djm@openbsd.org | 6bff952 | 2019-11-14 21:27:29 +0000 | [diff] [blame^] | 1 | /* $OpenBSD: ssh-sk.c,v 1.12 2019/11/14 21:27:30 djm Exp $ */ |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 2 | /* |
| 3 | * Copyright (c) 2019 Google LLC |
| 4 | * |
| 5 | * Permission to use, copy, modify, and distribute this software for any |
| 6 | * purpose with or without fee is hereby granted, provided that the above |
| 7 | * copyright notice and this permission notice appear in all copies. |
| 8 | * |
| 9 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| 10 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| 11 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| 12 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 13 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| 14 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| 15 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| 16 | */ |
| 17 | |
| 18 | /* #define DEBUG_SK 1 */ |
| 19 | |
| 20 | #include "includes.h" |
| 21 | |
Damien Miller | 764d51e | 2019-11-01 13:34:49 +1100 | [diff] [blame] | 22 | #ifdef ENABLE_SK |
| 23 | |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 24 | #include <dlfcn.h> |
| 25 | #include <stddef.h> |
| 26 | #include <stdint.h> |
| 27 | #include <string.h> |
| 28 | #include <stdio.h> |
| 29 | |
| 30 | #include <openssl/objects.h> |
| 31 | #include <openssl/ec.h> |
| 32 | |
| 33 | #include "log.h" |
| 34 | #include "misc.h" |
| 35 | #include "sshbuf.h" |
| 36 | #include "sshkey.h" |
| 37 | #include "ssherr.h" |
| 38 | #include "digest.h" |
| 39 | |
| 40 | #include "ssh-sk.h" |
| 41 | #include "sk-api.h" |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 42 | #include "crypto_api.h" |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 43 | |
| 44 | struct sshsk_provider { |
| 45 | char *path; |
| 46 | void *dlhandle; |
| 47 | |
| 48 | /* Return the version of the middleware API */ |
| 49 | uint32_t (*sk_api_version)(void); |
| 50 | |
| 51 | /* Enroll a U2F key (private key generation) */ |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 52 | int (*sk_enroll)(int alg, const uint8_t *challenge, |
| 53 | size_t challenge_len, const char *application, uint8_t flags, |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 54 | struct sk_enroll_response **enroll_response); |
| 55 | |
| 56 | /* Sign a challenge */ |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 57 | int (*sk_sign)(int alg, const uint8_t *message, size_t message_len, |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 58 | const char *application, |
| 59 | const uint8_t *key_handle, size_t key_handle_len, |
| 60 | uint8_t flags, struct sk_sign_response **sign_response); |
| 61 | }; |
| 62 | |
djm@openbsd.org | 6bff952 | 2019-11-14 21:27:29 +0000 | [diff] [blame^] | 63 | /* Built-in version */ |
| 64 | int ssh_sk_enroll(int alg, const uint8_t *challenge, |
| 65 | size_t challenge_len, const char *application, uint8_t flags, |
| 66 | struct sk_enroll_response **enroll_response); |
| 67 | int ssh_sk_sign(int alg, const uint8_t *message, size_t message_len, |
| 68 | const char *application, |
| 69 | const uint8_t *key_handle, size_t key_handle_len, |
| 70 | uint8_t flags, struct sk_sign_response **sign_response); |
| 71 | |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 72 | static void |
| 73 | sshsk_free(struct sshsk_provider *p) |
| 74 | { |
| 75 | if (p == NULL) |
| 76 | return; |
| 77 | free(p->path); |
| 78 | if (p->dlhandle != NULL) |
| 79 | dlclose(p->dlhandle); |
