openssh-portable/ssh-xmss.c

390 lines
10 KiB
C

/* $OpenBSD: ssh-xmss.c,v 1.14 2022/10/28 00:44:44 djm Exp $*/
/*
* Copyright (c) 2017 Stefan-Lukas Gazdag.
* Copyright (c) 2017 Markus Friedl.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "includes.h"
#ifdef WITH_XMSS
#define SSHKEY_INTERNAL
#include <sys/types.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#include <unistd.h>
#include "log.h"
#include "sshbuf.h"
#include "sshkey.h"
#include "sshkey-xmss.h"
#include "ssherr.h"
#include "ssh.h"
#include "xmss_fast.h"
static void
ssh_xmss_cleanup(struct sshkey *k)
{
freezero(k->xmss_pk, sshkey_xmss_pklen(k));
freezero(k->xmss_sk, sshkey_xmss_sklen(k));
sshkey_xmss_free_state(k);
free(k->xmss_name);
free(k->xmss_filename);
k->xmss_pk = NULL;
k->xmss_sk = NULL;
k->xmss_name = NULL;
k->xmss_filename = NULL;
}
static int
ssh_xmss_equal(const struct sshkey *a, const struct sshkey *b)
{
if (a->xmss_pk == NULL || b->xmss_pk == NULL)
return 0;
if (sshkey_xmss_pklen(a) != sshkey_xmss_pklen(b))
return 0;
if (memcmp(a->xmss_pk, b->xmss_pk, sshkey_xmss_pklen(a)) != 0)
return 0;
return 1;
}
static int
ssh_xmss_serialize_public(const struct sshkey *key, struct sshbuf *b,
enum sshkey_serialize_rep opts)
{
int r;
if (key->xmss_name == NULL || key->xmss_pk == NULL ||
sshkey_xmss_pklen(key) == 0)
return SSH_ERR_INVALID_ARGUMENT;
if ((r = sshbuf_put_cstring(b, key->xmss_name)) != 0 ||
(r = sshbuf_put_string(b, key->xmss_pk,
sshkey_xmss_pklen(key))) != 0 ||
(r = sshkey_xmss_serialize_pk_info(key, b, opts)) != 0)
return r;
return 0;
}
static int
ssh_xmss_serialize_private(const struct sshkey *key, struct sshbuf *b,
enum sshkey_serialize_rep opts)
{
int r;
if (key->xmss_name == NULL)
return SSH_ERR_INVALID_ARGUMENT;
/* Note: can't reuse ssh_xmss_serialize_public because of sk order */
if ((r = sshbuf_put_cstring(b, key->xmss_name)) != 0 ||
(r = sshbuf_put_string(b, key->xmss_pk,
sshkey_xmss_pklen(key))) != 0 ||
(r = sshbuf_put_string(b, key->xmss_sk,
sshkey_xmss_sklen(key))) != 0 ||
(r = sshkey_xmss_serialize_state_opt(key, b, opts)) != 0)
return r;
return 0;
}
static int
ssh_xmss_copy_public(const struct sshkey *from, struct sshkey *to)
{
int r = SSH_ERR_INTERNAL_ERROR;
u_int32_t left;
size_t pklen;
if ((r = sshkey_xmss_init(to, from->xmss_name)) != 0)
return r;
if (from->xmss_pk == NULL)
return 0; /* XXX SSH_ERR_INTERNAL_ERROR ? */
if ((pklen = sshkey_xmss_pklen(from)) == 0 ||
sshkey_xmss_pklen(to) != pklen)
return SSH_ERR_INTERNAL_ERROR;
if ((to->xmss_pk = malloc(pklen)) == NULL)
return SSH_ERR_ALLOC_FAIL;
memcpy(to->xmss_pk, from->xmss_pk, pklen);
/* simulate number of signatures left on pubkey */
left = sshkey_xmss_signatures_left(from);
if (left)
sshkey_xmss_enable_maxsign(to, left);
return 0;
}
static int
ssh_xmss_deserialize_public(const char *ktype, struct sshbuf *b,
struct sshkey *key)
{
size_t len = 0;
char *xmss_name = NULL;
u_char *pk = NULL;
int ret = SSH_ERR_INTERNAL_ERROR;
if ((ret = sshbuf_get_cstring(b, &xmss_name, NULL)) != 0)
goto out;
if ((ret = sshkey_xmss_init(key, xmss_name)) != 0)
