal("bcrypt_pbkdf");
1.213 djm 791: if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) {
1.203 dtucker 792: debug("agent unlocked");
793: locked = 0;
794: fail_count = 0;
1.213 djm 795: explicit_bzero(lock_pwhash, sizeof(lock_pwhash));
1.203 dtucker 796: success = 1;
797: } else {
798: /* delay in 0.1s increments up to 10s */
799: if (fail_count < 100)
800: fail_count++;
801: delay = 100000 * fail_count;
802: debug("unlock failed, delaying %0.1lf seconds",
803: (double)delay/1000000);
804: usleep(delay);
805: }
806: explicit_bzero(passwdhash, sizeof(passwdhash));
1.88 markus 807: } else if (!locked && lock) {
1.203 dtucker 808: debug("agent locked");
1.88 markus 809: locked = 1;
1.203 dtucker 810: arc4random_buf(lock_salt, sizeof(lock_salt));
811: if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
1.213 djm 812: lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0)
1.203 dtucker 813: fatal("bcrypt_pbkdf");
1.88 markus 814: success = 1;
815: }
1.256 jsg 816: freezero(passwd, pwlen);
1.194 markus 817: send_status(e, success);
1.88 markus 818: }
819:
820: static void
1.221 djm 821: no_identities(SocketEntry *e)
1.88 markus 822: {
1.194 markus 823: struct sshbuf *msg;
824: int r;
1.88 markus 825:
1.194 markus 826: if ((msg = sshbuf_new()) == NULL)
1.266 djm 827: fatal_f("sshbuf_new failed");
1.221 djm 828: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
1.194 markus 829: (r = sshbuf_put_u32(msg, 0)) != 0 ||
830: (r = sshbuf_put_stringb(e->output, msg)) != 0)
1.266 djm 831: fatal_fr(r, "compose");
1.194 markus 832: sshbuf_free(msg);
1.88 markus 833: }
1.59 markus 834:
1.163 markus 835: #ifdef ENABLE_PKCS11
1.59 markus 836: static void
1.158 djm 837: process_add_smartcard_key(SocketEntry *e)
1.59 markus 838: {
1.226 djm 839: char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
1.253 djm 840: char **comments = NULL;
1.221 djm 841: int r, i, count = 0, success = 0, confirm = 0;
1.271 djm 842: u_int seconds = 0;
1.174 dtucker 843: time_t death = 0;
1.194 markus 844: struct sshkey **keys = NULL, *k;
1.84 markus 845: Identity *id;
1.75 deraadt 846:
1.269 djm 847: debug2_f("entering");
1.194 markus 848: if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
1.226 djm 849: (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
1.266 djm 850: error_fr(r, "parse");
1.226 djm 851: goto send;
852: }
1.271 djm 853: if (parse_key_constraints(e->request, NULL, &death, &seconds, &confirm,
854: NULL) != 0) {
855: error_f("failed to parse constraints");
856: goto send;
1.110 djm 857: }
1.215 djm 858: if (realpath(provider, canonical_provider) == NULL) {
859: verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
860: provider, strerror(errno));
861: goto send;
862: }
1.260 djm 863: if (match_pattern_list(canonical_provider, allowed_providers, 0) != 1) {
1.215 djm 864: verbose("refusing PKCS#11 add of \"%.100s\": "
1.260 djm 865: "provider not allowed", canonical_provider);
1.215 djm 866: goto send;
867: }
1.266 djm 868: debug_f("add %.100s", canonical_provider);
1.110 djm 869: if (lifetime && !death)
1.175 dtucker 870: death = monotime() + lifetime;
1.110 djm 871:
1.253 djm 872: count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments);
1.163 markus 873: for (i = 0; i < count; i++) {
1.84 markus 874: k = keys[i];
1.221 djm 875: if (lookup_identity(k) == NULL) {
1.163 markus 876: id = xcalloc(1, sizeof(Identity));
1.84 markus 877: id->key = k;
1.253 djm 878: keys[i] = NULL; /* transferred */
1.215 djm 879: id->provider = xstrdup(canonical_provider);
1.253 djm 880: if (*comments[i] != '\0') {
881: id->comment = comments[i];
882: comments[i] = NULL; /* transferred */
883: } else {
884: id->comment = xstrdup(canonical_provider);