| 80 | free(p); |
| 81 | } |
| 82 | |
| 83 | static struct sshsk_provider * |
| 84 | sshsk_open(const char *path) |
| 85 | { |
| 86 | struct sshsk_provider *ret = NULL; |
| 87 | uint32_t version; |
| 88 | |
| 89 | if ((ret = calloc(1, sizeof(*ret))) == NULL) { |
| 90 | error("%s: calloc failed", __func__); |
| 91 | return NULL; |
| 92 | } |
| 93 | if ((ret->path = strdup(path)) == NULL) { |
| 94 | error("%s: strdup failed", __func__); |
| 95 | goto fail; |
| 96 | } |
djm@openbsd.org | 6bff952 | 2019-11-14 21:27:29 +0000 | [diff] [blame^] | 97 | /* Skip the rest if we're using the linked in middleware */ |
| 98 | if (strcasecmp(ret->path, "internal") == 0) { |
| 99 | #ifdef ENABLE_SK_INTERNAL |
| 100 | ret->sk_enroll = ssh_sk_enroll; |
| 101 | ret->sk_sign = ssh_sk_sign; |
| 102 | #else |
| 103 | error("internal security key support not enabled"); |
| 104 | #endif |
| 105 | return ret; |
| 106 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 107 | if ((ret->dlhandle = dlopen(path, RTLD_NOW)) == NULL) { |
| 108 | error("Security key provider %s dlopen failed: %s", |
| 109 | path, dlerror()); |
| 110 | goto fail; |
| 111 | } |
| 112 | if ((ret->sk_api_version = dlsym(ret->dlhandle, |
| 113 | "sk_api_version")) == NULL) { |
| 114 | error("Security key provider %s dlsym(sk_api_version) " |
| 115 | "failed: %s", path, dlerror()); |
| 116 | goto fail; |
| 117 | } |
| 118 | version = ret->sk_api_version(); |
| 119 | debug("%s: provider %s implements version 0x%08lx", __func__, |
| 120 | ret->path, (u_long)version); |
| 121 | if ((version & SSH_SK_VERSION_MAJOR_MASK) != SSH_SK_VERSION_MAJOR) { |
| 122 | error("Security key provider %s implements unsupported version " |
| 123 | "0x%08lx (supported: 0x%08lx)", path, (u_long)version, |
| 124 | (u_long)SSH_SK_VERSION_MAJOR); |
| 125 | goto fail; |
| 126 | } |
| 127 | if ((ret->sk_enroll = dlsym(ret->dlhandle, "sk_enroll")) == NULL) { |
| 128 | error("Security key provider %s dlsym(sk_enroll) " |
| 129 | "failed: %s", path, dlerror()); |
| 130 | goto fail; |
| 131 | } |
| 132 | if ((ret->sk_sign = dlsym(ret->dlhandle, "sk_sign")) == NULL) { |
| 133 | error("Security key provider %s dlsym(sk_sign) failed: %s", |
| 134 | path, dlerror()); |
| 135 | goto fail; |
| 136 | } |
| 137 | /* success */ |
| 138 | return ret; |
| 139 | fail: |
| 140 | sshsk_free(ret); |
| 141 | return NULL; |
| 142 | } |
| 143 | |
| 144 | static void |
| 145 | sshsk_free_enroll_response(struct sk_enroll_response *r) |
| 146 | { |
| 147 | if (r == NULL) |
| 148 | return; |
| 149 | freezero(r->key_handle, r->key_handle_len); |
| 150 | freezero(r->public_key, r->public_key_len); |
| 151 | freezero(r->signature, r->signature_len); |
| 152 | freezero(r->attestation_cert, r->attestation_cert_len); |
| 153 | freezero(r, sizeof(*r)); |
| 154 | }; |
| 155 | |
| 156 | static void |
| 157 | sshsk_free_sign_response(struct sk_sign_response *r) |
| 158 | { |
| 159 | if (r == NULL) |
| 160 | return; |
| 161 | freezero(r->sig_r, r->sig_r_len); |
| 162 | freezero(r->sig_s, r->sig_s_len); |
| 163 | freezero(r, sizeof(*r)); |
| 164 | }; |
| 165 | |
markus@openbsd.org | cef84a0 | 2019-11-12 19:29:54 +0000 | [diff] [blame] | 166 | /* Assemble key from response */ |
| 167 | static int |
| 168 | sshsk_ecdsa_assemble(struct sk_enroll_response *resp, struct sshkey **keyp) |
| 169 | { |
| 170 | struct sshkey *key = NULL; |
| 171 | struct sshbuf *b = NULL; |
| 172 | EC_POINT *q = NULL; |
| 173 | int r; |
| 174 | |
| 175 | *keyp = NULL; |
