Annotation of src/usr.bin/ssh/ssh-sk.c, Revision 1.32
1.32 ! djm 1: /* $OpenBSD: ssh-sk.c,v 1.31 2020/08/27 01:08:19 djm Exp $ */
1.1 djm 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 <dlfcn.h>
21: #include <stddef.h>
22: #include <stdint.h>
23: #include <string.h>
24: #include <stdio.h>
25:
1.15 naddy 26: #ifdef WITH_OPENSSL
1.1 djm 27: #include <openssl/objects.h>
28: #include <openssl/ec.h>
1.15 naddy 29: #endif /* WITH_OPENSSL */
1.1 djm 30:
31: #include "log.h"
32: #include "misc.h"
33: #include "sshbuf.h"
34: #include "sshkey.h"
35: #include "ssherr.h"
36: #include "digest.h"
37:
38: #include "ssh-sk.h"
39: #include "sk-api.h"
1.6 markus 40: #include "crypto_api.h"
1.1 djm 41:
42: struct sshsk_provider {
43: char *path;
44: void *dlhandle;
45:
46: /* Return the version of the middleware API */
47: uint32_t (*sk_api_version)(void);
48:
49: /* Enroll a U2F key (private key generation) */
1.7 markus 50: int (*sk_enroll)(int alg, const uint8_t *challenge,
51: size_t challenge_len, const char *application, uint8_t flags,
1.24 djm 52: const char *pin, struct sk_option **opts,
53: struct sk_enroll_response **enroll_response);
1.1 djm 54:
55: /* Sign a challenge */
1.7 markus 56: int (*sk_sign)(int alg, const uint8_t *message, size_t message_len,
1.1 djm 57: const char *application,
58: const uint8_t *key_handle, size_t key_handle_len,
1.24 djm 59: uint8_t flags, const char *pin, struct sk_option **opts,
1.21 djm 60: struct sk_sign_response **sign_response);
1.20 djm 61:
62: /* Enumerate resident keys */
1.24 djm 63: int (*sk_load_resident_keys)(const char *pin, struct sk_option **opts,
1.20 djm 64: struct sk_resident_key ***rks, size_t *nrks);
1.1 djm 65: };
66:
1.12 djm 67: /* Built-in version */
68: int ssh_sk_enroll(int alg, const uint8_t *challenge,
69: size_t challenge_len, const char *application, uint8_t flags,
1.24 djm 70: const char *pin, struct sk_option **opts,
71: struct sk_enroll_response **enroll_response);
1.12 djm 72: int ssh_sk_sign(int alg, const uint8_t *message, size_t message_len,
73: const char *application,
74: const uint8_t *key_handle, size_t key_handle_len,
1.24 djm 75: uint8_t flags, const char *pin, struct sk_option **opts,
76: struct sk_sign_response **sign_response);
77: int ssh_sk_load_resident_keys(const char *pin, struct sk_option **opts,
1.20 djm 78: struct sk_resident_key ***rks, size_t *nrks);
1.12 djm 79:
1.1 djm 80: static void
81: sshsk_free(struct sshsk_provider *p)
82: {
83: if (p == NULL)
84: return;
85: free(p->path);
86: if (p->dlhandle != NULL)
87: dlclose(p->dlhandle);
88: free(p);
89: }
90:
91: static struct sshsk_provider *
92: sshsk_open(const char *path)
93: {
94: struct sshsk_provider *ret = NULL;
95: uint32_t version;
96:
1.28 djm 97: if (path == NULL || *path == '\0') {
98: error("No FIDO SecurityKeyProvider specified");
99: return NULL;
100: }
1.1 djm 101: if ((ret = calloc(1, sizeof(*ret))) == NULL) {
102: error("%s: calloc failed", __func__);
103: return NULL;
104: }
105: if ((ret->path = strdup(path)) == NULL) {
106: error("%s: strdup failed", __func__);
107: goto fail;
1.12 djm 108: }
109: /* Skip the rest if we're using the linked in middleware */
110: if (strcasecmp(ret->path, "internal") == 0) {