goto out;
if ((ret = sshbuf_get_string(b, &pk, &len)) != 0)
goto out;
if (len == 0 || len != sshkey_xmss_pklen(key)) {
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
key->xmss_pk = pk;
pk = NULL;
if (!sshkey_is_cert(key) &&
(ret = sshkey_xmss_deserialize_pk_info(key, b)) != 0)
goto out;
/* success */
ret = 0;
out:
free(xmss_name);
freezero(pk, len);
return ret;
}
static int
ssh_xmss_deserialize_private(const char *ktype, struct sshbuf *b,
struct sshkey *key)
{
int r;
char *xmss_name = NULL;
size_t pklen = 0, sklen = 0;
u_char *xmss_pk = NULL, *xmss_sk = NULL;
/* Note: can't reuse ssh_xmss_deserialize_public because of sk order */
if ((r = sshbuf_get_cstring(b, &xmss_name, NULL)) != 0 ||
(r = sshbuf_get_string(b, &xmss_pk, &pklen)) != 0 ||
(r = sshbuf_get_string(b, &xmss_sk, &sklen)) != 0)
goto out;
if (!sshkey_is_cert(key) &&
(r = sshkey_xmss_init(key, xmss_name)) != 0)
goto out;
if (pklen != sshkey_xmss_pklen(key) ||
sklen != sshkey_xmss_sklen(key)) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
key->xmss_pk = xmss_pk;
key->xmss_sk = xmss_sk;
xmss_pk = xmss_sk = NULL;
/* optional internal state */
if ((r = sshkey_xmss_deserialize_state_opt(key, b)) != 0)
goto out;
/* success */
r = 0;
out:
free(xmss_name);
freezero(xmss_pk, pklen);
freezero(xmss_sk, sklen);
return r;
}
static int
ssh_xmss_sign(struct sshkey *key,
u_char **sigp, size_t *lenp,
const u_char *data, size_t datalen,
const char *alg, const char *sk_provider, const char *sk_pin, u_int compat)
{
u_char *sig = NULL;
size_t slen = 0, len = 0, required_siglen;
unsigned long long smlen;
int r, ret;
struct sshbuf *b = NULL;
if (lenp != NULL)
*lenp = 0;
if (sigp != NULL)
*sigp = NULL;
if (key == NULL ||
sshkey_type_plain(key->type) != KEY_XMSS ||
key->xmss_sk == NULL ||
sshkey_xmss_params(key) == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if ((r = sshkey_xmss_siglen(key, &required_siglen)) != 0)
return r;
if (datalen >= INT_MAX - required_siglen)
return SSH_ERR_INVALID_ARGUMENT;
smlen = slen = datalen + required_siglen;
if ((sig = malloc(slen)) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshkey_xmss_get_state(key, 1)) != 0)
goto out;
if ((ret = xmss_sign(key->xmss_sk, sshkey_xmss_bds_state(key), sig, &smlen,
data, datalen, sshkey_xmss_params(key))) != 0 || smlen <= datalen) {
r = SSH_ERR_INVALID_ARGUMENT; /* XXX better error? */
goto out;
}
/* encode signature */
if ((b = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_put_cstring(b, "ssh-xmss@openssh.com")) != 0 ||
(r = sshbuf_put_string(b, sig, smlen - datalen)) != 0)
goto out;
len = sshbuf_len(b);
if (sigp != NULL) {
if ((*sigp = malloc(len)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
memcpy(*sigp, sshbuf_ptr(b), len);
}
if (lenp != NULL)
*lenp = len;
/* success */
r = 0;
out:
if ((ret = sshkey_xmss_update_state(key, 1)) != 0) {
/* discard signature since we cannot update the state */
if (r == 0 && sigp != NULL && *sigp != NULL) {
explicit_bzero(*sigp, len);
free(*sigp);
}
if (sigp != NULL)
*sigp = NULL;
if (lenp != NULL)
*lenp = 0;