| 176 | if ((key = sshkey_new(KEY_ECDSA_SK)) == NULL) { |
| 177 | error("%s: sshkey_new failed", __func__); |
| 178 | r = SSH_ERR_ALLOC_FAIL; |
| 179 | goto out; |
| 180 | } |
| 181 | key->ecdsa_nid = NID_X9_62_prime256v1; |
| 182 | if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid)) == NULL || |
| 183 | (q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL || |
| 184 | (b = sshbuf_new()) == NULL) { |
| 185 | error("%s: allocation failed", __func__); |
| 186 | r = SSH_ERR_ALLOC_FAIL; |
| 187 | goto out; |
| 188 | } |
| 189 | if ((r = sshbuf_put_string(b, |
| 190 | resp->public_key, resp->public_key_len)) != 0) { |
| 191 | error("%s: buffer error: %s", __func__, ssh_err(r)); |
| 192 | goto out; |
| 193 | } |
| 194 | if ((r = sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa))) != 0) { |
| 195 | error("%s: parse key: %s", __func__, ssh_err(r)); |
| 196 | r = SSH_ERR_INVALID_FORMAT; |
| 197 | goto out; |
| 198 | } |
| 199 | if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa), q) != 0) { |
| 200 | error("Security key returned invalid ECDSA key"); |
| 201 | r = SSH_ERR_KEY_INVALID_EC_VALUE; |
| 202 | goto out; |
| 203 | } |
| 204 | if (EC_KEY_set_public_key(key->ecdsa, q) != 1) { |
| 205 | /* XXX assume it is a allocation error */ |
| 206 | error("%s: allocation failed", __func__); |
| 207 | r = SSH_ERR_ALLOC_FAIL; |
| 208 | goto out; |
| 209 | } |
| 210 | /* success */ |
| 211 | *keyp = key; |
| 212 | key = NULL; /* transferred */ |
| 213 | r = 0; |
| 214 | out: |
| 215 | EC_POINT_free(q); |
| 216 | sshkey_free(key); |
| 217 | sshbuf_free(b); |
| 218 | return r; |
| 219 | } |
| 220 | |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 221 | static int |
| 222 | sshsk_ed25519_assemble(struct sk_enroll_response *resp, struct sshkey **keyp) |
| 223 | { |
| 224 | struct sshkey *key = NULL; |
| 225 | int r; |
| 226 | |
| 227 | *keyp = NULL; |
| 228 | if (resp->public_key_len != ED25519_PK_SZ) { |
| 229 | error("%s: invalid size: %zu", __func__, resp->public_key_len); |
| 230 | r = SSH_ERR_INVALID_FORMAT; |
| 231 | goto out; |
| 232 | } |
| 233 | if ((key = sshkey_new(KEY_ED25519_SK)) == NULL) { |
| 234 | error("%s: sshkey_new failed", __func__); |
| 235 | r = SSH_ERR_ALLOC_FAIL; |
| 236 | goto out; |
| 237 | } |
| 238 | if ((key->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) { |
| 239 | error("%s: malloc failed", __func__); |
| 240 | r = SSH_ERR_ALLOC_FAIL; |
| 241 | goto out; |
| 242 | } |
| 243 | memcpy(key->ed25519_pk, resp->public_key, ED25519_PK_SZ); |
| 244 | /* success */ |
| 245 | *keyp = key; |
| 246 | key = NULL; /* transferred */ |
| 247 | r = 0; |
| 248 | out: |
| 249 | sshkey_free(key); |
| 250 | return r; |
| 251 | } |
| 252 | |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 253 | int |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 254 | sshsk_enroll(int type, const char *provider_path, const char *application, |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 255 | uint8_t flags, struct sshbuf *challenge_buf, struct sshkey **keyp, |
| 256 | struct sshbuf *attest) |
| 257 | { |
| 258 | struct sshsk_provider *skp = NULL; |
| 259 | struct sshkey *key = NULL; |
| 260 | u_char randchall[32]; |
| 261 | const u_char *challenge; |
| 262 | size_t challenge_len; |
| 263 | struct sk_enroll_response *resp = NULL; |
| 264 | int r = SSH_ERR_INTERNAL_ERROR; |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 265 | int alg; |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 266 | |
