1 /* $OpenBSD: ssh-ed25519.c,v 1.5 2014/10/14 03:09:59 daniel Exp $ */ 2 /* 3 * Copyright (c) 2013 Markus Friedl <markus@openbsd.org> 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 #define SSHKEY_INTERNAL 18 #include <sys/types.h> 19 #include <limits.h> 20 21 #include "crypto_api.h" 22 23 #include <string.h> 24 #include <stdarg.h> 25 26 #include "xmalloc.h" 27 #include "log.h" 28 #include "buffer.h" 29 #include "sshkey.h" 30 #include "ssherr.h" 31 #include "ssh.h" 32 33 int 34 ssh_ed25519_sign(const struct sshkey *key, u_char **sigp, size_t *lenp, 35 const u_char *data, size_t datalen, u_int compat) 36 { 37 u_char *sig = NULL; 38 size_t slen = 0, len; 39 unsigned long long smlen; 40 int r, ret; 41 struct sshbuf *b = NULL; 42 43 if (lenp != NULL) 44 *lenp = 0; 45 if (sigp != NULL) 46 *sigp = NULL; 47 48 if (key == NULL || 49 sshkey_type_plain(key->type) != KEY_ED25519 || 50 key->ed25519_sk == NULL || 51 datalen >= INT_MAX - crypto_sign_ed25519_BYTES) 52 return SSH_ERR_INVALID_ARGUMENT; 53 smlen = slen = datalen + crypto_sign_ed25519_BYTES; 54 if ((sig = malloc(slen)) == NULL) 55 return SSH_ERR_ALLOC_FAIL; 56 57 if ((ret = crypto_sign_ed25519(sig, &smlen, data, datalen, 58 key->ed25519_sk)) != 0 || smlen <= datalen) { 59 r = SSH_ERR_INVALID_ARGUMENT; /* XXX better error? */ 60 goto out; 61 } 62 /* encode signature */ 63 if ((b = sshbuf_new()) == NULL) { 64 r = SSH_ERR_ALLOC_FAIL; 65 goto out; 66 } 67 if ((r = sshbuf_put_cstring(b, "ssh-ed25519")) != 0 || 68 (r = sshbuf_put_string(b, sig, smlen - datalen)) != 0) 69 goto out; 70 len = sshbuf_len(b); 71 if (sigp != NULL) { 72 if ((*sigp = malloc(len)) == NULL) { 73 r = SSH_ERR_ALLOC_FAIL; 74 goto out; 75 } 76 memcpy(*sigp, sshbuf_ptr(b), len); 77 } 78 if (lenp != NULL) 79 *lenp = len; 80 /* success */ 81 r = 0; 82 out: 83 sshbuf_free(b); 84 if (sig != NULL) { 85 explicit_bzero(sig, slen); 86 free(sig); 87 } 88 89 return r; 90 } 91 92 int 93 ssh_ed25519_verify(const struct sshkey *key, 94 const u_char *signature, size_t signaturelen, 95 const u_char *data, size_t datalen, u_int compat) 96 { 97 struct sshbuf *b = NULL; 98 char *ktype = NULL; 99 const u_char *sigblob; 100 u_char *sm = NULL, *m = NULL; 101 size_t len; 102 unsigned long long smlen = 0, mlen = 0; 103 int r, ret; 104 105 if (key == NULL || 106 sshkey_type_plain(key->type) != KEY_ED25519 || 107 key->ed25519_pk == NULL || 108 datalen >= INT_MAX - crypto_sign_ed25519_BYTES) 109 return SSH_ERR_INVALID_ARGUMENT; 110 111 if ((b = sshbuf_from(signature, signaturelen)) == NULL) 112 return SSH_ERR_ALLOC_FAIL; 113 if ((r = sshbuf_get_cstring(b, &ktype, NULL)) != 0 || 114 (r = sshbuf_get_string_direct(b, &sigblob, &len)) != 0) 115 goto out; 116 if (strcmp("ssh-ed25519", ktype) != 0) { 117 r = SSH_ERR_KEY_TYPE_MISMATCH; 118 goto out; 119 } 120 if (sshbuf_len(b) != 0) { 121 r = SSH_ERR_UNEXPECTED_TRAILING_DATA; 122 goto out; 123 } 124 if (len > crypto_sign_ed25519_BYTES) { 125 r = SSH_ERR_INVALID_FORMAT; 126 goto out; 127 } 128 if (datalen >= SIZE_MAX - len) { 129 r = SSH_ERR_INVALID_ARGUMENT; 130 goto out; 131 } 132 smlen = len + datalen; 133 mlen = smlen; 134 if ((sm = malloc(smlen)) == NULL || (m = xmalloc(mlen)) == NULL) { 135 r = SSH_ERR_ALLOC_FAIL; 136 goto out; 137 } 138 memcpy(sm, sigblob, len); 139 memcpy(sm+len, data, datalen); 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", 143 __func__, ret); 144 } 145 if (ret != 0 || mlen != datalen) { 146 r = SSH_ERR_SIGNATURE_INVALID; 147 goto out; 148 } 149 /* XXX compare 'm' and 'data' ? */ 150 /* success */ 151 r = 0; 152 out: 153 if (sm != NULL) { 154 explicit_bzero(sm, smlen); 155 free(sm); 156 } 157 if (m != NULL) { 158 explicit_bzero(m, smlen); /* NB mlen may be invalid if r != 0 */ 159 free(m); 160 } 161 sshbuf_free(b); 162 free(ktype); 163 return r; 164 } 165 166