Annotation of src/usr.bin/ssh/ssh-agent.c, Revision 1.270
1.270 ! djm 1: /* $OpenBSD: ssh-agent.c,v 1.269 2021/01/26 00:47:47 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) */
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) {
1.228 markus 248: if ((r = sshkey_puts_opts(id->key, msg, SSHKEY_SERIALIZE_INFO))
249: != 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;
1.270 ! djm 416: size_t i, 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:
! 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: sshkey_free(key);
512: success = 1;
513: done:
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:
563: static void
1.221 djm 564: process_add_identity(SocketEntry *e)
1.1 deraadt 565: {
1.157 canacar 566: Identity *id;
1.194 markus 567: int success = 0, confirm = 0;
1.257 markus 568: u_int seconds = 0, maxsign;
1.238 djm 569: char *fp, *comment = NULL, *ext_name = NULL, *sk_provider = NULL;
1.254 djm 570: char canonical_provider[PATH_MAX];
1.174 dtucker 571: time_t death = 0;
1.194 markus 572: struct sshkey *k = NULL;
573: u_char ctype;
574: int r = SSH_ERR_INTERNAL_ERROR;
1.33 markus 575:
1.269 djm 576: debug2_f("entering");
1.221 djm 577: if ((r = sshkey_private_deserialize(e->request, &k)) != 0 ||
578: k == NULL ||
1.194 markus 579: (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) {
1.266 djm 580: error_fr(r, "parse");
1.194 markus 581: goto err;
582: }
583: while (sshbuf_len(e->request)) {
584: if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) {
1.266 djm 585: error_fr(r, "parse constraint type");
1.194 markus 586: goto err;
587: }
588: switch (ctype) {
1.94 markus 589: case SSH_AGENT_CONSTRAIN_LIFETIME:
1.194 markus 590: if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) {
1.266 djm 591: error_fr(r, "parse lifetime constraint");
1.194 markus 592: goto err;
593: }
594: death = monotime() + seconds;
1.94 markus 595: break;
1.107 markus 596: case SSH_AGENT_CONSTRAIN_CONFIRM:
597: confirm = 1;
598: break;
1.228 markus 599: case SSH_AGENT_CONSTRAIN_MAXSIGN:
600: if ((r = sshbuf_get_u32(e->request, &maxsign)) != 0) {
1.266 djm 601: error_fr(r, "parse maxsign constraint");
1.228 markus 602: goto err;
603: }
604: if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) {
1.266 djm 605: error_fr(r, "enable maxsign");
1.228 markus 606: goto err;
607: }
608: break;
1.238 djm 609: case SSH_AGENT_CONSTRAIN_EXTENSION:
610: if ((r = sshbuf_get_cstring(e->request,
611: &ext_name, NULL)) != 0) {
1.266 djm 612: error_fr(r, "parse constraint extension");
1.238 djm 613: goto err;
614: }
1.266 djm 615: debug_f("constraint ext %s", ext_name);
1.238 djm 616: if (strcmp(ext_name, "sk-provider@openssh.com") == 0) {
617: if (sk_provider != NULL) {
618: error("%s already set", ext_name);
619: goto err;
620: }
621: if ((r = sshbuf_get_cstring(e->request,
622: &sk_provider, NULL)) != 0) {
1.266 djm 623: error_fr(r, "parse %s", ext_name);
1.238 djm 624: goto err;
625: }
626: } else {
1.266 djm 627: error_f("unsupported constraint \"%s\"",
628: ext_name);
1.238 djm 629: goto err;
630: }
631: free(ext_name);
632: break;
1.94 markus 633: default:
1.266 djm 634: error_f("Unknown constraint %d", ctype);
1.194 markus 635: err:
1.238 djm 636: free(sk_provider);
637: free(ext_name);
1.194 markus 638: sshbuf_reset(e->request);
1.173 djm 639: free(comment);
1.194 markus 640: sshkey_free(k);
1.158 djm 641: goto send;
1.94 markus 642: }
643: }
1.238 djm 644: if (sk_provider != NULL) {
1.240 markus 645: if (!sshkey_is_sk(k)) {
1.255 naddy 646: error("Cannot add provider: %s is not an "
647: "authenticator-hosted key", sshkey_type(k));
1.238 djm 648: free(sk_provider);
649: goto send;
650: }
1.254 djm 651: if (strcasecmp(sk_provider, "internal") == 0) {
1.266 djm 652: debug_f("internal provider");
1.254 djm 653: } else {
654: if (realpath(sk_provider, canonical_provider) == NULL) {
655: verbose("failed provider \"%.100s\": "
656: "realpath: %s", sk_provider,
657: strerror(errno));
658: free(sk_provider);
659: goto send;
660: }
1.238 djm 661: free(sk_provider);
1.254 djm 662: sk_provider = xstrdup(canonical_provider);
663: if (match_pattern_list(sk_provider,
1.260 djm 664: allowed_providers, 0) != 1) {
1.254 djm 665: error("Refusing add key: "
1.260 djm 666: "provider %s not allowed", sk_provider);
1.254 djm 667: free(sk_provider);