| 267 | *keyp = NULL; |
| 268 | if (attest) |
| 269 | sshbuf_reset(attest); |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 270 | switch (type) { |
| 271 | case KEY_ECDSA_SK: |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 272 | alg = SSH_SK_ECDSA; |
| 273 | break; |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 274 | case KEY_ED25519_SK: |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 275 | alg = SSH_SK_ED25519; |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 276 | break; |
| 277 | default: |
| 278 | error("%s: unsupported key type", __func__); |
| 279 | r = SSH_ERR_INVALID_ARGUMENT; |
| 280 | goto out; |
| 281 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 282 | if (provider_path == NULL) { |
| 283 | error("%s: missing provider", __func__); |
| 284 | r = SSH_ERR_INVALID_ARGUMENT; |
| 285 | goto out; |
| 286 | } |
| 287 | if (application == NULL || *application == '\0') { |
| 288 | error("%s: missing application", __func__); |
| 289 | r = SSH_ERR_INVALID_ARGUMENT; |
| 290 | goto out; |
| 291 | } |
| 292 | if (challenge_buf == NULL) { |
| 293 | debug("%s: using random challenge", __func__); |
| 294 | arc4random_buf(randchall, sizeof(randchall)); |
| 295 | challenge = randchall; |
| 296 | challenge_len = sizeof(randchall); |
| 297 | } else if (sshbuf_len(challenge_buf) == 0) { |
| 298 | error("Missing enrollment challenge"); |
| 299 | r = SSH_ERR_INVALID_ARGUMENT; |
| 300 | goto out; |
| 301 | } else { |
| 302 | challenge = sshbuf_ptr(challenge_buf); |
| 303 | challenge_len = sshbuf_len(challenge_buf); |
| 304 | debug3("%s: using explicit challenge len=%zd", |
| 305 | __func__, challenge_len); |
| 306 | } |
| 307 | if ((skp = sshsk_open(provider_path)) == NULL) { |
| 308 | r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ |
| 309 | goto out; |
| 310 | } |
| 311 | /* XXX validate flags? */ |
| 312 | /* enroll key */ |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 313 | if ((r = skp->sk_enroll(alg, challenge, challenge_len, application, |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 314 | flags, &resp)) != 0) { |
| 315 | error("Security key provider %s returned failure %d", |
| 316 | provider_path, r); |
| 317 | r = SSH_ERR_INVALID_FORMAT; /* XXX error codes in API? */ |
| 318 | goto out; |
| 319 | } |
| 320 | /* Check response validity */ |
| 321 | if (resp->public_key == NULL || resp->key_handle == NULL || |
djm@openbsd.org | fccff33 | 2019-11-12 22:38:19 +0000 | [diff] [blame] | 322 | resp->signature == NULL || |
| 323 | (resp->attestation_cert == NULL && resp->attestation_cert_len != 0)) { |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 324 | error("%s: sk_enroll response invalid", __func__); |
| 325 | r = SSH_ERR_INVALID_FORMAT; |
| 326 | goto out; |
| 327 | } |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 328 | switch (type) { |
| 329 | case KEY_ECDSA_SK: |
| 330 | if ((r = sshsk_ecdsa_assemble(resp, &key)) != 0) |
| 331 | goto out; |
| 332 | break; |
| 333 | case KEY_ED25519_SK: |
| 334 | if ((r = sshsk_ed25519_assemble(resp, &key)) != 0) |
| 335 | goto out; |
| 336 | break; |
| 337 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 338 | key->sk_flags = flags; |
markus@openbsd.org | cef84a0 | 2019-11-12 19:29:54 +0000 | [diff] [blame] | 339 | if ((key->sk_key_handle = sshbuf_new()) == NULL || |
| 340 | (key->sk_reserved = sshbuf_new()) == NULL) { |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 341 | error("%s: allocation failed", __func__); |