885: }
1.110 djm 886: id->death = death;
887: id->confirm = confirm;
1.221 djm 888: TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
889: idtab->nentries++;
1.84 markus 890: success = 1;
891: }
1.271 djm 892: /* XXX update constraints for existing keys */
1.253 djm 893: sshkey_free(keys[i]);
894: free(comments[i]);
1.59 markus 895: }
896: send:
1.173 djm 897: free(pin);
898: free(provider);
899: free(keys);
1.253 djm 900: free(comments);
1.194 markus 901: send_status(e, success);
1.59 markus 902: }
903:
904: static void
905: process_remove_smartcard_key(SocketEntry *e)
906: {
1.217 djm 907: char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
1.221 djm 908: int r, success = 0;
1.163 markus 909: Identity *id, *nxt;
1.59 markus 910:
1.269 djm 911: debug2_f("entering");
1.194 markus 912: if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
1.226 djm 913: (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
1.266 djm 914: error_fr(r, "parse");
1.226 djm 915: goto send;
916: }
1.173 djm 917: free(pin);
1.59 markus 918:
1.217 djm 919: if (realpath(provider, canonical_provider) == NULL) {
920: verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
921: provider, strerror(errno));
922: goto send;
923: }
924:
1.266 djm 925: debug_f("remove %.100s", canonical_provider);
1.221 djm 926: for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
927: nxt = TAILQ_NEXT(id, next);
928: /* Skip file--based keys */
929: if (id->provider == NULL)
930: continue;
931: if (!strcmp(canonical_provider, id->provider)) {
932: TAILQ_REMOVE(&idtab->idlist, id, next);
933: free_identity(id);
934: idtab->nentries--;
1.59 markus 935: }
936: }
1.217 djm 937: if (pkcs11_del_provider(canonical_provider) == 0)
1.163 markus 938: success = 1;
939: else
1.266 djm 940: error_f("pkcs11_del_provider failed");
1.218 deraadt 941: send:
1.173 djm 942: free(provider);
1.194 markus 943: send_status(e, success);
1.59 markus 944: }
1.163 markus 945: #endif /* ENABLE_PKCS11 */
1.59 markus 946:
1.264 djm 947: /*
948: * dispatch incoming message.
949: * returns 1 on success, 0 for incomplete messages or -1 on error.
950: */
1.223 djm 951: static int
952: process_message(u_int socknum)
1.1 deraadt 953: {
1.194 markus 954: u_int msg_len;
955: u_char type;
956: const u_char *cp;
957: int r;
1.223 djm 958: SocketEntry *e;
959:
1.266 djm 960: if (socknum >= sockets_alloc)
961: fatal_f("sock %u >= allocated %u", socknum, sockets_alloc);
1.223 djm 962: e = &sockets[socknum];
1.89 markus 963:
1.194 markus 964: if (sshbuf_len(e->input) < 5)
1.223 djm 965: return 0; /* Incomplete message header. */
1.194 markus 966: cp = sshbuf_ptr(e->input);
967: msg_len = PEEK_U32(cp);
1.223 djm 968: if (msg_len > AGENT_MAX_LEN) {
1.266 djm 969: debug_f("socket %u (fd=%d) message too long %u > %u",
970: socknum, e->fd, msg_len, AGENT_MAX_LEN);
1.223 djm 971: return -1;
1.21 markus 972: }
1.194 markus 973: if (sshbuf_len(e->input) < msg_len + 4)
1.223 djm 974: return 0; /* Incomplete message body. */
1.87 markus 975:
976: /* move the current input to e->request */
1.194 markus 977: sshbuf_reset(e->request);
978: if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 ||
1.223 djm 979: (r = sshbuf_get_u8(e->request, &type)) != 0) {
980: if (r == SSH_ERR_MESSAGE_INCOMPLETE ||
981: r == SSH_ERR_STRING_TOO_LARGE) {
1.266 djm 982: error_fr(r, "parse");
1.223 djm 983: return -1;
984: }
1.266 djm 985: fatal_fr(r, "parse");
1.223 djm 986: }
987:
1.266 djm 988: debug_f("socket %u (fd=%d) type %d", socknum, e->fd, type);
1.21 markus 989:
1.230 djm 990: /* check whether agent is locked */
1.88 markus 991: if (locked && type != SSH_AGENTC_UNLOCK) {
1.194 markus 992: sshbuf_reset(e->request);
