djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2019 Google LLC |
| 3 | * |
| 4 | * Permission to use, copy, modify, and distribute this software for any |
| 5 | * purpose with or without fee is hereby granted, provided that the above |
| 6 | * copyright notice and this permission notice appear in all copies. |
| 7 | * |
| 8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| 9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| 10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| 11 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| 13 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| 14 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| 15 | */ |
| 16 | |
Damien Miller | 1a72c0d | 2019-09-03 18:44:10 +1000 | [diff] [blame] | 17 | #include "includes.h" |
| 18 | |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 19 | #include <stdio.h> |
| 20 | #include <stdlib.h> |
| 21 | #include <stdarg.h> |
| 22 | #include <errno.h> |
| 23 | #include <string.h> |
| 24 | #include <unistd.h> |
| 25 | |
| 26 | #include "authfd.h" |
| 27 | #include "authfile.h" |
| 28 | #include "log.h" |
| 29 | #include "misc.h" |
| 30 | #include "sshbuf.h" |
| 31 | #include "sshsig.h" |
| 32 | #include "ssherr.h" |
| 33 | #include "sshkey.h" |
| 34 | #include "match.h" |
| 35 | #include "digest.h" |
| 36 | |
| 37 | #define SIG_VERSION 0x01 |
| 38 | #define MAGIC_PREAMBLE "SSHSIG" |
| 39 | #define MAGIC_PREAMBLE_LEN (sizeof(MAGIC_PREAMBLE) - 1) |
| 40 | #define BEGIN_SIGNATURE "-----BEGIN SSH SIGNATURE-----\n" |
| 41 | #define END_SIGNATURE "-----END SSH SIGNATURE-----" |
| 42 | #define RSA_SIGN_ALG "rsa-sha2-512" /* XXX maybe make configurable */ |
| 43 | #define RSA_SIGN_ALLOWED "rsa-sha2-512,rsa-sha2-256" |
| 44 | #define HASHALG_DEFAULT "sha512" /* XXX maybe make configurable */ |
| 45 | #define HASHALG_ALLOWED "sha256,sha512" |
| 46 | |
| 47 | int |
| 48 | sshsig_armor(const struct sshbuf *blob, struct sshbuf **out) |
| 49 | { |
| 50 | struct sshbuf *buf = NULL; |
| 51 | int r = SSH_ERR_INTERNAL_ERROR; |
| 52 | |
| 53 | *out = NULL; |
| 54 | |
| 55 | if ((buf = sshbuf_new()) == NULL) { |
| 56 | error("%s: sshbuf_new failed", __func__); |
| 57 | r = SSH_ERR_ALLOC_FAIL; |
| 58 | goto out; |
| 59 | } |
| 60 | |
| 61 | if ((r = sshbuf_put(buf, BEGIN_SIGNATURE, |
| 62 | sizeof(BEGIN_SIGNATURE)-1)) != 0) { |
| 63 | error("%s: sshbuf_putf failed: %s", __func__, ssh_err(r)); |
| 64 | goto out; |
| 65 | } |
| 66 | |
| 67 | if ((r = sshbuf_dtob64(blob, buf, 1)) != 0) { |
| 68 | error("%s: Couldn't base64 encode signature blob: %s", |
| 69 | __func__, ssh_err(r)); |
| 70 | goto out; |
| 71 | } |
| 72 | |
| 73 | if ((r = sshbuf_put(buf, END_SIGNATURE, |
| 74 | sizeof(END_SIGNATURE)-1)) != 0 || |
| 75 | (r = sshbuf_put_u8(buf, '\n')) != 0) { |
| 76 | error("%s: sshbuf_put failed: %s", __func__, ssh_err(r)); |
| 77 | goto out; |
| 78 | } |
| 79 | /* success */ |
| 80 | *out = buf; |
| 81 | buf = NULL; /* transferred */ |
| 82 | r = 0; |
| 83 | out: |
| 84 | sshbuf_free(buf); |
| 85 | return r; |
| 86 | } |
| 87 | |
| 88 | int |
| 89 | sshsig_dearmor(struct sshbuf *sig, struct sshbuf **out) |
| 90 | { |
| 91 | int r; |
| 92 | size_t eoffset = 0; |
| 93 | struct sshbuf *buf = NULL; |
| 94 | struct sshbuf *sbuf = NULL; |
| 95 | char *b64 = NULL; |
| 96 | |
| 97 | if ((sbuf = sshbuf_fromb(sig)) == NULL) { |
| 98 | error("%s: sshbuf_fromb failed", __func__); |
| 99 | return SSH_ERR_ALLOC_FAIL; |
| 100 | } |
| 101 | |
| 102 | if ((r = sshbuf_cmp(sbuf, 0, |
| 103 | BEGIN_SIGNATURE, sizeof(BEGIN_SIGNATURE)-1)) != 0) { |
| 104 | error("Couldn't parse signature: missing header"); |
| 105 | goto done; |
| 106 | } |
| 107 | |
| 108 | if ((r = sshbuf_consume(sbuf, sizeof(BEGIN_SIGNATURE)-1)) != 0) { |
| 109 | error("%s: sshbuf_consume failed: %s", __func__, ssh_err(r)); |
| 110 | goto done; |
| 111 | } |
| 112 | |
| 113 | if ((r = sshbuf_find(sbuf, 0, "\n" END_SIGNATURE, |
| 114 | sizeof("\n" END_SIGNATURE)-1, &eoffset)) != 0) { |
| 115 | error("Couldn't parse signature: missing footer"); |
| 116 | goto done; |
| 117 | } |
| 118 | |
| 119 | if ((r = sshbuf_consume_end(sbuf, sshbuf_len(sbuf)-eoffset)) != 0) { |
| 120 | error("%s: sshbuf_consume failed: %s", __func__, ssh_err(r)); |
| 121 | goto done; |
| 122 | } |
| 123 | |
| 124 | if ((b64 = sshbuf_dup_string(sbuf)) == NULL) { |
| 125 | error("%s: sshbuf_dup_string failed", __func__); |
| 126 | r = SSH_ERR_ALLOC_FAIL; |
| 127 | goto done; |
| 128 | } |
| 129 | |
| 130 | if ((buf = sshbuf_new()) == NULL) { |
| 131 | error("%s: sshbuf_new() failed", __func__); |
| 132 | r = SSH_ERR_ALLOC_FAIL; |
| 133 | goto done; |
| 134 | } |
| 135 | |
| 136 | if ((r = sshbuf_b64tod(buf, b64)) != 0) { |
naddy@openbsd.org | 0f44e59 | 2019-09-03 20:51:49 +0000 | [diff] [blame] | 137 | error("Couldn't decode signature: %s", ssh_err(r)); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 138 | goto done; |
| 139 | } |
| 140 | |
| 141 | /* success */ |
| 142 | *out = buf; |
| 143 | r = 0; |
| 144 | buf = NULL; /* transferred */ |
| 145 | done: |
| 146 | sshbuf_free(buf); |
| 147 | sshbuf_free(sbuf); |
| 148 | free(b64); |
| 149 | return r; |
| 150 | } |
| 151 | |
| 152 | static int |
| 153 | sshsig_wrap_sign(struct sshkey *key, const char *hashalg, |
djm@openbsd.org | 9a14c64 | 2019-10-31 21:23:19 +0000 | [diff] [blame] | 154 | const char *sk_provider, const struct sshbuf *h_message, |
| 155 | const char *sig_namespace, struct sshbuf **out, |
| 156 | sshsig_signer *signer, void *signer_ctx) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 157 | { |
| 158 | int r; |
| 159 | size_t slen = 0; |
| 160 | u_char *sig = NULL; |
| 161 | struct sshbuf *blob = NULL; |
| 162 | struct sshbuf *tosign = NULL; |
| 163 | const char *sign_alg = NULL; |
| 164 | |
| 165 | if ((tosign = sshbuf_new()) == NULL || |
| 166 | (blob = sshbuf_new()) == NULL) { |
| 167 | error("%s: sshbuf_new failed", __func__); |
| 168 | r = SSH_ERR_ALLOC_FAIL; |
| 169 | goto done; |
| 170 | } |
| 171 | |
| 172 | if ((r = sshbuf_put(tosign, MAGIC_PREAMBLE, MAGIC_PREAMBLE_LEN)) != 0 || |
| 173 | (r = sshbuf_put_cstring(tosign, sig_namespace)) != 0 || |
| 174 | (r = sshbuf_put_string(tosign, NULL, 0)) != 0 || /* reserved */ |
| 175 | (r = sshbuf_put_cstring(tosign, hashalg)) != 0 || |
djm@openbsd.org | b5a89ee | 2019-10-02 08:07:13 +0000 | [diff] [blame] | 176 | (r = sshbuf_put_stringb(tosign, h_message)) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 177 | error("Couldn't construct message to sign: %s", ssh_err(r)); |
| 178 | goto done; |
| 179 | } |
| 180 | |
| 181 | /* If using RSA keys then default to a good signature algorithm */ |
| 182 | if (sshkey_type_plain(key->type) == KEY_RSA) |
| 183 | sign_alg = RSA_SIGN_ALG; |
| 184 | |
| 185 | if (signer != NULL) { |
| 186 | if ((r = signer(key, &sig, &slen, |
| 187 | sshbuf_ptr(tosign), sshbuf_len(tosign), |
djm@openbsd.org | 9a14c64 | 2019-10-31 21:23:19 +0000 | [diff] [blame] | 188 | sign_alg, sk_provider, 0, signer_ctx)) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 189 | error("Couldn't sign message: %s", ssh_err(r)); |
| 190 | goto done; |
| 191 | } |
| 192 | } else { |
| 193 | if ((r = sshkey_sign(key, &sig, &slen, |
| 194 | sshbuf_ptr(tosign), sshbuf_len(tosign), |
djm@openbsd.org | 9a14c64 | 2019-10-31 21:23:19 +0000 | [diff] [blame] | 195 | sign_alg, sk_provider, 0)) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 196 | error("Couldn't sign message: %s", ssh_err(r)); |
| 197 | goto done; |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | if ((r = sshbuf_put(blob, MAGIC_PREAMBLE, MAGIC_PREAMBLE_LEN)) != 0 || |
| 202 | (r = sshbuf_put_u32(blob, SIG_VERSION)) != 0 || |
| 203 | (r = sshkey_puts(key, blob)) != 0 || |
| 204 | (r = sshbuf_put_cstring(blob, sig_namespace)) != 0 || |
| 205 | (r = sshbuf_put_string(blob, NULL, 0)) != 0 || /* reserved */ |
| 206 | (r = sshbuf_put_cstring(blob, hashalg)) != 0 || |
| 207 | (r = sshbuf_put_string(blob, sig, slen)) != 0) { |
| 208 | error("Couldn't populate blob: %s", ssh_err(r)); |
| 209 | goto done; |
| 210 | } |
| 211 | |
markus@openbsd.org | 15be29e | 2020-03-06 18:13:29 +0000 | [diff] [blame] | 212 | if (out != NULL) { |
| 213 | *out = blob; |
| 214 | blob = NULL; |
| 215 | } |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 216 | r = 0; |
| 217 | done: |
| 218 | free(sig); |
| 219 | sshbuf_free(blob); |
| 220 | sshbuf_free(tosign); |
| 221 | return r; |
| 222 | } |
| 223 | |
| 224 | /* Check preamble and version. */ |
| 225 | static int |
| 226 | sshsig_parse_preamble(struct sshbuf *buf) |
| 227 | { |
| 228 | int r = SSH_ERR_INTERNAL_ERROR; |
| 229 | uint32_t sversion; |
| 230 | |
| 231 | if ((r = sshbuf_cmp(buf, 0, MAGIC_PREAMBLE, MAGIC_PREAMBLE_LEN)) != 0 || |
| 232 | (r = sshbuf_consume(buf, (sizeof(MAGIC_PREAMBLE)-1))) != 0 || |
| 233 | (r = sshbuf_get_u32(buf, &sversion)) != 0) { |
| 234 | error("Couldn't verify signature: invalid format"); |
| 235 | return r; |
| 236 | } |
| 237 | |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 238 | if (sversion > SIG_VERSION) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 239 | error("Signature version %lu is larger than supported " |
| 240 | "version %u", (unsigned long)sversion, SIG_VERSION); |
| 241 | return SSH_ERR_INVALID_FORMAT; |
| 242 | } |
| 243 | return 0; |
| 244 | } |
| 245 | |
| 246 | static int |
| 247 | sshsig_check_hashalg(const char *hashalg) |
| 248 | { |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 249 | if (hashalg == NULL || |
| 250 | match_pattern_list(hashalg, HASHALG_ALLOWED, 0) == 1) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 251 | return 0; |
| 252 | error("%s: unsupported hash algorithm \"%.100s\"", __func__, hashalg); |
| 253 | return SSH_ERR_SIGN_ALG_UNSUPPORTED; |
| 254 | } |
| 255 | |
| 256 | static int |
| 257 | sshsig_peek_hashalg(struct sshbuf *signature, char **hashalgp) |
| 258 | { |
| 259 | struct sshbuf *buf = NULL; |
| 260 | char *hashalg = NULL; |
| 261 | int r = SSH_ERR_INTERNAL_ERROR; |
| 262 | |
| 263 | if (hashalgp != NULL) |
| 264 | *hashalgp = NULL; |
| 265 | if ((buf = sshbuf_fromb(signature)) == NULL) |
| 266 | return SSH_ERR_ALLOC_FAIL; |
| 267 | if ((r = sshsig_parse_preamble(buf)) != 0) |
| 268 | goto done; |
| 269 | if ((r = sshbuf_get_string_direct(buf, NULL, NULL)) != 0 || |
| 270 | (r = sshbuf_get_string_direct(buf, NULL, NULL)) != 0 || |
| 271 | (r = sshbuf_get_string(buf, NULL, NULL)) != 0 || |
| 272 | (r = sshbuf_get_cstring(buf, &hashalg, NULL)) != 0 || |
| 273 | (r = sshbuf_get_string_direct(buf, NULL, NULL)) != 0) { |
| 274 | error("Couldn't parse signature blob: %s", ssh_err(r)); |
| 275 | goto done; |
| 276 | } |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 277 | |
| 278 | /* success */ |
| 279 | r = 0; |
| 280 | *hashalgp = hashalg; |
| 281 | hashalg = NULL; |
| 282 | done: |
| 283 | free(hashalg); |
| 284 | sshbuf_free(buf); |
| 285 | return r; |
| 286 | } |
| 287 | |
| 288 | static int |
| 289 | sshsig_wrap_verify(struct sshbuf *signature, const char *hashalg, |
| 290 | const struct sshbuf *h_message, const char *expect_namespace, |
djm@openbsd.org | b7e74ea | 2019-11-25 00:51:37 +0000 | [diff] [blame] | 291 | struct sshkey **sign_keyp, struct sshkey_sig_details **sig_details) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 292 | { |
| 293 | int r = SSH_ERR_INTERNAL_ERROR; |
| 294 | struct sshbuf *buf = NULL, *toverify = NULL; |
| 295 | struct sshkey *key = NULL; |