| 342 | r = SSH_ERR_ALLOC_FAIL; |
| 343 | goto out; |
| 344 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 345 | if ((key->sk_application = strdup(application)) == NULL) { |
| 346 | error("%s: strdup application failed", __func__); |
| 347 | r = SSH_ERR_ALLOC_FAIL; |
| 348 | goto out; |
| 349 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 350 | if ((r = sshbuf_put(key->sk_key_handle, resp->key_handle, |
| 351 | resp->key_handle_len)) != 0) { |
| 352 | error("%s: buffer error: %s", __func__, ssh_err(r)); |
| 353 | goto out; |
| 354 | } |
| 355 | /* Optionally fill in the attestation information */ |
| 356 | if (attest != NULL) { |
| 357 | if ((r = sshbuf_put_cstring(attest, "sk-attest-v00")) != 0 || |
| 358 | (r = sshbuf_put_u32(attest, 1)) != 0 || /* XXX U2F ver */ |
| 359 | (r = sshbuf_put_string(attest, |
| 360 | resp->attestation_cert, resp->attestation_cert_len)) != 0 || |
| 361 | (r = sshbuf_put_string(attest, |
| 362 | resp->signature, resp->signature_len)) != 0 || |
| 363 | (r = sshbuf_put_u32(attest, flags)) != 0 || /* XXX right? */ |
| 364 | (r = sshbuf_put_string(attest, NULL, 0)) != 0) { |
| 365 | error("%s: buffer error: %s", __func__, ssh_err(r)); |
| 366 | goto out; |
| 367 | } |
| 368 | } |
| 369 | /* success */ |
| 370 | *keyp = key; |
| 371 | key = NULL; /* transferred */ |
| 372 | r = 0; |
| 373 | out: |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 374 | sshsk_free(skp); |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 375 | sshkey_free(key); |
| 376 | sshsk_free_enroll_response(resp); |
| 377 | explicit_bzero(randchall, sizeof(randchall)); |
| 378 | return r; |
| 379 | } |
| 380 | |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 381 | static int |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 382 | sshsk_ecdsa_sig(struct sk_sign_response *resp, struct sshbuf *sig) |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 383 | { |
| 384 | struct sshbuf *inner_sig = NULL; |
| 385 | int r = SSH_ERR_INTERNAL_ERROR; |
| 386 | |
markus@openbsd.org | 3fcf69a | 2019-11-12 19:34:00 +0000 | [diff] [blame] | 387 | /* Check response validity */ |
markus@openbsd.org | dffd02e | 2019-11-13 20:25:45 +0000 | [diff] [blame] | 388 | if (resp->sig_r == NULL || resp->sig_s == NULL) { |
markus@openbsd.org | 3fcf69a | 2019-11-12 19:34:00 +0000 | [diff] [blame] | 389 | error("%s: sk_sign response invalid", __func__); |
| 390 | r = SSH_ERR_INVALID_FORMAT; |
| 391 | goto out; |
| 392 | } |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 393 | if ((inner_sig = sshbuf_new()) == NULL) { |
| 394 | r = SSH_ERR_ALLOC_FAIL; |
| 395 | goto out; |
| 396 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 397 | /* Prepare and append inner signature object */ |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 398 | if ((r = sshbuf_put_bignum2_bytes(inner_sig, |
| 399 | resp->sig_r, resp->sig_r_len)) != 0 || |
| 400 | (r = sshbuf_put_bignum2_bytes(inner_sig, |
| 401 | resp->sig_s, resp->sig_s_len)) != 0 || |
| 402 | (r = sshbuf_put_u8(inner_sig, resp->flags)) != 0 || |
| 403 | (r = sshbuf_put_u32(inner_sig, resp->counter)) != 0) { |
| 404 | debug("%s: buffer error: %s", __func__, ssh_err(r)); |
| 405 | goto out; |
| 406 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 407 | if ((r = sshbuf_put_stringb(sig, inner_sig)) != 0) { |
| 408 | debug("%s: buffer error: %s", __func__, ssh_err(r)); |
| 409 | goto out; |
| 410 | } |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 411 | #ifdef DEBUG_SK |