111: ret->sk_enroll = ssh_sk_enroll;
112: ret->sk_sign = ssh_sk_sign;
1.20 djm 113: ret->sk_load_resident_keys = ssh_sk_load_resident_keys;
1.12 djm 114: return ret;
1.1 djm 115: }
116: if ((ret->dlhandle = dlopen(path, RTLD_NOW)) == NULL) {
1.27 naddy 117: error("Provider \"%s\" dlopen failed: %s", path, dlerror());
1.1 djm 118: goto fail;
119: }
120: if ((ret->sk_api_version = dlsym(ret->dlhandle,
121: "sk_api_version")) == NULL) {
1.27 naddy 122: error("Provider \"%s\" dlsym(sk_api_version) failed: %s",
123: path, dlerror());
1.1 djm 124: goto fail;
125: }
126: version = ret->sk_api_version();
127: debug("%s: provider %s implements version 0x%08lx", __func__,
128: ret->path, (u_long)version);
129: if ((version & SSH_SK_VERSION_MAJOR_MASK) != SSH_SK_VERSION_MAJOR) {
1.27 naddy 130: error("Provider \"%s\" implements unsupported "
1.22 djm 131: "version 0x%08lx (supported: 0x%08lx)",
132: path, (u_long)version, (u_long)SSH_SK_VERSION_MAJOR);
1.1 djm 133: goto fail;
134: }
135: if ((ret->sk_enroll = dlsym(ret->dlhandle, "sk_enroll")) == NULL) {
1.27 naddy 136: error("Provider %s dlsym(sk_enroll) failed: %s",
137: path, dlerror());
1.1 djm 138: goto fail;
139: }
140: if ((ret->sk_sign = dlsym(ret->dlhandle, "sk_sign")) == NULL) {
1.27 naddy 141: error("Provider \"%s\" dlsym(sk_sign) failed: %s",
1.1 djm 142: path, dlerror());
143: goto fail;
144: }
1.20 djm 145: if ((ret->sk_load_resident_keys = dlsym(ret->dlhandle,
146: "sk_load_resident_keys")) == NULL) {
1.27 naddy 147: error("Provider \"%s\" dlsym(sk_load_resident_keys) "
148: "failed: %s", path, dlerror());
1.20 djm 149: goto fail;
150: }
1.1 djm 151: /* success */
152: return ret;
153: fail:
154: sshsk_free(ret);
155: return NULL;
156: }
157:
158: static void
159: sshsk_free_enroll_response(struct sk_enroll_response *r)
160: {
161: if (r == NULL)
162: return;
163: freezero(r->key_handle, r->key_handle_len);
164: freezero(r->public_key, r->public_key_len);
165: freezero(r->signature, r->signature_len);
166: freezero(r->attestation_cert, r->attestation_cert_len);
1.32 ! djm 167: freezero(r->authdata, r->authdata_len);
1.1 djm 168: freezero(r, sizeof(*r));
1.17 djm 169: }
1.1 djm 170:
171: static void
172: sshsk_free_sign_response(struct sk_sign_response *r)
173: {
174: if (r == NULL)
175: return;
176: freezero(r->sig_r, r->sig_r_len);
177: freezero(r->sig_s, r->sig_s_len);
178: freezero(r, sizeof(*r));
1.17 djm 179: }
1.1 djm 180:
1.15 naddy 181: #ifdef WITH_OPENSSL
1.2 markus 182: /* Assemble key from response */
183: static int
184: sshsk_ecdsa_assemble(struct sk_enroll_response *resp, struct sshkey **keyp)
185: {
186: struct sshkey *key = NULL;
187: struct sshbuf *b = NULL;
188: EC_POINT *q = NULL;
189: int r;
190:
191: *keyp = NULL;
192: if ((key = sshkey_new(KEY_ECDSA_SK)) == NULL) {
193: error("%s: sshkey_new failed", __func__);
194: r = SSH_ERR_ALLOC_FAIL;
195: goto out;
196: }
197: key->ecdsa_nid = NID_X9_62_prime256v1;
198: if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid)) == NULL ||
199: (q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL ||
200: (b = sshbuf_new()) == NULL) {
201: error("%s: allocation failed", __func__);
202: r = SSH_ERR_ALLOC_FAIL;
203: goto out;
