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openssh/sshkey.c
djm@openbsd.org 4e838120a7
upstream: make DSA key support compile-time optional, defaulting to 
on

ok markus@

OpenBSD-Commit-ID: 4f8e98fc1fd6de399d0921d5b31b3127a03f581d
2024-01-11 15:46:22 +11:00

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/* $OpenBSD: sshkey.c,v 1.142 2024/01/11 01:45:36 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Alexander von Gernler. All rights reserved.
* Copyright (c) 2010,2011 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"
#include <sys/types.h>
#include <netinet/in.h>
#ifdef WITH_OPENSSL
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/pem.h>
#endif
#include "crypto_api.h"
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <resolv.h>
#include <time.h>
#ifdef HAVE_UTIL_H
#include <util.h>
#endif /* HAVE_UTIL_H */
#include "ssh2.h"
#include "ssherr.h"
#include "misc.h"
#include "sshbuf.h"
#include "cipher.h"
#include "digest.h"
#define SSHKEY_INTERNAL
#include "sshkey.h"
#include "match.h"
#include "ssh-sk.h"
#ifdef WITH_XMSS
#include "sshkey-xmss.h"
#include "xmss_fast.h"
#endif
#include "openbsd-compat/openssl-compat.h"
/* openssh private key file format */
#define MARK_BEGIN "-----BEGIN OPENSSH PRIVATE KEY-----\n"
#define MARK_END "-----END OPENSSH PRIVATE KEY-----\n"
#define MARK_BEGIN_LEN (sizeof(MARK_BEGIN) - 1)
#define MARK_END_LEN (sizeof(MARK_END) - 1)
#define KDFNAME "bcrypt"
#define AUTH_MAGIC "openssh-key-v1"
#define SALT_LEN 16
#define DEFAULT_CIPHERNAME "aes256-ctr"
#define DEFAULT_ROUNDS 24
/* Version identification string for SSH v1 identity files. */
#define LEGACY_BEGIN "SSH PRIVATE KEY FILE FORMAT 1.1\n"
/*
* Constants relating to "shielding" support; protection of keys expected
* to remain in memory for long durations
*/
#define SSHKEY_SHIELD_PREKEY_LEN (16 * 1024)
#define SSHKEY_SHIELD_CIPHER "aes256-ctr" /* XXX want AES-EME* */
#define SSHKEY_SHIELD_PREKEY_HASH SSH_DIGEST_SHA512
int sshkey_private_serialize_opt(struct sshkey *key,
struct sshbuf *buf, enum sshkey_serialize_rep);
static int sshkey_from_blob_internal(struct sshbuf *buf,
struct sshkey **keyp, int allow_cert);
/* Supported key types */
extern const struct sshkey_impl sshkey_ed25519_impl;
extern const struct sshkey_impl sshkey_ed25519_cert_impl;
extern const struct sshkey_impl sshkey_ed25519_sk_impl;
extern const struct sshkey_impl sshkey_ed25519_sk_cert_impl;
#ifdef WITH_OPENSSL
# ifdef OPENSSL_HAS_ECC
# ifdef ENABLE_SK
extern const struct sshkey_impl sshkey_ecdsa_sk_impl;
extern const struct sshkey_impl sshkey_ecdsa_sk_cert_impl;
extern const struct sshkey_impl sshkey_ecdsa_sk_webauthn_impl;
# endif /* ENABLE_SK */
extern const struct sshkey_impl sshkey_ecdsa_nistp256_impl;
extern const struct sshkey_impl sshkey_ecdsa_nistp256_cert_impl;
extern const struct sshkey_impl sshkey_ecdsa_nistp384_impl;
extern const struct sshkey_impl sshkey_ecdsa_nistp384_cert_impl;
# ifdef OPENSSL_HAS_NISTP521
extern const struct sshkey_impl sshkey_ecdsa_nistp521_impl;
extern const struct sshkey_impl sshkey_ecdsa_nistp521_cert_impl;
# endif /* OPENSSL_HAS_NISTP521 */
# endif /* OPENSSL_HAS_ECC */
extern const struct sshkey_impl sshkey_rsa_impl;
extern const struct sshkey_impl sshkey_rsa_cert_impl;
extern const struct sshkey_impl sshkey_rsa_sha256_impl;
extern const struct sshkey_impl sshkey_rsa_sha256_cert_impl;
extern const struct sshkey_impl sshkey_rsa_sha512_impl;
extern const struct sshkey_impl sshkey_rsa_sha512_cert_impl;
# ifdef WITH_DSA
extern const struct sshkey_impl sshkey_dss_impl;
extern const struct sshkey_impl sshkey_dsa_cert_impl;
# endif
#endif /* WITH_OPENSSL */
#ifdef WITH_XMSS
extern const struct sshkey_impl sshkey_xmss_impl;
extern const struct sshkey_impl sshkey_xmss_cert_impl;
#endif
const struct sshkey_impl * const keyimpls[] = {
&sshkey_ed25519_impl,
&sshkey_ed25519_cert_impl,
#ifdef ENABLE_SK
&sshkey_ed25519_sk_impl,
&sshkey_ed25519_sk_cert_impl,
#endif
#ifdef WITH_OPENSSL
# ifdef OPENSSL_HAS_ECC
&sshkey_ecdsa_nistp256_impl,
&sshkey_ecdsa_nistp256_cert_impl,
&sshkey_ecdsa_nistp384_impl,
&sshkey_ecdsa_nistp384_cert_impl,
# ifdef OPENSSL_HAS_NISTP521
&sshkey_ecdsa_nistp521_impl,
&sshkey_ecdsa_nistp521_cert_impl,
# endif /* OPENSSL_HAS_NISTP521 */
# ifdef ENABLE_SK
&sshkey_ecdsa_sk_impl,
&sshkey_ecdsa_sk_cert_impl,
&sshkey_ecdsa_sk_webauthn_impl,
# endif /* ENABLE_SK */
# endif /* OPENSSL_HAS_ECC */
# ifdef WITH_DSA
&sshkey_dss_impl,
&sshkey_dsa_cert_impl,
# endif
&sshkey_rsa_impl,
&sshkey_rsa_cert_impl,
&sshkey_rsa_sha256_impl,
&sshkey_rsa_sha256_cert_impl,
&sshkey_rsa_sha512_impl,
&sshkey_rsa_sha512_cert_impl,
#endif /* WITH_OPENSSL */
#ifdef WITH_XMSS
&sshkey_xmss_impl,
&sshkey_xmss_cert_impl,
#endif
NULL
};
static const struct sshkey_impl *
sshkey_impl_from_type(int type)
{
int i;
for (i = 0; keyimpls[i] != NULL; i++) {
if (keyimpls[i]->type == type)
return keyimpls[i];
}
return NULL;
}
static const struct sshkey_impl *
sshkey_impl_from_type_nid(int type, int nid)
{
int i;
for (i = 0; keyimpls[i] != NULL; i++) {
if (keyimpls[i]->type == type &&
(keyimpls[i]->nid == 0 || keyimpls[i]->nid == nid))
return keyimpls[i];
}
return NULL;
}
static const struct sshkey_impl *
sshkey_impl_from_key(const struct sshkey *k)
{
if (k == NULL)
return NULL;
return sshkey_impl_from_type_nid(k->type, k->ecdsa_nid);
}
const char *
sshkey_type(const struct sshkey *k)
{
const struct sshkey_impl *impl;
if ((impl = sshkey_impl_from_key(k)) == NULL)
return "unknown";
return impl->shortname;
}
static const char *
sshkey_ssh_name_from_type_nid(int type, int nid)
{
const struct sshkey_impl *impl;
if ((impl = sshkey_impl_from_type_nid(type, nid)) == NULL)
return "ssh-unknown";
return impl->name;
}
int
sshkey_type_is_cert(int type)
{
const struct sshkey_impl *impl;
if ((impl = sshkey_impl_from_type(type)) == NULL)
return 0;
return impl->cert;
}
const char *
sshkey_ssh_name(const struct sshkey *k)
{
return sshkey_ssh_name_from_type_nid(k->type, k->ecdsa_nid);
}
const char *
sshkey_ssh_name_plain(const struct sshkey *k)
{
return sshkey_ssh_name_from_type_nid(sshkey_type_plain(k->type),
k->ecdsa_nid);
}
int
sshkey_type_from_name(const char *name)
{
int i;
const struct sshkey_impl *impl;
for (i = 0; keyimpls[i] != NULL; i++) {
impl = keyimpls[i];
/* Only allow shortname matches for plain key types */
if ((impl->name != NULL && strcmp(name, impl->name) == 0) ||
(!impl->cert && strcasecmp(impl->shortname, name) == 0))
return impl->type;
}
return KEY_UNSPEC;
}
static int
key_type_is_ecdsa_variant(int type)
{
switch (type) {
case KEY_ECDSA:
case KEY_ECDSA_CERT:
case KEY_ECDSA_SK:
case KEY_ECDSA_SK_CERT:
return 1;
}
return 0;
}
int
sshkey_ecdsa_nid_from_name(const char *name)
{
int i;
for (i = 0; keyimpls[i] != NULL; i++) {
if (!key_type_is_ecdsa_variant(keyimpls[i]->type))
continue;
if (keyimpls[i]->name != NULL &&
strcmp(name, keyimpls[i]->name) == 0)
return keyimpls[i]->nid;
}
return -1;
}
int
sshkey_match_keyname_to_sigalgs(const char *keyname, const char *sigalgs)
{
int ktype;
if (sigalgs == NULL || *sigalgs == '\0' ||
(ktype = sshkey_type_from_name(keyname)) == KEY_UNSPEC)
return 0;
else if (ktype == KEY_RSA) {
return match_pattern_list("ssh-rsa", sigalgs, 0) == 1 ||
match_pattern_list("rsa-sha2-256", sigalgs, 0) == 1 ||
match_pattern_list("rsa-sha2-512", sigalgs, 0) == 1;
} else if (ktype == KEY_RSA_CERT) {
return match_pattern_list("ssh-rsa-cert-v01@openssh.com",
sigalgs, 0) == 1 ||
match_pattern_list("rsa-sha2-256-cert-v01@openssh.com",
sigalgs, 0) == 1 ||
match_pattern_list("rsa-sha2-512-cert-v01@openssh.com",
sigalgs, 0) == 1;
} else
return match_pattern_list(keyname, sigalgs, 0) == 1;
}
char *
sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep)
{
char *tmp, *ret = NULL;
size_t i, nlen, rlen = 0;
const struct sshkey_impl *impl;
for (i = 0; keyimpls[i] != NULL; i++) {
impl = keyimpls[i];
if (impl->name == NULL)
continue;
if (!include_sigonly && impl->sigonly)
continue;
if ((certs_only && !impl->cert) || (plain_only && impl->cert))
continue;
if (ret != NULL)
ret[rlen++] = sep;
nlen = strlen(impl->name);
if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
free(ret);
return NULL;
}
ret = tmp;
memcpy(ret + rlen, impl->name, nlen + 1);
rlen += nlen;
}
return ret;
}
int
sshkey_names_valid2(const char *names, int allow_wildcard, int plain_only)
{
char *s, *cp, *p;
const struct sshkey_impl *impl;
int i, type;
if (names == NULL || strcmp(names, "") == 0)
return 0;
if ((s = cp = strdup(names)) == NULL)
return 0;
for ((p = strsep(&cp, ",")); p && *p != '\0';
(p = strsep(&cp, ","))) {
type = sshkey_type_from_name(p);
if (type == KEY_UNSPEC) {
if (allow_wildcard) {
/*
* Try matching key types against the string.