| 412 | fprintf(stderr, "%s: sig_r:\n", __func__); |
| 413 | sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr); |
| 414 | fprintf(stderr, "%s: sig_s:\n", __func__); |
| 415 | sshbuf_dump_data(resp->sig_s, resp->sig_s_len, stderr); |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 416 | fprintf(stderr, "%s: inner:\n", __func__); |
| 417 | sshbuf_dump(inner_sig, stderr); |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 418 | #endif |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 419 | r = 0; |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 420 | out: |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 421 | sshbuf_free(inner_sig); |
| 422 | return r; |
| 423 | } |
| 424 | |
| 425 | static int |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 426 | sshsk_ed25519_sig(struct sk_sign_response *resp, struct sshbuf *sig) |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 427 | { |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 428 | int r = SSH_ERR_INTERNAL_ERROR; |
| 429 | |
markus@openbsd.org | 3fcf69a | 2019-11-12 19:34:00 +0000 | [diff] [blame] | 430 | /* Check response validity */ |
| 431 | if (resp->sig_r == NULL) { |
| 432 | error("%s: sk_sign response invalid", __func__); |
| 433 | r = SSH_ERR_INVALID_FORMAT; |
| 434 | goto out; |
| 435 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 436 | if ((r = sshbuf_put_string(sig, |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 437 | resp->sig_r, resp->sig_r_len)) != 0 || |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 438 | (r = sshbuf_put_u8(sig, resp->flags)) != 0 || |
| 439 | (r = sshbuf_put_u32(sig, resp->counter)) != 0) { |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 440 | debug("%s: buffer error: %s", __func__, ssh_err(r)); |
| 441 | goto out; |
| 442 | } |
| 443 | #ifdef DEBUG_SK |
| 444 | fprintf(stderr, "%s: sig_r:\n", __func__); |
| 445 | sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr); |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 446 | #endif |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 447 | r = 0; |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 448 | out: |
| 449 | return 0; |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 450 | } |
| 451 | |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 452 | int |
markus@openbsd.org | e03a29e | 2019-11-12 19:30:50 +0000 | [diff] [blame] | 453 | sshsk_sign(const char *provider_path, const struct sshkey *key, |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 454 | u_char **sigp, size_t *lenp, const u_char *data, size_t datalen, |
| 455 | u_int compat) |
| 456 | { |
| 457 | struct sshsk_provider *skp = NULL; |
| 458 | int r = SSH_ERR_INTERNAL_ERROR; |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 459 | int type, alg; |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 460 | struct sk_sign_response *resp = NULL; |
| 461 | struct sshbuf *inner_sig = NULL, *sig = NULL; |
| 462 | uint8_t message[32]; |
| 463 | |
| 464 | if (sigp != NULL) |
| 465 | *sigp = NULL; |
| 466 | if (lenp != NULL) |
| 467 | *lenp = 0; |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 468 | type = sshkey_type_plain(key->type); |
| 469 | switch (type) { |
| 470 | case KEY_ECDSA_SK: |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 471 | alg = SSH_SK_ECDSA; |
| 472 | break; |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 473 | case KEY_ED25519_SK: |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 474 | alg = SSH_SK_ED25519; |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 475 | break; |