1.88 markus 993: switch (type) {
994: case SSH2_AGENTC_REQUEST_IDENTITIES:
995: /* send empty lists */
1.221 djm 996: no_identities(e);
1.88 markus 997: break;
998: default:
999: /* send a fail message for all other request types */
1.194 markus 1000: send_status(e, 0);
1.88 markus 1001: }
1.264 djm 1002: return 1;
1.88 markus 1003: }
1004:
1.21 markus 1005: switch (type) {
1.88 markus 1006: case SSH_AGENTC_LOCK:
1007: case SSH_AGENTC_UNLOCK:
1008: process_lock_agent(e, type == SSH_AGENTC_LOCK);
1009: break;
1.21 markus 1010: case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
1.221 djm 1011: process_remove_all_identities(e); /* safe for !WITH_SSH1 */
1.33 markus 1012: break;
1013: /* ssh2 */
1014: case SSH2_AGENTC_SIGN_REQUEST:
1015: process_sign_request2(e);
1016: break;
1017: case SSH2_AGENTC_REQUEST_IDENTITIES:
1.221 djm 1018: process_request_identities(e);
1.33 markus 1019: break;
1020: case SSH2_AGENTC_ADD_IDENTITY:
1.94 markus 1021: case SSH2_AGENTC_ADD_ID_CONSTRAINED:
1.221 djm 1022: process_add_identity(e);
1.33 markus 1023: break;
1024: case SSH2_AGENTC_REMOVE_IDENTITY:
1.221 djm 1025: process_remove_identity(e);
1.33 markus 1026: break;
1027: case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
1.221 djm 1028: process_remove_all_identities(e);
1.21 markus 1029: break;
1.163 markus 1030: #ifdef ENABLE_PKCS11
1.59 markus 1031: case SSH_AGENTC_ADD_SMARTCARD_KEY:
1.110 djm 1032: case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
1.59 markus 1033: process_add_smartcard_key(e);
1.75 deraadt 1034: break;
1.59 markus 1035: case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
1036: process_remove_smartcard_key(e);
1.75 deraadt 1037: break;
1.163 markus 1038: #endif /* ENABLE_PKCS11 */
1.21 markus 1039: default:
1040: /* Unknown message. Respond with failure. */
1041: error("Unknown message %d", type);
1.194 markus 1042: sshbuf_reset(e->request);
1043: send_status(e, 0);
1.21 markus 1044: break;
1045: }
1.264 djm 1046: return 1;
1.1 deraadt 1047: }
1048:
1.55 itojun 1049: static void
1.73 stevesk 1050: new_socket(sock_type type, int fd)
1.1 deraadt 1051: {
1.112 markus 1052: u_int i, old_alloc, new_alloc;
1.96 deraadt 1053:
1.269 djm 1054: debug_f("type = %s", type == AUTH_CONNECTION ? "CONNECTION" :
1055: (type == AUTH_SOCKET ? "SOCKET" : "UNKNOWN"));
1.119 djm 1056: set_nonblock(fd);
1.21 markus 1057:
1058: if (fd > max_fd)
1059: max_fd = fd;
1060:
1061: for (i = 0; i < sockets_alloc; i++)
1062: if (sockets[i].type == AUTH_UNUSED) {
1063: sockets[i].fd = fd;
1.266 djm 1064: if ((sockets[i].input = sshbuf_new()) == NULL ||
1065: (sockets[i].output = sshbuf_new()) == NULL ||
1066: (sockets[i].request = sshbuf_new()) == NULL)
1067: fatal_f("sshbuf_new failed");
1.112 markus 1068: sockets[i].type = type;
1.21 markus 1069: return;
1070: }
1071: old_alloc = sockets_alloc;
1.112 markus 1072: new_alloc = sockets_alloc + 10;
1.269 djm 1073: sockets = xrecallocarray(sockets, old_alloc, new_alloc,
1074: sizeof(sockets[0]));
1.112 markus 1075: for (i = old_alloc; i < new_alloc; i++)
1.21 markus 1076: sockets[i].type = AUTH_UNUSED;
1.112 markus 1077: sockets_alloc = new_alloc;
1.21 markus 1078: sockets[old_alloc].fd = fd;
1.266 djm 1079: if ((sockets[old_alloc].input = sshbuf_new()) == NULL ||
1080: (sockets[old_alloc].output = sshbuf_new()) == NULL ||
1081: (sockets[old_alloc].request = sshbuf_new()) == NULL)
1082: fatal_f("sshbuf_new failed");
1.112 markus 1083: sockets[old_alloc].type = type;
1.1 deraadt 1084: }
1085:
1.55 itojun 1086: static int
1.223 djm 1087: handle_socket_read(u_int socknum)
1.1 deraadt 1088: {
1.223 djm 1089: struct sockaddr_un sunaddr;
1090: socklen_t slen;
1091: uid_t euid;