* If any has a positive or negative match then
* the component is accepted.
*/
impl = NULL;
for (i = 0; keyimpls[i] != NULL; i++) {
if (match_pattern_list(
keyimpls[i]->name, p, 0) != 0) {
impl = keyimpls[i];
break;
}
}
if (impl != NULL)
continue;
}
free(s);
return 0;
} else if (plain_only && sshkey_type_is_cert(type)) {
free(s);
return 0;
}
}
free(s);
return 1;
}
u_int
sshkey_size(const struct sshkey *k)
{
const struct sshkey_impl *impl;
if ((impl = sshkey_impl_from_key(k)) == NULL)
return 0;
if (impl->funcs->size != NULL)
return impl->funcs->size(k);
return impl->keybits;
}
static int
sshkey_type_is_valid_ca(int type)
{
const struct sshkey_impl *impl;
if ((impl = sshkey_impl_from_type(type)) == NULL)
return 0;
/* All non-certificate types may act as CAs */
return !impl->cert;
}
int
sshkey_is_cert(const struct sshkey *k)
{
if (k == NULL)
return 0;
return sshkey_type_is_cert(k->type);
}
int
sshkey_is_sk(const struct sshkey *k)
{
if (k == NULL)
return 0;
switch (sshkey_type_plain(k->type)) {
case KEY_ECDSA_SK:
case KEY_ED25519_SK:
return 1;
default:
return 0;
}
}
/* Return the cert-less equivalent to a certified key type */
int
sshkey_type_plain(int type)
{
switch (type) {
case KEY_RSA_CERT:
return KEY_RSA;
case KEY_DSA_CERT:
return KEY_DSA;
case KEY_ECDSA_CERT:
return KEY_ECDSA;
case KEY_ECDSA_SK_CERT:
return KEY_ECDSA_SK;
case KEY_ED25519_CERT:
return KEY_ED25519;
case KEY_ED25519_SK_CERT:
return KEY_ED25519_SK;
case KEY_XMSS_CERT:
return KEY_XMSS;
default:
return type;
}
}
/* Return the cert equivalent to a plain key type */
static int
sshkey_type_certified(int type)
{
switch (type) {
case KEY_RSA:
return KEY_RSA_CERT;
case KEY_DSA:
return KEY_DSA_CERT;
case KEY_ECDSA:
return KEY_ECDSA_CERT;
case KEY_ECDSA_SK:
return KEY_ECDSA_SK_CERT;
case KEY_ED25519:
return KEY_ED25519_CERT;
case KEY_ED25519_SK:
return KEY_ED25519_SK_CERT;
case KEY_XMSS:
return KEY_XMSS_CERT;
default:
return -1;
}
}
#ifdef WITH_OPENSSL
/* XXX: these are really begging for a table-driven approach */
int
sshkey_curve_name_to_nid(const char *name)
{
if (strcmp(name, "nistp256") == 0)
return NID_X9_62_prime256v1;
else if (strcmp(name, "nistp384") == 0)
return NID_secp384r1;
# ifdef OPENSSL_HAS_NISTP521
else if (strcmp(name, "nistp521") == 0)
return NID_secp521r1;
# endif /* OPENSSL_HAS_NISTP521 */
else
return -1;
}
u_int
sshkey_curve_nid_to_bits(int nid)
{
switch (nid) {
case NID_X9_62_prime256v1:
return 256;
case NID_secp384r1:
return 384;
# ifdef OPENSSL_HAS_NISTP521
case NID_secp521r1:
return 521;
# endif /* OPENSSL_HAS_NISTP521 */
default:
return 0;
}
}
int
sshkey_ecdsa_bits_to_nid(int bits)
{
switch (bits) {
case 256:
return NID_X9_62_prime256v1;
case 384:
return NID_secp384r1;
# ifdef OPENSSL_HAS_NISTP521
case 521:
return NID_secp521r1;
# endif /* OPENSSL_HAS_NISTP521 */
default:
return -1;
}
}
const char *
sshkey_curve_nid_to_name(int nid)
{
switch (nid) {
case NID_X9_62_prime256v1:
return "nistp256";
case NID_secp384r1:
return "nistp384";
# ifdef OPENSSL_HAS_NISTP521
case NID_secp521r1:
return "nistp521";
# endif /* OPENSSL_HAS_NISTP521 */
default:
return NULL;
}
}
int
sshkey_ec_nid_to_hash_alg(int nid)
{
int kbits = sshkey_curve_nid_to_bits(nid);
if (kbits <= 0)
return -1;
/* RFC5656 section 6.2.1 */
if (kbits <= 256)
return SSH_DIGEST_SHA256;
else if (kbits <= 384)
return SSH_DIGEST_SHA384;
else
return SSH_DIGEST_SHA512;
}
#endif /* WITH_OPENSSL */
static void
cert_free(struct sshkey_cert *cert)
{
u_int i;
if (cert == NULL)
return;
sshbuf_free(cert->certblob);
sshbuf_free(cert->critical);
sshbuf_free(cert->extensions);
free(cert->key_id);
for (i = 0; i < cert->nprincipals; i++)
free(cert->principals[i]);
free(cert->principals);
sshkey_free(cert->signature_key);
free(cert->signature_type);
freezero(cert, sizeof(*cert));
}
static struct sshkey_cert *
cert_new(void)
{
struct sshkey_cert *cert;
if ((cert = calloc(1, sizeof(*cert))) == NULL)
return NULL;
if ((cert->certblob = sshbuf_new()) == NULL ||
(cert->critical = sshbuf_new()) == NULL ||
(cert->extensions = sshbuf_new()) == NULL) {
cert_free(cert);
return NULL;
}
cert->key_id = NULL;
cert->principals = NULL;
cert->signature_key = NULL;
cert->signature_type = NULL;
return cert;
}
struct sshkey *
sshkey_new(int type)
{
struct sshkey *k;
const struct sshkey_impl *impl = NULL;
if (type != KEY_UNSPEC &&
(impl = sshkey_impl_from_type(type)) == NULL)
return NULL;
/* All non-certificate types may act as CAs */
if ((k = calloc(1, sizeof(*k))) == NULL)
return NULL;
k->type = type;
k->ecdsa_nid = -1;
if (impl != NULL && impl->funcs->alloc != NULL) {
if (impl->funcs->alloc(k) != 0) {
free(k);
return NULL;
}
}
if (sshkey_is_cert(k)) {
if ((k->cert = cert_new()) == NULL) {
sshkey_free(k);
return NULL;
}
}
return k;
}
/* Frees common FIDO fields */
void
sshkey_sk_cleanup(struct sshkey *k)
{
free(k->sk_application);
sshbuf_free(k->sk_key_handle);
sshbuf_free(k->sk_reserved);
k->sk_application = NULL;
k->sk_key_handle = k->sk_reserved = NULL;
}
static void
sshkey_free_contents(struct sshkey *k)
{
const struct sshkey_impl *impl;
if (k == NULL)
return;
if ((impl = sshkey_impl_from_type(k->type)) != NULL &&
impl->funcs->cleanup != NULL)
impl->funcs->cleanup(k);
if (sshkey_is_cert(k))
cert_free(k->cert);
freezero(k->shielded_private, k->shielded_len);
freezero(k->shield_prekey, k->shield_prekey_len);
}
void
sshkey_free(struct sshkey *k)
{
sshkey_free_contents(k);
freezero(k, sizeof(*k));
}
static int
cert_compare(struct sshkey_cert *a, struct sshkey_cert *b)
{
if (a == NULL && b == NULL)
return 1;
if (a == NULL || b == NULL)
return 0;
if (sshbuf_len(a->certblob) != sshbuf_len(b->certblob))
return 0;
if (timingsafe_bcmp(sshbuf_ptr(a->certblob), sshbuf_ptr(b->certblob),
sshbuf_len(a->certblob)) != 0)
return 0;
return 1;
}
/* Compares FIDO-specific pubkey fields only */
int
sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b)
{
if (a->sk_application == NULL || b->sk_application == NULL)
return 0;
if (strcmp(a->sk_application, b->sk_application) != 0)
return 0;
return 1;
}
/*
* Compare public portions of key only, allowing comparisons between
* certificates and plain keys too.