668: goto send;
669: }
1.238 djm 670: }
1.242 markus 671: }
672: if ((r = sshkey_shield_private(k)) != 0) {
1.266 djm 673: error_fr(r, "shield private");
1.242 markus 674: goto err;
1.238 djm 675: }
1.194 markus 676:
1.158 djm 677: success = 1;
1.106 marc 678: if (lifetime && !death)
1.175 dtucker 679: death = monotime() + lifetime;
1.221 djm 680: if ((id = lookup_identity(k)) == NULL) {
1.163 markus 681: id = xcalloc(1, sizeof(Identity));
1.221 djm 682: TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
1.33 markus 683: /* Increment the number of identities. */
1.221 djm 684: idtab->nentries++;
1.33 markus 685: } else {
1.228 markus 686: /* key state might have been updated */
687: sshkey_free(id->key);
1.173 djm 688: free(id->comment);
1.238 djm 689: free(id->sk_provider);
1.33 markus 690: }
1.228 markus 691: id->key = k;
1.157 canacar 692: id->comment = comment;
693: id->death = death;
694: id->confirm = confirm;
1.238 djm 695: id->sk_provider = sk_provider;
696:
697: if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT,
698: SSH_FP_DEFAULT)) == NULL)
1.266 djm 699: fatal_f("sshkey_fingerprint failed");
700: debug_f("add %s %s \"%.100s\" (life: %u) (confirm: %u) "
701: "(provider: %s)", sshkey_ssh_name(k), fp, comment,
1.238 djm 702: seconds, confirm, sk_provider == NULL ? "none" : sk_provider);
703: free(fp);
1.33 markus 704: send:
1.194 markus 705: send_status(e, success);
1.1 deraadt 706: }
707:
1.88 markus 708: /* XXX todo: encrypt sensitive data with passphrase */
709: static void
710: process_lock_agent(SocketEntry *e, int lock)
711: {
1.203 dtucker 712: int r, success = 0, delay;
1.213 djm 713: char *passwd;
714: u_char passwdhash[LOCK_SIZE];
1.203 dtucker 715: static u_int fail_count = 0;
716: size_t pwlen;
717:
1.269 djm 718: debug2_f("entering");
1.226 djm 719: /*
720: * This is deliberately fatal: the user has requested that we lock,
721: * but we can't parse their request properly. The only safe thing to
722: * do is abort.
723: */
1.203 dtucker 724: if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0)
1.266 djm 725: fatal_fr(r, "parse");
1.203 dtucker 726: if (pwlen == 0) {
727: debug("empty password not supported");
728: } else if (locked && !lock) {
729: if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
730: passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0)
731: fatal("bcrypt_pbkdf");
1.213 djm 732: if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) {
1.203 dtucker 733: debug("agent unlocked");
734: locked = 0;
735: fail_count = 0;
1.213 djm 736: explicit_bzero(lock_pwhash, sizeof(lock_pwhash));
1.203 dtucker 737: success = 1;
738: } else {
739: /* delay in 0.1s increments up to 10s */
740: if (fail_count < 100)
741: fail_count++;
742: delay = 100000 * fail_count;
743: debug("unlock failed, delaying %0.1lf seconds",
744: (double)delay/1000000);
745: usleep(delay);
746: }
747: explicit_bzero(passwdhash, sizeof(passwdhash));
1.88 markus 748: } else if (!locked && lock) {
1.203 dtucker 749: debug("agent locked");
1.88 markus 750: locked = 1;
1.203 dtucker 751: arc4random_buf(lock_salt, sizeof(lock_salt));
752: if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
1.213 djm 753: lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0)
1.203 dtucker 754: fatal("bcrypt_pbkdf");
1.88 markus 755: success = 1;
756: }
1.256 jsg 757: freezero(passwd, pwlen);
1.194 markus 758: send_status(e, success);
1.88 markus 759: }
760:
761: static void
1.221 djm 762: no_identities(SocketEntry *e)
1.88 markus 763: {
1.194 markus 764: struct sshbuf *msg;
765: int r;
1.88 markus 766:
1.194 markus 767: if ((msg = sshbuf_new()) == NULL)
1.266 djm 768: fatal_f("sshbuf_new failed");
1.221 djm 769: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
1.194 markus 770: (r = sshbuf_put_u32(msg, 0)) != 0 ||
771: (r = sshbuf_put_stringb(e->output, msg)) != 0)
1.266 djm 772: fatal_fr(r, "compose");
1.194 markus 773: sshbuf_free(msg);
1.88 markus 774: }
1.59 markus 775:
1.163 markus 776: #ifdef ENABLE_PKCS11
1.59 markus 777: static void
1.158 djm 778: process_add_smartcard_key(SocketEntry *e)
1.59 markus 779: {
1.226 djm 780: char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
1.253 djm 781: char **comments = NULL;
1.221 djm 782: int r, i, count = 0, success = 0, confirm = 0;
1.194 markus 783: u_int seconds;