204: }
205: if ((r = sshbuf_put_string(b,
206: resp->public_key, resp->public_key_len)) != 0) {
207: error("%s: buffer error: %s", __func__, ssh_err(r));
208: goto out;
209: }
210: if ((r = sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa))) != 0) {
211: error("%s: parse key: %s", __func__, ssh_err(r));
212: r = SSH_ERR_INVALID_FORMAT;
213: goto out;
214: }
215: if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa), q) != 0) {
1.27 naddy 216: error("Authenticator returned invalid ECDSA key");
1.2 markus 217: r = SSH_ERR_KEY_INVALID_EC_VALUE;
218: goto out;
219: }
220: if (EC_KEY_set_public_key(key->ecdsa, q) != 1) {
221: /* XXX assume it is a allocation error */
222: error("%s: allocation failed", __func__);
223: r = SSH_ERR_ALLOC_FAIL;
224: goto out;
225: }
226: /* success */
227: *keyp = key;
228: key = NULL; /* transferred */
229: r = 0;
230: out:
231: EC_POINT_free(q);
232: sshkey_free(key);
233: sshbuf_free(b);
234: return r;
235: }
1.15 naddy 236: #endif /* WITH_OPENSSL */
1.2 markus 237:
1.6 markus 238: static int
239: sshsk_ed25519_assemble(struct sk_enroll_response *resp, struct sshkey **keyp)
240: {
241: struct sshkey *key = NULL;
242: int r;
243:
244: *keyp = NULL;
245: if (resp->public_key_len != ED25519_PK_SZ) {
246: error("%s: invalid size: %zu", __func__, resp->public_key_len);
247: r = SSH_ERR_INVALID_FORMAT;
248: goto out;
249: }
250: if ((key = sshkey_new(KEY_ED25519_SK)) == NULL) {
251: error("%s: sshkey_new failed", __func__);
252: r = SSH_ERR_ALLOC_FAIL;
253: goto out;
254: }
255: if ((key->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) {
256: error("%s: malloc failed", __func__);
257: r = SSH_ERR_ALLOC_FAIL;
258: goto out;
259: }
260: memcpy(key->ed25519_pk, resp->public_key, ED25519_PK_SZ);
261: /* success */
262: *keyp = key;
263: key = NULL; /* transferred */
264: r = 0;
265: out:
266: sshkey_free(key);
267: return r;
268: }
269:
1.19 djm 270: static int
271: sshsk_key_from_response(int alg, const char *application, uint8_t flags,
272: struct sk_enroll_response *resp, struct sshkey **keyp)
273: {
274: struct sshkey *key = NULL;
275: int r = SSH_ERR_INTERNAL_ERROR;
276:
277: *keyp = NULL;
278:
279: /* Check response validity */
1.20 djm 280: if (resp->public_key == NULL || resp->key_handle == NULL) {
1.19 djm 281: error("%s: sk_enroll response invalid", __func__);
282: r = SSH_ERR_INVALID_FORMAT;
283: goto out;
284: }
285: switch (alg) {
286: #ifdef WITH_OPENSSL
287: case SSH_SK_ECDSA:
288: if ((r = sshsk_ecdsa_assemble(resp, &key)) != 0)
289: goto out;
290: break;
291: #endif /* WITH_OPENSSL */
292: case SSH_SK_ED25519:
293: if ((r = sshsk_ed25519_assemble(resp, &key)) != 0)
294: goto out;
295: break;
296: default:
297: error("%s: unsupported algorithm %d", __func__, alg);
298: r = SSH_ERR_INVALID_ARGUMENT;
299: goto out;
300: }
301: key->sk_flags = flags;
302: if ((key->sk_key_handle = sshbuf_new()) == NULL ||
303: (key->sk_reserved = sshbuf_new()) == NULL) {
304: error("%s: allocation failed", __func__);
305: r = SSH_ERR_ALLOC_FAIL;
306: goto out;
307: }
308: if ((key->sk_application = strdup(application)) == NULL) {
309: error("%s: strdup application failed", __func__);
310: r = SSH_ERR_ALLOC_FAIL;
311: goto out;