1092: gid_t egid;
1093: int fd;
1094:
1095: slen = sizeof(sunaddr);
1096: fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen);
1.237 deraadt 1097: if (fd == -1) {
1.223 djm 1098: error("accept from AUTH_SOCKET: %s", strerror(errno));
1099: return -1;
1100: }
1.237 deraadt 1101: if (getpeereid(fd, &euid, &egid) == -1) {
1.223 djm 1102: error("getpeereid %d failed: %s", fd, strerror(errno));
1103: close(fd);
1104: return -1;
1105: }
1106: if ((euid != 0) && (getuid() != euid)) {
1107: error("uid mismatch: peer euid %u != uid %u",
1108: (u_int) euid, (u_int) getuid());
1109: close(fd);
1110: return -1;
1111: }
1112: new_socket(AUTH_CONNECTION, fd);
1113: return 0;
1114: }
1115:
1116: static int
1117: handle_conn_read(u_int socknum)
1118: {
1.233 djm 1119: char buf[AGENT_RBUF_LEN];
1.223 djm 1120: ssize_t len;
1121: int r;
1122:
1123: if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) {
1124: if (len == -1) {
1125: if (errno == EAGAIN || errno == EINTR)
1126: return 0;
1.266 djm 1127: error_f("read error on socket %u (fd %d): %s",
1128: socknum, sockets[socknum].fd, strerror(errno));
1.223 djm 1129: }
1130: return -1;
1131: }
1132: if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0)
1.266 djm 1133: fatal_fr(r, "compose");
1.223 djm 1134: explicit_bzero(buf, sizeof(buf));
1.264 djm 1135: for (;;) {
1136: if ((r = process_message(socknum)) == -1)
1137: return -1;
1138: else if (r == 0)
1139: break;
1140: }
1.223 djm 1141: return 0;
1142: }
1143:
1144: static int
1145: handle_conn_write(u_int socknum)
1146: {
1147: ssize_t len;
1148: int r;
1149:
1150: if (sshbuf_len(sockets[socknum].output) == 0)
1151: return 0; /* shouldn't happen */
1152: if ((len = write(sockets[socknum].fd,
1153: sshbuf_ptr(sockets[socknum].output),
1154: sshbuf_len(sockets[socknum].output))) <= 0) {
1155: if (len == -1) {
1156: if (errno == EAGAIN || errno == EINTR)
1157: return 0;
1.266 djm 1158: error_f("read error on socket %u (fd %d): %s",
1159: socknum, sockets[socknum].fd, strerror(errno));
1.223 djm 1160: }
1161: return -1;
1162: }
1163: if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0)
1.266 djm 1164: fatal_fr(r, "consume");
1.223 djm 1165: return 0;
1166: }
1167:
1168: static void
1.231 djm 1169: after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds)
1.223 djm 1170: {
1171: size_t i;
1.231 djm 1172: u_int socknum, activefds = npfd;
1.223 djm 1173:
1174: for (i = 0; i < npfd; i++) {
1175: if (pfd[i].revents == 0)
1176: continue;
1177: /* Find sockets entry */
1178: for (socknum = 0; socknum < sockets_alloc; socknum++) {
1179: if (sockets[socknum].type != AUTH_SOCKET &&
1180: sockets[socknum].type != AUTH_CONNECTION)
1181: continue;
1182: if (pfd[i].fd == sockets[socknum].fd)
1183: break;
1184: }
1185: if (socknum >= sockets_alloc) {
1.266 djm 1186: error_f("no socket for fd %d", pfd[i].fd);
1.223 djm 1187: continue;
1188: }
1189: /* Process events */
1190: switch (sockets[socknum].type) {
1191: case AUTH_SOCKET:
1.231 djm 1192: if ((pfd[i].revents & (POLLIN|POLLERR)) == 0)
1193: break;
1194: if (npfd > maxfds) {
1195: debug3("out of fds (active %u >= limit %u); "
1196: "skipping accept", activefds, maxfds);
1197: break;
1198: }
1199: if (handle_socket_read(socknum) == 0)
1200: activefds++;
1.223 djm 1201: break;
1202: case AUTH_CONNECTION:
1203: if ((pfd[i].revents & (POLLIN|POLLERR)) != 0 &&
1204: handle_conn_read(socknum) != 0) {
1.231 djm 1205: goto close_sock;
1206: }
1207: if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 &&
1208: handle_conn_write(socknum) != 0) {
1209: close_sock:
1210: if (activefds == 0)
1211: fatal("activefds == 0 at close_sock");
1.223 djm 1212: close_socket(&sockets[socknum]);