r = ret;
}
sshbuf_free(b);
if (sig != NULL)
freezero(sig, slen);
return r;
}
static int
ssh_xmss_verify(const struct sshkey *key,
const u_char *sig, size_t siglen,
const u_char *data, size_t dlen, const char *alg, u_int compat,
struct sshkey_sig_details **detailsp)
{
struct sshbuf *b = NULL;
char *ktype = NULL;
const u_char *sigblob;
u_char *sm = NULL, *m = NULL;
size_t len, required_siglen;
unsigned long long smlen = 0, mlen = 0;
int r, ret;
if (key == NULL ||
sshkey_type_plain(key->type) != KEY_XMSS ||
key->xmss_pk == NULL ||
sshkey_xmss_params(key) == NULL ||
sig == NULL || siglen == 0)
return SSH_ERR_INVALID_ARGUMENT;
if ((r = sshkey_xmss_siglen(key, &required_siglen)) != 0)
return r;
if (dlen >= INT_MAX - required_siglen)
return SSH_ERR_INVALID_ARGUMENT;
if ((b = sshbuf_from(sig, siglen)) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_get_cstring(b, &ktype, NULL)) != 0 ||
(r = sshbuf_get_string_direct(b, &sigblob, &len)) != 0)
goto out;
if (strcmp("ssh-xmss@openssh.com", ktype) != 0) {
r = SSH_ERR_KEY_TYPE_MISMATCH;
goto out;
}
if (sshbuf_len(b) != 0) {
r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
goto out;
}
if (len != required_siglen) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if (dlen >= SIZE_MAX - len) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
smlen = len + dlen;
mlen = smlen;
if ((sm = malloc(smlen)) == NULL || (m = malloc(mlen)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
memcpy(sm, sigblob, len);
memcpy(sm+len, data, dlen);
if ((ret = xmss_sign_open(m, &mlen, sm, smlen,
key->xmss_pk, sshkey_xmss_params(key))) != 0) {
debug2_f("xmss_sign_open failed: %d", ret);
}
if (ret != 0 || mlen != dlen) {
r = SSH_ERR_SIGNATURE_INVALID;
goto out;
}
/* XXX compare 'm' and 'data' ? */
/* success */
r = 0;
out:
if (sm != NULL)
freezero(sm, smlen);
if (m != NULL)
freezero(m, smlen);
sshbuf_free(b);
free(ktype);
return r;
}
static const struct sshkey_impl_funcs sshkey_xmss_funcs = {
/* .size = */ NULL,
/* .alloc = */ NULL,
/* .cleanup = */ ssh_xmss_cleanup,
/* .equal = */ ssh_xmss_equal,
/* .ssh_serialize_public = */ ssh_xmss_serialize_public,
/* .ssh_deserialize_public = */ ssh_xmss_deserialize_public,
/* .ssh_serialize_private = */ ssh_xmss_serialize_private,
/* .ssh_deserialize_private = */ ssh_xmss_deserialize_private,
/* .generate = */ sshkey_xmss_generate_private_key,
/* .copy_public = */ ssh_xmss_copy_public,
/* .sign = */ ssh_xmss_sign,
/* .verify = */ ssh_xmss_verify,
};
const struct sshkey_impl sshkey_xmss_impl = {
/* .name = */ "ssh-xmss@openssh.com",
/* .shortname = */ "XMSS",
/* .sigalg = */ NULL,
/* .type = */ KEY_XMSS,
/* .nid = */ 0,
/* .cert = */ 0,
/* .sigonly = */ 0,
/* .keybits = */ 256,
/* .funcs = */ &sshkey_xmss_funcs,
};
const struct sshkey_impl sshkey_xmss_cert_impl = {
/* .name = */ "ssh-xmss-cert-v01@openssh.com",
/* .shortname = */ "XMSS-CERT",
/* .sigalg = */ NULL,
/* .type = */ KEY_XMSS_CERT,
/* .nid = */ 0,
/* .cert = */ 1,
/* .sigonly = */ 0,
/* .keybits = */ 256,
/* .funcs = */ &sshkey_xmss_funcs,
};
#endif /* WITH_XMSS */