| 296 | const u_char *sig; |
| 297 | char *got_namespace = NULL, *sigtype = NULL, *sig_hashalg = NULL; |
| 298 | size_t siglen; |
| 299 | |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 300 | debug("%s: verify message length %zu", __func__, sshbuf_len(h_message)); |
djm@openbsd.org | b7e74ea | 2019-11-25 00:51:37 +0000 | [diff] [blame] | 301 | if (sig_details != NULL) |
| 302 | *sig_details = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 303 | if (sign_keyp != NULL) |
| 304 | *sign_keyp = NULL; |
| 305 | |
| 306 | if ((toverify = sshbuf_new()) == NULL) { |
| 307 | error("%s: sshbuf_new failed", __func__); |
| 308 | r = SSH_ERR_ALLOC_FAIL; |
| 309 | goto done; |
| 310 | } |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 311 | if ((r = sshbuf_put(toverify, MAGIC_PREAMBLE, |
| 312 | MAGIC_PREAMBLE_LEN)) != 0 || |
| 313 | (r = sshbuf_put_cstring(toverify, expect_namespace)) != 0 || |
| 314 | (r = sshbuf_put_string(toverify, NULL, 0)) != 0 || /* reserved */ |
| 315 | (r = sshbuf_put_cstring(toverify, hashalg)) != 0 || |
djm@openbsd.org | b5a89ee | 2019-10-02 08:07:13 +0000 | [diff] [blame] | 316 | (r = sshbuf_put_stringb(toverify, h_message)) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 317 | error("Couldn't construct message to verify: %s", ssh_err(r)); |
| 318 | goto done; |
| 319 | } |
| 320 | |
| 321 | if ((r = sshsig_parse_preamble(signature)) != 0) |
| 322 | goto done; |
| 323 | |
| 324 | if ((r = sshkey_froms(signature, &key)) != 0 || |
| 325 | (r = sshbuf_get_cstring(signature, &got_namespace, NULL)) != 0 || |
| 326 | (r = sshbuf_get_string(signature, NULL, NULL)) != 0 || |
| 327 | (r = sshbuf_get_cstring(signature, &sig_hashalg, NULL)) != 0 || |
| 328 | (r = sshbuf_get_string_direct(signature, &sig, &siglen)) != 0) { |
| 329 | error("Couldn't parse signature blob: %s", ssh_err(r)); |
| 330 | goto done; |
| 331 | } |
| 332 | |
| 333 | if (sshbuf_len(signature) != 0) { |
| 334 | error("Signature contains trailing data"); |
| 335 | r = SSH_ERR_INVALID_FORMAT; |
| 336 | goto done; |
| 337 | } |
| 338 | |
| 339 | if (strcmp(expect_namespace, got_namespace) != 0) { |
| 340 | error("Couldn't verify signature: namespace does not match"); |
| 341 | debug("%s: expected namespace \"%s\" received \"%s\"", |
| 342 | __func__, expect_namespace, got_namespace); |
| 343 | r = SSH_ERR_SIGNATURE_INVALID; |
| 344 | goto done; |
| 345 | } |
| 346 | if (strcmp(hashalg, sig_hashalg) != 0) { |
| 347 | error("Couldn't verify signature: hash algorithm mismatch"); |
| 348 | debug("%s: expected algorithm \"%s\" received \"%s\"", |
| 349 | __func__, hashalg, sig_hashalg); |
| 350 | r = SSH_ERR_SIGNATURE_INVALID; |
| 351 | goto done; |
| 352 | } |
| 353 | /* Ensure that RSA keys use an acceptable signature algorithm */ |
| 354 | if (sshkey_type_plain(key->type) == KEY_RSA) { |
| 355 | if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0) { |
| 356 | error("Couldn't verify signature: unable to get " |
| 357 | "signature type: %s", ssh_err(r)); |
| 358 | goto done; |
| 359 | } |
| 360 | if (match_pattern_list(sigtype, RSA_SIGN_ALLOWED, 0) != 1) { |
| 361 | error("Couldn't verify signature: unsupported RSA " |
| 362 | "signature algorithm %s", sigtype); |
| 363 | r = SSH_ERR_SIGN_ALG_UNSUPPORTED; |
| 364 | goto done; |
| 365 | } |
| 366 | } |
| 367 | if ((r = sshkey_verify(key, sig, siglen, sshbuf_ptr(toverify), |
djm@openbsd.org | b7e74ea | 2019-11-25 00:51:37 +0000 | [diff] [blame] | 368 | sshbuf_len(toverify), NULL, 0, sig_details)) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 369 | error("Signature verification failed: %s", ssh_err(r)); |
| 370 | goto done; |
| 371 | } |
| 372 | |
| 373 | /* success */ |
| 374 | r = 0; |
| 375 | if (sign_keyp != NULL) { |
| 376 | *sign_keyp = key; |
| 377 | key = NULL; /* transferred */ |
| 378 | } |
| 379 | done: |
| 380 | free(got_namespace); |
| 381 | free(sigtype); |
| 382 | free(sig_hashalg); |
| 383 | sshbuf_free(buf); |
| 384 | sshbuf_free(toverify); |
| 385 | sshkey_free(key); |
| 386 | return r; |
| 387 | } |
| 388 | |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 389 | static int |
| 390 | hash_buffer(const struct sshbuf *m, const char *hashalg, struct sshbuf **bp) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 391 | { |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 392 | char *hex, hash[SSH_DIGEST_MAX_LENGTH]; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 393 | int alg, r = SSH_ERR_INTERNAL_ERROR; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 394 | struct sshbuf *b = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 395 | |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 396 | *bp = NULL; |
| 397 | memset(hash, 0, sizeof(hash)); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 398 | |
| 399 | if ((r = sshsig_check_hashalg(hashalg)) != 0) |
| 400 | return r; |
| 401 | if ((alg = ssh_digest_alg_by_name(hashalg)) == -1) { |
| 402 | error("%s: can't look up hash algorithm %s", |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 403 | __func__, hashalg); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 404 | return SSH_ERR_INTERNAL_ERROR; |
| 405 | } |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 406 | if ((r = ssh_digest_buffer(alg, m, hash, sizeof(hash))) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 407 | error("%s: ssh_digest_buffer failed: %s", __func__, ssh_err(r)); |
| 408 | return r; |
| 409 | } |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 410 | if ((hex = tohex(hash, ssh_digest_bytes(alg))) != NULL) { |
| 411 | debug3("%s: final hash: %s", __func__, hex); |
| 412 | freezero(hex, strlen(hex)); |
| 413 | } |
| 414 | if ((b = sshbuf_new()) == NULL) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 415 | r = SSH_ERR_ALLOC_FAIL; |
| 416 | goto out; |
| 417 | } |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 418 | if ((r = sshbuf_put(b, hash, ssh_digest_bytes(alg))) != 0) { |
| 419 | error("%s: sshbuf_put: %s", __func__, ssh_err(r)); |
| 420 | goto out; |
| 421 | } |
| 422 | *bp = b; |
| 423 | b = NULL; /* transferred */ |
| 424 | /* success */ |
| 425 | r = 0; |
| 426 | out: |
| 427 | sshbuf_free(b); |
| 428 | explicit_bzero(hash, sizeof(hash)); |
markus@openbsd.org | 15be29e | 2020-03-06 18:13:29 +0000 | [diff] [blame] | 429 | return r; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 430 | } |
| 431 | |
| 432 | int |
djm@openbsd.org | 9a14c64 | 2019-10-31 21:23:19 +0000 | [diff] [blame] | 433 | sshsig_signb(struct sshkey *key, const char *hashalg, const char *sk_provider, |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 434 | const struct sshbuf *message, const char *sig_namespace, |
| 435 | struct sshbuf **out, sshsig_signer *signer, void *signer_ctx) |
| 436 | { |
| 437 | struct sshbuf *b = NULL; |
| 438 | int r = SSH_ERR_INTERNAL_ERROR; |
| 439 | |
| 440 | if (hashalg == NULL) |
| 441 | hashalg = HASHALG_DEFAULT; |
| 442 | if (out != NULL) |
| 443 | *out = NULL; |
| 444 | if ((r = hash_buffer(message, hashalg, &b)) != 0) { |
| 445 | error("%s: hash_buffer failed: %s", __func__, ssh_err(r)); |
| 446 | goto out; |
| 447 | } |
djm@openbsd.org | 9a14c64 | 2019-10-31 21:23:19 +0000 | [diff] [blame] | 448 | if ((r = sshsig_wrap_sign(key, hashalg, sk_provider, b, |
| 449 | sig_namespace, out, signer, signer_ctx)) != 0) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 450 | goto out; |
| 451 | /* success */ |
| 452 | r = 0; |
| 453 | out: |
| 454 | sshbuf_free(b); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 455 | return r; |
| 456 | } |
| 457 | |
| 458 | int |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 459 | sshsig_verifyb(struct sshbuf *signature, const struct sshbuf *message, |
djm@openbsd.org | b7e74ea | 2019-11-25 00:51:37 +0000 | [diff] [blame] | 460 | const char *expect_namespace, struct sshkey **sign_keyp, |
| 461 | struct sshkey_sig_details **sig_details) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 462 | { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 463 | struct sshbuf *b = NULL; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 464 | int r = SSH_ERR_INTERNAL_ERROR; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 465 | char *hashalg = NULL; |
| 466 | |
djm@openbsd.org | b7e74ea | 2019-11-25 00:51:37 +0000 | [diff] [blame] | 467 | if (sig_details != NULL) |
| 468 | *sig_details = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 469 | if (sign_keyp != NULL) |
| 470 | *sign_keyp = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 471 | if ((r = sshsig_peek_hashalg(signature, &hashalg)) != 0) |
| 472 | return r; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 473 | debug("%s: signature made with hash \"%s\"", __func__, hashalg); |
| 474 | if ((r = hash_buffer(message, hashalg, &b)) != 0) { |
| 475 | error("%s: hash_buffer failed: %s", __func__, ssh_err(r)); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 476 | goto out; |
| 477 | } |
| 478 | if ((r = sshsig_wrap_verify(signature, hashalg, b, expect_namespace, |
djm@openbsd.org | b7e74ea | 2019-11-25 00:51:37 +0000 | [diff] [blame] | 479 | sign_keyp, sig_details)) != 0) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 480 | goto out; |
| 481 | /* success */ |
| 482 | r = 0; |
| 483 | out: |
| 484 | sshbuf_free(b); |
| 485 | free(hashalg); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 486 | return r; |
| 487 | } |
| 488 | |
| 489 | static int |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 490 | hash_file(int fd, const char *hashalg, struct sshbuf **bp) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 491 | { |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 492 | char *hex, rbuf[8192], hash[SSH_DIGEST_MAX_LENGTH]; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 493 | ssize_t n, total = 0; |
| 494 | struct ssh_digest_ctx *ctx; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 495 | int alg, oerrno, r = SSH_ERR_INTERNAL_ERROR; |
| 496 | struct sshbuf *b = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 497 | |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 498 | *bp = NULL; |
| 499 | memset(hash, 0, sizeof(hash)); |
| 500 | |
| 501 | if ((r = sshsig_check_hashalg(hashalg)) != 0) |
| 502 | return r; |
| 503 | if ((alg = ssh_digest_alg_by_name(hashalg)) == -1) { |
| 504 | error("%s: can't look up hash algorithm %s", |
| 505 | __func__, hashalg); |
| 506 | return SSH_ERR_INTERNAL_ERROR; |
| 507 | } |
| 508 | if ((ctx = ssh_digest_start(alg)) == NULL) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 509 | error("%s: ssh_digest_start failed", __func__); |
| 510 | return SSH_ERR_INTERNAL_ERROR; |
| 511 | } |
| 512 | for (;;) { |
| 513 | if ((n = read(fd, rbuf, sizeof(rbuf))) == -1) { |
| 514 | if (errno == EINTR || errno == EAGAIN) |
| 515 | continue; |
| 516 | oerrno = errno; |
| 517 | error("%s: read: %s", __func__, strerror(errno)); |
| 518 | ssh_digest_free(ctx); |
| 519 | errno = oerrno; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 520 | r = SSH_ERR_SYSTEM_ERROR; |
| 521 | goto out; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 522 | } else if (n == 0) { |
| 523 | debug2("%s: hashed %zu bytes", __func__, total); |
| 524 | break; /* EOF */ |
| 525 | } |
| 526 | total += (size_t)n; |
| 527 | if ((r = ssh_digest_update(ctx, rbuf, (size_t)n)) != 0) { |
| 528 | error("%s: ssh_digest_update: %s", |
| 529 | __func__, ssh_err(r)); |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 530 | goto out; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 531 | } |
