1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595
|
/* $OpenBSD: authfile.c,v 1.122 2016/11/25 23:24:45 djm Exp $ */
/*
* Copyright (c) 2000, 2013 Markus Friedl. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include "cipher.h"
#include "ssh.h"
#include "log.h"
#include "authfile.h"
#include "rsa.h"
#include "misc.h"
#include "atomicio.h"
#include "sshkey.h"
#include "sshbuf.h"
#include "ssherr.h"
#include "krl.h"
#define MAX_KEY_FILE_SIZE (1024 * 1024)
/* Save a key blob to a file */
static int
sshkey_save_private_blob(struct sshbuf *keybuf, const char *filename)
{
int fd, oerrno;
if ((fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600)) < 0)
return SSH_ERR_SYSTEM_ERROR;
if (atomicio(vwrite, fd, (u_char *)sshbuf_ptr(keybuf),
sshbuf_len(keybuf)) != sshbuf_len(keybuf)) {
oerrno = errno;
close(fd);
unlink(filename);
errno = oerrno;
return SSH_ERR_SYSTEM_ERROR;
}
close(fd);
return 0;
}
int
sshkey_save_private(struct sshkey *key, const char *filename,
const char *passphrase, const char *comment,
int force_new_format, const char *new_format_cipher, int new_format_rounds)
{
struct sshbuf *keyblob = NULL;
int r;
if ((keyblob = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshkey_private_to_fileblob(key, keyblob, passphrase, comment,
force_new_format, new_format_cipher, new_format_rounds)) != 0)
goto out;
if ((r = sshkey_save_private_blob(keyblob, filename)) != 0)
goto out;
r = 0;
out:
sshbuf_free(keyblob);
return r;
}
/* Load a key from a fd into a buffer */
int
sshkey_load_file(int fd, struct sshbuf *blob)
{
u_char buf[1024];
size_t len;
struct stat st;
int r, dontmax = 0;
if (fstat(fd, &st) < 0)
return SSH_ERR_SYSTEM_ERROR;
if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
st.st_size > MAX_KEY_FILE_SIZE)
return SSH_ERR_INVALID_FORMAT;
/*
* Pre-allocate the buffer used for the key contents and clamp its
* maximum size. This ensures that key contents are never leaked via
* implicit realloc() in the sshbuf code.
*/
if ((st.st_mode & S_IFREG) == 0 || st.st_size <= 0) {
st.st_size = 64*1024; /* 64k should be enough for anyone :) */
dontmax = 1;
}
if ((r = sshbuf_allocate(blob, st.st_size)) != 0 ||
(dontmax && (r = sshbuf_set_max_size(blob, st.st_size)) != 0))
return r;
for (;;) {
if ((len = atomicio(read, fd, buf, sizeof(buf))) == 0) {
if (errno == EPIPE)
break;
r = SSH_ERR_SYSTEM_ERROR;
goto out;
}
if ((r = sshbuf_put(blob, buf, len)) != 0)
goto out;
if (sshbuf_len(blob) > MAX_KEY_FILE_SIZE) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
}
if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
st.st_size != (off_t)sshbuf_len(blob)) {
r = SSH_ERR_FILE_CHANGED;
goto out;
}
r = 0;
out:
explicit_bzero(buf, sizeof(buf));
if (r != 0)
sshbuf_reset(blob);
return r;
}
#ifdef WITH_SSH1
/*
* Loads the public part of the ssh v1 key file. Returns NULL if an error was
* encountered (the file does not exist or is not readable), and the key
* otherwise.
*/
static int
sshkey_load_public_rsa1(int fd, struct sshkey **keyp, char **commentp)
{
struct sshbuf *b = NULL;
int r;
if (keyp != NULL)
*keyp = NULL;
if (commentp != NULL)
*commentp = NULL;
if ((b = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshkey_load_file(fd, b)) != 0)
goto out;
if ((r = sshkey_parse_public_rsa1_fileblob(b, keyp, commentp)) != 0)
goto out;
r = 0;
out:
sshbuf_free(b);
return r;
}
#endif /* WITH_SSH1 */
/* XXX remove error() calls from here? */
int
sshkey_perm_ok(int fd, const char *filename)
{
struct stat st;
if (fstat(fd, &st) < 0)
return SSH_ERR_SYSTEM_ERROR;
/*
* if a key owned by the user is accessed, then we check the
* permissions of the file. if the key owned by a different user,
* then we don't care.