| 476 | default: |
| 477 | return SSH_ERR_INVALID_ARGUMENT; |
| 478 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 479 | if (provider_path == NULL || |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 480 | key->sk_key_handle == NULL || |
| 481 | key->sk_application == NULL || *key->sk_application == '\0') { |
| 482 | r = SSH_ERR_INVALID_ARGUMENT; |
| 483 | goto out; |
| 484 | } |
| 485 | if ((skp = sshsk_open(provider_path)) == NULL) { |
| 486 | r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ |
| 487 | goto out; |
| 488 | } |
| 489 | |
| 490 | /* hash data to be signed before it goes to the security key */ |
| 491 | if ((r = ssh_digest_memory(SSH_DIGEST_SHA256, data, datalen, |
| 492 | message, sizeof(message))) != 0) { |
| 493 | error("%s: hash application failed: %s", __func__, ssh_err(r)); |
| 494 | r = SSH_ERR_INTERNAL_ERROR; |
| 495 | goto out; |
| 496 | } |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 497 | if ((r = skp->sk_sign(alg, message, sizeof(message), |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 498 | key->sk_application, |
| 499 | sshbuf_ptr(key->sk_key_handle), sshbuf_len(key->sk_key_handle), |
| 500 | key->sk_flags, &resp)) != 0) { |
| 501 | debug("%s: sk_sign failed with code %d", __func__, r); |
| 502 | goto out; |
| 503 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 504 | /* Assemble signature */ |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 505 | if ((sig = sshbuf_new()) == NULL) { |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 506 | r = SSH_ERR_ALLOC_FAIL; |
| 507 | goto out; |
| 508 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 509 | if ((r = sshbuf_put_cstring(sig, sshkey_ssh_name_plain(key))) != 0) { |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 510 | debug("%s: buffer error (outer): %s", __func__, ssh_err(r)); |
| 511 | goto out; |
| 512 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 513 | switch (type) { |
| 514 | case KEY_ECDSA_SK: |
| 515 | if ((r = sshsk_ecdsa_sig(resp, sig)) != 0) |
| 516 | goto out; |
| 517 | break; |
| 518 | case KEY_ED25519_SK: |
| 519 | if ((r = sshsk_ed25519_sig(resp, sig)) != 0) |
| 520 | goto out; |
| 521 | break; |
| 522 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 523 | #ifdef DEBUG_SK |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 524 | fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n", |
| 525 | __func__, resp->flags, resp->counter); |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 526 | fprintf(stderr, "%s: hashed message:\n", __func__); |
| 527 | sshbuf_dump_data(message, sizeof(message), stderr); |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 528 | fprintf(stderr, "%s: sigbuf:\n", __func__); |
| 529 | sshbuf_dump(sig, stderr); |
| 530 | #endif |
| 531 | if (sigp != NULL) { |
| 532 | if ((*sigp = malloc(sshbuf_len(sig))) == NULL) { |
| 533 | r = SSH_ERR_ALLOC_FAIL; |
| 534 | goto out; |
| 535 | } |
| 536 | memcpy(*sigp, sshbuf_ptr(sig), sshbuf_len(sig)); |
| 537 | } |
| 538 | if (lenp != NULL) |
| 539 | *lenp = sshbuf_len(sig); |
| 540 | /* success */ |
| 541 | r = 0; |
| 542 | out: |
| 543 | explicit_bzero(message, sizeof(message)); |
| 544 | sshsk_free(skp); |
| 545 | sshsk_free_sign_response(resp); |
| 546 | sshbuf_free(sig); |
| 547 | sshbuf_free(inner_sig); |
| 548 | return r; |
| 549 | } |
Damien Miller | 764d51e | 2019-11-01 13:34:49 +1100 | [diff] [blame] | 550 | #endif /* ENABLE_SK */ |