| 532 | } |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 533 | if ((r = ssh_digest_final(ctx, hash, sizeof(hash))) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 534 | error("%s: ssh_digest_final: %s", __func__, ssh_err(r)); |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 535 | goto out; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 536 | } |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 537 | if ((hex = tohex(hash, ssh_digest_bytes(alg))) != NULL) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 538 | debug3("%s: final hash: %s", __func__, hex); |
| 539 | freezero(hex, strlen(hex)); |
| 540 | } |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 541 | if ((b = sshbuf_new()) == NULL) { |
| 542 | r = SSH_ERR_ALLOC_FAIL; |
| 543 | goto out; |
| 544 | } |
| 545 | if ((r = sshbuf_put(b, hash, ssh_digest_bytes(alg))) != 0) { |
| 546 | error("%s: sshbuf_put: %s", __func__, ssh_err(r)); |
| 547 | goto out; |
| 548 | } |
| 549 | *bp = b; |
| 550 | b = NULL; /* transferred */ |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 551 | /* success */ |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 552 | r = 0; |
| 553 | out: |
| 554 | sshbuf_free(b); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 555 | ssh_digest_free(ctx); |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 556 | explicit_bzero(hash, sizeof(hash)); |
markus@openbsd.org | 15be29e | 2020-03-06 18:13:29 +0000 | [diff] [blame] | 557 | return r; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 558 | } |
| 559 | |
| 560 | int |
djm@openbsd.org | 9a14c64 | 2019-10-31 21:23:19 +0000 | [diff] [blame] | 561 | sshsig_sign_fd(struct sshkey *key, const char *hashalg, const char *sk_provider, |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 562 | int fd, const char *sig_namespace, struct sshbuf **out, |
| 563 | sshsig_signer *signer, void *signer_ctx) |
| 564 | { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 565 | struct sshbuf *b = NULL; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 566 | int r = SSH_ERR_INTERNAL_ERROR; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 567 | |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 568 | if (hashalg == NULL) |
| 569 | hashalg = HASHALG_DEFAULT; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 570 | if (out != NULL) |
| 571 | *out = NULL; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 572 | if ((r = hash_file(fd, hashalg, &b)) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 573 | error("%s: hash_file failed: %s", __func__, ssh_err(r)); |
| 574 | return r; |
| 575 | } |
djm@openbsd.org | 9a14c64 | 2019-10-31 21:23:19 +0000 | [diff] [blame] | 576 | if ((r = sshsig_wrap_sign(key, hashalg, sk_provider, b, |
| 577 | sig_namespace, out, signer, signer_ctx)) != 0) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 578 | goto out; |
| 579 | /* success */ |
| 580 | r = 0; |
| 581 | out: |
| 582 | sshbuf_free(b); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 583 | return r; |
| 584 | } |
| 585 | |
| 586 | int |
| 587 | sshsig_verify_fd(struct sshbuf *signature, int fd, |
djm@openbsd.org | b7e74ea | 2019-11-25 00:51:37 +0000 | [diff] [blame] | 588 | const char *expect_namespace, struct sshkey **sign_keyp, |
| 589 | struct sshkey_sig_details **sig_details) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 590 | { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 591 | struct sshbuf *b = NULL; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 592 | int r = SSH_ERR_INTERNAL_ERROR; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 593 | char *hashalg = NULL; |
| 594 | |
djm@openbsd.org | b7e74ea | 2019-11-25 00:51:37 +0000 | [diff] [blame] | 595 | if (sig_details != NULL) |
| 596 | *sig_details = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 597 | if (sign_keyp != NULL) |
| 598 | *sign_keyp = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 599 | if ((r = sshsig_peek_hashalg(signature, &hashalg)) != 0) |
| 600 | return r; |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 601 | debug("%s: signature made with hash \"%s\"", __func__, hashalg); |
| 602 | if ((r = hash_file(fd, hashalg, &b)) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 603 | error("%s: hash_file failed: %s", __func__, ssh_err(r)); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 604 | goto out; |
| 605 | } |
| 606 | if ((r = sshsig_wrap_verify(signature, hashalg, b, expect_namespace, |
djm@openbsd.org | b7e74ea | 2019-11-25 00:51:37 +0000 | [diff] [blame] | 607 | sign_keyp, sig_details)) != 0) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 608 | goto out; |
| 609 | /* success */ |
| 610 | r = 0; |
| 611 | out: |
| 612 | sshbuf_free(b); |
| 613 | free(hashalg); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 614 | return r; |
| 615 | } |
| 616 | |
djm@openbsd.org | bab6feb | 2019-09-05 04:55:32 +0000 | [diff] [blame] | 617 | struct sshsigopt { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 618 | int ca; |
| 619 | char *namespaces; |
| 620 | }; |
| 621 | |
djm@openbsd.org | bab6feb | 2019-09-05 04:55:32 +0000 | [diff] [blame] | 622 | struct sshsigopt * |
| 623 | sshsigopt_parse(const char *opts, const char *path, u_long linenum, |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 624 | const char **errstrp) |
| 625 | { |
djm@openbsd.org | bab6feb | 2019-09-05 04:55:32 +0000 | [diff] [blame] | 626 | struct sshsigopt *ret; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 627 | int r; |
| 628 | const char *errstr = NULL; |
| 629 | |
| 630 | if ((ret = calloc(1, sizeof(*ret))) == NULL) |
| 631 | return NULL; |
| 632 | if (opts == NULL || *opts == '\0') |
