djm@openbsd.org | a70d92f | 2019-11-19 22:23:19 +0000 | [diff] [blame] | 1 | /* $OpenBSD: ssh-sk.c,v 1.16 2019/11/19 22:23:19 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 | |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 30 | #ifdef WITH_OPENSSL |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 31 | #include <openssl/objects.h> |
| 32 | #include <openssl/ec.h> |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 33 | #endif /* WITH_OPENSSL */ |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 34 | |
| 35 | #include "log.h" |
| 36 | #include "misc.h" |
| 37 | #include "sshbuf.h" |
| 38 | #include "sshkey.h" |
| 39 | #include "ssherr.h" |
| 40 | #include "digest.h" |
| 41 | |
| 42 | #include "ssh-sk.h" |
| 43 | #include "sk-api.h" |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 44 | #include "crypto_api.h" |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 45 | |
| 46 | struct sshsk_provider { |
| 47 | char *path; |
| 48 | void *dlhandle; |
| 49 | |
| 50 | /* Return the version of the middleware API */ |
| 51 | uint32_t (*sk_api_version)(void); |
| 52 | |
| 53 | /* Enroll a U2F key (private key generation) */ |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 54 | int (*sk_enroll)(int alg, const uint8_t *challenge, |
| 55 | size_t challenge_len, const char *application, uint8_t flags, |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 56 | struct sk_enroll_response **enroll_response); |
| 57 | |
| 58 | /* Sign a challenge */ |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 59 | 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] | 60 | const char *application, |
| 61 | const uint8_t *key_handle, size_t key_handle_len, |
| 62 | uint8_t flags, struct sk_sign_response **sign_response); |
| 63 | }; |
| 64 | |
djm@openbsd.org | 6bff952 | 2019-11-14 21:27:29 +0000 | [diff] [blame] | 65 | /* Built-in version */ |
| 66 | int ssh_sk_enroll(int alg, const uint8_t *challenge, |
| 67 | size_t challenge_len, const char *application, uint8_t flags, |
| 68 | struct sk_enroll_response **enroll_response); |
| 69 | int ssh_sk_sign(int alg, const uint8_t *message, size_t message_len, |
| 70 | const char *application, |
| 71 | const uint8_t *key_handle, size_t key_handle_len, |
| 72 | uint8_t flags, struct sk_sign_response **sign_response); |
| 73 | |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 74 | static void |
| 75 | sshsk_free(struct sshsk_provider *p) |
| 76 | { |
| 77 | if (p == NULL) |
| 78 | return; |
| 79 | free(p->path); |
| 80 | if (p->dlhandle != NULL) |
| 81 | dlclose(p->dlhandle); |
| 82 | free(p); |
| 83 | } |
| 84 | |
| 85 | static struct sshsk_provider * |
| 86 | sshsk_open(const char *path) |
| 87 | { |
| 88 | struct sshsk_provider *ret = NULL; |
| 89 | uint32_t version; |
| 90 | |
| 91 | if ((ret = calloc(1, sizeof(*ret))) == NULL) { |
| 92 | error("%s: calloc failed", __func__); |
| 93 | return NULL; |
| 94 | } |
| 95 | if ((ret->path = strdup(path)) == NULL) { |
| 96 | error("%s: strdup failed", __func__); |
| 97 | goto fail; |
| 98 | } |
djm@openbsd.org | 6bff952 | 2019-11-14 21:27:29 +0000 | [diff] [blame] | 99 | /* Skip the rest if we're using the linked in middleware */ |
| 100 | if (strcasecmp(ret->path, "internal") == 0) { |
| 101 | #ifdef ENABLE_SK_INTERNAL |
| 102 | ret->sk_enroll = ssh_sk_enroll; |
| 103 | ret->sk_sign = ssh_sk_sign; |
| 104 | #else |
| 105 | error("internal security key support not enabled"); |
| 106 | #endif |
| 107 | return ret; |
| 108 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 109 | if ((ret->dlhandle = dlopen(path, RTLD_NOW)) == NULL) { |
| 110 | error("Security key provider %s dlopen failed: %s", |
| 111 | path, dlerror()); |
| 112 | goto fail; |
