diff options
Diffstat (limited to 'ssh-ecdsa.c')
| -rw-r--r-- | ssh-ecdsa.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/ssh-ecdsa.c b/ssh-ecdsa.c new file mode 100644 index 0000000..599c719 --- /dev/null +++ b/ssh-ecdsa.c @@ -0,0 +1,200 @@ +/* $OpenBSD: ssh-ecdsa.c,v 1.16 2019/01/21 09:54:11 djm Exp $ */ +/* + * Copyright (c) 2000 Markus Friedl. All rights reserved. + * Copyright (c) 2010 Damien Miller. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" + +#if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) + +#include <sys/types.h> + +#include <openssl/bn.h> +#include <openssl/ec.h> +#include <openssl/ecdsa.h> +#include <openssl/evp.h> + +#include <string.h> + +#include "sshbuf.h" +#include "ssherr.h" +#include "digest.h" +#define SSHKEY_INTERNAL +#include "sshkey.h" + +#include "openbsd-compat/openssl-compat.h" + +/* ARGSUSED */ +int +ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp, + const u_char *data, size_t datalen, u_int compat) +{ + ECDSA_SIG *sig = NULL; + const BIGNUM *sig_r, *sig_s; + int hash_alg; + u_char digest[SSH_DIGEST_MAX_LENGTH]; + size_t len, dlen; + struct sshbuf *b = NULL, *bb = NULL; + int ret = SSH_ERR_INTERNAL_ERROR; + + if (lenp != NULL) + *lenp = 0; + if (sigp != NULL) + *sigp = NULL; + + if (key == NULL || key->ecdsa == NULL || + sshkey_type_plain(key->type) != KEY_ECDSA) + return SSH_ERR_INVALID_ARGUMENT; + + if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 || + (dlen = ssh_digest_bytes(hash_alg)) == 0) + return SSH_ERR_INTERNAL_ERROR; + if ((ret = ssh_digest_memory(hash_alg, data, datalen, + digest, sizeof(digest))) != 0) + goto out; + + if ((sig = ECDSA_do_sign(digest, dlen, key->ecdsa)) == NULL) { + ret = SSH_ERR_LIBCRYPTO_ERROR; + goto out; + } + + if ((bb = sshbuf_new()) == NULL || (b = sshbuf_new()) == NULL) { + ret = SSH_ERR_ALLOC_FAIL; + goto out; + } + ECDSA_SIG_get0(sig, &sig_r, &sig_s); + if ((ret = sshbuf_put_bignum2(bb, sig_r)) != 0 || + (ret = sshbuf_put_bignum2(bb, sig_s)) != 0) + goto out; + if ((ret = sshbuf_put_cstring(b, sshkey_ssh_name_plain(key))) != 0 || + (ret = sshbuf_put_stringb(b, bb)) != 0) + goto out; + len = sshbuf_len(b); + if (sigp != NULL) { + if ((*sigp = malloc(len)) == NULL) { + ret = SSH_ERR_ALLOC_FAIL; + goto out; + } + memcpy(*sigp, sshbuf_ptr(b), len); + } + if (lenp != NULL) + *lenp = len; + ret = 0; + out: + explicit_bzero(digest, sizeof(digest)); + sshbuf_free(b); + sshbuf_free(bb); + ECDSA_SIG_free(sig); + return ret; +} + +/* ARGSUSED */ +int +ssh_ecdsa_verify(const struct sshkey *key, + const u_char *signature, size_t signaturelen, + const u_char *data, size_t datalen, u_int compat) +{ + ECDSA_SIG *sig = NULL; + BIGNUM *sig_r = NULL, *sig_s = NULL; + int hash_alg; + u_char digest[SSH_DIGEST_MAX_LENGTH]; + size_t dlen; + int ret = SSH_ERR_INTERNAL_ERROR; + struct sshbuf *b = NULL, *sigbuf = NULL; + char *ktype = NULL; + + if (key == NULL || key->ecdsa == NULL || + sshkey_type_plain(key->type) != KEY_ECDSA || + signature == NULL || signaturelen == 0) + return SSH_ERR_INVALID_ARGUMENT; + + if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 || + (dlen = ssh_digest_bytes(hash_alg)) == 0) + return SSH_ERR_INTERNAL_ERROR; + + /* fetch signature */ + if ((b = sshbuf_from(signature, signaturelen)) == NULL) + return SSH_ERR_ALLOC_FAIL; + if (sshbuf_get_cstring(b, &ktype, NULL) != 0 || + sshbuf_froms(b, &sigbuf) != 0) { + ret = SSH_ERR_INVALID_FORMAT; + goto out; + } + if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) { + ret = SSH_ERR_KEY_TYPE_MISMATCH; + goto out; + } + if (sshbuf_len(b) != 0) { + ret = SSH_ERR_UNEXPECTED_TRAILING_DATA; + goto out; + } + + /* parse signature */ + if (sshbuf_get_bignum2(sigbuf, &sig_r) != 0 || + sshbuf_get_bignum2(sigbuf, &sig_s) != 0) { + ret = SSH_ERR_INVALID_FORMAT; + goto out; + } + if ((sig = ECDSA_SIG_new()) == NULL) { + ret = SSH_ERR_ALLOC_FAIL; + goto out; + } + if (!ECDSA_SIG_set0(sig, sig_r, sig_s)) { + ret = SSH_ERR_LIBCRYPTO_ERROR; + goto out; + } + sig_r = sig_s = NULL; /* transferred */ + + if (sshbuf_len(sigbuf) != 0) { + ret = SSH_ERR_UNEXPECTED_TRAILING_DATA; + goto out; + } + if ((ret = ssh_digest_memory(hash_alg, data, datalen, + digest, sizeof(digest))) != 0) + goto out; + + switch (ECDSA_do_verify(digest, dlen, sig, key->ecdsa)) { + case 1: + ret = 0; + break; + case 0: + ret = SSH_ERR_SIGNATURE_INVALID; + goto out; + default: + ret = SSH_ERR_LIBCRYPTO_ERROR; + goto out; + } + + out: + explicit_bzero(digest, sizeof(digest)); + sshbuf_free(sigbuf); + sshbuf_free(b); + ECDSA_SIG_free(sig); + BN_clear_free(sig_r); + BN_clear_free(sig_s); + free(ktype); + return ret; +} + +#endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */ |