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- /* $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 */
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