1.231 djm 1213: activefds--;
1.223 djm 1214: break;
1215: }
1216: break;
1217: default:
1218: break;
1219: }
1220: }
1221: }
1222:
1223: static int
1.231 djm 1224: prepare_poll(struct pollfd **pfdp, size_t *npfdp, int *timeoutp, u_int maxfds)
1.223 djm 1225: {
1226: struct pollfd *pfd = *pfdp;
1227: size_t i, j, npfd = 0;
1.174 dtucker 1228: time_t deadline;
1.233 djm 1229: int r;
1.46 markus 1230:
1.223 djm 1231: /* Count active sockets */
1.46 markus 1232: for (i = 0; i < sockets_alloc; i++) {
1.21 markus 1233: switch (sockets[i].type) {
1234: case AUTH_SOCKET:
1235: case AUTH_CONNECTION:
1.223 djm 1236: npfd++;
1.21 markus 1237: break;
1238: case AUTH_UNUSED:
1239: break;
1240: default:
1241: fatal("Unknown socket type %d", sockets[i].type);
1242: break;
1243: }
1.46 markus 1244: }
1.223 djm 1245: if (npfd != *npfdp &&
1246: (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL)
1.266 djm 1247: fatal_f("recallocarray failed");
1.223 djm 1248: *pfdp = pfd;
1249: *npfdp = npfd;
1.46 markus 1250:
1.223 djm 1251: for (i = j = 0; i < sockets_alloc; i++) {
1.46 markus 1252: switch (sockets[i].type) {
1253: case AUTH_SOCKET:
1.231 djm 1254: if (npfd > maxfds) {
1255: debug3("out of fds (active %zu >= limit %u); "
1256: "skipping arming listener", npfd, maxfds);
1257: break;
1258: }
1259: pfd[j].fd = sockets[i].fd;
1260: pfd[j].revents = 0;
1261: pfd[j].events = POLLIN;
1262: j++;
1263: break;
1.46 markus 1264: case AUTH_CONNECTION:
1.223 djm 1265: pfd[j].fd = sockets[i].fd;
1266: pfd[j].revents = 0;
1.233 djm 1267: /*
1268: * Only prepare to read if we can handle a full-size
1269: * input read buffer and enqueue a max size reply..
1270: */
1271: if ((r = sshbuf_check_reserve(sockets[i].input,
1272: AGENT_RBUF_LEN)) == 0 &&
1273: (r = sshbuf_check_reserve(sockets[i].output,
1.278 ! djm 1274: AGENT_MAX_LEN)) == 0)
1.233 djm 1275: pfd[j].events = POLLIN;
1.266 djm 1276: else if (r != SSH_ERR_NO_BUFFER_SPACE)
1277: fatal_fr(r, "reserve");
1.194 markus 1278: if (sshbuf_len(sockets[i].output) > 0)
1.223 djm 1279: pfd[j].events |= POLLOUT;
1280: j++;
1.46 markus 1281: break;
1282: default:
1283: break;
1284: }
1285: }
1.155 dtucker 1286: deadline = reaper();
1287: if (parent_alive_interval != 0)
1288: deadline = (deadline == 0) ? parent_alive_interval :
1.214 deraadt 1289: MINIMUM(deadline, parent_alive_interval);
1.155 dtucker 1290: if (deadline == 0) {
1.224 djm 1291: *timeoutp = -1; /* INFTIM */
1.155 dtucker 1292: } else {
1.223 djm 1293: if (deadline > INT_MAX / 1000)
1294: *timeoutp = INT_MAX / 1000;
1295: else
1296: *timeoutp = deadline * 1000;
1.155 dtucker 1297: }
1.46 markus 1298: return (1);
1.21 markus 1299: }
1300:
1.55 itojun 1301: static void
1.113 markus 1302: cleanup_socket(void)
1.15 markus 1303: {
1.187 djm 1304: if (cleanup_pid != 0 && getpid() != cleanup_pid)
1305: return;
1.266 djm 1306: debug_f("cleanup");
1.48 deraadt 1307: if (socket_name[0])
1308: unlink(socket_name);
1309: if (socket_dir[0])
1310: rmdir(socket_dir);
1.10 markus 1311: }
1312:
1.114 markus 1313: void
1.15 markus 1314: cleanup_exit(int i)
1315: {
1.113 markus 1316: cleanup_socket();
1317: _exit(i);
1.15 markus 1318: }
1319:
1.135 deraadt 1320: /*ARGSUSED*/
1.55 itojun 1321: static void
1.48 deraadt 1322: cleanup_handler(int sig)
1323: {
1.113 markus 1324: cleanup_socket();
1.163 markus 1325: #ifdef ENABLE_PKCS11
1326: pkcs11_terminate();
1327: #endif
1.48 deraadt 1328: _exit(2);
1.113 markus 1329: }
1330:
1.68 markus 1331: static void
1.155 dtucker 1332: check_parent_exists(void)
1.68 markus 1333: {
1.172 dtucker 1334: /*
1335: * If our parent has exited then getppid() will return (pid_t)1,
1336: * so testing for that should be safe.