312: }
313: if ((r = sshbuf_put(key->sk_key_handle, resp->key_handle,
314: resp->key_handle_len)) != 0) {
315: error("%s: buffer error: %s", __func__, ssh_err(r));
316: goto out;
317: }
318: /* success */
319: r = 0;
320: *keyp = key;
321: key = NULL;
322: out:
323: sshkey_free(key);
324: return r;
325: }
326:
1.23 djm 327: static int
328: skerr_to_ssherr(int skerr)
329: {
330: switch (skerr) {
331: case SSH_SK_ERR_UNSUPPORTED:
332: return SSH_ERR_FEATURE_UNSUPPORTED;
333: case SSH_SK_ERR_PIN_REQUIRED:
334: return SSH_ERR_KEY_WRONG_PASSPHRASE;
1.25 djm 335: case SSH_SK_ERR_DEVICE_NOT_FOUND:
336: return SSH_ERR_DEVICE_NOT_FOUND;
1.23 djm 337: case SSH_SK_ERR_GENERAL:
338: default:
339: return SSH_ERR_INVALID_FORMAT;
340: }
341: }
342:
1.24 djm 343: static void
344: sshsk_free_options(struct sk_option **opts)
345: {
346: size_t i;
347:
348: if (opts == NULL)
349: return;
350: for (i = 0; opts[i] != NULL; i++) {
351: free(opts[i]->name);
352: free(opts[i]->value);
353: free(opts[i]);
354: }
355: free(opts);
356: }
357:
358: static int
359: sshsk_add_option(struct sk_option ***optsp, size_t *noptsp,
360: const char *name, const char *value, uint8_t required)
361: {
362: struct sk_option **opts = *optsp;
363: size_t nopts = *noptsp;
364:
365: if ((opts = recallocarray(opts, nopts, nopts + 2, /* extra for NULL */
366: sizeof(*opts))) == NULL) {
367: error("%s: array alloc failed", __func__);
368: return SSH_ERR_ALLOC_FAIL;
369: }
370: *optsp = opts;
371: *noptsp = nopts + 1;
372: if ((opts[nopts] = calloc(1, sizeof(**opts))) == NULL) {
373: error("%s: alloc failed", __func__);
374: return SSH_ERR_ALLOC_FAIL;
375: }
376: if ((opts[nopts]->name = strdup(name)) == NULL ||
377: (opts[nopts]->value = strdup(value)) == NULL) {
378: error("%s: alloc failed", __func__);
379: return SSH_ERR_ALLOC_FAIL;
380: }
381: opts[nopts]->required = required;
382: return 0;
383: }
384:
385: static int
386: make_options(const char *device, const char *user_id,
387: struct sk_option ***optsp)
388: {
389: struct sk_option **opts = NULL;
390: size_t nopts = 0;
391: int r, ret = SSH_ERR_INTERNAL_ERROR;
392:
393: if (device != NULL &&
394: (r = sshsk_add_option(&opts, &nopts, "device", device, 0)) != 0) {
395: ret = r;
396: goto out;
397: }
398: if (user_id != NULL &&
399: (r = sshsk_add_option(&opts, &nopts, "user", user_id, 0)) != 0) {
400: ret = r;
401: goto out;
402: }
403: /* success */
404: *optsp = opts;
405: opts = NULL;
406: nopts = 0;
407: ret = 0;
408: out:
409: sshsk_free_options(opts);
410: return ret;
411: }
412:
1.32 ! djm 413:
! 414: static int
! 415: fill_attestation_blob(const struct sk_enroll_response *resp,
! 416: struct sshbuf *attest)
! 417: {
! 418: int r;
! 419:
! 420: if (attest == NULL)
! 421: return 0; /* nothing to do */
! 422: if ((r = sshbuf_put_cstring(attest, "ssh-sk-attest-v01")) != 0 ||
! 423: (r = sshbuf_put_string(attest,
! 424: resp->attestation_cert, resp->attestation_cert_len)) != 0 ||
! 425: (r = sshbuf_put_string(attest,
! 426: resp->signature, resp->signature_len)) != 0 ||
! 427: (r = sshbuf_put_string(attest,
! 428: resp->authdata, resp->authdata_len)) != 0 ||
! 429: (r = sshbuf_put_u32(attest, 0)) != 0 || /* resvd flags */