*/
#ifdef HAVE_CYGWIN
if (check_ntsec(filename))
#endif
if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("Permissions 0%3.3o for '%s' are too open.",
(u_int)st.st_mode & 0777, filename);
error("It is required that your private key files are NOT accessible by others.");
error("This private key will be ignored.");
return SSH_ERR_KEY_BAD_PERMISSIONS;
}
return 0;
}
/* XXX kill perm_ok now that we have SSH_ERR_KEY_BAD_PERMISSIONS? */
int
sshkey_load_private_type(int type, const char *filename, const char *passphrase,
struct sshkey **keyp, char **commentp, int *perm_ok)
{
int fd, r;
if (keyp != NULL)
*keyp = NULL;
if (commentp != NULL)
*commentp = NULL;
if ((fd = open(filename, O_RDONLY)) < 0) {
if (perm_ok != NULL)
*perm_ok = 0;
return SSH_ERR_SYSTEM_ERROR;
}
if (sshkey_perm_ok(fd, filename) != 0) {
if (perm_ok != NULL)
*perm_ok = 0;
r = SSH_ERR_KEY_BAD_PERMISSIONS;
goto out;
}
if (perm_ok != NULL)
*perm_ok = 1;
r = sshkey_load_private_type_fd(fd, type, passphrase, keyp, commentp);
out:
close(fd);
return r;
}
int
sshkey_load_private_type_fd(int fd, int type, const char *passphrase,
struct sshkey **keyp, char **commentp)
{
struct sshbuf *buffer = NULL;
int r;
if (keyp != NULL)
*keyp = NULL;
if ((buffer = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshkey_load_file(fd, buffer)) != 0 ||
(r = sshkey_parse_private_fileblob_type(buffer, type,
passphrase, keyp, commentp)) != 0)
goto out;
/* success */
r = 0;
out:
sshbuf_free(buffer);
return r;
}
/* XXX this is almost identical to sshkey_load_private_type() */
int
sshkey_load_private(const char *filename, const char *passphrase,
struct sshkey **keyp, char **commentp)
{
struct sshbuf *buffer = NULL;
int r, fd;
if (keyp != NULL)
*keyp = NULL;
if (commentp != NULL)
*commentp = NULL;
if ((fd = open(filename, O_RDONLY)) < 0)
return SSH_ERR_SYSTEM_ERROR;
if (sshkey_perm_ok(fd, filename) != 0) {
r = SSH_ERR_KEY_BAD_PERMISSIONS;
goto out;
}
if ((buffer = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshkey_load_file(fd, buffer)) != 0 ||
(r = sshkey_parse_private_fileblob(buffer, passphrase, keyp,
commentp)) != 0)
goto out;
r = 0;
out:
close(fd);
sshbuf_free(buffer);
return r;
}
static int
sshkey_try_load_public(struct sshkey *k, const char *filename, char **commentp)
{
FILE *f;
char line[SSH_MAX_PUBKEY_BYTES];
char *cp;
u_long linenum = 0;
int r;
if (commentp != NULL)
*commentp = NULL;
if ((f = fopen(filename, "r")) == NULL)
return SSH_ERR_SYSTEM_ERROR;
while (read_keyfile_line(f, filename, line, sizeof(line),
&linenum) != -1) {
cp = line;
switch (*cp) {
case '#':
case '\n':
case '\0':
continue;
}
/* Abort loading if this looks like a private key */
if (strncmp(cp, "-----BEGIN", 10) == 0 ||
strcmp(cp, "SSH PRIVATE KEY FILE") == 0)
break;
/* Skip leading whitespace. */
for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
;
if (*cp) {
if ((r = sshkey_read(k, &cp)) == 0) {
cp[strcspn(cp, "\r\n")] = '\0';
if (commentp) {
*commentp = strdup(*cp ?
cp : filename);
if (*commentp == NULL)
r = SSH_ERR_ALLOC_FAIL;
}
fclose(f);
return r;
}
}
}
fclose(f);
return SSH_ERR_INVALID_FORMAT;
}
/* load public key from ssh v1 private or any pubkey file */
int
sshkey_load_public(const char *filename, struct sshkey **keyp, char **commentp)
{
struct sshkey *pub = NULL;
char file[PATH_MAX];
int r, fd;
if (keyp != NULL)
*keyp = NULL;
if (commentp != NULL)
*commentp = NULL;
/* XXX should load file once and attempt to parse each format */
if ((fd = open(filename, O_RDONLY)) < 0)
goto skip;
#ifdef WITH_SSH1
/* try rsa1 private key */
r = sshkey_load_public_rsa1(fd, keyp, commentp);
close(fd);
switch (r) {
case SSH_ERR_INTERNAL_ERROR:
case SSH_ERR_ALLOC_FAIL:
case SSH_ERR_INVALID_ARGUMENT:
case SSH_ERR_SYSTEM_ERROR:
case 0:
return r;
}
#else /* WITH_SSH1 */
close(fd);
#endif /* WITH_SSH1 */
/* try ssh2 public key */
if ((pub = sshkey_new(KEY_UNSPEC)) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshkey_try_load_public(pub, filename, commentp)) == 0) {
if (keyp != NULL)
*keyp = pub;
return 0;
}
sshkey_free(pub);
#ifdef WITH_SSH1
/* try rsa1 public key */
if ((pub = sshkey_new(KEY_RSA1)) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshkey_try_load_public(pub, filename, commentp)) == 0) {
if (keyp != NULL)
*keyp = pub;
return 0;
}
sshkey_free(pub);
#endif /* WITH_SSH1 */
skip:
/* try .pub suffix */
if ((pub = sshkey_new(KEY_UNSPEC)) == NULL)
return SSH_ERR_ALLOC_FAIL;
r = SSH_ERR_ALLOC_FAIL; /* in case strlcpy or strlcat fail */
if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
(strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
(r = sshkey_try_load_public(pub, file, commentp)) == 0) {
if (keyp != NULL)
*keyp = pub;
return 0;
}
sshkey_free(pub);
return r;
}
/* Load the certificate associated with the named private key */
int
sshkey_load_cert(const char *filename, struct sshkey **keyp)
{
struct sshkey *pub = NULL;
char *file = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
if (keyp != NULL)
*keyp = NULL;
if (asprintf(&file, "%s-cert.pub", filename) == -1)
return SSH_ERR_ALLOC_FAIL;
if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
goto out;
}
if ((r = sshkey_try_load_public(pub, file, NULL)) != 0)
goto out;
/* success */
if (keyp != NULL) {
*keyp = pub;
pub = NULL;
}
r = 0;
out:
free(file);
sshkey_free(pub);
return r;
}
/* Load private key and certificate */
int
sshkey_load_private_cert(int type, const char *filename, const char *passphrase,
struct sshkey **keyp, int *perm_ok)
{
struct sshkey *key = NULL, *cert = NULL;
int r;
if (keyp != NULL)
*keyp = NULL;
switch (type) {
#ifdef WITH_OPENSSL
case KEY_RSA:
case KEY_DSA:
case KEY_ECDSA:
#endif /* WITH_OPENSSL */
case KEY_ED25519:
case KEY_UNSPEC:
break;
default:
return SSH_ERR_KEY_TYPE_UNKNOWN;
}
if ((r = sshkey_load_private_type(type, filename,
passphrase, &key, NULL, perm_ok)) != 0 ||
(r = sshkey_load_cert(filename, &cert)) != 0)
goto out;
/* Make sure the private key matches the certificate */
if (sshkey_equal_public(key, cert) == 0) {
r = SSH_ERR_KEY_CERT_MISMATCH;
goto out;
}
if ((r = sshkey_to_certified(key)) != 0 ||
(r = sshkey_cert_copy(cert, key)) != 0)
goto out;
r = 0;
if (keyp != NULL) {
*keyp = key;
key = NULL;
}
out:
sshkey_free(key);
sshkey_free(cert);
return r;
}
/*
* Returns success if the specified "key" is listed in the file "filename",
* SSH_ERR_KEY_NOT_FOUND: if the key is not listed or another error.
* If "strict_type" is set then the key type must match exactly,
* otherwise a comparison that ignores certficiate data is performed.
* If "check_ca" is set and "key" is a certificate, then its CA key is
* also checked and sshkey_in_file() will return success if either is found.
*/
int
sshkey_in_file(struct sshkey *key, const char *filename, int strict_type,
int check_ca)
{
FILE *f;
char line[SSH_MAX_PUBKEY_BYTES];
char *cp;
u_long linenum = 0;
int r = 0;
struct sshkey *pub = NULL;
int (*sshkey_compare)(const struct sshkey *, const struct sshkey *) =
strict_type ? sshkey_equal : sshkey_equal_public;
if ((f = fopen(filename, "r")) == NULL)
return SSH_ERR_SYSTEM_ERROR;
while (read_keyfile_line(f, filename, line, sizeof(line),
&linenum) != -1) {
cp = line;
/* Skip leading whitespace. */
for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
;
/* Skip comments and empty lines */
switch (*cp) {
case '#':
case '\n':
case '\0':
continue;
}
if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshkey_read(pub, &cp)) != 0)
goto out;
if (sshkey_compare(key, pub) ||
(check_ca && sshkey_is_cert(key) &&
sshkey_compare(key->cert->signature_key, pub))) {
r = 0;
goto out;
}
sshkey_free(pub);
pub = NULL;
}
r = SSH_ERR_KEY_NOT_FOUND;
out:
sshkey_free(pub);
fclose(f);
return r;
}
/*
* Checks whether the specified key is revoked, returning 0 if not,
* SSH_ERR_KEY_REVOKED if it is or another error code if something
* unexpected happened.
* This will check both the key and, if it is a certificate, its CA key too.
* "revoked_keys_file" may be a KRL or a one-per-line list of public keys.
*/
int
sshkey_check_revoked(struct sshkey *key, const char *revoked_keys_file)
{
int r;
r = ssh_krl_file_contains_key(revoked_keys_file, key);
/* If this was not a KRL to begin with then continue below */
if (r != SSH_ERR_KRL_BAD_MAGIC)
return r;
/*
* If the file is not a KRL or we can't handle KRLs then attempt to
* parse the file as a flat list of keys.
*/
switch ((r = sshkey_in_file(key, revoked_keys_file, 0, 1))) {
case 0:
/* Key found => revoked */
return SSH_ERR_KEY_REVOKED;
case SSH_ERR_KEY_NOT_FOUND:
/* Key not found => not revoked */
return 0;
default:
/* Some other error occurred */
return r;
}
}
|