Damien Miller | 5be9d9e | 2013-12-07 11:24:01 +1100 | [diff] [blame^] | 1 | /* $OpenBSD: ssh-ed25519.c,v 1.1 2013/12/06 13:39:49 markus 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 | |
| 18 | #include <sys/types.h> |
| 19 | |
| 20 | #include "crypto_api.h" |
| 21 | |
| 22 | #include <string.h> |
| 23 | #include <stdarg.h> |
| 24 | |
| 25 | #include "xmalloc.h" |
| 26 | #include "log.h" |
| 27 | #include "buffer.h" |
| 28 | #include "key.h" |
| 29 | #include "ssh.h" |
| 30 | |
| 31 | int |
| 32 | ssh_ed25519_sign(const Key *key, u_char **sigp, u_int *lenp, |
| 33 | const u_char *data, u_int datalen) |
| 34 | { |
| 35 | u_char *sig; |
| 36 | u_int slen, len; |
| 37 | unsigned long long smlen; |
| 38 | int ret; |
| 39 | Buffer b; |
| 40 | |
| 41 | if (key == NULL || key_type_plain(key->type) != KEY_ED25519 || |
| 42 | key->ed25519_sk == NULL) { |
| 43 | error("%s: no ED25519 key", __func__); |
| 44 | return -1; |
| 45 | } |
| 46 | smlen = slen = datalen + crypto_sign_ed25519_BYTES; |
| 47 | sig = xmalloc(slen); |
| 48 | |
| 49 | if ((ret = crypto_sign_ed25519(sig, &smlen, data, datalen, |
| 50 | key->ed25519_sk)) != 0 || smlen <= datalen) { |
| 51 | error("%s: crypto_sign_ed25519 failed: %d", __func__, ret); |
| 52 | free(sig); |
| 53 | return -1; |
| 54 | } |
| 55 | /* encode signature */ |
| 56 | buffer_init(&b); |
| 57 | buffer_put_cstring(&b, "ssh-ed25519"); |
| 58 | buffer_put_string(&b, sig, smlen - datalen); |
| 59 | len = buffer_len(&b); |
| 60 | if (lenp != NULL) |
| 61 | *lenp = len; |
| 62 | if (sigp != NULL) { |
| 63 | *sigp = xmalloc(len); |
| 64 | memcpy(*sigp, buffer_ptr(&b), len); |
| 65 | } |
| 66 | buffer_free(&b); |
| 67 | memset(sig, 's', slen); |
| 68 | free(sig); |
| 69 | |
| 70 | return 0; |
| 71 | } |
| 72 | |
| 73 | int |
| 74 | ssh_ed25519_verify(const Key *key, const u_char *signature, u_int signaturelen, |
| 75 | const u_char *data, u_int datalen) |
| 76 | { |
| 77 | Buffer b; |
| 78 | char *ktype; |
| 79 | u_char *sigblob, *sm, *m; |
| 80 | u_int len; |
| 81 | unsigned long long smlen, mlen; |
| 82 | int rlen, ret; |
| 83 | |
| 84 | if (key == NULL || key_type_plain(key->type) != KEY_ED25519 || |
| 85 | key->ed25519_pk == NULL) { |
| 86 | error("%s: no ED25519 key", __func__); |
| 87 | return -1; |
| 88 | } |
| 89 | buffer_init(&b); |
| 90 | buffer_append(&b, signature, signaturelen); |
| 91 | ktype = buffer_get_cstring(&b, NULL); |
| 92 | if (strcmp("ssh-ed25519", ktype) != 0) { |
| 93 | error("%s: cannot handle type %s", __func__, ktype); |
| 94 | buffer_free(&b); |
| 95 | free(ktype); |
| 96 | return -1; |
| 97 | } |
| 98 | free(ktype); |
| 99 | sigblob = buffer_get_string(&b, &len); |
| 100 | rlen = buffer_len(&b); |
| 101 | buffer_free(&b); |
| 102 | if (rlen != 0) { |
| 103 | error("%s: remaining bytes in signature %d", __func__, rlen); |
| 104 | free(sigblob); |
| 105 | return -1; |
| 106 | } |
| 107 | if (len > crypto_sign_ed25519_BYTES) { |
| 108 | error("%s: len %u > crypto_sign_ed25519_BYTES %u", __func__, |
| 109 | len, crypto_sign_ed25519_BYTES); |
| 110 | free(sigblob); |
| 111 | return -1; |
| 112 | } |
| 113 | smlen = len + datalen; |
| 114 | sm = xmalloc(smlen); |
| 115 | memcpy(sm, sigblob, len); |
| 116 | memcpy(sm+len, data, datalen); |
| 117 | mlen = smlen; |
| 118 | m = xmalloc(mlen); |
| 119 | if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen, |
| 120 | key->ed25519_pk)) != 0) { |
| 121 | debug2("%s: crypto_sign_ed25519_open failed: %d", |
| 122 | __func__, ret); |
| 123 | } |
| 124 | if (ret == 0 && mlen != datalen) { |
| 125 | debug2("%s: crypto_sign_ed25519_open " |
| 126 | "mlen != datalen (%llu != %u)", __func__, mlen, datalen); |
| 127 | ret = -1; |
| 128 | } |
| 129 | /* XXX compare 'm' and 'data' ? */ |
| 130 | |
| 131 | memset(sigblob, 's', len); |
| 132 | memset(sm, 'S', smlen); |
| 133 | memset(m, 'm', smlen); /* NB. mlen may be invalid if ret != 0 */ |
| 134 | free(sigblob); |
| 135 | free(sm); |
| 136 | free(m); |
| 137 | debug("%s: signature %scorrect", __func__, (ret != 0) ? "in" : ""); |
| 138 | |
| 139 | /* translate return code carefully */ |
| 140 | return (ret == 0) ? 1 : -1; |
| 141 | } |