| 633 | return ret; /* Empty options yields empty options :) */ |
| 634 | |
| 635 | while (*opts && *opts != ' ' && *opts != '\t') { |
| 636 | /* flag options */ |
| 637 | if ((r = opt_flag("cert-authority", 0, &opts)) != -1) { |
| 638 | ret->ca = 1; |
| 639 | } else if (opt_match(&opts, "namespaces")) { |
| 640 | if (ret->namespaces != NULL) { |
| 641 | errstr = "multiple \"namespaces\" clauses"; |
| 642 | goto fail; |
| 643 | } |
| 644 | ret->namespaces = opt_dequote(&opts, &errstr); |
| 645 | if (ret->namespaces == NULL) |
| 646 | goto fail; |
| 647 | } |
| 648 | /* |
| 649 | * Skip the comma, and move to the next option |
| 650 | * (or break out if there are no more). |
| 651 | */ |
| 652 | if (*opts == '\0' || *opts == ' ' || *opts == '\t') |
| 653 | break; /* End of options. */ |
| 654 | /* Anything other than a comma is an unknown option */ |
| 655 | if (*opts != ',') { |
| 656 | errstr = "unknown key option"; |
| 657 | goto fail; |
| 658 | } |
| 659 | opts++; |
| 660 | if (*opts == '\0') { |
| 661 | errstr = "unexpected end-of-options"; |
| 662 | goto fail; |
| 663 | } |
| 664 | } |
| 665 | /* success */ |
| 666 | return ret; |
| 667 | fail: |
| 668 | if (errstrp != NULL) |
| 669 | *errstrp = errstr; |
djm@openbsd.org | 69159af | 2019-09-05 05:42:59 +0000 | [diff] [blame] | 670 | sshsigopt_free(ret); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 671 | return NULL; |
| 672 | } |
| 673 | |
djm@openbsd.org | bab6feb | 2019-09-05 04:55:32 +0000 | [diff] [blame] | 674 | void |
| 675 | sshsigopt_free(struct sshsigopt *opts) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 676 | { |
| 677 | if (opts == NULL) |
| 678 | return; |
| 679 | free(opts->namespaces); |
| 680 | free(opts); |
| 681 | } |
| 682 | |
| 683 | static int |
djm@openbsd.org | e2031b0 | 2020-01-22 02:25:21 +0000 | [diff] [blame] | 684 | parse_principals_key_and_options(const char *path, u_long linenum, char *line, |
| 685 | const char *required_principal, char **principalsp, struct sshkey **keyp, |
| 686 | struct sshsigopt **sigoptsp) |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 687 | { |
djm@openbsd.org | e2031b0 | 2020-01-22 02:25:21 +0000 | [diff] [blame] | 688 | char *opts = NULL, *tmp, *cp, *principals = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 689 | const char *reason = NULL; |
djm@openbsd.org | bab6feb | 2019-09-05 04:55:32 +0000 | [diff] [blame] | 690 | struct sshsigopt *sigopts = NULL; |
djm@openbsd.org | e2031b0 | 2020-01-22 02:25:21 +0000 | [diff] [blame] | 691 | struct sshkey *key = NULL; |
| 692 | int r = SSH_ERR_INTERNAL_ERROR; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 693 | |
djm@openbsd.org | e2031b0 | 2020-01-22 02:25:21 +0000 | [diff] [blame] | 694 | if (principalsp != NULL) |
| 695 | *principalsp = NULL; |
| 696 | if (sigoptsp != NULL) |
| 697 | *sigoptsp = NULL; |
| 698 | if (keyp != NULL) |
| 699 | *keyp = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 700 | |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 701 | cp = line; |
| 702 | cp = cp + strspn(cp, " \t"); /* skip leading whitespace */ |
| 703 | if (*cp == '#' || *cp == '\0') |
djm@openbsd.org | e2031b0 | 2020-01-22 02:25:21 +0000 | [diff] [blame] | 704 | return SSH_ERR_KEY_NOT_FOUND; /* blank or all-comment line */ |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 705 | |
djm@openbsd.org | e2031b0 | 2020-01-22 02:25:21 +0000 | [diff] [blame] | 706 | /* format: identity[,identity...] [option[,option...]] key */ |
| 707 | if ((tmp = strdelimw(&cp)) == NULL) { |
| 708 | error("%s:%lu: invalid line", path, linenum); |
| 709 | r = SSH_ERR_INVALID_FORMAT; |
| 710 | goto out; |
| 711 | } |
| 712 | if ((principals = strdup(tmp)) == NULL) { |
| 713 | error("%s: strdup failed", __func__); |
| 714 | r = SSH_ERR_ALLOC_FAIL; |
| 715 | goto out; |
| 716 | } |
| 717 | /* |
| 718 | * Bail out early if we're looking for a particular principal and this |
| 719 | * line does not list it. |
| 720 | */ |
| 721 | if (required_principal != NULL) { |
| 722 | if (match_pattern_list(required_principal, |
| 723 | principals, 0) != 1) { |
| 724 | /* principal didn't match */ |
| 725 | r = SSH_ERR_KEY_NOT_FOUND; |
| 726 | goto out; |
| 727 | } |
| 728 | debug("%s: %s:%lu: matched principal \"%s\"", |
| 729 | __func__, path, linenum, required_principal); |
| 730 | } |
| 731 | |
| 732 | if ((key = sshkey_new(KEY_UNSPEC)) == NULL) { |
| 733 | error("%s: sshkey_new failed", __func__); |
| 734 | r = SSH_ERR_ALLOC_FAIL; |
| 735 | goto out; |
| 736 | } |
| 737 | if (sshkey_read(key, &cp) != 0) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 738 | /* no key? Check for options */ |
| 739 | opts = cp; |
| 740 | if (sshkey_advance_past_options(&cp) != 0) { |
djm@openbsd.org | e2031b0 | 2020-01-22 02:25:21 +0000 | [diff] [blame] | 741 | error("%s:%lu: invalid options", path, linenum); |
| 742 | r = SSH_ERR_INVALID_FORMAT; |
| 743 | goto out; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 744 | } |
| 745 | *cp++ = '\0'; |
| 746 | skip_space(&cp); |
djm@openbsd.org | e2031b0 | 2020-01-22 02:25:21 +0000 | [diff] [blame] | 747 | if (sshkey_read(key, &cp) != 0) { |
| 748 | error("%s:%lu: invalid key", path, linenum); |
| 749 | r = SSH_ERR_INVALID_FORMAT; |
| 750 | goto out; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 751 | } |
| 752 | } |
| 753 | debug3("%s:%lu: options %s", path, linenum, opts == NULL ? "" : opts); |
djm@openbsd.org | bab6feb | 2019-09-05 04:55:32 +0000 | [diff] [blame] | 754 | if ((sigopts = sshsigopt_parse(opts, path, linenum, &reason)) == NULL) { |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 755 | error("%s:%lu: bad options: %s", path, linenum, reason); |