*/
int
sshkey_equal_public(const struct sshkey *a, const struct sshkey *b)
{
const struct sshkey_impl *impl;
if (a == NULL || b == NULL ||
sshkey_type_plain(a->type) != sshkey_type_plain(b->type))
return 0;
if ((impl = sshkey_impl_from_type(a->type)) == NULL)
return 0;
return impl->funcs->equal(a, b);
}
int
sshkey_equal(const struct sshkey *a, const struct sshkey *b)
{
if (a == NULL || b == NULL || a->type != b->type)
return 0;
if (sshkey_is_cert(a)) {
if (!cert_compare(a->cert, b->cert))
return 0;
}
return sshkey_equal_public(a, b);
}
/* Serialise common FIDO key parts */
int
sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b)
{
int r;
if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0)
return r;
return 0;
}
static int
to_blob_buf(const struct sshkey *key, struct sshbuf *b, int force_plain,
enum sshkey_serialize_rep opts)
{
int type, ret = SSH_ERR_INTERNAL_ERROR;
const char *typename;
const struct sshkey_impl *impl;
if (key == NULL)
return SSH_ERR_INVALID_ARGUMENT;
type = force_plain ? sshkey_type_plain(key->type) : key->type;
if (sshkey_type_is_cert(type)) {
if (key->cert == NULL)
return SSH_ERR_EXPECTED_CERT;
if (sshbuf_len(key->cert->certblob) == 0)
return SSH_ERR_KEY_LACKS_CERTBLOB;
/* Use the existing blob */
if ((ret = sshbuf_putb(b, key->cert->certblob)) != 0)
return ret;
return 0;
}
if ((impl = sshkey_impl_from_type(type)) == NULL)
return SSH_ERR_KEY_TYPE_UNKNOWN;
typename = sshkey_ssh_name_from_type_nid(type, key->ecdsa_nid);
if ((ret = sshbuf_put_cstring(b, typename)) != 0)
return ret;
return impl->funcs->serialize_public(key, b, opts);
}
int
sshkey_putb(const struct sshkey *key, struct sshbuf *b)
{
return to_blob_buf(key, b, 0, SSHKEY_SERIALIZE_DEFAULT);
}
int
sshkey_puts_opts(const struct sshkey *key, struct sshbuf *b,
enum sshkey_serialize_rep opts)
{
struct sshbuf *tmp;
int r;
if ((tmp = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
r = to_blob_buf(key, tmp, 0, opts);
if (r == 0)
r = sshbuf_put_stringb(b, tmp);
sshbuf_free(tmp);
return r;
}
int
sshkey_puts(const struct sshkey *key, struct sshbuf *b)
{
return sshkey_puts_opts(key, b, SSHKEY_SERIALIZE_DEFAULT);
}
int
sshkey_putb_plain(const struct sshkey *key, struct sshbuf *b)
{
return to_blob_buf(key, b, 1, SSHKEY_SERIALIZE_DEFAULT);
}
static int
to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp, int force_plain,
enum sshkey_serialize_rep opts)
{
int ret = SSH_ERR_INTERNAL_ERROR;
size_t len;
struct sshbuf *b = NULL;
if (lenp != NULL)
*lenp = 0;
if (blobp != NULL)
*blobp = NULL;
if ((b = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((ret = to_blob_buf(key, b, force_plain, opts)) != 0)
goto out;
len = sshbuf_len(b);
if (lenp != NULL)
*lenp = len;
if (blobp != NULL) {
if ((*blobp = malloc(len)) == NULL) {
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
memcpy(*blobp, sshbuf_ptr(b), len);
}
ret = 0;
out:
sshbuf_free(b);
return ret;
}
int
sshkey_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
{
return to_blob(key, blobp, lenp, 0, SSHKEY_SERIALIZE_DEFAULT);
}
int
sshkey_plain_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
{
return to_blob(key, blobp, lenp, 1, SSHKEY_SERIALIZE_DEFAULT);
}
int
sshkey_fingerprint_raw(const struct sshkey *k, int dgst_alg,
u_char **retp, size_t *lenp)
{
u_char *blob = NULL, *ret = NULL;
size_t blob_len = 0;
int r = SSH_ERR_INTERNAL_ERROR;
if (retp != NULL)
*retp = NULL;
if (lenp != NULL)
*lenp = 0;
if (ssh_digest_bytes(dgst_alg) == 0) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if ((r = to_blob(k, &blob, &blob_len, 1, SSHKEY_SERIALIZE_DEFAULT))
!= 0)
goto out;
if ((ret = calloc(1, SSH_DIGEST_MAX_LENGTH)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = ssh_digest_memory(dgst_alg, blob, blob_len,
ret, SSH_DIGEST_MAX_LENGTH)) != 0)
goto out;
/* success */
if (retp != NULL) {
*retp = ret;
ret = NULL;
}
if (lenp != NULL)
*lenp = ssh_digest_bytes(dgst_alg);
r = 0;
out:
free(ret);
if (blob != NULL)
freezero(blob, blob_len);
return r;
}
static char *
fingerprint_b64(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
{
char *ret;
size_t plen = strlen(alg) + 1;
size_t rlen = ((dgst_raw_len + 2) / 3) * 4 + plen + 1;
if (dgst_raw_len > 65536 || (ret = calloc(1, rlen)) == NULL)
return NULL;
strlcpy(ret, alg, rlen);
strlcat(ret, ":", rlen);
if (dgst_raw_len == 0)
return ret;
if (b64_ntop(dgst_raw, dgst_raw_len, ret + plen, rlen - plen) == -1) {
freezero(ret, rlen);
return NULL;
}
/* Trim padding characters from end */
ret[strcspn(ret, "=")] = '\0';
return ret;
}
static char *
fingerprint_hex(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
{
char *retval, hex[5];
size_t i, rlen = dgst_raw_len * 3 + strlen(alg) + 2;
if (dgst_raw_len > 65536 || (retval = calloc(1, rlen)) == NULL)
return NULL;
strlcpy(retval, alg, rlen);
strlcat(retval, ":", rlen);
for (i = 0; i < dgst_raw_len; i++) {
snprintf(hex, sizeof(hex), "%s%02x",
i > 0 ? ":" : "", dgst_raw[i]);
strlcat(retval, hex, rlen);
}
return retval;
}
static char *
fingerprint_bubblebabble(u_char *dgst_raw, size_t dgst_raw_len)
{
char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
u_int i, j = 0, rounds, seed = 1;
char *retval;
rounds = (dgst_raw_len / 2) + 1;
if ((retval = calloc(rounds, 6)) == NULL)
return NULL;
retval[j++] = 'x';
for (i = 0; i < rounds; i++) {
u_int idx0, idx1, idx2, idx3, idx4;
if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) {
idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) +
seed) % 6;
idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15;
idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) +
(seed / 6)) % 6;
retval[j++] = vowels[idx0];
retval[j++] = consonants[idx1];
retval[j++] = vowels[idx2];
if ((i + 1) < rounds) {
idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15;
idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15;
retval[j++] = consonants[idx3];
retval[j++] = '-';
retval[j++] = consonants[idx4];
seed = ((seed * 5) +
((((u_int)(dgst_raw[2 * i])) * 7) +
((u_int)(dgst_raw[(2 * i) + 1])))) % 36;
}
} else {
idx0 = seed % 6;
idx1 = 16;
idx2 = seed / 6;
retval[j++] = vowels[idx0];
retval[j++] = consonants[idx1];
retval[j++] = vowels[idx2];
}
}
retval[j++] = 'x';
retval[j++] = '\0';
return retval;
}
/*
* Draw an ASCII-Art representing the fingerprint so human brain can
* profit from its built-in pattern recognition ability.
* This technique is called "random art" and can be found in some
* scientific publications like this original paper:
*
* "Hash Visualization: a New Technique to improve Real-World Security",
* Perrig A. and Song D., 1999, International Workshop on Cryptographic
* Techniques and E-Commerce (CrypTEC '99)
* sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
*
* The subject came up in a talk by Dan Kaminsky, too.
*
* If you see the picture is different, the key is different.
* If the picture looks the same, you still know nothing.
*
* The algorithm used here is a worm crawling over a discrete plane,
* leaving a trace (augmenting the field) everywhere it goes.
* Movement is taken from dgst_raw 2bit-wise. Bumping into walls
* makes the respective movement vector be ignored for this turn.
