1 /* $OpenBSD: ssh-ed25519-sk.c,v 1.5 2020/02/26 13:40:09 jsg Exp $ */
3 * Copyright (c) 2019 Markus Friedl. All rights reserved.
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.
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.
18 /* #define DEBUG_SK 1 */
22 #define SSHKEY_INTERNAL
23 #include <sys/types.h>
26 #include "crypto_api.h"
39 ssh_ed25519_sk_verify(const struct sshkey *key,
40 const u_char *signature, size_t signaturelen,
41 const u_char *data, size_t datalen, u_int compat,
42 struct sshkey_sig_details **detailsp)
44 struct sshbuf *b = NULL;
45 struct sshbuf *encoded = NULL;
47 const u_char *sigblob;
55 unsigned long long smlen = 0, mlen = 0;
56 int r = SSH_ERR_INTERNAL_ERROR;
58 struct sshkey_sig_details *details = NULL;
64 sshkey_type_plain(key->type) != KEY_ED25519_SK ||
65 key->ed25519_pk == NULL ||
66 signature == NULL || signaturelen == 0)
67 return SSH_ERR_INVALID_ARGUMENT;
69 if ((b = sshbuf_from(signature, signaturelen)) == NULL)
70 return SSH_ERR_ALLOC_FAIL;
71 if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
72 sshbuf_get_string_direct(b, &sigblob, &len) != 0 ||
73 sshbuf_get_u8(b, &sig_flags) != 0 ||
74 sshbuf_get_u32(b, &sig_counter) != 0) {
75 r = SSH_ERR_INVALID_FORMAT;
79 fprintf(stderr, "%s: data:\n", __func__);
80 /* sshbuf_dump_data(data, datalen, stderr); */
81 fprintf(stderr, "%s: sigblob:\n", __func__);
82 sshbuf_dump_data(sigblob, len, stderr);
83 fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n",
84 __func__, sig_flags, sig_counter);
86 if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
87 r = SSH_ERR_KEY_TYPE_MISMATCH;
90 if (sshbuf_len(b) != 0) {
91 r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
94 if (len > crypto_sign_ed25519_BYTES) {
95 r = SSH_ERR_INVALID_FORMAT;
98 if (ssh_digest_memory(SSH_DIGEST_SHA256, key->sk_application,
99 strlen(key->sk_application), apphash, sizeof(apphash)) != 0 ||
100 ssh_digest_memory(SSH_DIGEST_SHA256, data, datalen,
101 msghash, sizeof(msghash)) != 0) {
102 r = SSH_ERR_INVALID_ARGUMENT;
106 fprintf(stderr, "%s: hashed application:\n", __func__);
107 sshbuf_dump_data(apphash, sizeof(apphash), stderr);
108 fprintf(stderr, "%s: hashed message:\n", __func__);
109 sshbuf_dump_data(msghash, sizeof(msghash), stderr);
111 if ((details = calloc(1, sizeof(*details))) == NULL) {
112 r = SSH_ERR_ALLOC_FAIL;
115 details->sk_counter = sig_counter;
116 details->sk_flags = sig_flags;
117 if ((encoded = sshbuf_new()) == NULL) {
118 r = SSH_ERR_ALLOC_FAIL;
121 if (sshbuf_put(encoded, sigblob, len) != 0 ||
122 sshbuf_put(encoded, apphash, sizeof(apphash)) != 0 ||
123 sshbuf_put_u8(encoded, sig_flags) != 0 ||
124 sshbuf_put_u32(encoded, sig_counter) != 0 ||
125 sshbuf_put(encoded, msghash, sizeof(msghash)) != 0) {
126 r = SSH_ERR_ALLOC_FAIL;
130 fprintf(stderr, "%s: signed buf:\n", __func__);
131 sshbuf_dump(encoded, stderr);
133 sm = sshbuf_ptr(encoded);
134 smlen = sshbuf_len(encoded);
136 if ((m = malloc(smlen)) == NULL) {
137 r = SSH_ERR_ALLOC_FAIL;
140 if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen,
141 key->ed25519_pk)) != 0) {
142 debug2("%s: crypto_sign_ed25519_open failed: %d",
145 if (ret != 0 || mlen != smlen - len) {
146 r = SSH_ERR_SIGNATURE_INVALID;
149 /* XXX compare 'm' and 'sm + len' ? */
152 if (detailsp != NULL) {
158 freezero(m, smlen); /* NB mlen may be invalid if r != 0 */
159 sshkey_sig_details_free(details);
161 sshbuf_free(encoded);