Annotation of src/usr.bin/ssh/ssh-ed25519-sk.c, Revision 1.14
1.14 ! djm 1: /* $OpenBSD: ssh-ed25519-sk.c,v 1.13 2022/10/28 00:43:08 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
1.14 ! djm 71: ssh_ed25519_sk_serialize_private(const struct sshkey *key, struct sshbuf *b,
! 72: enum sshkey_serialize_rep opts)
! 73: {
! 74: int r;
! 75:
! 76: if ((r = sshkey_ed25519_funcs.serialize_public(key, b, opts)) != 0)
! 77: return r;
! 78: if ((r = sshkey_serialize_private_sk(key, b)) != 0)
! 79: return r;
! 80:
! 81: return 0;
! 82: }
! 83:
! 84: static int
1.11 djm 85: ssh_ed25519_sk_copy_public(const struct sshkey *from, struct sshkey *to)
86: {
87: int r;
88:
89: if ((r = sshkey_ed25519_funcs.copy_public(from, to)) != 0)
90: return r;
91: if ((r = sshkey_copy_public_sk(from, to)) != 0)
92: return r;
93: return 0;
94: }
95:
1.12 djm 96: static int
97: ssh_ed25519_sk_deserialize_public(const char *ktype, struct sshbuf *b,
98: struct sshkey *key)
99: {
100: int r;
101:
102: if ((r = sshkey_ed25519_funcs.deserialize_public(ktype, b, key)) != 0)
103: return r;
104: if ((r = sshkey_deserialize_sk(b, key)) != 0)
105: return r;
106: return 0;
107: }
108:
1.13 djm 109: static int
1.1 markus 110: ssh_ed25519_sk_verify(const struct sshkey *key,
1.13 djm 111: const u_char *sig, size_t siglen,
112: const u_char *data, size_t dlen, const char *alg, u_int compat,
1.3 djm 113: struct sshkey_sig_details **detailsp)
1.1 markus 114: {
115: struct sshbuf *b = NULL;
116: struct sshbuf *encoded = NULL;
117: char *ktype = NULL;
118: const u_char *sigblob;
119: const u_char *sm;
120: u_char *m = NULL;
121: u_char apphash[32];
122: u_char msghash[32];
123: u_char sig_flags;
124: u_int sig_counter;
125: size_t len;
126: unsigned long long smlen = 0, mlen = 0;
127: int r = SSH_ERR_INTERNAL_ERROR;
128: int ret;
1.3 djm 129: struct sshkey_sig_details *details = NULL;
130:
131: if (detailsp != NULL)
132: *detailsp = NULL;
1.1 markus 133:
134: if (key == NULL ||
135: sshkey_type_plain(key->type) != KEY_ED25519_SK ||
136: key->ed25519_pk == NULL ||
1.13 djm 137: sig == NULL || siglen == 0)
1.1 markus 138: return SSH_ERR_INVALID_ARGUMENT;
139:
1.13 djm 140: if ((b = sshbuf_from(sig, siglen)) == NULL)
1.1 markus 141: return SSH_ERR_ALLOC_FAIL;
142: if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
1.2 markus 143: sshbuf_get_string_direct(b, &sigblob, &len) != 0 ||
144: sshbuf_get_u8(b, &sig_flags) != 0 ||
145: sshbuf_get_u32(b, &sig_counter) != 0) {
1.1 markus 146: r = SSH_ERR_INVALID_FORMAT;
147: goto out;
148: }
1.4 djm 149: #ifdef DEBUG_SK
150: fprintf(stderr, "%s: data:\n", __func__);
151: /* sshbuf_dump_data(data, datalen, stderr); */
152: fprintf(stderr, "%s: sigblob:\n", __func__);
153: sshbuf_dump_data(sigblob, len, stderr);
154: fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n",
155: __func__, sig_flags, sig_counter);
156: #endif
1.1 markus 157: if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
158: r = SSH_ERR_KEY_TYPE_MISMATCH;
159: goto out;
160: }
161: if (sshbuf_len(b) != 0) {
162: r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
163: goto out;
164: }
165: if (len > crypto_sign_ed25519_BYTES) {
166: r = SSH_ERR_INVALID_FORMAT;
167: goto out;
168: }
169: if (ssh_digest_memory(SSH_DIGEST_SHA256, key->sk_application,
170: strlen(key->sk_application), apphash, sizeof(apphash)) != 0 ||
1.13 djm 171: ssh_digest_memory(SSH_DIGEST_SHA256, data, dlen,
1.1 markus 172: msghash, sizeof(msghash)) != 0) {