* Graphs are not unambiguous, because circles in graphs can be
* walked in either direction.
*/
/*
* Field sizes for the random art. Have to be odd, so the starting point
* can be in the exact middle of the picture, and FLDBASE should be >=8 .
* Else pictures would be too dense, and drawing the frame would
* fail, too, because the key type would not fit in anymore.
*/
#define FLDBASE 8
#define FLDSIZE_Y (FLDBASE + 1)
#define FLDSIZE_X (FLDBASE * 2 + 1)
static char *
fingerprint_randomart(const char *alg, u_char *dgst_raw, size_t dgst_raw_len,
const struct sshkey *k)
{
/*
* Chars to be used after each other every time the worm
* intersects with itself. Matter of taste.
*/
char *augmentation_string = " .o+=*BOX@%&#/^SE";
char *retval, *p, title[FLDSIZE_X], hash[FLDSIZE_X];
u_char field[FLDSIZE_X][FLDSIZE_Y];
size_t i, tlen, hlen;
u_int b;
int x, y, r;
size_t len = strlen(augmentation_string) - 1;
if ((retval = calloc((FLDSIZE_X + 3), (FLDSIZE_Y + 2))) == NULL)
return NULL;
/* initialize field */
memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char));
x = FLDSIZE_X / 2;
y = FLDSIZE_Y / 2;
/* process raw key */
for (i = 0; i < dgst_raw_len; i++) {
int input;
/* each byte conveys four 2-bit move commands */
input = dgst_raw[i];
for (b = 0; b < 4; b++) {
/* evaluate 2 bit, rest is shifted later */
x += (input & 0x1) ? 1 : -1;
y += (input & 0x2) ? 1 : -1;
/* assure we are still in bounds */
x = MAXIMUM(x, 0);
y = MAXIMUM(y, 0);
x = MINIMUM(x, FLDSIZE_X - 1);
y = MINIMUM(y, FLDSIZE_Y - 1);
/* augment the field */
if (field[x][y] < len - 2)
field[x][y]++;
input = input >> 2;
}
}
/* mark starting point and end point*/
field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1;
field[x][y] = len;
/* assemble title */
r = snprintf(title, sizeof(title), "[%s %u]",
sshkey_type(k), sshkey_size(k));
/* If [type size] won't fit, then try [type]; fits "[ED25519-CERT]" */
if (r < 0 || r > (int)sizeof(title))
r = snprintf(title, sizeof(title), "[%s]", sshkey_type(k));
tlen = (r <= 0) ? 0 : strlen(title);
/* assemble hash ID. */
r = snprintf(hash, sizeof(hash), "[%s]", alg);
hlen = (r <= 0) ? 0 : strlen(hash);
/* output upper border */
p = retval;
*p++ = '+';
for (i = 0; i < (FLDSIZE_X - tlen) / 2; i++)
*p++ = '-';
memcpy(p, title, tlen);
p += tlen;
for (i += tlen; i < FLDSIZE_X; i++)
*p++ = '-';
*p++ = '+';
*p++ = '\n';
/* output content */
for (y = 0; y < FLDSIZE_Y; y++) {
*p++ = '|';
for (x = 0; x < FLDSIZE_X; x++)
*p++ = augmentation_string[MINIMUM(field[x][y], len)];
*p++ = '|';
*p++ = '\n';
}
/* output lower border */
*p++ = '+';
for (i = 0; i < (FLDSIZE_X - hlen) / 2; i++)
*p++ = '-';
memcpy(p, hash, hlen);
p += hlen;
for (i += hlen; i < FLDSIZE_X; i++)
*p++ = '-';
*p++ = '+';
return retval;
}
char *
sshkey_fingerprint(const struct sshkey *k, int dgst_alg,
enum sshkey_fp_rep dgst_rep)
{
char *retval = NULL;
u_char *dgst_raw;
size_t dgst_raw_len;
if (sshkey_fingerprint_raw(k, dgst_alg, &dgst_raw, &dgst_raw_len) != 0)
return NULL;
switch (dgst_rep) {
case SSH_FP_DEFAULT:
if (dgst_alg == SSH_DIGEST_MD5) {
retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
dgst_raw, dgst_raw_len);
} else {
retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
dgst_raw, dgst_raw_len);
}
break;
case SSH_FP_HEX:
retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
dgst_raw, dgst_raw_len);
break;
case SSH_FP_BASE64:
retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
dgst_raw, dgst_raw_len);
break;
case SSH_FP_BUBBLEBABBLE:
retval = fingerprint_bubblebabble(dgst_raw, dgst_raw_len);
break;
case SSH_FP_RANDOMART:
retval = fingerprint_randomart(ssh_digest_alg_name(dgst_alg),
dgst_raw, dgst_raw_len, k);
break;
default:
freezero(dgst_raw, dgst_raw_len);
return NULL;
}
freezero(dgst_raw, dgst_raw_len);
return retval;
}
static int
peek_type_nid(const char *s, size_t l, int *nid)
{
const struct sshkey_impl *impl;
int i;
for (i = 0; keyimpls[i] != NULL; i++) {
impl = keyimpls[i];
if (impl->name == NULL || strlen(impl->name) != l)
continue;
if (memcmp(s, impl->name, l) == 0) {
*nid = -1;
if (key_type_is_ecdsa_variant(impl->type))
*nid = impl->nid;
return impl->type;
}
}
return KEY_UNSPEC;
}
/* XXX this can now be made const char * */
int
sshkey_read(struct sshkey *ret, char **cpp)
{
struct sshkey *k;
char *cp, *blobcopy;
size_t space;
int r, type, curve_nid = -1;
struct sshbuf *blob;
if (ret == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if (ret->type != KEY_UNSPEC && sshkey_impl_from_type(ret->type) == NULL)
return SSH_ERR_INVALID_ARGUMENT;
/* Decode type */
cp = *cpp;
space = strcspn(cp, " \t");
if (space == strlen(cp))
return SSH_ERR_INVALID_FORMAT;
if ((type = peek_type_nid(cp, space, &curve_nid)) == KEY_UNSPEC)
return SSH_ERR_INVALID_FORMAT;
/* skip whitespace */
for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
;
if (*cp == '\0')
return SSH_ERR_INVALID_FORMAT;
if (ret->type != KEY_UNSPEC && ret->type != type)
return SSH_ERR_KEY_TYPE_MISMATCH;
if ((blob = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
/* find end of keyblob and decode */
space = strcspn(cp, " \t");
if ((blobcopy = strndup(cp, space)) == NULL) {
sshbuf_free(blob);
return SSH_ERR_ALLOC_FAIL;
}
if ((r = sshbuf_b64tod(blob, blobcopy)) != 0) {
free(blobcopy);
sshbuf_free(blob);
return r;
}
free(blobcopy);
if ((r = sshkey_fromb(blob, &k)) != 0) {
sshbuf_free(blob);
return r;
}
sshbuf_free(blob);
/* skip whitespace and leave cp at start of comment */
for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
;
/* ensure type of blob matches type at start of line */
if (k->type != type) {
sshkey_free(k);
return SSH_ERR_KEY_TYPE_MISMATCH;
}
if (key_type_is_ecdsa_variant(type) && curve_nid != k->ecdsa_nid) {
sshkey_free(k);
return SSH_ERR_EC_CURVE_MISMATCH;
}
/* Fill in ret from parsed key */
sshkey_free_contents(ret);
*ret = *k;
freezero(k, sizeof(*k));
/* success */
*cpp = cp;
return 0;
}
int
sshkey_to_base64(const struct sshkey *key, char **b64p)
{
int r = SSH_ERR_INTERNAL_ERROR;
struct sshbuf *b = NULL;
char *uu = NULL;
if (b64p != NULL)
*b64p = NULL;
if ((b = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshkey_putb(key, b)) != 0)
goto out;
if ((uu = sshbuf_dtob64_string(b, 0)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
/* Success */
if (b64p != NULL) {
*b64p = uu;
uu = NULL;
}
r = 0;
out:
sshbuf_free(b);
free(uu);
return r;
}
int
sshkey_format_text(const struct sshkey *key, struct sshbuf *b)
{
int r = SSH_ERR_INTERNAL_ERROR;
char *uu = NULL;
if ((r = sshkey_to_base64(key, &uu)) != 0)
goto out;
if ((r = sshbuf_putf(b, "%s %s",
sshkey_ssh_name(key), uu)) != 0)
goto out;
r = 0;
out:
free(uu);
return r;
}
int
sshkey_write(const struct sshkey *key, FILE *f)
{
struct sshbuf *b = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
if ((b = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshkey_format_text(key, b)) != 0)
goto out;
if (fwrite(sshbuf_ptr(b), sshbuf_len(b), 1, f) != 1) {
if (feof(f))
errno = EPIPE;
r = SSH_ERR_SYSTEM_ERROR;
goto out;
}
/* Success */
r = 0;
out:
sshbuf_free(b);
return r;
}
const char *
sshkey_cert_type(const struct sshkey *k)
{
switch (k->cert->type) {
case SSH2_CERT_TYPE_USER:
return "user";
case SSH2_CERT_TYPE_HOST:
return "host";
default:
return "unknown";
}
}
int
sshkey_check_rsa_length(const struct sshkey *k, int min_size)
{
#ifdef WITH_OPENSSL
const BIGNUM *rsa_n;
int nbits;
if (k == NULL || k->rsa == NULL ||
(k->type != KEY_RSA && k->type != KEY_RSA_CERT))
return 0;
RSA_get0_key(k->rsa, &rsa_n, NULL, NULL);
nbits = BN_num_bits(rsa_n);
if (nbits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
(min_size > 0 && nbits < min_size))
return SSH_ERR_KEY_LENGTH;
#endif /* WITH_OPENSSL */
return 0;
}
#ifdef WITH_OPENSSL
# ifdef OPENSSL_HAS_ECC
int
sshkey_ecdsa_key_to_nid(EC_KEY *k)
{
EC_GROUP *eg;
int nids[] = {
NID_X9_62_prime256v1,
NID_secp384r1,
# ifdef OPENSSL_HAS_NISTP521
NID_secp521r1,
# endif /* OPENSSL_HAS_NISTP521 */
-1
};
int nid;
u_int i;
const EC_GROUP *g = EC_KEY_get0_group(k);
/*
* The group may be stored in a ASN.1 encoded private key in one of two
* ways: as a "named group", which is reconstituted by ASN.1 object ID
* or explicit group parameters encoded into the key blob. Only the
* "named group" case sets the group NID for us, but we can figure
* it out for the other case by comparing against all the groups that
* are supported.