! 430: (r = sshbuf_put_string(attest, NULL, 0)) != 0 /* resvd */) {
! 431: error("%s: buffer error: %s", __func__, ssh_err(r));
! 432: return r;
! 433: }
! 434: /* success */
! 435: return 0;
! 436: }
! 437:
1.1 djm 438: int
1.24 djm 439: sshsk_enroll(int type, const char *provider_path, const char *device,
440: const char *application, const char *userid, uint8_t flags,
441: const char *pin, struct sshbuf *challenge_buf,
1.21 djm 442: struct sshkey **keyp, struct sshbuf *attest)
1.1 djm 443: {
444: struct sshsk_provider *skp = NULL;
445: struct sshkey *key = NULL;
446: u_char randchall[32];
447: const u_char *challenge;
448: size_t challenge_len;
449: struct sk_enroll_response *resp = NULL;
1.24 djm 450: struct sk_option **opts = NULL;
1.1 djm 451: int r = SSH_ERR_INTERNAL_ERROR;
1.7 markus 452: int alg;
1.1 djm 453:
1.24 djm 454: debug("%s: provider \"%s\", device \"%s\", application \"%s\", "
455: "userid \"%s\", flags 0x%02x, challenge len %zu%s", __func__,
456: provider_path, device, application, userid, flags,
457: challenge_buf == NULL ? 0 : sshbuf_len(challenge_buf),
1.21 djm 458: (pin != NULL && *pin != '\0') ? " with-pin" : "");
1.13 djm 459:
1.1 djm 460: *keyp = NULL;
461: if (attest)
462: sshbuf_reset(attest);
1.24 djm 463:
464: if ((r = make_options(device, userid, &opts)) != 0)
465: goto out;
466:
1.6 markus 467: switch (type) {
1.15 naddy 468: #ifdef WITH_OPENSSL
1.6 markus 469: case KEY_ECDSA_SK:
1.7 markus 470: alg = SSH_SK_ECDSA;
471: break;
1.15 naddy 472: #endif /* WITH_OPENSSL */
1.6 markus 473: case KEY_ED25519_SK:
1.7 markus 474: alg = SSH_SK_ED25519;
1.6 markus 475: break;
476: default:
477: error("%s: unsupported key type", __func__);
478: r = SSH_ERR_INVALID_ARGUMENT;
479: goto out;
480: }
1.1 djm 481: if (provider_path == NULL) {
482: error("%s: missing provider", __func__);
483: r = SSH_ERR_INVALID_ARGUMENT;
484: goto out;
485: }
486: if (application == NULL || *application == '\0') {
487: error("%s: missing application", __func__);
488: r = SSH_ERR_INVALID_ARGUMENT;
489: goto out;
490: }
491: if (challenge_buf == NULL) {
492: debug("%s: using random challenge", __func__);
493: arc4random_buf(randchall, sizeof(randchall));
494: challenge = randchall;
495: challenge_len = sizeof(randchall);
496: } else if (sshbuf_len(challenge_buf) == 0) {
497: error("Missing enrollment challenge");
498: r = SSH_ERR_INVALID_ARGUMENT;
499: goto out;
500: } else {
501: challenge = sshbuf_ptr(challenge_buf);
502: challenge_len = sshbuf_len(challenge_buf);
503: debug3("%s: using explicit challenge len=%zd",
504: __func__, challenge_len);
505: }
506: if ((skp = sshsk_open(provider_path)) == NULL) {
507: r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */
508: goto out;
509: }
510: /* XXX validate flags? */
511: /* enroll key */
1.7 markus 512: if ((r = skp->sk_enroll(alg, challenge, challenge_len, application,
1.24 djm 513: flags, pin, opts, &resp)) != 0) {
1.25 djm 514: debug("%s: provider \"%s\" returned failure %d", __func__,
1.1 djm 515: provider_path, r);
1.23 djm 516: r = skerr_to_ssherr(r);
1.1 djm 517: goto out;
518: }
1.19 djm 519:
520: if ((r = sshsk_key_from_response(alg, application, flags,
521: resp, &key)) != 0)
1.1 djm 522: goto out;
