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Diffstat (limited to '')
| -rw-r--r-- | ssh-xmss.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/ssh-xmss.c b/ssh-xmss.c new file mode 100644 index 0000000..ccd4c76 --- /dev/null +++ b/ssh-xmss.c @@ -0,0 +1,186 @@ +/* $OpenBSD: ssh-xmss.c,v 1.2 2020/02/26 13:40:09 jsg 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) + freezero(sig, slen); + + 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) + freezero(sm, smlen); + if (m != NULL) + freezero(m, smlen); + sshbuf_free(b); + free(ktype); + return r; +} +#endif /* WITH_XMSS */ |