Annotation of src/usr.bin/ssh/ssh-ed25519-sk.c, Revision 1.12
1.12 ! djm 1: /* $OpenBSD: ssh-ed25519-sk.c,v 1.11 2022/10/28 00:41:17 djm Exp $ */
1.1 markus 2: /*
3: * Copyright (c) 2019 Markus Friedl. All rights reserved.
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: */
1.4 djm 17:
18: /* #define DEBUG_SK 1 */
19:
1.1 markus 20: #define SSHKEY_INTERNAL
21: #include <sys/types.h>
22: #include <limits.h>
23:
24: #include "crypto_api.h"
25:
26: #include <string.h>
27: #include <stdarg.h>
28:
29: #include "log.h"
30: #include "sshbuf.h"
31: #include "sshkey.h"
32: #include "ssherr.h"
33: #include "ssh.h"
34: #include "digest.h"
35:
1.8 djm 36: /* Reuse some ED25519 internals */
37: extern struct sshkey_impl_funcs sshkey_ed25519_funcs;
38:
1.7 djm 39: static void
40: ssh_ed25519_sk_cleanup(struct sshkey *k)
41: {
1.8 djm 42: sshkey_sk_cleanup(k);
43: sshkey_ed25519_funcs.cleanup(k);
44: }
45:
46: static int
47: ssh_ed25519_sk_equal(const struct sshkey *a, const struct sshkey *b)
48: {
49: if (!sshkey_sk_fields_equal(a, b))
50: return 0;
51: if (!sshkey_ed25519_funcs.equal(a, b))
52: return 0;
53: return 1;
1.7 djm 54: }
55:
1.9 djm 56: static int
57: ssh_ed25519_sk_serialize_public(const struct sshkey *key, struct sshbuf *b,
1.12 ! djm 58: enum sshkey_serialize_rep opts)
1.9 djm 59: {
60: int r;
61:
1.12 ! djm 62: if ((r = sshkey_ed25519_funcs.serialize_public(key, b, opts)) != 0)
1.9 djm 63: return r;
64: if ((r = sshkey_serialize_sk(key, b)) != 0)
65: return r;
66:
67: return 0;
68: }
69:
1.11 djm 70: static int
71: ssh_ed25519_sk_copy_public(const struct sshkey *from, struct sshkey *to)
72: {
73: int r;
74:
75: if ((r = sshkey_ed25519_funcs.copy_public(from, to)) != 0)
76: return r;
77: if ((r = sshkey_copy_public_sk(from, to)) != 0)
78: return r;
79: return 0;
80: }
81:
1.12 ! djm 82: static int
! 83: ssh_ed25519_sk_deserialize_public(const char *ktype, struct sshbuf *b,
! 84: struct sshkey *key)
! 85: {
! 86: int r;
! 87:
! 88: if ((r = sshkey_ed25519_funcs.deserialize_public(ktype, b, key)) != 0)
! 89: return r;
! 90: if ((r = sshkey_deserialize_sk(b, key)) != 0)
! 91: return r;
! 92: return 0;
! 93: }
! 94:
1.1 markus 95: int
96: ssh_ed25519_sk_verify(const struct sshkey *key,
97: const u_char *signature, size_t signaturelen,
1.3 djm 98: const u_char *data, size_t datalen, u_int compat,
99: struct sshkey_sig_details **detailsp)
1.1 markus 100: {
101: struct sshbuf *b = NULL;
102: struct sshbuf *encoded = NULL;
103: char *ktype = NULL;
104: const u_char *sigblob;
105: const u_char *sm;
106: u_char *m = NULL;
107: u_char apphash[32];
108: u_char msghash[32];
109: u_char sig_flags;
110: u_int sig_counter;
111: size_t len;
112: unsigned long long smlen = 0, mlen = 0;
113: int r = SSH_ERR_INTERNAL_ERROR;
114: int ret;
1.3 djm 115: struct sshkey_sig_details *details = NULL;
116:
117: if (detailsp != NULL)
118: *detailsp = NULL;
1.1 markus 119:
120: if (key == NULL ||
121: sshkey_type_plain(key->type) != KEY_ED25519_SK ||
122: key->ed25519_pk == NULL ||
123: signature == NULL || signaturelen == 0)
124: return SSH_ERR_INVALID_ARGUMENT;
125:
126: if ((b = sshbuf_from(signature, signaturelen)) == NULL)
127: return SSH_ERR_ALLOC_FAIL;
128: if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
1.2 markus 129: sshbuf_get_string_direct(b, &sigblob, &len) != 0 ||
130: sshbuf_get_u8(b, &sig_flags) != 0 ||
131: sshbuf_get_u32(b, &sig_counter) != 0) {
1.1 markus 132: r = SSH_ERR_INVALID_FORMAT;
133: goto out;
134: }
1.4 djm 135: #ifdef DEBUG_SK
136: fprintf(stderr, "%s: data:\n", __func__);
137: /* sshbuf_dump_data(data, datalen, stderr); */
138: fprintf(stderr, "%s: sigblob:\n", __func__);
139: sshbuf_dump_data(sigblob, len, stderr);
140: fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n",
141: __func__, sig_flags, sig_counter);