1.19 djm 523:
1.1 djm 524: /* Optionally fill in the attestation information */
1.32 ! djm 525: if ((r = fill_attestation_blob(resp, attest)) != 0)
! 526: goto out;
! 527:
1.1 djm 528: /* success */
529: *keyp = key;
530: key = NULL; /* transferred */
531: r = 0;
532: out:
1.24 djm 533: sshsk_free_options(opts);
1.1 djm 534: sshsk_free(skp);
535: sshkey_free(key);
536: sshsk_free_enroll_response(resp);
537: explicit_bzero(randchall, sizeof(randchall));
538: return r;
539: }
540:
1.15 naddy 541: #ifdef WITH_OPENSSL
1.3 markus 542: static int
1.9 markus 543: sshsk_ecdsa_sig(struct sk_sign_response *resp, struct sshbuf *sig)
1.3 markus 544: {
545: struct sshbuf *inner_sig = NULL;
546: int r = SSH_ERR_INTERNAL_ERROR;
547:
1.8 markus 548: /* Check response validity */
1.11 markus 549: if (resp->sig_r == NULL || resp->sig_s == NULL) {
1.8 markus 550: error("%s: sk_sign response invalid", __func__);
551: r = SSH_ERR_INVALID_FORMAT;
552: goto out;
553: }
1.3 markus 554: if ((inner_sig = sshbuf_new()) == NULL) {
555: r = SSH_ERR_ALLOC_FAIL;
556: goto out;
557: }
1.9 markus 558: /* Prepare and append inner signature object */
1.3 markus 559: if ((r = sshbuf_put_bignum2_bytes(inner_sig,
560: resp->sig_r, resp->sig_r_len)) != 0 ||
561: (r = sshbuf_put_bignum2_bytes(inner_sig,
1.16 djm 562: resp->sig_s, resp->sig_s_len)) != 0) {
1.3 markus 563: debug("%s: buffer error: %s", __func__, ssh_err(r));
564: goto out;
565: }
1.16 djm 566: if ((r = sshbuf_put_stringb(sig, inner_sig)) != 0 ||
567: (r = sshbuf_put_u8(sig, resp->flags)) != 0 ||
568: (r = sshbuf_put_u32(sig, resp->counter)) != 0) {
1.9 markus 569: debug("%s: buffer error: %s", __func__, ssh_err(r));
570: goto out;
571: }
1.3 markus 572: #ifdef DEBUG_SK
573: fprintf(stderr, "%s: sig_r:\n", __func__);
574: sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr);
575: fprintf(stderr, "%s: sig_s:\n", __func__);
576: sshbuf_dump_data(resp->sig_s, resp->sig_s_len, stderr);
1.9 markus 577: fprintf(stderr, "%s: inner:\n", __func__);
578: sshbuf_dump(inner_sig, stderr);
1.5 markus 579: #endif
580: r = 0;
1.9 markus 581: out:
1.5 markus 582: sshbuf_free(inner_sig);
583: return r;
584: }
1.15 naddy 585: #endif /* WITH_OPENSSL */
1.5 markus 586:
587: static int
1.9 markus 588: sshsk_ed25519_sig(struct sk_sign_response *resp, struct sshbuf *sig)
1.5 markus 589: {
590: int r = SSH_ERR_INTERNAL_ERROR;
591:
1.8 markus 592: /* Check response validity */
593: if (resp->sig_r == NULL) {
594: error("%s: sk_sign response invalid", __func__);
595: r = SSH_ERR_INVALID_FORMAT;
596: goto out;
597: }
1.9 markus 598: if ((r = sshbuf_put_string(sig,
1.5 markus 599: resp->sig_r, resp->sig_r_len)) != 0 ||
1.9 markus 600: (r = sshbuf_put_u8(sig, resp->flags)) != 0 ||
601: (r = sshbuf_put_u32(sig, resp->counter)) != 0) {
1.5 markus 602: debug("%s: buffer error: %s", __func__, ssh_err(r));
603: goto out;
604: }
605: #ifdef DEBUG_SK
606: fprintf(stderr, "%s: sig_r:\n", __func__);
607: sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr);
1.3 markus 608: #endif
609: r = 0;
1.9 markus 610: out:
1.29 markus 611: return r;
1.3 markus 612: }
613:
1.1 djm 614: int
1.18 djm 615: sshsk_sign(const char *provider_path, struct sshkey *key,
