| /* $OpenBSD: ssh-ed25519.c,v 1.19 2022/10/28 00:44:44 djm Exp $ */ |
| /* |
| * Copyright (c) 2013 Markus Friedl <markus@openbsd.org> |
| * |
| * 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" |
| |
| #include <sys/types.h> |
| #include <limits.h> |
| |
| #include "crypto_api.h" |
| |
| #include <string.h> |
| #include <stdarg.h> |
| |
| #include "log.h" |
| #include "sshbuf.h" |
| #define SSHKEY_INTERNAL |
| #include "sshkey.h" |
| #include "ssherr.h" |
| #include "ssh.h" |
| |
| static void |
| ssh_ed25519_cleanup(struct sshkey *k) |
| { |
| freezero(k->ed25519_pk, ED25519_PK_SZ); |
| freezero(k->ed25519_sk, ED25519_SK_SZ); |
| k->ed25519_pk = NULL; |
| k->ed25519_sk = NULL; |
| } |
| |
| static int |
| ssh_ed25519_equal(const struct sshkey *a, const struct sshkey *b) |
| { |
| if (a->ed25519_pk == NULL || b->ed25519_pk == NULL) |
| return 0; |
| if (memcmp(a->ed25519_pk, b->ed25519_pk, ED25519_PK_SZ) != 0) |
| return 0; |
| return 1; |
| } |
| |
| static int |
| ssh_ed25519_serialize_public(const struct sshkey *key, struct sshbuf *b, |
| enum sshkey_serialize_rep opts) |
| { |
| int r; |
| |
| if (key->ed25519_pk == NULL) |
| return SSH_ERR_INVALID_ARGUMENT; |
| if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0) |
| return r; |
| |
| return 0; |
| } |
| |
| static int |
| ssh_ed25519_serialize_private(const struct sshkey *key, struct sshbuf *b, |
| enum sshkey_serialize_rep opts) |
| { |
| int r; |
| |
| if ((r = sshbuf_put_string(b, key->ed25519_pk, ED25519_PK_SZ)) != 0 || |
| (r = sshbuf_put_string(b, key->ed25519_sk, ED25519_SK_SZ)) != 0) |
| return r; |
| |
| return 0; |
| } |
| |
| static int |
| ssh_ed25519_generate(struct sshkey *k, int bits) |
| { |
| if ((k->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL || |
| (k->ed25519_sk = malloc(ED25519_SK_SZ)) == NULL) |
| return SSH_ERR_ALLOC_FAIL; |
| crypto_sign_ed25519_keypair(k->ed25519_pk, k->ed25519_sk); |
| return 0; |
| } |
| |
| static int |
| ssh_ed25519_copy_public(const struct sshkey *from, struct sshkey *to) |
| { |
| if (from->ed25519_pk == NULL) |
| return 0; /* XXX SSH_ERR_INTERNAL_ERROR ? */ |
| if ((to->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) |
| return SSH_ERR_ALLOC_FAIL; |
| memcpy(to->ed25519_pk, from->ed25519_pk, ED25519_PK_SZ); |
| return 0; |
| } |
| |
| static int |
| ssh_ed25519_deserialize_public(const char *ktype, struct sshbuf *b, |
| struct sshkey *key) |
| { |
| u_char *pk = NULL; |
| size_t len = 0; |
| int r; |
| |
| if ((r = sshbuf_get_string(b, &pk, &len)) != 0) |
| return r; |
| if (len != ED25519_PK_SZ) { |
| freezero(pk, len); |
| return SSH_ERR_INVALID_FORMAT; |
| } |
| key->ed25519_pk = pk; |
| return 0; |
| } |
| |
| static int |
| ssh_ed25519_deserialize_private(const char *ktype, struct sshbuf *b, |
| struct sshkey *key) |
| { |
| int r; |
| size_t sklen = 0; |
| u_char *ed25519_sk = NULL; |
| |
| if ((r = ssh_ed25519_deserialize_public(NULL, b, key)) != 0) |
| goto out; |
| if ((r = sshbuf_get_string(b, &ed25519_sk, &sklen)) != 0) |
| goto out; |
| if (sklen != ED25519_SK_SZ) { |
| r = SSH_ERR_INVALID_FORMAT; |
