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-rw-r--r--ssh-xmss.c389
1 files changed, 389 insertions, 0 deletions
diff --git a/ssh-xmss.c b/ssh-xmss.c
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--- /dev/null
+++ b/ssh-xmss.c
@@ -0,0 +1,389 @@
+/* $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 */