173: r = SSH_ERR_INVALID_ARGUMENT;
174: goto out;
175: }
1.4 djm 176: #ifdef DEBUG_SK
177: fprintf(stderr, "%s: hashed application:\n", __func__);
178: sshbuf_dump_data(apphash, sizeof(apphash), stderr);
179: fprintf(stderr, "%s: hashed message:\n", __func__);
180: sshbuf_dump_data(msghash, sizeof(msghash), stderr);
181: #endif
1.3 djm 182: if ((details = calloc(1, sizeof(*details))) == NULL) {
183: r = SSH_ERR_ALLOC_FAIL;
184: goto out;
185: }
186: details->sk_counter = sig_counter;
187: details->sk_flags = sig_flags;
1.1 markus 188: if ((encoded = sshbuf_new()) == NULL) {
189: r = SSH_ERR_ALLOC_FAIL;
190: goto out;
191: }
192: if (sshbuf_put(encoded, sigblob, len) != 0 ||
193: sshbuf_put(encoded, apphash, sizeof(apphash)) != 0 ||
194: sshbuf_put_u8(encoded, sig_flags) != 0 ||
195: sshbuf_put_u32(encoded, sig_counter) != 0 ||
196: sshbuf_put(encoded, msghash, sizeof(msghash)) != 0) {
197: r = SSH_ERR_ALLOC_FAIL;
198: goto out;
199: }
1.4 djm 200: #ifdef DEBUG_SK
201: fprintf(stderr, "%s: signed buf:\n", __func__);
202: sshbuf_dump(encoded, stderr);
203: #endif
1.1 markus 204: sm = sshbuf_ptr(encoded);
205: smlen = sshbuf_len(encoded);
206: mlen = smlen;
207: if ((m = malloc(smlen)) == NULL) {
208: r = SSH_ERR_ALLOC_FAIL;
209: goto out;
210: }
211: if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen,
212: key->ed25519_pk)) != 0) {
1.6 djm 213: debug2_f("crypto_sign_ed25519_open failed: %d", ret);
1.1 markus 214: }
215: if (ret != 0 || mlen != smlen - len) {
216: r = SSH_ERR_SIGNATURE_INVALID;
217: goto out;
218: }
219: /* XXX compare 'm' and 'sm + len' ? */
220: /* success */
221: r = 0;
1.3 djm 222: if (detailsp != NULL) {
223: *detailsp = details;
224: details = NULL;
225: }
1.1 markus 226: out:
1.5 jsg 227: if (m != NULL)
228: freezero(m, smlen); /* NB mlen may be invalid if r != 0 */
1.3 djm 229: sshkey_sig_details_free(details);
1.1 markus 230: sshbuf_free(b);
231: sshbuf_free(encoded);
232: free(ktype);
233: return r;
234: }
1.7 djm 235:
236: static const struct sshkey_impl_funcs sshkey_ed25519_sk_funcs = {
237: /* .size = */ NULL,
238: /* .alloc = */ NULL,
239: /* .cleanup = */ ssh_ed25519_sk_cleanup,
1.8 djm 240: /* .equal = */ ssh_ed25519_sk_equal,
1.9 djm 241: /* .ssh_serialize_public = */ ssh_ed25519_sk_serialize_public,
1.12 djm 242: /* .ssh_deserialize_public = */ ssh_ed25519_sk_deserialize_public,
1.14 ! djm 243: /* .ssh_serialize_private = */ ssh_ed25519_sk_serialize_private,
1.10 djm 244: /* .generate = */ NULL,
1.11 djm 245: /* .copy_public = */ ssh_ed25519_sk_copy_public,
1.13 djm 246: /* .sign = */ NULL,
247: /* .verify = */ ssh_ed25519_sk_verify,
1.7 djm 248: };
249:
250: const struct sshkey_impl sshkey_ed25519_sk_impl = {
251: /* .name = */ "sk-ssh-ed25519@openssh.com",
252: /* .shortname = */ "ED25519-SK",
253: /* .sigalg = */ NULL,
254: /* .type = */ KEY_ED25519_SK,
255: /* .nid = */ 0,
256: /* .cert = */ 0,
257: /* .sigonly = */ 0,
258: /* .keybits = */ 256,
259: /* .funcs = */ &sshkey_ed25519_sk_funcs,
260: };
261:
262: const struct sshkey_impl sshkey_ed25519_sk_cert_impl = {
263: /* .name = */ "sk-ssh-ed25519-cert-v01@openssh.com",
264: /* .shortname = */ "ED25519-SK-CERT",
265: /* .sigalg = */ NULL,
266: /* .type = */ KEY_ED25519_SK_CERT,
267: /* .nid = */ 0,
268: /* .cert = */ 1,
269: /* .sigonly = */ 0,
270: /* .keybits = */ 256,
271: /* .funcs = */ &sshkey_ed25519_sk_funcs,
272: };
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