1.174 dtucker 784: time_t death = 0;
1.194 markus 785: u_char type;
786: struct sshkey **keys = NULL, *k;
1.84 markus 787: Identity *id;
1.75 deraadt 788:
1.269 djm 789: debug2_f("entering");
1.194 markus 790: if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
1.226 djm 791: (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
1.266 djm 792: error_fr(r, "parse");
1.226 djm 793: goto send;
794: }
1.194 markus 795:
796: while (sshbuf_len(e->request)) {
1.226 djm 797: if ((r = sshbuf_get_u8(e->request, &type)) != 0) {
1.266 djm 798: error_fr(r, "parse type");
1.226 djm 799: goto send;
800: }
1.194 markus 801: switch (type) {
1.110 djm 802: case SSH_AGENT_CONSTRAIN_LIFETIME:
1.226 djm 803: if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) {
1.266 djm 804: error_fr(r, "parse lifetime");
1.226 djm 805: goto send;
806: }
1.194 markus 807: death = monotime() + seconds;
1.110 djm 808: break;
809: case SSH_AGENT_CONSTRAIN_CONFIRM:
810: confirm = 1;
811: break;
812: default:
1.266 djm 813: error_f("Unknown constraint type %d", type);
1.158 djm 814: goto send;
1.110 djm 815: }
816: }
1.215 djm 817: if (realpath(provider, canonical_provider) == NULL) {
818: verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
819: provider, strerror(errno));
820: goto send;
821: }
1.260 djm 822: if (match_pattern_list(canonical_provider, allowed_providers, 0) != 1) {
1.215 djm 823: verbose("refusing PKCS#11 add of \"%.100s\": "
1.260 djm 824: "provider not allowed", canonical_provider);
1.215 djm 825: goto send;
826: }
1.266 djm 827: debug_f("add %.100s", canonical_provider);
1.110 djm 828: if (lifetime && !death)
1.175 dtucker 829: death = monotime() + lifetime;
1.110 djm 830:
1.253 djm 831: count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments);
1.163 markus 832: for (i = 0; i < count; i++) {
1.84 markus 833: k = keys[i];
1.221 djm 834: if (lookup_identity(k) == NULL) {
1.163 markus 835: id = xcalloc(1, sizeof(Identity));
1.84 markus 836: id->key = k;
1.253 djm 837: keys[i] = NULL; /* transferred */
1.215 djm 838: id->provider = xstrdup(canonical_provider);
1.253 djm 839: if (*comments[i] != '\0') {
840: id->comment = comments[i];
841: comments[i] = NULL; /* transferred */
842: } else {
843: id->comment = xstrdup(canonical_provider);
844: }
1.110 djm 845: id->death = death;
846: id->confirm = confirm;
1.221 djm 847: TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
848: idtab->nentries++;
1.84 markus 849: success = 1;
850: }
1.253 djm 851: sshkey_free(keys[i]);
852: free(comments[i]);
1.59 markus 853: }
854: send:
1.173 djm 855: free(pin);
856: free(provider);
857: free(keys);
1.253 djm 858: free(comments);
1.194 markus 859: send_status(e, success);
1.59 markus 860: }
861:
862: static void
863: process_remove_smartcard_key(SocketEntry *e)
864: {
1.217 djm 865: char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
1.221 djm 866: int r, success = 0;
1.163 markus 867: Identity *id, *nxt;
1.59 markus 868:
1.269 djm 869: debug2_f("entering");
1.194 markus 870: if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
1.226 djm 871: (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
1.266 djm 872: error_fr(r, "parse");
1.226 djm 873: goto send;
874: }
1.173 djm 875: free(pin);
1.59 markus 876:
1.217 djm 877: if (realpath(provider, canonical_provider) == NULL) {
878: verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
879: provider, strerror(errno));
880: goto send;
881: }
882:
1.266 djm 883: debug_f("remove %.100s", canonical_provider);
1.221 djm 884: for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
885: nxt = TAILQ_NEXT(id, next);
886: /* Skip file--based keys */
887: if (id->provider == NULL)
888: continue;
889: if (!strcmp(canonical_provider, id->provider)) {
890: TAILQ_REMOVE(&idtab->idlist, id, next);
891: free_identity(id);
892: idtab->nentries--;
1.59 markus 893: }
894: }
1.217 djm 895: if (pkcs11_del_provider(canonical_provider) == 0)
1.163 markus 896: success = 1;
897: else
1.266 djm 898: error_f("pkcs11_del_provider failed");
1.218 deraadt 899: send:
1.173 djm 900: free(provider);
1.194 markus 901: send_status(e, success);
1.59 markus 902: }
1.163 markus 903: #endif /* ENABLE_PKCS11 */
1.59 markus 904:
1.264 djm 905: /*
906: * dispatch incoming message.
907: * returns 1 on success, 0 for incomplete messages or -1 on error.