djm@openbsd.org | e2031b0 | 2020-01-22 02:25:21 +0000 | [diff] [blame] | 756 | r = SSH_ERR_INVALID_FORMAT; |
| 757 | goto out; |
| 758 | } |
| 759 | /* success */ |
| 760 | if (principalsp != NULL) { |
| 761 | *principalsp = principals; |
| 762 | principals = NULL; /* transferred */ |
| 763 | } |
| 764 | if (sigoptsp != NULL) { |
| 765 | *sigoptsp = sigopts; |
| 766 | sigopts = NULL; /* transferred */ |
| 767 | } |
| 768 | if (keyp != NULL) { |
| 769 | *keyp = key; |
| 770 | key = NULL; /* transferred */ |
| 771 | } |
| 772 | r = 0; |
| 773 | out: |
| 774 | free(principals); |
| 775 | sshsigopt_free(sigopts); |
| 776 | sshkey_free(key); |
| 777 | return r; |
| 778 | } |
| 779 | |
| 780 | static int |
| 781 | check_allowed_keys_line(const char *path, u_long linenum, char *line, |
| 782 | const struct sshkey *sign_key, const char *principal, |
| 783 | const char *sig_namespace) |
| 784 | { |
| 785 | struct sshkey *found_key = NULL; |
| 786 | int r, found = 0; |
| 787 | const char *reason = NULL; |
| 788 | struct sshsigopt *sigopts = NULL; |
| 789 | |
| 790 | /* Parse the line */ |
| 791 | if ((r = parse_principals_key_and_options(path, linenum, line, |
| 792 | principal, NULL, &found_key, &sigopts)) != 0) { |
| 793 | /* error already logged */ |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 794 | goto done; |
| 795 | } |
| 796 | |
| 797 | /* Check whether options preclude the use of this key */ |
| 798 | if (sigopts->namespaces != NULL && |
| 799 | match_pattern_list(sig_namespace, sigopts->namespaces, 0) != 1) { |
| 800 | error("%s:%lu: key is not permitted for use in signature " |
| 801 | "namespace \"%s\"", path, linenum, sig_namespace); |
| 802 | goto done; |
| 803 | } |
| 804 | |
| 805 | if (!sigopts->ca && sshkey_equal(found_key, sign_key)) { |
| 806 | /* Exact match of key */ |
| 807 | debug("%s:%lu: matched key and principal", path, linenum); |
| 808 | /* success */ |
| 809 | found = 1; |
| 810 | } else if (sigopts->ca && sshkey_is_cert(sign_key) && |
| 811 | sshkey_equal_public(sign_key->cert->signature_key, found_key)) { |
| 812 | /* Match of certificate's CA key */ |
| 813 | if ((r = sshkey_cert_check_authority(sign_key, 0, 1, |
| 814 | principal, &reason)) != 0) { |
| 815 | error("%s:%lu: certificate not authorized: %s", |
| 816 | path, linenum, reason); |
| 817 | goto done; |
| 818 | } |
| 819 | debug("%s:%lu: matched certificate CA key", path, linenum); |
| 820 | /* success */ |
| 821 | found = 1; |
| 822 | } else { |
| 823 | /* Principal matched but key didn't */ |
| 824 | goto done; |
| 825 | } |
| 826 | done: |
| 827 | sshkey_free(found_key); |
djm@openbsd.org | bab6feb | 2019-09-05 04:55:32 +0000 | [diff] [blame] | 828 | sshsigopt_free(sigopts); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 829 | return found ? 0 : SSH_ERR_KEY_NOT_FOUND; |
| 830 | } |
| 831 | |
| 832 | int |
| 833 | sshsig_check_allowed_keys(const char *path, const struct sshkey *sign_key, |
| 834 | const char *principal, const char *sig_namespace) |
| 835 | { |
| 836 | FILE *f = NULL; |
| 837 | char *line = NULL; |
| 838 | size_t linesize = 0; |
| 839 | u_long linenum = 0; |
markus@openbsd.org | 15be29e | 2020-03-06 18:13:29 +0000 | [diff] [blame] | 840 | int r = SSH_ERR_INTERNAL_ERROR, oerrno; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 841 | |
| 842 | /* Check key and principal against file */ |
| 843 | if ((f = fopen(path, "r")) == NULL) { |
| 844 | oerrno = errno; |
| 845 | error("Unable to open allowed keys file \"%s\": %s", |
| 846 | path, strerror(errno)); |
| 847 | errno = oerrno; |
| 848 | return SSH_ERR_SYSTEM_ERROR; |
| 849 | } |
| 850 | |
| 851 | while (getline(&line, &linesize, f) != -1) { |
| 852 | linenum++; |
| 853 | r = check_allowed_keys_line(path, linenum, line, sign_key, |
| 854 | principal, sig_namespace); |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 855 | free(line); |
| 856 | line = NULL; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 857 | if (r == SSH_ERR_KEY_NOT_FOUND) |
| 858 | continue; |
| 859 | else if (r == 0) { |
| 860 | /* success */ |
| 861 | fclose(f); |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 862 | return 0; |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 863 | } else |
| 864 | break; |
| 865 | } |
| 866 | /* Either we hit an error parsing or we simply didn't find the key */ |
| 867 | fclose(f); |
| 868 | free(line); |
| 869 | return r == 0 ? SSH_ERR_KEY_NOT_FOUND : r; |
| 870 | } |
djm@openbsd.org | 56cffcc | 2020-01-23 02:43:48 +0000 | [diff] [blame] | 871 | |
| 872 | static int |
djm@openbsd.org | 72a8bea | 2020-01-23 23:31:52 +0000 | [diff] [blame] | 873 | cert_filter_principals(const char *path, u_long linenum, |
| 874 | char **principalsp, const struct sshkey *cert) |
| 875 | { |
| 876 | char *cp, *oprincipals, *principals; |
| 877 | const char *reason; |
| 878 | struct sshbuf *nprincipals; |
| 879 | int r = SSH_ERR_INTERNAL_ERROR, success = 0; |
| 880 | |
| 881 | oprincipals = principals = *principalsp; |
| 882 | *principalsp = NULL; |
| 883 | |
markus@openbsd.org | 5732d58 | 2020-03-06 18:28:50 +0000 | [diff] [blame] | 884 | if ((nprincipals = sshbuf_new()) == NULL) { |
| 885 | r = SSH_ERR_ALLOC_FAIL; |
| 886 | goto out; |
| 887 | } |
djm@openbsd.org | 72a8bea | 2020-01-23 23:31:52 +0000 | [diff] [blame] | 888 | |
| 889 | while ((cp = strsep(&principals, ",")) != NULL && *cp != '\0') { |
| 890 | if (strcspn(cp, "!?*") != strlen(cp)) { |
| 891 | debug("%s:%lu: principal \"%s\" not authorized: " |
| 892 | "contains wildcards", path, linenum, cp); |
| 893 | continue; |
| 894 | } |
| 895 | /* Check against principals list in certificate */ |
| 896 | if ((r = sshkey_cert_check_authority(cert, 0, 1, |
| 897 | cp, &reason)) != 0) { |
| 898 | debug("%s:%lu: principal \"%s\" not authorized: %s", |