1.1 djm 616: u_char **sigp, size_t *lenp, const u_char *data, size_t datalen,
1.21 djm 617: u_int compat, const char *pin)
1.1 djm 618: {
619: struct sshsk_provider *skp = NULL;
620: int r = SSH_ERR_INTERNAL_ERROR;
1.7 markus 621: int type, alg;
1.1 djm 622: struct sk_sign_response *resp = NULL;
623: struct sshbuf *inner_sig = NULL, *sig = NULL;
1.24 djm 624: struct sk_option **opts = NULL;
1.13 djm 625:
1.21 djm 626: debug("%s: provider \"%s\", key %s, flags 0x%02x%s", __func__,
627: provider_path, sshkey_type(key), key->sk_flags,
628: (pin != NULL && *pin != '\0') ? " with-pin" : "");
1.1 djm 629:
630: if (sigp != NULL)
631: *sigp = NULL;
632: if (lenp != NULL)
633: *lenp = 0;
1.5 markus 634: type = sshkey_type_plain(key->type);
635: switch (type) {
1.15 naddy 636: #ifdef WITH_OPENSSL
1.5 markus 637: case KEY_ECDSA_SK:
1.7 markus 638: alg = SSH_SK_ECDSA;
639: break;
1.15 naddy 640: #endif /* WITH_OPENSSL */
1.5 markus 641: case KEY_ED25519_SK:
1.7 markus 642: alg = SSH_SK_ED25519;
1.5 markus 643: break;
644: default:
645: return SSH_ERR_INVALID_ARGUMENT;
646: }
1.1 djm 647: if (provider_path == NULL ||
648: key->sk_key_handle == NULL ||
649: key->sk_application == NULL || *key->sk_application == '\0') {
650: r = SSH_ERR_INVALID_ARGUMENT;
651: goto out;
652: }
653: if ((skp = sshsk_open(provider_path)) == NULL) {
654: r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */
655: goto out;
656: }
657:
1.30 djm 658: if ((r = skp->sk_sign(alg, data, datalen, key->sk_application,
1.1 djm 659: sshbuf_ptr(key->sk_key_handle), sshbuf_len(key->sk_key_handle),
1.24 djm 660: key->sk_flags, pin, opts, &resp)) != 0) {
1.1 djm 661: debug("%s: sk_sign failed with code %d", __func__, r);
1.23 djm 662: r = skerr_to_ssherr(r);
1.1 djm 663: goto out;
664: }
1.9 markus 665: /* Assemble signature */
666: if ((sig = sshbuf_new()) == NULL) {
667: r = SSH_ERR_ALLOC_FAIL;
668: goto out;
669: }
670: if ((r = sshbuf_put_cstring(sig, sshkey_ssh_name_plain(key))) != 0) {
671: debug("%s: buffer error (outer): %s", __func__, ssh_err(r));
672: goto out;
673: }
1.5 markus 674: switch (type) {
1.15 naddy 675: #ifdef WITH_OPENSSL
1.5 markus 676: case KEY_ECDSA_SK:
1.9 markus 677: if ((r = sshsk_ecdsa_sig(resp, sig)) != 0)
1.5 markus 678: goto out;
679: break;
1.15 naddy 680: #endif /* WITH_OPENSSL */
1.5 markus 681: case KEY_ED25519_SK:
1.9 markus 682: if ((r = sshsk_ed25519_sig(resp, sig)) != 0)
1.5 markus 683: goto out;
684: break;
685: }
1.1 djm 686: #ifdef DEBUG_SK
1.5 markus 687: fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n",
688: __func__, resp->flags, resp->counter);
1.1 djm 689: fprintf(stderr, "%s: hashed message:\n", __func__);
690: sshbuf_dump_data(message, sizeof(message), stderr);
691: fprintf(stderr, "%s: sigbuf:\n", __func__);
692: sshbuf_dump(sig, stderr);
693: #endif
694: if (sigp != NULL) {
695: if ((*sigp = malloc(sshbuf_len(sig))) == NULL) {
696: r = SSH_ERR_ALLOC_FAIL;
697: goto out;
698: }
699: memcpy(*sigp, sshbuf_ptr(sig), sshbuf_len(sig));
700: }
701: if (lenp != NULL)
702: *lenp = sshbuf_len(sig);
703: /* success */
704: r = 0;
705: out:
1.24 djm 706: sshsk_free_options(opts);
1.1 djm 707: sshsk_free(skp);
708: sshsk_free_sign_response(resp);
709: sshbuf_free(sig);