1337: */
1338: if (parent_pid != -1 && getppid() != parent_pid) {
1.68 markus 1339: /* printf("Parent has died - Authentication agent exiting.\n"); */
1.155 dtucker 1340: cleanup_socket();
1341: _exit(2);
1.68 markus 1342: }
1.48 deraadt 1343: }
1344:
1.55 itojun 1345: static void
1.50 itojun 1346: usage(void)
1.15 markus 1347: {
1.184 deraadt 1348: fprintf(stderr,
1.250 jmc 1349: "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n"
1.261 jmc 1350: " [-P allowed_providers] [-t life]\n"
1.260 djm 1351: " ssh-agent [-a bind_address] [-E fingerprint_hash] [-P allowed_providers]\n"
1.259 dtucker 1352: " [-t life] command [arg ...]\n"
1.250 jmc 1353: " ssh-agent [-c | -s] -k\n");
1.21 markus 1354: exit(1);
1.15 markus 1355: }
1356:
1.2 provos 1357: int
1358: main(int ac, char **av)
1.1 deraadt 1359: {
1.201 djm 1360: int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0;
1.265 djm 1361: int sock, ch, result, saved_errno;
1.96 deraadt 1362: char *shell, *format, *pidstr, *agentsocket = NULL;
1.41 markus 1363: struct rlimit rlim;
1.96 deraadt 1364: extern int optind;
1.98 stevesk 1365: extern char *optarg;
1.21 markus 1366: pid_t pid;
1.96 deraadt 1367: char pidstrbuf[1 + 3 * sizeof pid];
1.161 tobias 1368: size_t len;
1.189 djm 1369: mode_t prev_mask;
1.224 djm 1370: int timeout = -1; /* INFTIM */
1.223 djm 1371: struct pollfd *pfd = NULL;
1372: size_t npfd = 0;
1.231 djm 1373: u_int maxfds;
1.123 djm 1374:
1375: /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1376: sanitise_stdfd();
1.99 markus 1377:
1378: /* drop */
1379: setegid(getgid());
1380: setgid(getgid());
1.53 markus 1381:
1.231 djm 1382: if (getrlimit(RLIMIT_NOFILE, &rlim) == -1)
1383: fatal("%s: getrlimit: %s", __progname, strerror(errno));
1384:
1.185 markus 1385: #ifdef WITH_OPENSSL
1.170 djm 1386: OpenSSL_add_all_algorithms();
1.185 markus 1387: #endif
1.21 markus 1388:
1.258 djm 1389: while ((ch = getopt(ac, av, "cDdksE:a:O:P:t:")) != -1) {
1.21 markus 1390: switch (ch) {
1.192 djm 1391: case 'E':
1392: fingerprint_hash = ssh_digest_alg_by_name(optarg);
1393: if (fingerprint_hash == -1)
1394: fatal("Invalid hash algorithm \"%s\"", optarg);
1395: break;
1.21 markus 1396: case 'c':
1397: if (s_flag)
1398: usage();
1399: c_flag++;
1400: break;
1401: case 'k':
1402: k_flag++;
1.258 djm 1403: break;
1404: case 'O':
1405: if (strcmp(optarg, "no-restrict-websafe") == 0)
1406: restrict_websafe = 0;
1407: else
1408: fatal("Unknown -O option");
1.21 markus 1409: break;
1.215 djm 1410: case 'P':
1.260 djm 1411: if (allowed_providers != NULL)
1.215 djm 1412: fatal("-P option already specified");
1.260 djm 1413: allowed_providers = xstrdup(optarg);
1.215 djm 1414: break;
1.21 markus 1415: case 's':
1416: if (c_flag)
1417: usage();
1418: s_flag++;
1419: break;
1.57 markus 1420: case 'd':
1.201 djm 1421: if (d_flag || D_flag)
1.57 markus 1422: usage();
1423: d_flag++;
1424: break;
1.201 djm 1425: case 'D':
1426: if (d_flag || D_flag)
1427: usage();
1428: D_flag++;
1429: break;