*/
if ((nid = EC_GROUP_get_curve_name(g)) > 0)
return nid;
for (i = 0; nids[i] != -1; i++) {
if ((eg = EC_GROUP_new_by_curve_name(nids[i])) == NULL)
return -1;
if (EC_GROUP_cmp(g, eg, NULL) == 0)
break;
EC_GROUP_free(eg);
}
if (nids[i] != -1) {
/* Use the group with the NID attached */
EC_GROUP_set_asn1_flag(eg, OPENSSL_EC_NAMED_CURVE);
if (EC_KEY_set_group(k, eg) != 1) {
EC_GROUP_free(eg);
return -1;
}
}
return nids[i];
}
# endif /* OPENSSL_HAS_ECC */
#endif /* WITH_OPENSSL */
int
sshkey_generate(int type, u_int bits, struct sshkey **keyp)
{
struct sshkey *k;
int ret = SSH_ERR_INTERNAL_ERROR;
const struct sshkey_impl *impl;
if (keyp == NULL || sshkey_type_is_cert(type))
return SSH_ERR_INVALID_ARGUMENT;
*keyp = NULL;
if ((impl = sshkey_impl_from_type(type)) == NULL)
return SSH_ERR_KEY_TYPE_UNKNOWN;
if (impl->funcs->generate == NULL)
return SSH_ERR_FEATURE_UNSUPPORTED;
if ((k = sshkey_new(KEY_UNSPEC)) == NULL)
return SSH_ERR_ALLOC_FAIL;
k->type = type;
if ((ret = impl->funcs->generate(k, bits)) != 0) {
sshkey_free(k);
return ret;
}
/* success */
*keyp = k;
return 0;
}
int
sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key)
{
u_int i;
const struct sshkey_cert *from;
struct sshkey_cert *to;
int r = SSH_ERR_INTERNAL_ERROR;
if (to_key == NULL || (from = from_key->cert) == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if ((to = cert_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_putb(to->certblob, from->certblob)) != 0 ||
(r = sshbuf_putb(to->critical, from->critical)) != 0 ||
(r = sshbuf_putb(to->extensions, from->extensions)) != 0)
goto out;
to->serial = from->serial;
to->type = from->type;
if (from->key_id == NULL)
to->key_id = NULL;
else if ((to->key_id = strdup(from->key_id)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
to->valid_after = from->valid_after;
to->valid_before = from->valid_before;
if (from->signature_key == NULL)
to->signature_key = NULL;
else if ((r = sshkey_from_private(from->signature_key,
&to->signature_key)) != 0)
goto out;
if (from->signature_type != NULL &&
(to->signature_type = strdup(from->signature_type)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (from->nprincipals > SSHKEY_CERT_MAX_PRINCIPALS) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if (from->nprincipals > 0) {
if ((to->principals = calloc(from->nprincipals,
sizeof(*to->principals))) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
for (i = 0; i < from->nprincipals; i++) {
to->principals[i] = strdup(from->principals[i]);
if (to->principals[i] == NULL) {
to->nprincipals = i;
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
}
}
to->nprincipals = from->nprincipals;
/* success */
cert_free(to_key->cert);
to_key->cert = to;
to = NULL;
r = 0;
out:
cert_free(to);
return r;
}
int
sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to)
{
/* Append security-key application string */
if ((to->sk_application = strdup(from->sk_application)) == NULL)
return SSH_ERR_ALLOC_FAIL;
return 0;
}
int
sshkey_from_private(const struct sshkey *k, struct sshkey **pkp)
{
struct sshkey *n = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
const struct sshkey_impl *impl;
*pkp = NULL;
if ((impl = sshkey_impl_from_key(k)) == NULL)
return SSH_ERR_KEY_TYPE_UNKNOWN;
if ((n = sshkey_new(k->type)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = impl->funcs->copy_public(k, n)) != 0)
goto out;
if (sshkey_is_cert(k) && (r = sshkey_cert_copy(k, n)) != 0)
goto out;
/* success */
*pkp = n;
n = NULL;
r = 0;
out:
sshkey_free(n);
return r;
}
int
sshkey_is_shielded(struct sshkey *k)
{
return k != NULL && k->shielded_private != NULL;
}
int
sshkey_shield_private(struct sshkey *k)
{
struct sshbuf *prvbuf = NULL;
u_char *prekey = NULL, *enc = NULL, keyiv[SSH_DIGEST_MAX_LENGTH];
struct sshcipher_ctx *cctx = NULL;
const struct sshcipher *cipher;
size_t i, enclen = 0;
struct sshkey *kswap = NULL, tmp;
int r = SSH_ERR_INTERNAL_ERROR;
#ifdef DEBUG_PK
fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
#endif
if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
r = SSH_ERR_INTERNAL_ERROR;
goto out;
}
/* Prepare a random pre-key, and from it an ephemeral key */
if ((prekey = malloc(SSHKEY_SHIELD_PREKEY_LEN)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
arc4random_buf(prekey, SSHKEY_SHIELD_PREKEY_LEN);
if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
prekey, SSHKEY_SHIELD_PREKEY_LEN,
keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
goto out;
#ifdef DEBUG_PK
fprintf(stderr, "%s: key+iv\n", __func__);
sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
stderr);
#endif
if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 1)) != 0)
goto out;
/* Serialise and encrypt the private key using the ephemeral key */
if ((prvbuf = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (sshkey_is_shielded(k) && (r = sshkey_unshield_private(k)) != 0)
goto out;
if ((r = sshkey_private_serialize_opt(k, prvbuf,
SSHKEY_SERIALIZE_SHIELD)) != 0)
goto out;
/* pad to cipher blocksize */
i = 0;
while (sshbuf_len(prvbuf) % cipher_blocksize(cipher)) {
if ((r = sshbuf_put_u8(prvbuf, ++i & 0xff)) != 0)
goto out;
}
#ifdef DEBUG_PK
fprintf(stderr, "%s: serialised\n", __func__);
sshbuf_dump(prvbuf, stderr);
#endif
/* encrypt */
enclen = sshbuf_len(prvbuf);
if ((enc = malloc(enclen)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = cipher_crypt(cctx, 0, enc,
sshbuf_ptr(prvbuf), sshbuf_len(prvbuf), 0, 0)) != 0)
goto out;
#ifdef DEBUG_PK
fprintf(stderr, "%s: encrypted\n", __func__);
sshbuf_dump_data(enc, enclen, stderr);
#endif
/* Make a scrubbed, public-only copy of our private key argument */
if ((r = sshkey_from_private(k, &kswap)) != 0)
goto out;
/* Swap the private key out (it will be destroyed below) */
tmp = *kswap;
*kswap = *k;
*k = tmp;
/* Insert the shielded key into our argument */
k->shielded_private = enc;
k->shielded_len = enclen;
k->shield_prekey = prekey;
k->shield_prekey_len = SSHKEY_SHIELD_PREKEY_LEN;
enc = prekey = NULL; /* transferred */
enclen = 0;
/* preserve key fields that are required for correct operation */
k->sk_flags = kswap->sk_flags;
/* success */
r = 0;
out:
/* XXX behaviour on error - invalidate original private key? */
cipher_free(cctx);
explicit_bzero(keyiv, sizeof(keyiv));
explicit_bzero(&tmp, sizeof(tmp));
freezero(enc, enclen);
freezero(prekey, SSHKEY_SHIELD_PREKEY_LEN);
sshkey_free(kswap);
sshbuf_free(prvbuf);
return r;
}
/* Check deterministic padding after private key */
static int
private2_check_padding(struct sshbuf *decrypted)
{
u_char pad;
size_t i;
int r;
i = 0;
while (sshbuf_len(decrypted)) {
if ((r = sshbuf_get_u8(decrypted, &pad)) != 0)
goto out;
if (pad != (++i & 0xff)) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
}
/* success */
r = 0;
out:
explicit_bzero(&pad, sizeof(pad));
explicit_bzero(&i, sizeof(i));
return r;
}
int
sshkey_unshield_private(struct sshkey *k)
{
struct sshbuf *prvbuf = NULL;
u_char *cp, keyiv[SSH_DIGEST_MAX_LENGTH];
struct sshcipher_ctx *cctx = NULL;
const struct sshcipher *cipher;
struct sshkey *kswap = NULL, tmp;
int r = SSH_ERR_INTERNAL_ERROR;
#ifdef DEBUG_PK
fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
#endif
if (!sshkey_is_shielded(k))
return 0; /* nothing to do */
if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
r = SSH_ERR_INTERNAL_ERROR;
goto out;
}
/* check size of shielded key blob */
if (k->shielded_len < cipher_blocksize(cipher) ||
(k->shielded_len % cipher_blocksize(cipher)) != 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* Calculate the ephemeral key from the prekey */
if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
k->shield_prekey, k->shield_prekey_len,
keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
goto out;
if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0)) != 0)
goto out;
#ifdef DEBUG_PK
fprintf(stderr, "%s: key+iv\n", __func__);
sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
stderr);
#endif
/* Decrypt and parse the shielded private key using the ephemeral key */
if ((prvbuf = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0)
goto out;
/* decrypt */
#ifdef DEBUG_PK
fprintf(stderr, "%s: encrypted\n", __func__);
sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr);
#endif
if ((r = cipher_crypt(cctx, 0, cp,
k->shielded_private, k->shielded_len, 0, 0)) != 0)
goto out;
#ifdef DEBUG_PK
fprintf(stderr, "%s: serialised\n", __func__);
sshbuf_dump(prvbuf, stderr);
#endif
/* Parse private key */
if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0)
goto out;
if ((r = private2_check_padding(prvbuf)) != 0)
goto out;
/* Swap the parsed key back into place */
tmp = *kswap;
*kswap = *k;
*k = tmp;
/* success */
r = 0;
out:
cipher_free(cctx);
explicit_bzero(keyiv, sizeof(keyiv));
explicit_bzero(&tmp, sizeof(tmp));
sshkey_free(kswap);
sshbuf_free(prvbuf);
return r;
}
static int
cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf)
{
struct sshbuf *principals = NULL, *crit = NULL;
struct sshbuf *exts = NULL, *ca = NULL;
u_char *sig = NULL;
size_t signed_len = 0, slen = 0, kidlen = 0;
int ret = SSH_ERR_INTERNAL_ERROR;
/* Copy the entire key blob for verification and later serialisation */
if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0)
return ret;
/* Parse body of certificate up to signature */
if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 ||
(ret = sshbuf_get_u32(b, &key->cert->type)) != 0 ||
(ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 ||
(ret = sshbuf_froms(b, &principals)) != 0 ||
(ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 ||
(ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 ||
(ret = sshbuf_froms(b, &crit)) != 0 ||
(ret = sshbuf_froms(b, &exts)) != 0 ||
(ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 ||
(ret = sshbuf_froms(b, &ca)) != 0) {
/* XXX debug print error for ret */
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* Signature is left in the buffer so we can calculate this length */
signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b);
if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) {
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
if (key->cert->type != SSH2_CERT_TYPE_USER &&
key->cert->type != SSH2_CERT_TYPE_HOST) {
ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE;
goto out;
}
/* Parse principals section */
while (sshbuf_len(principals) > 0) {
char *principal = NULL;
char **oprincipals = NULL;
if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) {
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
if ((ret = sshbuf_get_cstring(principals, &principal,
NULL)) != 0) {
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
oprincipals = key->cert->principals;
key->cert->principals = recallocarray(key->cert->principals,
key->cert->nprincipals, key->cert->nprincipals + 1,
sizeof(*key->cert->principals));
if (key->cert->principals == NULL) {
free(principal);
key->cert->principals = oprincipals;
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
key->cert->principals[key->cert->nprincipals++] = principal;
}
/*
* Stash a copies of the critical options and extensions sections
* for later use.
*/
if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 ||
(exts != NULL &&
(ret = sshbuf_putb(key->cert->extensions, exts)) != 0))
goto out;
/*
* Validate critical options and extensions sections format.
*/
while (sshbuf_len(crit) != 0) {
if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 ||
(ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) {
sshbuf_reset(key->cert->critical);
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
}
while (exts != NULL && sshbuf_len(exts) != 0) {
if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 ||
(ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) {
sshbuf_reset(key->cert->extensions);
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
}
/* Parse CA key and check signature */
if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0) != 0) {
ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
goto out;
}
if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) {
ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
goto out;
}
if ((ret = sshkey_verify(key->cert->signature_key, sig, slen,
sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0, NULL)) != 0)
goto out;
if ((ret = sshkey_get_sigtype(sig, slen,
&key->cert->signature_type)) != 0)
goto out;
/* Success */
ret = 0;
out:
sshbuf_free(ca);
sshbuf_free(crit);
sshbuf_free(exts);
sshbuf_free(principals);
free(sig);
return ret;
}
int
sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key)
{
/* Parse additional security-key application string */
if (sshbuf_get_cstring(b, &key->sk_application, NULL) != 0)
return SSH_ERR_INVALID_FORMAT;
return 0;
}
static int
sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp,
int allow_cert)
{
int type, ret = SSH_ERR_INTERNAL_ERROR;
char *ktype = NULL;
struct sshkey *key = NULL;
struct sshbuf *copy;
const struct sshkey_impl *impl;
#ifdef DEBUG_PK /* XXX */
sshbuf_dump(b, stderr);
#endif
if (keyp != NULL)
*keyp = NULL;
if ((copy = sshbuf_fromb(b)) == NULL) {
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (sshbuf_get_cstring(b, &ktype, NULL) != 0) {
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
type = sshkey_type_from_name(ktype);
if (!allow_cert && sshkey_type_is_cert(type)) {
ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
goto out;
}
if ((impl = sshkey_impl_from_type(type)) == NULL) {
ret = SSH_ERR_KEY_TYPE_UNKNOWN;
goto out;
}
if ((key = sshkey_new(type)) == NULL) {
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (sshkey_type_is_cert(type)) {
/* Skip nonce that precedes all certificates */
if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
}
if ((ret = impl->funcs->deserialize_public(ktype, b, key)) != 0)
goto out;
/* Parse certificate potion */
if (sshkey_is_cert(key) && (ret = cert_parse(b, key, copy)) != 0)
goto out;
if (key != NULL && sshbuf_len(b) != 0) {
ret = SSH_ERR_INVALID_FORMAT;
goto out;
}
ret = 0;
if (keyp != NULL) {
*keyp = key;
key = NULL;
}
out:
sshbuf_free(copy);
sshkey_free(key);
free(ktype);
return ret;
}
int
sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp)
{
struct sshbuf *b;
int r;
if ((b = sshbuf_from(blob, blen)) == NULL)
return SSH_ERR_ALLOC_FAIL;
r = sshkey_from_blob_internal(b, keyp, 1);
sshbuf_free(b);
return r;
}
int
sshkey_fromb(struct sshbuf *b, struct sshkey **keyp)
{
return sshkey_from_blob_internal(b, keyp, 1);
}
int
sshkey_froms(struct sshbuf *buf, struct sshkey **keyp)
{
struct sshbuf *b;
int r;
if ((r = sshbuf_froms(buf, &b)) != 0)
return r;
r = sshkey_from_blob_internal(b, keyp, 1);
sshbuf_free(b);
return r;
}
int
sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep)
{
int r;
struct sshbuf *b = NULL;
char *sigtype = NULL;
if (sigtypep != NULL)
*sigtypep = NULL;
if ((b = sshbuf_from(sig, siglen)) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0)
goto out;
/* success */
if (sigtypep != NULL) {
*sigtypep = sigtype;
sigtype = NULL;
}
r = 0;
out:
free(sigtype);
sshbuf_free(b);
return r;
}
/*
*
* Checks whether a certificate's signature type is allowed.
* Returns 0 (success) if the certificate signature type appears in the
* "allowed" pattern-list, or the key is not a certificate to begin with.
* Otherwise returns a ssherr.h code.
*/
int
sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed)
{
if (key == NULL || allowed == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if (!sshkey_type_is_cert(key->type))
return 0;
if (key->cert == NULL || key->cert->signature_type == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1)
return SSH_ERR_SIGN_ALG_UNSUPPORTED;
return 0;
}
/*
* Returns the expected signature algorithm for a given public key algorithm.
*/
const char *
sshkey_sigalg_by_name(const char *name)
{
const struct sshkey_impl *impl;
int i;
for (i = 0; keyimpls[i] != NULL; i++) {
impl = keyimpls[i];
if (strcmp(impl->name, name) != 0)
continue;
if (impl->sigalg != NULL)
return impl->sigalg;
if (!impl->cert)
return impl->name;
return sshkey_ssh_name_from_type_nid(
sshkey_type_plain(impl->type), impl->nid);
}
return NULL;
}
/*
* Verifies that the signature algorithm appearing inside the signature blob
* matches that which was requested.