| 899 | path, linenum, cp, reason); |
| 900 | continue; |
| 901 | } |
| 902 | if ((r = sshbuf_putf(nprincipals, "%s%s", |
| 903 | sshbuf_len(nprincipals) != 0 ? "," : "", cp)) != 0) { |
| 904 | error("%s: buffer error", __func__); |
| 905 | goto out; |
| 906 | } |
| 907 | } |
| 908 | if (sshbuf_len(nprincipals) == 0) { |
| 909 | error("%s:%lu: no valid principals found", path, linenum); |
| 910 | r = SSH_ERR_KEY_CERT_INVALID; |
| 911 | goto out; |
| 912 | } |
| 913 | if ((principals = sshbuf_dup_string(nprincipals)) == NULL) { |
| 914 | error("%s: buffer error", __func__); |
| 915 | goto out; |
| 916 | } |
| 917 | /* success */ |
| 918 | success = 1; |
| 919 | *principalsp = principals; |
| 920 | out: |
| 921 | sshbuf_free(nprincipals); |
| 922 | free(oprincipals); |
| 923 | return success ? 0 : r; |
| 924 | } |
| 925 | |
| 926 | static int |
| 927 | get_matching_principals_from_line(const char *path, u_long linenum, char *line, |
djm@openbsd.org | 56cffcc | 2020-01-23 02:43:48 +0000 | [diff] [blame] | 928 | const struct sshkey *sign_key, char **principalsp) |
| 929 | { |
| 930 | struct sshkey *found_key = NULL; |
| 931 | char *principals = NULL; |
| 932 | int r, found = 0; |
djm@openbsd.org | 56cffcc | 2020-01-23 02:43:48 +0000 | [diff] [blame] | 933 | struct sshsigopt *sigopts = NULL; |
| 934 | |
| 935 | if (principalsp != NULL) |
| 936 | *principalsp = NULL; |
| 937 | |
| 938 | /* Parse the line */ |
| 939 | if ((r = parse_principals_key_and_options(path, linenum, line, |
| 940 | NULL, &principals, &found_key, &sigopts)) != 0) { |
| 941 | /* error already logged */ |
| 942 | goto done; |
| 943 | } |
| 944 | |
| 945 | if (!sigopts->ca && sshkey_equal(found_key, sign_key)) { |
| 946 | /* Exact match of key */ |
| 947 | debug("%s:%lu: matched key", path, linenum); |
| 948 | /* success */ |
| 949 | found = 1; |
| 950 | } else if (sigopts->ca && sshkey_is_cert(sign_key) && |
| 951 | sshkey_equal_public(sign_key->cert->signature_key, found_key)) { |
djm@openbsd.org | 72a8bea | 2020-01-23 23:31:52 +0000 | [diff] [blame] | 952 | /* Remove principals listed in file but not allowed by cert */ |
| 953 | if ((r = cert_filter_principals(path, linenum, |
| 954 | &principals, sign_key)) != 0) { |
| 955 | /* error already displayed */ |
| 956 | debug("%s:%lu: cert_filter_principals: %s", |
| 957 | path, linenum, ssh_err(r)); |
djm@openbsd.org | 56cffcc | 2020-01-23 02:43:48 +0000 | [diff] [blame] | 958 | goto done; |
| 959 | } |
| 960 | debug("%s:%lu: matched certificate CA key", path, linenum); |
| 961 | /* success */ |
| 962 | found = 1; |
| 963 | } else { |
| 964 | /* Key didn't match */ |
| 965 | goto done; |
| 966 | } |
| 967 | done: |
markus@openbsd.org | 31c39e7 | 2020-03-06 18:27:15 +0000 | [diff] [blame] | 968 | if (found && principalsp != NULL) { |
djm@openbsd.org | 56cffcc | 2020-01-23 02:43:48 +0000 | [diff] [blame] | 969 | *principalsp = principals; |
| 970 | principals = NULL; /* transferred */ |
| 971 | } |
| 972 | free(principals); |
| 973 | sshkey_free(found_key); |
| 974 | sshsigopt_free(sigopts); |
| 975 | return found ? 0 : SSH_ERR_KEY_NOT_FOUND; |
| 976 | } |
| 977 | |
| 978 | int |
djm@openbsd.org | 72a8bea | 2020-01-23 23:31:52 +0000 | [diff] [blame] | 979 | sshsig_find_principals(const char *path, const struct sshkey *sign_key, |
| 980 | char **principals) |
djm@openbsd.org | 56cffcc | 2020-01-23 02:43:48 +0000 | [diff] [blame] | 981 | { |
| 982 | FILE *f = NULL; |
| 983 | char *line = NULL; |
| 984 | size_t linesize = 0; |
| 985 | u_long linenum = 0; |
markus@openbsd.org | 46e5c4c | 2020-03-06 18:27:50 +0000 | [diff] [blame] | 986 | int r = SSH_ERR_INTERNAL_ERROR, oerrno; |
djm@openbsd.org | 56cffcc | 2020-01-23 02:43:48 +0000 | [diff] [blame] | 987 | |
| 988 | if ((f = fopen(path, "r")) == NULL) { |
| 989 | oerrno = errno; |
| 990 | error("Unable to open allowed keys file \"%s\": %s", |
| 991 | path, strerror(errno)); |
| 992 | errno = oerrno; |
| 993 | return SSH_ERR_SYSTEM_ERROR; |
| 994 | } |
| 995 | |
| 996 | while (getline(&line, &linesize, f) != -1) { |
| 997 | linenum++; |
djm@openbsd.org | 72a8bea | 2020-01-23 23:31:52 +0000 | [diff] [blame] | 998 | r = get_matching_principals_from_line(path, linenum, line, |
| 999 | sign_key, principals); |
djm@openbsd.org | 56cffcc | 2020-01-23 02:43:48 +0000 | [diff] [blame] | 1000 | free(line); |
| 1001 | line = NULL; |
| 1002 | if (r == SSH_ERR_KEY_NOT_FOUND) |
| 1003 | continue; |
| 1004 | else if (r == 0) { |
| 1005 | /* success */ |
| 1006 | fclose(f); |
| 1007 | return 0; |
| 1008 | } else |
| 1009 | break; |
| 1010 | } |
| 1011 | free(line); |
| 1012 | /* Either we hit an error parsing or we simply didn't find the key */ |
| 1013 | if (ferror(f) != 0) { |
| 1014 | oerrno = errno; |
| 1015 | fclose(f); |
| 1016 | error("Unable to read allowed keys file \"%s\": %s", |
| 1017 | path, strerror(errno)); |
| 1018 | errno = oerrno; |
| 1019 | return SSH_ERR_SYSTEM_ERROR; |
| 1020 | } |
| 1021 | fclose(f); |
| 1022 | return r == 0 ? SSH_ERR_KEY_NOT_FOUND : r; |
| 1023 | } |
| 1024 | |
| 1025 | int |
| 1026 | sshsig_get_pubkey(struct sshbuf *signature, struct sshkey **pubkey) |
| 1027 | { |
| 1028 | struct sshkey *pk = NULL; |
| 1029 | int r = SSH_ERR_SIGNATURE_INVALID; |
| 1030 | |
markus@openbsd.org | 31c39e7 | 2020-03-06 18:27:15 +0000 | [diff] [blame] | 1031 | if (pubkey == NULL) |
| 1032 | return SSH_ERR_INTERNAL_ERROR; |
djm@openbsd.org | 56cffcc | 2020-01-23 02:43:48 +0000 | [diff] [blame] | 1033 | if ((r = sshsig_parse_preamble(signature)) != 0) |
| 1034 | return r; |
| 1035 | if ((r = sshkey_froms(signature, &pk)) != 0) |
| 1036 | return r; |
| 1037 | |
| 1038 | *pubkey = pk; |
| 1039 | pk = NULL; |
| 1040 | return 0; |
| 1041 | } |