1.86 markus 1430: case 'a':
1431: agentsocket = optarg;
1.106 marc 1432: break;
1433: case 't':
1434: if ((lifetime = convtime(optarg)) == -1) {
1435: fprintf(stderr, "Invalid lifetime\n");
1436: usage();
1437: }
1.86 markus 1438: break;
1.21 markus 1439: default:
1440: usage();
1441: }
1442: }
1443: ac -= optind;
1444: av += optind;
1445:
1.201 djm 1446: if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag))
1.21 markus 1447: usage();
1448:
1.260 djm 1449: if (allowed_providers == NULL)
1.262 djm 1450: allowed_providers = xstrdup(DEFAULT_ALLOWED_PROVIDERS);
1.215 djm 1451:
1.85 markus 1452: if (ac == 0 && !c_flag && !s_flag) {
1.21 markus 1453: shell = getenv("SHELL");
1.161 tobias 1454: if (shell != NULL && (len = strlen(shell)) > 2 &&
1455: strncmp(shell + len - 3, "csh", 3) == 0)
1.21 markus 1456: c_flag = 1;
1457: }
1458: if (k_flag) {
1.136 deraadt 1459: const char *errstr = NULL;
1460:
1.21 markus 1461: pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1462: if (pidstr == NULL) {
1463: fprintf(stderr, "%s not set, cannot kill agent\n",
1.46 markus 1464: SSH_AGENTPID_ENV_NAME);
1.21 markus 1465: exit(1);
1466: }
1.136 deraadt 1467: pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1468: if (errstr) {
1469: fprintf(stderr,
1470: "%s=\"%s\", which is not a good PID: %s\n",
1471: SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1.21 markus 1472: exit(1);
1473: }
1474: if (kill(pid, SIGTERM) == -1) {
1475: perror("kill");
1476: exit(1);
1477: }
1478: format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1.140 djm 1479: printf(format, SSH_AUTHSOCKET_ENV_NAME);
1480: printf(format, SSH_AGENTPID_ENV_NAME);
1.91 mpech 1481: printf("echo Agent pid %ld killed;\n", (long)pid);
1.21 markus 1482: exit(0);
1483: }
1.231 djm 1484:
1485: /*
1486: * Minimum file descriptors:
1487: * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) +
1488: * a few spare for libc / stack protectors / sanitisers, etc.
1489: */
1490: #define SSH_AGENT_MIN_FDS (3+1+1+1+4)
1491: if (rlim.rlim_cur < SSH_AGENT_MIN_FDS)
1.232 djm 1492: fatal("%s: file descriptor rlimit %lld too low (minimum %u)",
1.231 djm 1493: __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS);
1494: maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS;
1495:
1.21 markus 1496: parent_pid = getpid();
1497:
1.86 markus 1498: if (agentsocket == NULL) {
1499: /* Create private directory for agent socket */
1.171 djm 1500: mktemp_proto(socket_dir, sizeof(socket_dir));
1.86 markus 1501: if (mkdtemp(socket_dir) == NULL) {
1502: perror("mkdtemp: private socket dir");
1503: exit(1);
1504: }
1.91 mpech 1505: snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1506: (long)parent_pid);
1.86 markus 1507: } else {
1508: /* Try to use specified agent socket */
1509: socket_dir[0] = '\0';
1510: strlcpy(socket_name, agentsocket, sizeof socket_name);
1.21 markus 1511: }
1512:
1.23 markus 1513: /*
1514: * Create socket early so it will exist before command gets run from
1515: * the parent.
1516: */
1.189 djm 1517: prev_mask = umask(0177);
1.188 millert 1518: sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0);
1.21 markus 1519: if (sock < 0) {
1.188 millert 1520: /* XXX - unix_listener() calls error() not perror() */
1.121 djm 1521: *socket_name = '\0'; /* Don't unlink any existing file */
1.21 markus 1522: cleanup_exit(1);
1523: }
1.189 djm 1524: umask(prev_mask);
1.46 markus 1525:
1.23 markus 1526: /*
1527: * Fork, and have the parent execute the command, if any, or present
1528: * the socket data. The child continues as the authentication agent.
1529: */
1.201 djm 1530: if (D_flag || d_flag) {
1531: log_init(__progname,
1532: d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO,
1533: SYSLOG_FACILITY_AUTH, 1);
1.57 markus 1534: format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1535: printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1536: SSH_AUTHSOCKET_ENV_NAME);
1.91 mpech 1537: printf("echo Agent pid %ld;\n", (long)parent_pid);
1.210 dtucker 1538: fflush(stdout);
1.57 markus 1539: goto skip;
1540: }
1.21 markus 1541: pid = fork();
1542: if (pid == -1) {
1543: perror("fork");
1.81 stevesk 1544: cleanup_exit(1);
1.21 markus 1545: }
1546: if (pid != 0) { /* Parent - execute the given command. */
1547: close(sock);
1.91 mpech 1548: snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1.21 markus 1549: if (ac == 0) {
1550: format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1551: printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1.46 markus 1552: SSH_AUTHSOCKET_ENV_NAME);
1.21 markus 1553: printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1.46 markus 1554: SSH_AGENTPID_ENV_NAME);
1.91 mpech 1555: printf("echo Agent pid %ld;\n", (long)pid);
1.21 markus 1556: exit(0);
1557: }
1.36 deraadt 1558: if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1559: setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1560: perror("setenv");
1561: exit(1);
1562: }
1.21 markus 1563: execvp(av[0], av);
1564: perror(av[0]);
1565: exit(1);
1566: }
1.81 stevesk 1567: /* child */
1568: log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1.67 stevesk 1569:
1570: if (setsid() == -1) {
1.81 stevesk 1571: error("setsid: %s", strerror(errno));
1.67 stevesk 1572: cleanup_exit(1);
1573: }
1574:
1575: (void)chdir("/");
1.265 djm 1576: if (stdfd_devnull(1, 1, 1) == -1)
1.266 djm 1577: error_f("stdfd_devnull failed");
1.21 markus 1578:
1.41 markus 1579: /* deny core dumps, since memory contains unencrypted private keys */
1580: rlim.rlim_cur = rlim.rlim_max = 0;
1.237 deraadt 1581: if (setrlimit(RLIMIT_CORE, &rlim) == -1) {
1.81 stevesk 1582: error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1.21 markus 1583: cleanup_exit(1);
1584: }
1.57 markus 1585:
1586: skip:
1.187 djm 1587:
1588: cleanup_pid = getpid();
1.163 markus 1589:
1590: #ifdef ENABLE_PKCS11
1591: pkcs11_init(0);
1592: #endif
1.21 markus 1593: new_socket(AUTH_SOCKET, sock);
1.155 dtucker 1594: if (ac > 0)
1595: parent_alive_interval = 10;
1.33 markus 1596: idtab_init();
1.252 dtucker 1597: ssh_signal(SIGPIPE, SIG_IGN);
1598: ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN);
1599: ssh_signal(SIGHUP, cleanup_handler);
1600: ssh_signal(SIGTERM, cleanup_handler);
1.205 djm 1601:
1.215 djm 1602: if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1)
1.205 djm 1603: fatal("%s: pledge: %s", __progname, strerror(errno));
1.66 markus 1604:
1.21 markus 1605: while (1) {
1.231 djm 1606: prepare_poll(&pfd, &npfd, &timeout, maxfds);
1.223 djm 1607: result = poll(pfd, npfd, timeout);
1.154 dtucker 1608: saved_errno = errno;
1.155 dtucker 1609: if (parent_alive_interval != 0)
1610: check_parent_exists();
1611: (void) reaper(); /* remove expired keys */
1.237 deraadt 1612: if (result == -1) {
1.154 dtucker 1613: if (saved_errno == EINTR)
1.21 markus 1614: continue;
1.223 djm 1615: fatal("poll: %s", strerror(saved_errno));
1.154 dtucker 1616: } else if (result > 0)
1.231 djm 1617: after_poll(pfd, npfd, maxfds);
1.15 markus 1618: }
1.21 markus 1619: /* NOTREACHED */
1.1 deraadt 1620: }
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