908: */
1.223 djm 909: static int
910: process_message(u_int socknum)
1.1 deraadt 911: {
1.194 markus 912: u_int msg_len;
913: u_char type;
914: const u_char *cp;
915: int r;
1.223 djm 916: SocketEntry *e;
917:
1.266 djm 918: if (socknum >= sockets_alloc)
919: fatal_f("sock %u >= allocated %u", socknum, sockets_alloc);
1.223 djm 920: e = &sockets[socknum];
1.89 markus 921:
1.194 markus 922: if (sshbuf_len(e->input) < 5)
1.223 djm 923: return 0; /* Incomplete message header. */
1.194 markus 924: cp = sshbuf_ptr(e->input);
925: msg_len = PEEK_U32(cp);
1.223 djm 926: if (msg_len > AGENT_MAX_LEN) {
1.266 djm 927: debug_f("socket %u (fd=%d) message too long %u > %u",
928: socknum, e->fd, msg_len, AGENT_MAX_LEN);
1.223 djm 929: return -1;
1.21 markus 930: }
1.194 markus 931: if (sshbuf_len(e->input) < msg_len + 4)
1.223 djm 932: return 0; /* Incomplete message body. */
1.87 markus 933:
934: /* move the current input to e->request */
1.194 markus 935: sshbuf_reset(e->request);
936: if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 ||
1.223 djm 937: (r = sshbuf_get_u8(e->request, &type)) != 0) {
938: if (r == SSH_ERR_MESSAGE_INCOMPLETE ||
939: r == SSH_ERR_STRING_TOO_LARGE) {
1.266 djm 940: error_fr(r, "parse");
1.223 djm 941: return -1;
942: }
1.266 djm 943: fatal_fr(r, "parse");
1.223 djm 944: }
945:
1.266 djm 946: debug_f("socket %u (fd=%d) type %d", socknum, e->fd, type);
1.21 markus 947:
1.230 djm 948: /* check whether agent is locked */
1.88 markus 949: if (locked && type != SSH_AGENTC_UNLOCK) {
1.194 markus 950: sshbuf_reset(e->request);
1.88 markus 951: switch (type) {
952: case SSH2_AGENTC_REQUEST_IDENTITIES:
953: /* send empty lists */
1.221 djm 954: no_identities(e);
1.88 markus 955: break;
956: default:
957: /* send a fail message for all other request types */
1.194 markus 958: send_status(e, 0);
1.88 markus 959: }
1.264 djm 960: return 1;
1.88 markus 961: }
962:
1.21 markus 963: switch (type) {
1.88 markus 964: case SSH_AGENTC_LOCK:
965: case SSH_AGENTC_UNLOCK:
966: process_lock_agent(e, type == SSH_AGENTC_LOCK);
967: break;
1.21 markus 968: case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
1.221 djm 969: process_remove_all_identities(e); /* safe for !WITH_SSH1 */
1.33 markus 970: break;
971: /* ssh2 */
972: case SSH2_AGENTC_SIGN_REQUEST:
973: process_sign_request2(e);
974: break;
975: case SSH2_AGENTC_REQUEST_IDENTITIES:
1.221 djm 976: process_request_identities(e);
1.33 markus 977: break;
978: case SSH2_AGENTC_ADD_IDENTITY:
1.94 markus 979: case SSH2_AGENTC_ADD_ID_CONSTRAINED:
1.221 djm 980: process_add_identity(e);
1.33 markus 981: break;
982: case SSH2_AGENTC_REMOVE_IDENTITY:
1.221 djm 983: process_remove_identity(e);
1.33 markus 984: break;
985: case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
1.221 djm 986: process_remove_all_identities(e);
1.21 markus 987: break;
1.163 markus 988: #ifdef ENABLE_PKCS11
1.59 markus 989: case SSH_AGENTC_ADD_SMARTCARD_KEY:
1.110 djm 990: case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
1.59 markus 991: process_add_smartcard_key(e);
1.75 deraadt 992: break;
1.59 markus 993: case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
994: process_remove_smartcard_key(e);
1.75 deraadt 995: break;
1.163 markus 996: #endif /* ENABLE_PKCS11 */
1.21 markus 997: default:
998: /* Unknown message. Respond with failure. */
999: error("Unknown message %d", type);
1.194 markus 1000: sshbuf_reset(e->request);
1001: send_status(e, 0);
1.21 markus 1002: break;
1003: }
1.264 djm 1004: return 1;
1.1 deraadt 1005: }
1006:
1.55 itojun 1007: static void
1.73 stevesk 1008: new_socket(sock_type type, int fd)
1.1 deraadt 1009: {
1.112 markus 1010: u_int i, old_alloc, new_alloc;
1.96 deraadt 1011:
1.269 djm 1012: debug_f("type = %s", type == AUTH_CONNECTION ? "CONNECTION" :
1013: (type == AUTH_SOCKET ? "SOCKET" : "UNKNOWN"));
1.119 djm 1014: set_nonblock(fd);
1.21 markus 1015:
1016: if (fd > max_fd)
1017: max_fd = fd;
1018:
1019: for (i = 0; i < sockets_alloc; i++)
1020: if (sockets[i].type == AUTH_UNUSED) {
1021: sockets[i].fd = fd;
1.266 djm 1022: if ((sockets[i].input = sshbuf_new()) == NULL ||
1023: (sockets[i].output = sshbuf_new()) == NULL ||
1024: (sockets[i].request = sshbuf_new()) == NULL)
1025: fatal_f("sshbuf_new failed");
1.112 markus 1026: sockets[i].type = type;
1.21 markus 1027: return;
1028: }
1029: old_alloc = sockets_alloc;
1.112 markus 1030: new_alloc = sockets_alloc + 10;
1.269 djm 1031: sockets = xrecallocarray(sockets, old_alloc, new_alloc,
1032: sizeof(sockets[0]));
1.112 markus 1033: for (i = old_alloc; i < new_alloc; i++)
1.21 markus 1034: sockets[i].type = AUTH_UNUSED;
1.112 markus 1035: sockets_alloc = new_alloc;
1.21 markus 1036: sockets[old_alloc].fd = fd;
1.266 djm 1037: if ((sockets[old_alloc].input = sshbuf_new()) == NULL ||
1038: (sockets[old_alloc].output = sshbuf_new()) == NULL ||
1039: (sockets[old_alloc].request = sshbuf_new()) == NULL)
1040: fatal_f("sshbuf_new failed");
1.112 markus 1041: sockets[old_alloc].type = type;
1.1 deraadt 1042: }
1043:
1.55 itojun 1044: static int
1.223 djm 1045: handle_socket_read(u_int socknum)
1.1 deraadt 1046: {
1.223 djm 1047: struct sockaddr_un sunaddr;
1048: socklen_t slen;
1049: uid_t euid;
1050: gid_t egid;
1051: int fd;
1052:
1053: slen = sizeof(sunaddr);