*/
int
sshkey_check_sigtype(const u_char *sig, size_t siglen,
const char *requested_alg)
{
const char *expected_alg;
char *sigtype = NULL;
int r;
if (requested_alg == NULL)
return 0;
if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0)
return r;
r = strcmp(expected_alg, sigtype) == 0;
free(sigtype);
return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED;
}
int
sshkey_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)
{
int was_shielded = sshkey_is_shielded(key);
int r2, r = SSH_ERR_INTERNAL_ERROR;
const struct sshkey_impl *impl;
if (sigp != NULL)
*sigp = NULL;
if (lenp != NULL)
*lenp = 0;
if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
return SSH_ERR_INVALID_ARGUMENT;
if ((impl = sshkey_impl_from_key(key)) == NULL)
return SSH_ERR_KEY_TYPE_UNKNOWN;
if ((r = sshkey_unshield_private(key)) != 0)
return r;
if (sshkey_is_sk(key)) {
r = sshsk_sign(sk_provider, key, sigp, lenp, data,
datalen, compat, sk_pin);
} else {
if (impl->funcs->sign == NULL)
r = SSH_ERR_SIGN_ALG_UNSUPPORTED;
else {
r = impl->funcs->sign(key, sigp, lenp, data, datalen,
alg, sk_provider, sk_pin, compat);
}
}
if (was_shielded && (r2 = sshkey_shield_private(key)) != 0)
return r2;
return r;
}
/*
* ssh_key_verify returns 0 for a correct signature and < 0 on error.
* If "alg" specified, then the signature must use that algorithm.
*/
int
sshkey_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)
{
const struct sshkey_impl *impl;
if (detailsp != NULL)
*detailsp = NULL;
if (siglen == 0 || dlen > SSH_KEY_MAX_SIGN_DATA_SIZE)
return SSH_ERR_INVALID_ARGUMENT;
if ((impl = sshkey_impl_from_key(key)) == NULL)
return SSH_ERR_KEY_TYPE_UNKNOWN;
return impl->funcs->verify(key, sig, siglen, data, dlen,
alg, compat, detailsp);
}
/* Convert a plain key to their _CERT equivalent */
int
sshkey_to_certified(struct sshkey *k)
{
int newtype;
if ((newtype = sshkey_type_certified(k->type)) == -1)
return SSH_ERR_INVALID_ARGUMENT;
if ((k->cert = cert_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
k->type = newtype;
return 0;
}
/* Convert a certificate to its raw key equivalent */
int
sshkey_drop_cert(struct sshkey *k)
{
if (!sshkey_type_is_cert(k->type))
return SSH_ERR_KEY_TYPE_UNKNOWN;
cert_free(k->cert);
k->cert = NULL;
k->type = sshkey_type_plain(k->type);
return 0;
}
/* Sign a certified key, (re-)generating the signed certblob. */
int
sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg,
const char *sk_provider, const char *sk_pin,
sshkey_certify_signer *signer, void *signer_ctx)
{
const struct sshkey_impl *impl;
struct sshbuf *principals = NULL;
u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32];
size_t i, ca_len, sig_len;
int ret = SSH_ERR_INTERNAL_ERROR;
struct sshbuf *cert = NULL;
char *sigtype = NULL;
if (k == NULL || k->cert == NULL ||
k->cert->certblob == NULL || ca == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if (!sshkey_is_cert(k))
return SSH_ERR_KEY_TYPE_UNKNOWN;
if (!sshkey_type_is_valid_ca(ca->type))
return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
if ((impl = sshkey_impl_from_key(k)) == NULL)
return SSH_ERR_INTERNAL_ERROR;
/*
* If no alg specified as argument but a signature_type was set,
* then prefer that. If both were specified, then they must match.
*/
if (alg == NULL)
alg = k->cert->signature_type;
else if (k->cert->signature_type != NULL &&
strcmp(alg, k->cert->signature_type) != 0)
return SSH_ERR_INVALID_ARGUMENT;
/*
* If no signing algorithm or signature_type was specified and we're
* using a RSA key, then default to a good signature algorithm.
*/
if (alg == NULL && ca->type == KEY_RSA)
alg = "rsa-sha2-512";
if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0)
return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
cert = k->cert->certblob; /* for readability */
sshbuf_reset(cert);
if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0)
goto out;
/* -v01 certs put nonce first */
arc4random_buf(&nonce, sizeof(nonce));
if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0)
goto out;
/* Public key next */
if ((ret = impl->funcs->serialize_public(k, cert,
SSHKEY_SERIALIZE_DEFAULT)) != 0)
goto out;
/* Then remaining cert fields */
if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 ||
(ret = sshbuf_put_u32(cert, k->cert->type)) != 0 ||
(ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0)
goto out;
if ((principals = sshbuf_new()) == NULL) {
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
for (i = 0; i < k->cert->nprincipals; i++) {
if ((ret = sshbuf_put_cstring(principals,
k->cert->principals[i])) != 0)
goto out;
}
if ((ret = sshbuf_put_stringb(cert, principals)) != 0 ||
(ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 ||
(ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 ||
(ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 ||
(ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 ||
(ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */
(ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0)
goto out;
/* Sign the whole mess */
if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert),
sshbuf_len(cert), alg, sk_provider, sk_pin, 0, signer_ctx)) != 0)
goto out;
/* Check and update signature_type against what was actually used */
if ((ret = sshkey_get_sigtype(sig_blob, sig_len, &sigtype)) != 0)
goto out;
if (alg != NULL && strcmp(alg, sigtype) != 0) {
ret = SSH_ERR_SIGN_ALG_UNSUPPORTED;
goto out;
}
if (k->cert->signature_type == NULL) {
k->cert->signature_type = sigtype;
sigtype = NULL;
}
/* Append signature and we are done */
if ((ret = sshbuf_put_string(cert, sig_blob, sig_len)) != 0)
goto out;
ret = 0;
out:
if (ret != 0)
sshbuf_reset(cert);
free(sig_blob);
free(ca_blob);
free(sigtype);
sshbuf_free(principals);
return ret;
}
static int
default_key_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, void *ctx)
{
if (ctx != NULL)
return SSH_ERR_INVALID_ARGUMENT;
return sshkey_sign(key, sigp, lenp, data, datalen, alg,
sk_provider, sk_pin, compat);
}
int
sshkey_certify(struct sshkey *k, struct sshkey *ca, const char *alg,
const char *sk_provider, const char *sk_pin)
{
return sshkey_certify_custom(k, ca, alg, sk_provider, sk_pin,
default_key_sign, NULL);
}
int
sshkey_cert_check_authority(const struct sshkey *k,
int want_host, int require_principal, int wildcard_pattern,
uint64_t verify_time, const char *name, const char **reason)
{
u_int i, principal_matches;
if (reason == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if (!sshkey_is_cert(k)) {
*reason = "Key is not a certificate";
return SSH_ERR_KEY_CERT_INVALID;
}
if (want_host) {
if (k->cert->type != SSH2_CERT_TYPE_HOST) {
*reason = "Certificate invalid: not a host certificate";
return SSH_ERR_KEY_CERT_INVALID;
}
} else {
if (k->cert->type != SSH2_CERT_TYPE_USER) {
*reason = "Certificate invalid: not a user certificate";
return SSH_ERR_KEY_CERT_INVALID;
}
}
if (verify_time < k->cert->valid_after) {
*reason = "Certificate invalid: not yet valid";
return SSH_ERR_KEY_CERT_INVALID;
}
if (verify_time >= k->cert->valid_before) {
*reason = "Certificate invalid: expired";
return SSH_ERR_KEY_CERT_INVALID;
}
if (k->cert->nprincipals == 0) {
if (require_principal) {
*reason = "Certificate lacks principal list";
return SSH_ERR_KEY_CERT_INVALID;
}
} else if (name != NULL) {
principal_matches = 0;
for (i = 0; i < k->cert->nprincipals; i++) {
if (wildcard_pattern) {
if (match_pattern(k->cert->principals[i],
name)) {
principal_matches = 1;
break;
}
} else if (strcmp(name, k->cert->principals[i]) == 0) {
principal_matches = 1;
break;
}
}
if (!principal_matches) {
*reason = "Certificate invalid: name is not a listed "
"principal";
return SSH_ERR_KEY_CERT_INVALID;
}
}
return 0;
}
int
sshkey_cert_check_authority_now(const struct sshkey *k,
int want_host, int require_principal, int wildcard_pattern,
const char *name, const char **reason)
{
time_t now;
if ((now = time(NULL)) < 0) {
/* yikes - system clock before epoch! */
*reason = "Certificate invalid: not yet valid";
return SSH_ERR_KEY_CERT_INVALID;
}
return sshkey_cert_check_authority(k, want_host, require_principal,
wildcard_pattern, (uint64_t)now, name, reason);
}
int
sshkey_cert_check_host(const struct sshkey *key, const char *host,
int wildcard_principals, const char *ca_sign_algorithms,
const char **reason)
{
int r;
if ((r = sshkey_cert_check_authority_now(key, 1, 0, wildcard_principals,
host, reason)) != 0)
return r;
if (sshbuf_len(key->cert->critical) != 0) {
*reason = "Certificate contains unsupported critical options";
return SSH_ERR_KEY_CERT_INVALID;
}
if (ca_sign_algorithms != NULL &&
(r = sshkey_check_cert_sigtype(key, ca_sign_algorithms)) != 0) {
*reason = "Certificate signed with disallowed algorithm";
return SSH_ERR_KEY_CERT_INVALID;
}
return 0;