| goto out; |
| } |
| key->ed25519_sk = ed25519_sk; |
| ed25519_sk = NULL; /* transferred */ |
| /* success */ |
| r = 0; |
| out: |
| freezero(ed25519_sk, sklen); |
| return r; |
| } |
| |
| static int |
| ssh_ed25519_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; |
| 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_ED25519 || |
| key->ed25519_sk == NULL || |
| datalen >= INT_MAX - crypto_sign_ed25519_BYTES) |
| return SSH_ERR_INVALID_ARGUMENT; |
| smlen = slen = datalen + crypto_sign_ed25519_BYTES; |
| if ((sig = malloc(slen)) == NULL) |
| return SSH_ERR_ALLOC_FAIL; |
| |
| if ((ret = crypto_sign_ed25519(sig, &smlen, data, datalen, |
| key->ed25519_sk)) != 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-ed25519")) != 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: |
| sshbuf_free(b); |
| if (sig != NULL) |
| freezero(sig, slen); |
| |
| return r; |
| } |
| |
| static int |
| ssh_ed25519_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; |
| unsigned long long smlen = 0, mlen = 0; |
| int r, ret; |
| |
| if (key == NULL || |
| sshkey_type_plain(key->type) != KEY_ED25519 || |
| key->ed25519_pk == NULL || |
| dlen >= INT_MAX - crypto_sign_ed25519_BYTES || |
| sig == NULL || siglen == 0) |
| 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-ed25519", 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 > crypto_sign_ed25519_BYTES) { |
| 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 = crypto_sign_ed25519_open(m, &mlen, sm, smlen, |
| key->ed25519_pk)) != 0) { |
| debug2_f("crypto_sign_ed25519_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); /* NB mlen may be invalid if r != 0 */ |
| sshbuf_free(b); |
| free(ktype); |
| return r; |
| } |
| |
| /* NB. not static; used by ED25519-SK */ |
| const struct sshkey_impl_funcs sshkey_ed25519_funcs = { |
| /* .size = */ NULL, |
| /* .alloc = */ NULL, |
| /* .cleanup = */ ssh_ed25519_cleanup, |
| /* .equal = */ ssh_ed25519_equal, |
| /* .ssh_serialize_public = */ ssh_ed25519_serialize_public, |
| /* .ssh_deserialize_public = */ ssh_ed25519_deserialize_public, |
| /* .ssh_serialize_private = */ ssh_ed25519_serialize_private, |
| /* .ssh_deserialize_private = */ ssh_ed25519_deserialize_private, |
| /* .generate = */ ssh_ed25519_generate, |
| /* .copy_public = */ ssh_ed25519_copy_public, |
| /* .sign = */ ssh_ed25519_sign, |
| /* .verify = */ ssh_ed25519_verify, |
| }; |
| |
| const struct sshkey_impl sshkey_ed25519_impl = { |
| /* .name = */ "ssh-ed25519", |
| /* .shortname = */ "ED25519", |
| /* .sigalg = */ NULL, |
| /* .type = */ KEY_ED25519, |
| /* .nid = */ 0, |
| /* .cert = */ 0, |
| /* .sigonly = */ 0, |
| /* .keybits = */ 256, |
| /* .funcs = */ &sshkey_ed25519_funcs, |
| }; |
| |
| const struct sshkey_impl sshkey_ed25519_cert_impl = { |
| /* .name = */ "ssh-ed25519-cert-v01@openssh.com", |
| /* .shortname = */ "ED25519-CERT", |
| /* .sigalg = */ NULL, |
| /* .type = */ KEY_ED25519_CERT, |
| /* .nid = */ 0, |
| /* .cert = */ 1, |
| /* .sigonly = */ 0, |
| /* .keybits = */ 256, |
| /* .funcs = */ &sshkey_ed25519_funcs, |
| }; |