710: sshbuf_free(inner_sig);
711: return r;
712: }
1.20 djm 713:
714: static void
715: sshsk_free_sk_resident_keys(struct sk_resident_key **rks, size_t nrks)
716: {
717: size_t i;
718:
719: if (nrks == 0 || rks == NULL)
720: return;
721: for (i = 0; i < nrks; i++) {
722: free(rks[i]->application);
723: freezero(rks[i]->key.key_handle, rks[i]->key.key_handle_len);
724: freezero(rks[i]->key.public_key, rks[i]->key.public_key_len);
725: freezero(rks[i]->key.signature, rks[i]->key.signature_len);
726: freezero(rks[i]->key.attestation_cert,
727: rks[i]->key.attestation_cert_len);
728: freezero(rks[i], sizeof(**rks));
729: }
730: free(rks);
731: }
732:
733: int
1.24 djm 734: sshsk_load_resident(const char *provider_path, const char *device,
735: const char *pin, struct sshkey ***keysp, size_t *nkeysp)
1.20 djm 736: {
737: struct sshsk_provider *skp = NULL;
738: int r = SSH_ERR_INTERNAL_ERROR;
739: struct sk_resident_key **rks = NULL;
740: size_t i, nrks = 0, nkeys = 0;
741: struct sshkey *key = NULL, **keys = NULL, **tmp;
742: uint8_t flags;
1.24 djm 743: struct sk_option **opts = NULL;
1.20 djm 744:
745: debug("%s: provider \"%s\"%s", __func__, provider_path,
746: (pin != NULL && *pin != '\0') ? ", have-pin": "");
747:
748: if (keysp == NULL || nkeysp == NULL)
749: return SSH_ERR_INVALID_ARGUMENT;
750: *keysp = NULL;
751: *nkeysp = 0;
752:
1.24 djm 753: if ((r = make_options(device, NULL, &opts)) != 0)
754: goto out;
1.20 djm 755: if ((skp = sshsk_open(provider_path)) == NULL) {
756: r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */
757: goto out;
758: }
1.24 djm 759: if ((r = skp->sk_load_resident_keys(pin, opts, &rks, &nrks)) != 0) {
1.27 naddy 760: error("Provider \"%s\" returned failure %d", provider_path, r);
1.23 djm 761: r = skerr_to_ssherr(r);
1.20 djm 762: goto out;
763: }
764: for (i = 0; i < nrks; i++) {
765: debug3("%s: rk %zu: slot = %zu, alg = %d, application = \"%s\"",
766: __func__, i, rks[i]->slot, rks[i]->alg,
767: rks[i]->application);
768: /* XXX need better filter here */
769: if (strncmp(rks[i]->application, "ssh:", 4) != 0)
770: continue;
771: switch (rks[i]->alg) {
772: case SSH_SK_ECDSA:
773: case SSH_SK_ED25519:
774: break;
775: default:
776: continue;
777: }
778: flags = SSH_SK_USER_PRESENCE_REQD|SSH_SK_RESIDENT_KEY;
1.31 djm 779: if ((rks[i]->flags & SSH_SK_USER_VERIFICATION_REQD))
780: flags |= SSH_SK_USER_VERIFICATION_REQD;
1.20 djm 781: if ((r = sshsk_key_from_response(rks[i]->alg,
782: rks[i]->application, flags, &rks[i]->key, &key)) != 0)
783: goto out;
784: if ((tmp = recallocarray(keys, nkeys, nkeys + 1,
785: sizeof(*tmp))) == NULL) {
786: error("%s: recallocarray failed", __func__);
787: r = SSH_ERR_ALLOC_FAIL;
788: goto out;
789: }
790: keys = tmp;
791: keys[nkeys++] = key;
792: key = NULL;
793: /* XXX synthesise comment */
794: }
795: /* success */
796: *keysp = keys;
797: *nkeysp = nkeys;
798: keys = NULL;
799: nkeys = 0;
800: r = 0;
801: out:
1.24 djm 802: sshsk_free_options(opts);
1.20 djm 803: sshsk_free(skp);
804: sshsk_free_sk_resident_keys(rks, nrks);
805: sshkey_free(key);
806: if (nkeys != 0) {
807: for (i = 0; i < nkeys; i++)
808: sshkey_free(keys[i]);
809: free(keys);
810: }
811: return r;
812: }
813: