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-rw-r--r--ssh-xmss.c192
1 files changed, 192 insertions, 0 deletions
diff --git a/ssh-xmss.c b/ssh-xmss.c
new file mode 100644
index 0000000..4c734fd
--- /dev/null
+++ b/ssh-xmss.c
@@ -0,0 +1,192 @@
+/* $OpenBSD: ssh-xmss.c,v 1.1 2018/02/23 15:58:38 markus 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 <string.h>
+#include <stdarg.h>
+#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"
+
+int
+ssh_xmss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
+ const u_char *data, size_t datalen, 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, error)) != 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, error)) != 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) {
+ explicit_bzero(sig, slen);
+ free(sig);
+ }
+
+ return r;
+}
+
+int
+ssh_xmss_verify(const struct sshkey *key,
+ const u_char *signature, size_t signaturelen,
+ const u_char *data, size_t datalen, u_int compat)
+{
+ 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 ||
+ signature == NULL || signaturelen == 0)
+ 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;
+
+ if ((b = sshbuf_from(signature, signaturelen)) == 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 (datalen >= SIZE_MAX - len) {
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto out;
+ }
+ smlen = len + datalen;
+ 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, datalen);
+ if ((ret = xmss_sign_open(m, &mlen, sm, smlen,
+ key->xmss_pk, sshkey_xmss_params(key))) != 0) {
+ debug2("%s: crypto_sign_xmss_open failed: %d",
+ __func__, ret);
+ }
+ if (ret != 0 || mlen != datalen) {
+ r = SSH_ERR_SIGNATURE_INVALID;
+ goto out;
+ }
+ /* XXX compare 'm' and 'data' ? */
+ /* success */
+ r = 0;
+ out:
+ if (sm != NULL) {
+ explicit_bzero(sm, smlen);
+ free(sm);
+ }
+ if (m != NULL) {
+ explicit_bzero(m, smlen); /* NB mlen may be invalid if r != 0 */
+ free(m);
+ }
+ sshbuf_free(b);
+ free(ktype);
+ return r;
+}
+#endif /* WITH_XMSS */