| 113 | } |
| 114 | if ((ret->sk_api_version = dlsym(ret->dlhandle, |
| 115 | "sk_api_version")) == NULL) { |
| 116 | error("Security key provider %s dlsym(sk_api_version) " |
| 117 | "failed: %s", path, dlerror()); |
| 118 | goto fail; |
| 119 | } |
| 120 | version = ret->sk_api_version(); |
| 121 | debug("%s: provider %s implements version 0x%08lx", __func__, |
| 122 | ret->path, (u_long)version); |
| 123 | if ((version & SSH_SK_VERSION_MAJOR_MASK) != SSH_SK_VERSION_MAJOR) { |
| 124 | error("Security key provider %s implements unsupported version " |
| 125 | "0x%08lx (supported: 0x%08lx)", path, (u_long)version, |
| 126 | (u_long)SSH_SK_VERSION_MAJOR); |
| 127 | goto fail; |
| 128 | } |
| 129 | if ((ret->sk_enroll = dlsym(ret->dlhandle, "sk_enroll")) == NULL) { |
| 130 | error("Security key provider %s dlsym(sk_enroll) " |
| 131 | "failed: %s", path, dlerror()); |
| 132 | goto fail; |
| 133 | } |
| 134 | if ((ret->sk_sign = dlsym(ret->dlhandle, "sk_sign")) == NULL) { |
| 135 | error("Security key provider %s dlsym(sk_sign) failed: %s", |
| 136 | path, dlerror()); |
| 137 | goto fail; |
| 138 | } |
| 139 | /* success */ |
| 140 | return ret; |
| 141 | fail: |
| 142 | sshsk_free(ret); |
| 143 | return NULL; |
| 144 | } |
| 145 | |
| 146 | static void |
| 147 | sshsk_free_enroll_response(struct sk_enroll_response *r) |
| 148 | { |
| 149 | if (r == NULL) |
| 150 | return; |
| 151 | freezero(r->key_handle, r->key_handle_len); |
| 152 | freezero(r->public_key, r->public_key_len); |
| 153 | freezero(r->signature, r->signature_len); |
| 154 | freezero(r->attestation_cert, r->attestation_cert_len); |
| 155 | freezero(r, sizeof(*r)); |
| 156 | }; |
| 157 | |
| 158 | static void |
| 159 | sshsk_free_sign_response(struct sk_sign_response *r) |
| 160 | { |
| 161 | if (r == NULL) |
| 162 | return; |
| 163 | freezero(r->sig_r, r->sig_r_len); |
| 164 | freezero(r->sig_s, r->sig_s_len); |
| 165 | freezero(r, sizeof(*r)); |
| 166 | }; |
| 167 | |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 168 | #ifdef WITH_OPENSSL |
markus@openbsd.org | cef84a0 | 2019-11-12 19:29:54 +0000 | [diff] [blame] | 169 | /* Assemble key from response */ |
| 170 | static int |
| 171 | sshsk_ecdsa_assemble(struct sk_enroll_response *resp, struct sshkey **keyp) |
| 172 | { |
| 173 | struct sshkey *key = NULL; |
| 174 | struct sshbuf *b = NULL; |
| 175 | EC_POINT *q = NULL; |
| 176 | int r; |
| 177 | |
| 178 | *keyp = NULL; |
| 179 | if ((key = sshkey_new(KEY_ECDSA_SK)) == NULL) { |
| 180 | error("%s: sshkey_new failed", __func__); |
| 181 | r = SSH_ERR_ALLOC_FAIL; |
| 182 | goto out; |
| 183 | } |
| 184 | key->ecdsa_nid = NID_X9_62_prime256v1; |
| 185 | if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid)) == NULL || |
| 186 | (q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL || |
| 187 | (b = sshbuf_new()) == NULL) { |
| 188 | error("%s: allocation failed", __func__); |
| 189 | r = SSH_ERR_ALLOC_FAIL; |
| 190 | goto out; |
| 191 | } |
| 192 | if ((r = sshbuf_put_string(b, |
| 193 | resp->public_key, resp->public_key_len)) != 0) { |
| 194 | error("%s: buffer error: %s", __func__, ssh_err(r)); |
| 195 | goto out; |
| 196 | } |
| 197 | if ((r = sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa))) != 0) { |
| 198 | error("%s: parse key: %s", __func__, ssh_err(r)); |
| 199 | r = SSH_ERR_INVALID_FORMAT; |
| 200 | goto out; |
| 201 | } |
| 202 | if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa), q) != 0) { |
| 203 | error("Security key returned invalid ECDSA key"); |
| 204 | r = SSH_ERR_KEY_INVALID_EC_VALUE; |
| 205 | goto out; |
| 206 | } |
| 207 | if (EC_KEY_set_public_key(key->ecdsa, q) != 1) { |
| 208 | /* XXX assume it is a allocation error */ |
| 209 | error("%s: allocation failed", __func__); |
| 210 | r = SSH_ERR_ALLOC_FAIL; |
| 211 | goto out; |
| 212 | } |
| 213 | /* success */ |
| 214 | *keyp = key; |
| 215 | key = NULL; /* transferred */ |
| 216 | r = 0; |
| 217 | out: |
| 218 | EC_POINT_free(q); |
| 219 | sshkey_free(key); |
| 220 | sshbuf_free(b); |
| 221 | return r; |
| 222 | } |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 223 | #endif /* WITH_OPENSSL */ |
markus@openbsd.org | cef84a0 | 2019-11-12 19:29:54 +0000 | [diff] [blame] | 224 | |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 225 | static int |
| 226 | sshsk_ed25519_assemble(struct sk_enroll_response *resp, struct sshkey **keyp) |
| 227 | { |
| 228 | struct sshkey *key = NULL; |
| 229 | int r; |
| 230 | |
| 231 | *keyp = NULL; |
| 232 | if (resp->public_key_len != ED25519_PK_SZ) { |
| 233 | error("%s: invalid size: %zu", __func__, resp->public_key_len); |
| 234 | r = SSH_ERR_INVALID_FORMAT; |
| 235 | goto out; |
| 236 | } |
| 237 | if ((key = sshkey_new(KEY_ED25519_SK)) == NULL) { |
| 238 | error("%s: sshkey_new failed", __func__); |
| 239 | r = SSH_ERR_ALLOC_FAIL; |
| 240 | goto out; |
| 241 | } |
| 242 | if ((key->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) { |
| 243 | error("%s: malloc failed", __func__); |
| 244 | r = SSH_ERR_ALLOC_FAIL; |
| 245 | goto out; |
| 246 | } |
| 247 | memcpy(key->ed25519_pk, resp->public_key, ED25519_PK_SZ); |
| 248 | /* success */ |
| 249 | *keyp = key; |
| 250 | key = NULL; /* transferred */ |
| 251 | r = 0; |
| 252 | out: |
| 253 | sshkey_free(key); |
| 254 | return r; |
| 255 | } |
| 256 | |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 257 | int |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 258 | sshsk_enroll(int type, const char *provider_path, const char *application, |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 259 | uint8_t flags, struct sshbuf *challenge_buf, struct sshkey **keyp, |
| 260 | struct sshbuf *attest) |
| 261 | { |
| 262 | struct sshsk_provider *skp = NULL; |
| 263 | struct sshkey *key = NULL; |
| 264 | u_char randchall[32]; |
| 265 | const u_char *challenge; |
| 266 | size_t challenge_len; |
| 267 | struct sk_enroll_response *resp = NULL; |
| 268 | int r = SSH_ERR_INTERNAL_ERROR; |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 269 | int alg; |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 270 | |
djm@openbsd.org | 4103a3e | 2019-11-16 22:42:30 +0000 | [diff] [blame] | 271 | debug("%s: provider \"%s\", application \"%s\", flags 0x%02x, " |
| 272 | "challenge len %zu", __func__, provider_path, application, |
| 273 | flags, challenge_buf == NULL ? 0 : sshbuf_len(challenge_buf)); |
| 274 | |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 275 | *keyp = NULL; |
| 276 | if (attest) |
| 277 | sshbuf_reset(attest); |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 278 | switch (type) { |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 279 | #ifdef WITH_OPENSSL |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 280 | case KEY_ECDSA_SK: |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 281 | alg = SSH_SK_ECDSA; |
| 282 | break; |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 283 | #endif /* WITH_OPENSSL */ |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 284 | case KEY_ED25519_SK: |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 285 | alg = SSH_SK_ED25519; |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 286 | break; |
| 287 | default: |
| 288 | error("%s: unsupported key type", __func__); |
| 289 | r = SSH_ERR_INVALID_ARGUMENT; |
| 290 | goto out; |
| 291 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 292 | if (provider_path == NULL) { |
