144 lines
3.8 KiB
C
144 lines
3.8 KiB
C
/* $OpenBSD: ssh-ed25519.c,v 1.2 2014/02/02 03:44:31 djm Exp $ */
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/*
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* Copyright (c) 2013 Markus Friedl <markus@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include "crypto_api.h"
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#include <string.h>
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#include <stdarg.h>
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#include "xmalloc.h"
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#include "log.h"
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#include "buffer.h"
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#include "key.h"
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#include "ssh.h"
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int
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ssh_ed25519_sign(const Key *key, u_char **sigp, u_int *lenp,
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const u_char *data, u_int datalen)
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{
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u_char *sig;
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u_int slen, len;
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unsigned long long smlen;
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int ret;
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Buffer b;
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if (key == NULL || key_type_plain(key->type) != KEY_ED25519 ||
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key->ed25519_sk == NULL) {
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error("%s: no ED25519 key", __func__);
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return -1;
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}
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smlen = slen = datalen + crypto_sign_ed25519_BYTES;
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sig = xmalloc(slen);
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if ((ret = crypto_sign_ed25519(sig, &smlen, data, datalen,
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key->ed25519_sk)) != 0 || smlen <= datalen) {
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error("%s: crypto_sign_ed25519 failed: %d", __func__, ret);
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free(sig);
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return -1;
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}
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/* encode signature */
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buffer_init(&b);
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buffer_put_cstring(&b, "ssh-ed25519");
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buffer_put_string(&b, sig, smlen - datalen);
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len = buffer_len(&b);
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if (lenp != NULL)
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*lenp = len;
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if (sigp != NULL) {
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*sigp = xmalloc(len);
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memcpy(*sigp, buffer_ptr(&b), len);
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}
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buffer_free(&b);
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explicit_bzero(sig, slen);
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free(sig);
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return 0;
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}
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int
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ssh_ed25519_verify(const Key *key, const u_char *signature, u_int signaturelen,
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const u_char *data, u_int datalen)
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{
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Buffer b;
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char *ktype;
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u_char *sigblob, *sm, *m;
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u_int len;
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unsigned long long smlen, mlen;
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int rlen, ret;
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if (key == NULL || key_type_plain(key->type) != KEY_ED25519 ||
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key->ed25519_pk == NULL) {
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error("%s: no ED25519 key", __func__);
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return -1;
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}
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buffer_init(&b);
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buffer_append(&b, signature, signaturelen);
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ktype = buffer_get_cstring(&b, NULL);
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if (strcmp("ssh-ed25519", ktype) != 0) {
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error("%s: cannot handle type %s", __func__, ktype);
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buffer_free(&b);
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free(ktype);
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return -1;
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}
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free(ktype);
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sigblob = buffer_get_string(&b, &len);
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rlen = buffer_len(&b);
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buffer_free(&b);
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if (rlen != 0) {
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error("%s: remaining bytes in signature %d", __func__, rlen);
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free(sigblob);
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return -1;
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}
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if (len > crypto_sign_ed25519_BYTES) {
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error("%s: len %u > crypto_sign_ed25519_BYTES %u", __func__,
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len, crypto_sign_ed25519_BYTES);
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free(sigblob);
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return -1;
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}
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smlen = len + datalen;
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sm = xmalloc(smlen);
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memcpy(sm, sigblob, len);
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memcpy(sm+len, data, datalen);
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mlen = smlen;
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m = xmalloc(mlen);
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if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen,
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key->ed25519_pk)) != 0) {
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debug2("%s: crypto_sign_ed25519_open failed: %d",
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__func__, ret);
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}
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if (ret == 0 && mlen != datalen) {
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debug2("%s: crypto_sign_ed25519_open "
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"mlen != datalen (%llu != %u)", __func__, mlen, datalen);
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ret = -1;
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}
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/* XXX compare 'm' and 'data' ? */
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explicit_bzero(sigblob, len);
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explicit_bzero(sm, smlen);
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explicit_bzero(m, smlen); /* NB. mlen may be invalid if ret != 0 */
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free(sigblob);
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free(sm);
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free(m);
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debug("%s: signature %scorrect", __func__, (ret != 0) ? "in" : "");
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/* translate return code carefully */
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return (ret == 0) ? 1 : -1;
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}
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