142: #endif
1.1 markus 143: if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
144: r = SSH_ERR_KEY_TYPE_MISMATCH;
145: goto out;
146: }
147: if (sshbuf_len(b) != 0) {
148: r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
149: goto out;
150: }
151: if (len > crypto_sign_ed25519_BYTES) {
152: r = SSH_ERR_INVALID_FORMAT;
153: goto out;
154: }
155: if (ssh_digest_memory(SSH_DIGEST_SHA256, key->sk_application,
156: strlen(key->sk_application), apphash, sizeof(apphash)) != 0 ||
157: ssh_digest_memory(SSH_DIGEST_SHA256, data, datalen,
158: msghash, sizeof(msghash)) != 0) {
159: r = SSH_ERR_INVALID_ARGUMENT;
160: goto out;
161: }
1.4 djm 162: #ifdef DEBUG_SK
163: fprintf(stderr, "%s: hashed application:\n", __func__);
164: sshbuf_dump_data(apphash, sizeof(apphash), stderr);
165: fprintf(stderr, "%s: hashed message:\n", __func__);
166: sshbuf_dump_data(msghash, sizeof(msghash), stderr);
167: #endif
1.3 djm 168: if ((details = calloc(1, sizeof(*details))) == NULL) {
169: r = SSH_ERR_ALLOC_FAIL;
170: goto out;
171: }
172: details->sk_counter = sig_counter;
173: details->sk_flags = sig_flags;
1.1 markus 174: if ((encoded = sshbuf_new()) == NULL) {
175: r = SSH_ERR_ALLOC_FAIL;
176: goto out;
177: }
178: if (sshbuf_put(encoded, sigblob, len) != 0 ||
179: sshbuf_put(encoded, apphash, sizeof(apphash)) != 0 ||
180: sshbuf_put_u8(encoded, sig_flags) != 0 ||
181: sshbuf_put_u32(encoded, sig_counter) != 0 ||
182: sshbuf_put(encoded, msghash, sizeof(msghash)) != 0) {
183: r = SSH_ERR_ALLOC_FAIL;
184: goto out;
185: }
1.4 djm 186: #ifdef DEBUG_SK
187: fprintf(stderr, "%s: signed buf:\n", __func__);
188: sshbuf_dump(encoded, stderr);
189: #endif
1.1 markus 190: sm = sshbuf_ptr(encoded);
191: smlen = sshbuf_len(encoded);
192: mlen = smlen;
193: if ((m = malloc(smlen)) == NULL) {
194: r = SSH_ERR_ALLOC_FAIL;
195: goto out;
196: }
197: if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen,
198: key->ed25519_pk)) != 0) {
1.6 djm 199: debug2_f("crypto_sign_ed25519_open failed: %d", ret);
1.1 markus 200: }
201: if (ret != 0 || mlen != smlen - len) {
202: r = SSH_ERR_SIGNATURE_INVALID;
203: goto out;
204: }
205: /* XXX compare 'm' and 'sm + len' ? */
206: /* success */
207: r = 0;
1.3 djm 208: if (detailsp != NULL) {
209: *detailsp = details;
210: details = NULL;
211: }
1.1 markus 212: out:
1.5 jsg 213: if (m != NULL)
214: freezero(m, smlen); /* NB mlen may be invalid if r != 0 */
1.3 djm 215: sshkey_sig_details_free(details);
1.1 markus 216: sshbuf_free(b);
217: sshbuf_free(encoded);
218: free(ktype);
219: return r;
220: }
1.7 djm 221:
222: static const struct sshkey_impl_funcs sshkey_ed25519_sk_funcs = {
223: /* .size = */ NULL,
224: /* .alloc = */ NULL,
225: /* .cleanup = */ ssh_ed25519_sk_cleanup,
1.8 djm 226: /* .equal = */ ssh_ed25519_sk_equal,
1.9 djm 227: /* .ssh_serialize_public = */ ssh_ed25519_sk_serialize_public,
1.12 ! djm 228: /* .ssh_deserialize_public = */ ssh_ed25519_sk_deserialize_public,
1.10 djm 229: /* .generate = */ NULL,
1.11 djm 230: /* .copy_public = */ ssh_ed25519_sk_copy_public,
1.7 djm 231: };
232:
233: const struct sshkey_impl sshkey_ed25519_sk_impl = {
234: /* .name = */ "sk-ssh-ed25519@openssh.com",
235: /* .shortname = */ "ED25519-SK",
236: /* .sigalg = */ NULL,
237: /* .type = */ KEY_ED25519_SK,
238: /* .nid = */ 0,
239: /* .cert = */ 0,
240: /* .sigonly = */ 0,
241: /* .keybits = */ 256,
242: /* .funcs = */ &sshkey_ed25519_sk_funcs,
243: };
244:
245: const struct sshkey_impl sshkey_ed25519_sk_cert_impl = {
246: /* .name = */ "sk-ssh-ed25519-cert-v01@openssh.com",
247: /* .shortname = */ "ED25519-SK-CERT",
248: /* .sigalg = */ NULL,
249: /* .type = */ KEY_ED25519_SK_CERT,
250: /* .nid = */ 0,
251: /* .cert = */ 1,
252: /* .sigonly = */ 0,
253: /* .keybits = */ 256,
254: /* .funcs = */ &sshkey_ed25519_sk_funcs,
255: };