| 293 | error("%s: missing provider", __func__); |
| 294 | r = SSH_ERR_INVALID_ARGUMENT; |
| 295 | goto out; |
| 296 | } |
| 297 | if (application == NULL || *application == '\0') { |
| 298 | error("%s: missing application", __func__); |
| 299 | r = SSH_ERR_INVALID_ARGUMENT; |
| 300 | goto out; |
| 301 | } |
| 302 | if (challenge_buf == NULL) { |
| 303 | debug("%s: using random challenge", __func__); |
| 304 | arc4random_buf(randchall, sizeof(randchall)); |
| 305 | challenge = randchall; |
| 306 | challenge_len = sizeof(randchall); |
| 307 | } else if (sshbuf_len(challenge_buf) == 0) { |
| 308 | error("Missing enrollment challenge"); |
| 309 | r = SSH_ERR_INVALID_ARGUMENT; |
| 310 | goto out; |
| 311 | } else { |
| 312 | challenge = sshbuf_ptr(challenge_buf); |
| 313 | challenge_len = sshbuf_len(challenge_buf); |
| 314 | debug3("%s: using explicit challenge len=%zd", |
| 315 | __func__, challenge_len); |
| 316 | } |
| 317 | if ((skp = sshsk_open(provider_path)) == NULL) { |
| 318 | r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ |
| 319 | goto out; |
| 320 | } |
| 321 | /* XXX validate flags? */ |
| 322 | /* enroll key */ |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 323 | if ((r = skp->sk_enroll(alg, challenge, challenge_len, application, |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 324 | flags, &resp)) != 0) { |
| 325 | error("Security key provider %s returned failure %d", |
| 326 | provider_path, r); |
| 327 | r = SSH_ERR_INVALID_FORMAT; /* XXX error codes in API? */ |
| 328 | goto out; |
| 329 | } |
| 330 | /* Check response validity */ |
| 331 | if (resp->public_key == NULL || resp->key_handle == NULL || |
djm@openbsd.org | fccff33 | 2019-11-12 22:38:19 +0000 | [diff] [blame] | 332 | resp->signature == NULL || |
| 333 | (resp->attestation_cert == NULL && resp->attestation_cert_len != 0)) { |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 334 | error("%s: sk_enroll response invalid", __func__); |
| 335 | r = SSH_ERR_INVALID_FORMAT; |
| 336 | goto out; |
| 337 | } |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 338 | switch (type) { |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 339 | #ifdef WITH_OPENSSL |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 340 | case KEY_ECDSA_SK: |
| 341 | if ((r = sshsk_ecdsa_assemble(resp, &key)) != 0) |
| 342 | goto out; |
| 343 | break; |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 344 | #endif /* WITH_OPENSSL */ |
markus@openbsd.org | 7c32b51 | 2019-11-12 19:31:45 +0000 | [diff] [blame] | 345 | case KEY_ED25519_SK: |
| 346 | if ((r = sshsk_ed25519_assemble(resp, &key)) != 0) |
| 347 | goto out; |
| 348 | break; |
| 349 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 350 | key->sk_flags = flags; |
markus@openbsd.org | cef84a0 | 2019-11-12 19:29:54 +0000 | [diff] [blame] | 351 | if ((key->sk_key_handle = sshbuf_new()) == NULL || |
| 352 | (key->sk_reserved = sshbuf_new()) == NULL) { |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 353 | error("%s: allocation failed", __func__); |
| 354 | r = SSH_ERR_ALLOC_FAIL; |
| 355 | goto out; |
| 356 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 357 | if ((key->sk_application = strdup(application)) == NULL) { |
| 358 | error("%s: strdup application failed", __func__); |
| 359 | r = SSH_ERR_ALLOC_FAIL; |
| 360 | goto out; |
| 361 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 362 | if ((r = sshbuf_put(key->sk_key_handle, resp->key_handle, |
| 363 | resp->key_handle_len)) != 0) { |
| 364 | error("%s: buffer error: %s", __func__, ssh_err(r)); |
| 365 | goto out; |
| 366 | } |
| 367 | /* Optionally fill in the attestation information */ |
| 368 | if (attest != NULL) { |
| 369 | if ((r = sshbuf_put_cstring(attest, "sk-attest-v00")) != 0 || |
| 370 | (r = sshbuf_put_u32(attest, 1)) != 0 || /* XXX U2F ver */ |
| 371 | (r = sshbuf_put_string(attest, |
| 372 | resp->attestation_cert, resp->attestation_cert_len)) != 0 || |
| 373 | (r = sshbuf_put_string(attest, |
| 374 | resp->signature, resp->signature_len)) != 0 || |
| 375 | (r = sshbuf_put_u32(attest, flags)) != 0 || /* XXX right? */ |
| 376 | (r = sshbuf_put_string(attest, NULL, 0)) != 0) { |
| 377 | error("%s: buffer error: %s", __func__, ssh_err(r)); |
| 378 | goto out; |
| 379 | } |
| 380 | } |
| 381 | /* success */ |
| 382 | *keyp = key; |
| 383 | key = NULL; /* transferred */ |
| 384 | r = 0; |
| 385 | out: |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 386 | sshsk_free(skp); |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 387 | sshkey_free(key); |
| 388 | sshsk_free_enroll_response(resp); |
| 389 | explicit_bzero(randchall, sizeof(randchall)); |
| 390 | return r; |
| 391 | } |
| 392 | |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 393 | #ifdef WITH_OPENSSL |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 394 | static int |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 395 | sshsk_ecdsa_sig(struct sk_sign_response *resp, struct sshbuf *sig) |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 396 | { |
| 397 | struct sshbuf *inner_sig = NULL; |
| 398 | int r = SSH_ERR_INTERNAL_ERROR; |
| 399 | |
markus@openbsd.org | 3fcf69a | 2019-11-12 19:34:00 +0000 | [diff] [blame] | 400 | /* Check response validity */ |
markus@openbsd.org | dffd02e | 2019-11-13 20:25:45 +0000 | [diff] [blame] | 401 | if (resp->sig_r == NULL || resp->sig_s == NULL) { |
markus@openbsd.org | 3fcf69a | 2019-11-12 19:34:00 +0000 | [diff] [blame] | 402 | error("%s: sk_sign response invalid", __func__); |
| 403 | r = SSH_ERR_INVALID_FORMAT; |
| 404 | goto out; |
| 405 | } |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 406 | if ((inner_sig = sshbuf_new()) == NULL) { |
| 407 | r = SSH_ERR_ALLOC_FAIL; |
| 408 | goto out; |
| 409 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 410 | /* Prepare and append inner signature object */ |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 411 | if ((r = sshbuf_put_bignum2_bytes(inner_sig, |
| 412 | resp->sig_r, resp->sig_r_len)) != 0 || |
| 413 | (r = sshbuf_put_bignum2_bytes(inner_sig, |
djm@openbsd.org | a70d92f | 2019-11-19 22:23:19 +0000 | [diff] [blame] | 414 | resp->sig_s, resp->sig_s_len)) != 0) { |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 415 | debug("%s: buffer error: %s", __func__, ssh_err(r)); |
| 416 | goto out; |
| 417 | } |
djm@openbsd.org | a70d92f | 2019-11-19 22:23:19 +0000 | [diff] [blame] | 418 | if ((r = sshbuf_put_stringb(sig, inner_sig)) != 0 || |
| 419 | (r = sshbuf_put_u8(sig, resp->flags)) != 0 || |
| 420 | (r = sshbuf_put_u32(sig, resp->counter)) != 0) { |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 421 | debug("%s: buffer error: %s", __func__, ssh_err(r)); |
| 422 | goto out; |
| 423 | } |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 424 | #ifdef DEBUG_SK |
| 425 | fprintf(stderr, "%s: sig_r:\n", __func__); |
| 426 | sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr); |
| 427 | fprintf(stderr, "%s: sig_s:\n", __func__); |
| 428 | sshbuf_dump_data(resp->sig_s, resp->sig_s_len, stderr); |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 429 | fprintf(stderr, "%s: inner:\n", __func__); |
| 430 | sshbuf_dump(inner_sig, stderr); |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 431 | #endif |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 432 | r = 0; |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 433 | out: |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 434 | sshbuf_free(inner_sig); |
| 435 | return r; |
| 436 | } |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 437 | #endif /* WITH_OPENSSL */ |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 438 | |
| 439 | static int |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 440 | sshsk_ed25519_sig(struct sk_sign_response *resp, struct sshbuf *sig) |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 441 | { |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 442 | int r = SSH_ERR_INTERNAL_ERROR; |
| 443 | |
markus@openbsd.org | 3fcf69a | 2019-11-12 19:34:00 +0000 | [diff] [blame] | 444 | /* Check response validity */ |
| 445 | if (resp->sig_r == NULL) { |
| 446 | error("%s: sk_sign response invalid", __func__); |
| 447 | r = SSH_ERR_INVALID_FORMAT; |
| 448 | goto out; |
| 449 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 450 | if ((r = sshbuf_put_string(sig, |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 451 | resp->sig_r, resp->sig_r_len)) != 0 || |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 452 | (r = sshbuf_put_u8(sig, resp->flags)) != 0 || |
| 453 | (r = sshbuf_put_u32(sig, resp->counter)) != 0) { |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 454 | debug("%s: buffer error: %s", __func__, ssh_err(r)); |
| 455 | goto out; |
| 456 | } |
| 457 | #ifdef DEBUG_SK |
| 458 | fprintf(stderr, "%s: sig_r:\n", __func__); |
| 459 | sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr); |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 460 | #endif |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 461 | r = 0; |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 462 | out: |
| 463 | return 0; |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 464 | } |
| 465 | |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 466 | int |
markus@openbsd.org | e03a29e | 2019-11-12 19:30:50 +0000 | [diff] [blame] | 467 | sshsk_sign(const char *provider_path, const struct sshkey *key, |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 468 | u_char **sigp, size_t *lenp, const u_char *data, size_t datalen, |
| 469 | u_int compat) |
| 470 | { |
| 471 | struct sshsk_provider *skp = NULL; |
| 472 | int r = SSH_ERR_INTERNAL_ERROR; |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 473 | int type, alg; |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 474 | struct sk_sign_response *resp = NULL; |
| 475 | struct sshbuf *inner_sig = NULL, *sig = NULL; |
| 476 | uint8_t message[32]; |
| 477 | |
djm@openbsd.org | 9a1225e | 2019-11-16 23:17:20 +0000 | [diff] [blame] | 478 | debug("%s: provider \"%s\", key %s, flags 0x%02x", __func__, |
djm@openbsd.org | 4103a3e | 2019-11-16 22:42:30 +0000 | [diff] [blame] | 479 | provider_path, sshkey_type(key), key->sk_flags); |
| 480 | |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 481 | if (sigp != NULL) |
| 482 | *sigp = NULL; |
| 483 | if (lenp != NULL) |
| 484 | *lenp = 0; |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 485 | type = sshkey_type_plain(key->type); |
| 486 | switch (type) { |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 487 | #ifdef WITH_OPENSSL |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 488 | case KEY_ECDSA_SK: |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 489 | alg = SSH_SK_ECDSA; |
| 490 | break; |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 491 | #endif /* WITH_OPENSSL */ |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 492 | case KEY_ED25519_SK: |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 493 | alg = SSH_SK_ED25519; |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 494 | break; |
| 495 | default: |
| 496 | return SSH_ERR_INVALID_ARGUMENT; |
| 497 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 498 | if (provider_path == NULL || |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 499 | key->sk_key_handle == NULL || |
| 500 | key->sk_application == NULL || *key->sk_application == '\0') { |
| 501 | r = SSH_ERR_INVALID_ARGUMENT; |
| 502 | goto out; |
| 503 | } |
| 504 | if ((skp = sshsk_open(provider_path)) == NULL) { |
| 505 | r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ |
| 506 | goto out; |
| 507 | } |
| 508 | |
| 509 | /* hash data to be signed before it goes to the security key */ |
| 510 | if ((r = ssh_digest_memory(SSH_DIGEST_SHA256, data, datalen, |
| 511 | message, sizeof(message))) != 0) { |
| 512 | error("%s: hash application failed: %s", __func__, ssh_err(r)); |
| 513 | r = SSH_ERR_INTERNAL_ERROR; |
| 514 | goto out; |
| 515 | } |
markus@openbsd.org | fd1a3b5 | 2019-11-12 19:32:30 +0000 | [diff] [blame] | 516 | if ((r = skp->sk_sign(alg, message, sizeof(message), |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 517 | key->sk_application, |
| 518 | sshbuf_ptr(key->sk_key_handle), sshbuf_len(key->sk_key_handle), |
| 519 | key->sk_flags, &resp)) != 0) { |
| 520 | debug("%s: sk_sign failed with code %d", __func__, r); |
| 521 | goto out; |
| 522 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 523 | /* Assemble signature */ |
markus@openbsd.org | bc7b5d6 | 2019-11-12 19:30:21 +0000 | [diff] [blame] | 524 | if ((sig = sshbuf_new()) == NULL) { |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 525 | r = SSH_ERR_ALLOC_FAIL; |
| 526 | goto out; |
| 527 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 528 | 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] | 529 | debug("%s: buffer error (outer): %s", __func__, ssh_err(r)); |
| 530 | goto out; |
| 531 | } |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 532 | switch (type) { |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 533 | #ifdef WITH_OPENSSL |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 534 | case KEY_ECDSA_SK: |
| 535 | if ((r = sshsk_ecdsa_sig(resp, sig)) != 0) |
| 536 | goto out; |
| 537 | break; |
naddy@openbsd.org | 723a536 | 2019-11-18 16:08:57 +0000 | [diff] [blame] | 538 | #endif /* WITH_OPENSSL */ |
markus@openbsd.org | b556cc3 | 2019-11-12 19:34:40 +0000 | [diff] [blame] | 539 | case KEY_ED25519_SK: |
| 540 | if ((r = sshsk_ed25519_sig(resp, sig)) != 0) |
| 541 | goto out; |
| 542 | break; |
| 543 | } |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 544 | #ifdef DEBUG_SK |
markus@openbsd.org | fe05a36 | 2019-11-12 19:31:18 +0000 | [diff] [blame] | 545 | fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n", |
| 546 | __func__, resp->flags, resp->counter); |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 547 | fprintf(stderr, "%s: hashed message:\n", __func__); |
| 548 | sshbuf_dump_data(message, sizeof(message), stderr); |
djm@openbsd.org | ed3467c | 2019-10-31 21:16:20 +0000 | [diff] [blame] | 549 | fprintf(stderr, "%s: sigbuf:\n", __func__); |
| 550 | sshbuf_dump(sig, stderr); |
| 551 | #endif |
| 552 | if (sigp != NULL) { |
| 553 | if ((*sigp = malloc(sshbuf_len(sig))) == NULL) { |
| 554 | r = SSH_ERR_ALLOC_FAIL; |
| 555 | goto out; |
| 556 | } |
| 557 | memcpy(*sigp, sshbuf_ptr(sig), sshbuf_len(sig)); |
| 558 | } |
| 559 | if (lenp != NULL) |
| 560 | *lenp = sshbuf_len(sig); |
| 561 | /* success */ |
| 562 | r = 0; |
| 563 | out: |
| 564 | explicit_bzero(message, sizeof(message)); |
| 565 | sshsk_free(skp); |
| 566 | sshsk_free_sign_response(resp); |
| 567 | sshbuf_free(sig); |
| 568 | sshbuf_free(inner_sig); |
| 569 | return r; |
| 570 | } |
Damien Miller | 764d51e | 2019-11-01 13:34:49 +1100 | [diff] [blame] | 571 | #endif /* ENABLE_SK */ |