1054: fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen);
1.237 deraadt 1055: if (fd == -1) {
1.223 djm 1056: error("accept from AUTH_SOCKET: %s", strerror(errno));
1057: return -1;
1058: }
1.237 deraadt 1059: if (getpeereid(fd, &euid, &egid) == -1) {
1.223 djm 1060: error("getpeereid %d failed: %s", fd, strerror(errno));
1061: close(fd);
1062: return -1;
1063: }
1064: if ((euid != 0) && (getuid() != euid)) {
1065: error("uid mismatch: peer euid %u != uid %u",
1066: (u_int) euid, (u_int) getuid());
1067: close(fd);
1068: return -1;
1069: }
1070: new_socket(AUTH_CONNECTION, fd);
1071: return 0;
1072: }
1073:
1074: static int
1075: handle_conn_read(u_int socknum)
1076: {
1.233 djm 1077: char buf[AGENT_RBUF_LEN];
1.223 djm 1078: ssize_t len;
1079: int r;
1080:
1081: if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) {
1082: if (len == -1) {
1083: if (errno == EAGAIN || errno == EINTR)
1084: return 0;
1.266 djm 1085: error_f("read error on socket %u (fd %d): %s",
1086: socknum, sockets[socknum].fd, strerror(errno));
1.223 djm 1087: }
1088: return -1;
1089: }
1090: if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0)
1.266 djm 1091: fatal_fr(r, "compose");
1.223 djm 1092: explicit_bzero(buf, sizeof(buf));
1.264 djm 1093: for (;;) {
1094: if ((r = process_message(socknum)) == -1)
1095: return -1;
1096: else if (r == 0)
1097: break;
1098: }
1.223 djm 1099: return 0;
1100: }
1101:
1102: static int
1103: handle_conn_write(u_int socknum)
1104: {
1105: ssize_t len;
1106: int r;
1107:
1108: if (sshbuf_len(sockets[socknum].output) == 0)
1109: return 0; /* shouldn't happen */
1110: if ((len = write(sockets[socknum].fd,
1111: sshbuf_ptr(sockets[socknum].output),
1112: sshbuf_len(sockets[socknum].output))) <= 0) {
1113: if (len == -1) {
1114: if (errno == EAGAIN || errno == EINTR)
1115: return 0;
1.266 djm 1116: error_f("read error on socket %u (fd %d): %s",
1117: socknum, sockets[socknum].fd, strerror(errno));
1.223 djm 1118: }
1119: return -1;
1120: }
1121: if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0)
1.266 djm 1122: fatal_fr(r, "consume");
1.223 djm 1123: return 0;
1124: }
1125:
1126: static void
1.231 djm 1127: after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds)
1.223 djm 1128: {
1129: size_t i;
1.231 djm 1130: u_int socknum, activefds = npfd;
1.223 djm 1131:
1132: for (i = 0; i < npfd; i++) {
1133: if (pfd[i].revents == 0)
1134: continue;
1135: /* Find sockets entry */
1136: for (socknum = 0; socknum < sockets_alloc; socknum++) {
1137: if (sockets[socknum].type != AUTH_SOCKET &&
1138: sockets[socknum].type != AUTH_CONNECTION)
1139: continue;
1140: if (pfd[i].fd == sockets[socknum].fd)
1141: break;
1142: }
1143: if (socknum >= sockets_alloc) {
1.266 djm 1144: error_f("no socket for fd %d", pfd[i].fd);
1.223 djm 1145: continue;
1146: }
1147: /* Process events */
1148: switch (sockets[socknum].type) {
1149: case AUTH_SOCKET:
1.231 djm 1150: if ((pfd[i].revents & (POLLIN|POLLERR)) == 0)
1151: break;
1152: if (npfd > maxfds) {
1153: debug3("out of fds (active %u >= limit %u); "
1154: "skipping accept", activefds, maxfds);
1155: break;
1156: }
1157: if (handle_socket_read(socknum) == 0)
1158: activefds++;
1.223 djm 1159: break;
1160: case AUTH_CONNECTION:
1161: if ((pfd[i].revents & (POLLIN|POLLERR)) != 0 &&
1162: handle_conn_read(socknum) != 0) {
1.231 djm 1163: goto close_sock;
1164: }
1165: if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 &&
1166: handle_conn_write(socknum) != 0) {
1167: close_sock:
1168: if (activefds == 0)
1169: fatal("activefds == 0 at close_sock");
1.223 djm 1170: close_socket(&sockets[socknum]);
1.231 djm 1171: activefds--;
1.223 djm 1172: break;
1173: }
1174: break;
1175: default:
1176: break;
1177: }
1178: }
1179: }
1180:
1181: static int
1.231 djm 1182: prepare_poll(struct pollfd **pfdp, size_t *npfdp, int *timeoutp, u_int maxfds)
1.223 djm 1183: {
1184: struct pollfd *pfd = *pfdp;
1185: size_t i, j, npfd = 0;
1.174 dtucker 1186: time_t deadline;
1.233 djm 1187: int r;
1.46 markus 1188:
1.223 djm 1189: /* Count active sockets */
1.46 markus 1190: for (i = 0; i < sockets_alloc; i++) {
1.21 markus 1191: switch (sockets[i].type) {
1192: case AUTH_SOCKET:
1193: case AUTH_CONNECTION:
1.223 djm 1194: npfd++;
1.21 markus 1195: break;
1196: case AUTH_UNUSED:
1197: break;
1198: default:
1199: fatal("Unknown socket type %d", sockets[i].type);
1200: break;
1201: }
1.46 markus 1202: }
1.223 djm 1203: if (npfd != *npfdp &&
1204: (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL)
1.266 djm 1205: fatal_f("recallocarray failed");
1.223 djm 1206: *pfdp = pfd;
1207: *npfdp = npfd;
1.46 markus 1208:
1.223 djm 1209: for (i = j = 0; i < sockets_alloc; i++) {
1.46 markus 1210: switch (sockets[i].type) {
1211: case AUTH_SOCKET:
1.231 djm 1212: if (npfd > maxfds) {
1213: debug3("out of fds (active %zu >= limit %u); "
1214: "skipping arming listener", npfd, maxfds);
1215: break;
1216: }
1217: pfd[j].fd = sockets[i].fd;
1218: pfd[j].revents = 0;
1219: pfd[j].events = POLLIN;
1220: j++;
1221: break;
1.46 markus 1222: case AUTH_CONNECTION:
1.223 djm 1223: pfd[j].fd = sockets[i].fd;
1224: pfd[j].revents = 0;
1.233 djm 1225: /*
1226: * Only prepare to read if we can handle a full-size
1227: * input read buffer and enqueue a max size reply..
1228: */
1229: if ((r = sshbuf_check_reserve(sockets[i].input,
1230: AGENT_RBUF_LEN)) == 0 &&
1231: (r = sshbuf_check_reserve(sockets[i].output,
1232: AGENT_MAX_LEN)) == 0)
1233: pfd[j].events = POLLIN;
1.266 djm 1234: else if (r != SSH_ERR_NO_BUFFER_SPACE)
1235: fatal_fr(r, "reserve");
1.194 markus 1236: if (sshbuf_len(sockets[i].output) > 0)
1.223 djm 1237: pfd[j].events |= POLLOUT;
1238: j++;
1.46 markus 1239: break;
1240: default:
1241: break;
1242: }
1243: }
1.155 dtucker 1244: deadline = reaper();
1245: if (parent_alive_interval != 0)
1246: deadline = (deadline == 0) ? parent_alive_interval :
1.214 deraadt 1247: MINIMUM(deadline, parent_alive_interval);
1.155 dtucker 1248: if (deadline == 0) {
1.224 djm 1249: *timeoutp = -1; /* INFTIM */
1.155 dtucker 1250: } else {
1.223 djm 1251: if (deadline > INT_MAX / 1000)
1252: *timeoutp = INT_MAX / 1000;
1253: else
1254: *timeoutp = deadline * 1000;
1.155 dtucker 1255: }
1.46 markus 1256: return (1);
1.21 markus 1257: }
1258:
1.55 itojun 1259: static void
1.113 markus 1260: cleanup_socket(void)
1.15 markus 1261: {
1.187 djm 1262: if (cleanup_pid != 0 && getpid() != cleanup_pid)
1263: return;
1.266 djm 1264: debug_f("cleanup");
1.48 deraadt 1265: if (socket_name[0])
1266: unlink(socket_name);
1267: if (socket_dir[0])
1268: rmdir(socket_dir);
1.10 markus 1269: }
1270:
1.114 markus 1271: void
1.15 markus 1272: cleanup_exit(int i)
1273: {
1.113 markus 1274: cleanup_socket();
1275: _exit(i);
1.15 markus 1276: }
1277:
1.135 deraadt 1278: /*ARGSUSED*/
1.55 itojun 1279: static void
1.48 deraadt 1280: cleanup_handler(int sig)
1281: {
1.113 markus 1282: cleanup_socket();
1.163 markus 1283: #ifdef ENABLE_PKCS11
1284: pkcs11_terminate();
1285: #endif
1.48 deraadt 1286: _exit(2);
1.113 markus 1287: }
1288:
1.68 markus 1289: static void
1.155 dtucker 1290: check_parent_exists(void)
1.68 markus 1291: {
1.172 dtucker 1292: /*
1293: * If our parent has exited then getppid() will return (pid_t)1,
1294: * so testing for that should be safe.
1295: */
1296: if (parent_pid != -1 && getppid() != parent_pid) {
1.68 markus 1297: /* printf("Parent has died - Authentication agent exiting.\n"); */
1.155 dtucker 1298: cleanup_socket();
1299: _exit(2);
1.68 markus 1300: }
1.48 deraadt 1301: }
1302:
1.55 itojun 1303: static void
1.50 itojun 1304: usage(void)
1.15 markus 1305: {
1.184 deraadt 1306: fprintf(stderr,
1.250 jmc 1307: "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n"
1.261 jmc 1308: " [-P allowed_providers] [-t life]\n"
1.260 djm 1309: " ssh-agent [-a bind_address] [-E fingerprint_hash] [-P allowed_providers]\n"
1.259 dtucker 1310: " [-t life] command [arg ...]\n"
1.250 jmc 1311: " ssh-agent [-c | -s] -k\n");
1.21 markus 1312: exit(1);
1.15 markus 1313: }
1314:
1.2 provos 1315: int
1316: main(int ac, char **av)
1.1 deraadt 1317: {
1.201 djm 1318: int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0;
1.265 djm 1319: int sock, ch, result, saved_errno;
1.96 deraadt 1320: char *shell, *format, *pidstr, *agentsocket = NULL;
1.41 markus 1321: struct rlimit rlim;
1.96 deraadt 1322: extern int optind;
1.98 stevesk 1323: extern char *optarg;
1.21 markus 1324: pid_t pid;
1.96 deraadt 1325: char pidstrbuf[1 + 3 * sizeof pid];
1.161 tobias 1326: size_t len;
1.189 djm 1327: mode_t prev_mask;
1.224 djm 1328: int timeout = -1; /* INFTIM */
1.223 djm 1329: struct pollfd *pfd = NULL;
1330: size_t npfd = 0;
1.231 djm 1331: u_int maxfds;
1.123 djm 1332:
1333: /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1334: sanitise_stdfd();
1.99 markus 1335:
1336: /* drop */
1337: setegid(getgid());
1338: setgid(getgid());
1.53 markus 1339:
1.231 djm 1340: if (getrlimit(RLIMIT_NOFILE, &rlim) == -1)
1341: fatal("%s: getrlimit: %s", __progname, strerror(errno));
1342:
1.185 markus 1343: #ifdef WITH_OPENSSL
1.170 djm 1344: OpenSSL_add_all_algorithms();
1.185 markus 1345: #endif
1.21 markus 1346:
1.258 djm 1347: while ((ch = getopt(ac, av, "cDdksE:a:O:P:t:")) != -1) {
1.21 markus 1348: switch (ch) {
1.192 djm 1349: case 'E':
1350: fingerprint_hash = ssh_digest_alg_by_name(optarg);
1351: if (fingerprint_hash == -1)
1352: fatal("Invalid hash algorithm \"%s\"", optarg);
1353: break;
1.21 markus 1354: case 'c':
1355: if (s_flag)
1356: usage();
1357: c_flag++;
1358: break;
1359: case 'k':
1360: k_flag++;
1.258 djm 1361: break;
1362: case 'O':
1363: if (strcmp(optarg, "no-restrict-websafe") == 0)
1364: restrict_websafe = 0;
1365: else
1366: fatal("Unknown -O option");
1.21 markus 1367: break;
1.215 djm 1368: case 'P':
1.260 djm 1369: if (allowed_providers != NULL)
1.215 djm 1370: fatal("-P option already specified");
1.260 djm 1371: allowed_providers = xstrdup(optarg);
1.215 djm 1372: break;
1.21 markus 1373: case 's':
1374: if (c_flag)
1375: usage();
1376: s_flag++;
1377: break;
1.57 markus 1378: case 'd':
1.201 djm 1379: if (d_flag || D_flag)
1.57 markus 1380: usage();
1381: d_flag++;
1382: break;
1.201 djm 1383: case 'D':
1384: if (d_flag || D_flag)
1385: usage();
1386: D_flag++;
1387: break;
1.86 markus 1388: case 'a':
1389: agentsocket = optarg;
1.106 marc 1390: break;
1391: case 't':
1392: if ((lifetime = convtime(optarg)) == -1) {
1393: fprintf(stderr, "Invalid lifetime\n");
1394: usage();
1395: }
1.86 markus 1396: break;
1.21 markus 1397: default:
1398: usage();
1399: }
1400: }
1401: ac -= optind;
1402: av += optind;
1403:
1.201 djm 1404: if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag))
1.21 markus 1405: usage();
1406:
1.260 djm 1407: if (allowed_providers == NULL)
1.262 djm 1408: allowed_providers = xstrdup(DEFAULT_ALLOWED_PROVIDERS);
1.215 djm 1409:
1.85 markus 1410: if (ac == 0 && !c_flag && !s_flag) {
1.21 markus 1411: shell = getenv("SHELL");
1.161 tobias 1412: if (shell != NULL && (len = strlen(shell)) > 2 &&
1413: strncmp(shell + len - 3, "csh", 3) == 0)
1.21 markus 1414: c_flag = 1;
1415: }
1416: if (k_flag) {
1.136 deraadt 1417: const char *errstr = NULL;
1418:
1.21 markus 1419: pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1420: if (pidstr == NULL) {
1421: fprintf(stderr, "%s not set, cannot kill agent\n",
1.46 markus 1422: SSH_AGENTPID_ENV_NAME);
1.21 markus 1423: exit(1);
1424: }
1.136 deraadt 1425: pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1426: if (errstr) {
1427: fprintf(stderr,
1428: "%s=\"%s\", which is not a good PID: %s\n",
1429: SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1.21 markus 1430: exit(1);
1431: }
1432: if (kill(pid, SIGTERM) == -1) {
1433: perror("kill");
1434: exit(1);
1435: }
1436: format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1.140 djm 1437: printf(format, SSH_AUTHSOCKET_ENV_NAME);
1438: printf(format, SSH_AGENTPID_ENV_NAME);
1.91 mpech 1439: printf("echo Agent pid %ld killed;\n", (long)pid);
1.21 markus 1440: exit(0);
1441: }
1.231 djm 1442:
1443: /*
1444: * Minimum file descriptors:
1445: * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) +
1446: * a few spare for libc / stack protectors / sanitisers, etc.
1447: */
1448: #define SSH_AGENT_MIN_FDS (3+1+1+1+4)
1449: if (rlim.rlim_cur < SSH_AGENT_MIN_FDS)
1.232 djm 1450: fatal("%s: file descriptor rlimit %lld too low (minimum %u)",
1.231 djm 1451: __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS);
1452: maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS;
1453:
1.21 markus 1454: parent_pid = getpid();
1455:
1.86 markus 1456: if (agentsocket == NULL) {
1457: /* Create private directory for agent socket */
1.171 djm 1458: mktemp_proto(socket_dir, sizeof(socket_dir));
1.86 markus 1459: if (mkdtemp(socket_dir) == NULL) {
1460: perror("mkdtemp: private socket dir");
1461: exit(1);
1462: }
1.91 mpech 1463: snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1464: (long)parent_pid);
1.86 markus 1465: } else {
1466: /* Try to use specified agent socket */
1467: socket_dir[0] = '\0';
1468: strlcpy(socket_name, agentsocket, sizeof socket_name);
1.21 markus 1469: }
1470:
1.23 markus 1471: /*
1472: * Create socket early so it will exist before command gets run from
1473: * the parent.
1474: */
1.189 djm 1475: prev_mask = umask(0177);
1.188 millert 1476: sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0);
1.21 markus 1477: if (sock < 0) {
1.188 millert 1478: /* XXX - unix_listener() calls error() not perror() */
1.121 djm 1479: *socket_name = '\0'; /* Don't unlink any existing file */
1.21 markus 1480: cleanup_exit(1);
1481: }
1.189 djm 1482: umask(prev_mask);
1.46 markus 1483:
1.23 markus 1484: /*
1485: * Fork, and have the parent execute the command, if any, or present
1486: * the socket data. The child continues as the authentication agent.
1487: */
1.201 djm 1488: if (D_flag || d_flag) {
1489: log_init(__progname,
1490: d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO,
1491: SYSLOG_FACILITY_AUTH, 1);
1.57 markus 1492: format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1493: printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1494: SSH_AUTHSOCKET_ENV_NAME);
1.91 mpech 1495: printf("echo Agent pid %ld;\n", (long)parent_pid);
1.210 dtucker 1496: fflush(stdout);
1.57 markus 1497: goto skip;
1498: }
1.21 markus 1499: pid = fork();
1500: if (pid == -1) {
1501: perror("fork");
1.81 stevesk 1502: cleanup_exit(1);
1.21 markus 1503: }
1504: if (pid != 0) { /* Parent - execute the given command. */
1505: close(sock);
1.91 mpech 1506: snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1.21 markus 1507: if (ac == 0) {
1508: format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1509: printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1.46 markus 1510: SSH_AUTHSOCKET_ENV_NAME);
1.21 markus 1511: printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1.46 markus 1512: SSH_AGENTPID_ENV_NAME);
1.91 mpech 1513: printf("echo Agent pid %ld;\n", (long)pid);
1.21 markus 1514: exit(0);
1515: }
1.36 deraadt 1516: if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1517: setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1518: perror("setenv");
1519: exit(1);
1520: }
1.21 markus 1521: execvp(av[0], av);
1522: perror(av[0]);
1523: exit(1);
1524: }
1.81 stevesk 1525: /* child */
1526: log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1.67 stevesk 1527:
1528: if (setsid() == -1) {
1.81 stevesk 1529: error("setsid: %s", strerror(errno));
1.67 stevesk 1530: cleanup_exit(1);
1531: }
1532:
1533: (void)chdir("/");
1.265 djm 1534: if (stdfd_devnull(1, 1, 1) == -1)
1.266 djm 1535: error_f("stdfd_devnull failed");
1.21 markus 1536:
1.41 markus 1537: /* deny core dumps, since memory contains unencrypted private keys */
1538: rlim.rlim_cur = rlim.rlim_max = 0;
1.237 deraadt 1539: if (setrlimit(RLIMIT_CORE, &rlim) == -1) {
1.81 stevesk 1540: error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1.21 markus 1541: cleanup_exit(1);
1542: }
1.57 markus 1543:
1544: skip:
1.187 djm 1545:
1546: cleanup_pid = getpid();
1.163 markus 1547:
1548: #ifdef ENABLE_PKCS11
1549: pkcs11_init(0);
1550: #endif
1.21 markus 1551: new_socket(AUTH_SOCKET, sock);
1.155 dtucker 1552: if (ac > 0)
1553: parent_alive_interval = 10;
1.33 markus 1554: idtab_init();
1.252 dtucker 1555: ssh_signal(SIGPIPE, SIG_IGN);
1556: ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN);
1557: ssh_signal(SIGHUP, cleanup_handler);
1558: ssh_signal(SIGTERM, cleanup_handler);
1.205 djm 1559:
1.215 djm 1560: if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1)
1.205 djm 1561: fatal("%s: pledge: %s", __progname, strerror(errno));
1.66 markus 1562:
1.21 markus 1563: while (1) {
1.231 djm 1564: prepare_poll(&pfd, &npfd, &timeout, maxfds);
1.223 djm 1565: result = poll(pfd, npfd, timeout);
1.154 dtucker 1566: saved_errno = errno;
1.155 dtucker 1567: if (parent_alive_interval != 0)
1568: check_parent_exists();
1569: (void) reaper(); /* remove expired keys */
1.237 deraadt 1570: if (result == -1) {
1.154 dtucker 1571: if (saved_errno == EINTR)
1.21 markus 1572: continue;
1.223 djm 1573: fatal("poll: %s", strerror(saved_errno));
1.154 dtucker 1574: } else if (result > 0)
1.231 djm 1575: after_poll(pfd, npfd, maxfds);
1.15 markus 1576: }
1.21 markus 1577: /* NOTREACHED */
1.1 deraadt 1578: }
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