}
size_t
sshkey_format_cert_validity(const struct sshkey_cert *cert, char *s, size_t l)
{
char from[32], to[32], ret[128];
*from = *to = '\0';
if (cert->valid_after == 0 &&
cert->valid_before == 0xffffffffffffffffULL)
return strlcpy(s, "forever", l);
if (cert->valid_after != 0)
format_absolute_time(cert->valid_after, from, sizeof(from));
if (cert->valid_before != 0xffffffffffffffffULL)
format_absolute_time(cert->valid_before, to, sizeof(to));
if (cert->valid_after == 0)
snprintf(ret, sizeof(ret), "before %s", to);
else if (cert->valid_before == 0xffffffffffffffffULL)
snprintf(ret, sizeof(ret), "after %s", from);
else
snprintf(ret, sizeof(ret), "from %s to %s", from, to);
return strlcpy(s, ret, l);
}
/* Common serialization for FIDO private keys */
int
sshkey_serialize_private_sk(const struct sshkey *key, struct sshbuf *b)
{
int r;
if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0 ||
(r = sshbuf_put_u8(b, key->sk_flags)) != 0 ||
(r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 ||
(r = sshbuf_put_stringb(b, key->sk_reserved)) != 0)
return r;
return 0;
}
int
sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
enum sshkey_serialize_rep opts)
{
int r = SSH_ERR_INTERNAL_ERROR;
int was_shielded = sshkey_is_shielded(key);
struct sshbuf *b = NULL;
const struct sshkey_impl *impl;
if ((impl = sshkey_impl_from_key(key)) == NULL)
return SSH_ERR_INTERNAL_ERROR;
if ((r = sshkey_unshield_private(key)) != 0)
return r;
if ((b = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_put_cstring(b, sshkey_ssh_name(key))) != 0)
goto out;
if (sshkey_is_cert(key)) {
if (key->cert == NULL ||
sshbuf_len(key->cert->certblob) == 0) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0)
goto out;
}
if ((r = impl->funcs->serialize_private(key, b, opts)) != 0)
goto out;
/*
* success (but we still need to append the output to buf after
* possibly re-shielding the private key)
*/
r = 0;
out:
if (was_shielded)
r = sshkey_shield_private(key);
if (r == 0)
r = sshbuf_putb(buf, b);
sshbuf_free(b);
return r;
}
int
sshkey_private_serialize(struct sshkey *key, struct sshbuf *b)
{
return sshkey_private_serialize_opt(key, b,
SSHKEY_SERIALIZE_DEFAULT);
}
/* Shared deserialization of FIDO private key components */
int
sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k)
{
int r;
if ((k->sk_key_handle = sshbuf_new()) == NULL ||
(k->sk_reserved = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_get_cstring(buf, &k->sk_application, NULL)) != 0 ||
(r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 ||
(r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 ||
(r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0)
return r;
return 0;
}
int
sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
{
const struct sshkey_impl *impl;
char *tname = NULL;
char *expect_sk_application = NULL;
u_char *expect_ed25519_pk = NULL;
struct sshkey *k = NULL;
int type, r = SSH_ERR_INTERNAL_ERROR;
if (kp != NULL)
*kp = NULL;
if ((r = sshbuf_get_cstring(buf, &tname, NULL)) != 0)
goto out;
type = sshkey_type_from_name(tname);
if (sshkey_type_is_cert(type)) {
/*
* Certificate key private keys begin with the certificate
* itself. Make sure this matches the type of the enclosing
* private key.
*/
if ((r = sshkey_froms(buf, &k)) != 0)
goto out;
if (k->type != type) {
r = SSH_ERR_KEY_CERT_MISMATCH;
goto out;
}
/* For ECDSA keys, the group must match too */
if (k->type == KEY_ECDSA &&
k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) {
r = SSH_ERR_KEY_CERT_MISMATCH;
goto out;
}
/*
* Several fields are redundant between certificate and
* private key body, we require these to match.
*/
expect_sk_application = k->sk_application;
expect_ed25519_pk = k->ed25519_pk;
k->sk_application = NULL;
k->ed25519_pk = NULL;
/* XXX xmss too or refactor */
} else {
if ((k = sshkey_new(type)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
}
if ((impl = sshkey_impl_from_type(type)) == NULL) {
r = SSH_ERR_INTERNAL_ERROR;
goto out;
}
if ((r = impl->funcs->deserialize_private(tname, buf, k)) != 0)
goto out;
/* XXX xmss too or refactor */
if ((expect_sk_application != NULL && (k->sk_application == NULL ||
strcmp(expect_sk_application, k->sk_application) != 0)) ||
(expect_ed25519_pk != NULL && (k->ed25519_pk == NULL ||
memcmp(expect_ed25519_pk, k->ed25519_pk, ED25519_PK_SZ) != 0))) {
r = SSH_ERR_KEY_CERT_MISMATCH;
goto out;
}
/* success */
r = 0;
if (kp != NULL) {
*kp = k;
k = NULL;
}
out:
free(tname);
sshkey_free(k);
free(expect_sk_application);
free(expect_ed25519_pk);
return r;
}
#if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC)
int
sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
{
EC_POINT *nq = NULL;
BIGNUM *order = NULL, *x = NULL, *y = NULL, *tmp = NULL;
int ret = SSH_ERR_KEY_INVALID_EC_VALUE;
/*
* NB. This assumes OpenSSL has already verified that the public
* point lies on the curve. This is done by EC_POINT_oct2point()
* implicitly calling EC_POINT_is_on_curve(). If this code is ever
* reachable with public points not unmarshalled using
* EC_POINT_oct2point then the caller will need to explicitly check.
*/
/*
* We shouldn't ever hit this case because bignum_get_ecpoint()
* refuses to load GF2m points.
*/
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
NID_X9_62_prime_field)
goto out;
/* Q != infinity */
if (EC_POINT_is_at_infinity(group, public))
goto out;
if ((x = BN_new()) == NULL ||
(y = BN_new()) == NULL ||
(order = BN_new()) == NULL ||
(tmp = BN_new()) == NULL) {
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
/* log2(x) > log2(order)/2, log2(y) > log2(order)/2 */
if (EC_GROUP_get_order(group, order, NULL) != 1 ||
EC_POINT_get_affine_coordinates_GFp(group, public,
x, y, NULL) != 1) {
ret = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (BN_num_bits(x) <= BN_num_bits(order) / 2 ||
BN_num_bits(y) <= BN_num_bits(order) / 2)
goto out;
/* nQ == infinity (n == order of subgroup) */
if ((nq = EC_POINT_new(group)) == NULL) {
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (EC_POINT_mul(group, nq, NULL, public, order, NULL) != 1) {
ret = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (EC_POINT_is_at_infinity(group, nq) != 1)
goto out;
/* x < order - 1, y < order - 1 */
if (!BN_sub(tmp, order, BN_value_one())) {
ret = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (BN_cmp(x, tmp) >= 0 || BN_cmp(y, tmp) >= 0)
goto out;
ret = 0;
out:
BN_clear_free(x);
BN_clear_free(y);
BN_clear_free(order);
BN_clear_free(tmp);
EC_POINT_free(nq);
return ret;
}
int
sshkey_ec_validate_private(const EC_KEY *key)
{
BIGNUM *order = NULL, *tmp = NULL;
int ret = SSH_ERR_KEY_INVALID_EC_VALUE;
if ((order = BN_new()) == NULL || (tmp = BN_new()) == NULL) {
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
/* log2(private) > log2(order)/2 */
if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, NULL) != 1) {
ret = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (BN_num_bits(EC_KEY_get0_private_key(key)) <=
BN_num_bits(order) / 2)
goto out;
/* private < order - 1 */
if (!BN_sub(tmp, order, BN_value_one())) {
ret = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (BN_cmp(EC_KEY_get0_private_key(key), tmp) >= 0)
goto out;
ret = 0;
out:
BN_clear_free(order);
BN_clear_free(tmp);
return ret;
}
void
sshkey_dump_ec_point(const EC_GROUP *group, const EC_POINT *point)
{
BIGNUM *x = NULL, *y = NULL;
if (point == NULL) {
fputs("point=(NULL)\n", stderr);
return;
}
if ((x = BN_new()) == NULL || (y = BN_new()) == NULL) {
fprintf(stderr, "%s: BN_new failed\n", __func__);
goto out;
}
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
NID_X9_62_prime_field) {
fprintf(stderr, "%s: group is not a prime field\n", __func__);
goto out;
}
if (EC_POINT_get_affine_coordinates_GFp(group, point,
x, y, NULL) != 1) {
fprintf(stderr, "%s: EC_POINT_get_affine_coordinates_GFp\n",
__func__);
goto out;
}
fputs("x=", stderr);
BN_print_fp(stderr, x);
fputs("\ny=", stderr);
BN_print_fp(stderr, y);
fputs("\n", stderr);
out:
BN_clear_free(x);
BN_clear_free(y);
}
void
sshkey_dump_ec_key(const EC_KEY *key)
{
const BIGNUM *exponent;
sshkey_dump_ec_point(EC_KEY_get0_group(key),
EC_KEY_get0_public_key(key));
fputs("exponent=", stderr);
if ((exponent = EC_KEY_get0_private_key(key)) == NULL)
fputs("(NULL)", stderr);
else
BN_print_fp(stderr, EC_KEY_get0_private_key(key));
fputs("\n", stderr);
}
#endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */
static int
sshkey_private_to_blob2(struct sshkey *prv, struct sshbuf *blob,
const char *passphrase, const char *comment, const char *ciphername,
int rounds)
{
u_char *cp, *key = NULL, *pubkeyblob = NULL;
u_char salt[SALT_LEN];
size_t i, pubkeylen, keylen, ivlen, blocksize, authlen;
u_int check;
int r = SSH_ERR_INTERNAL_ERROR;
struct sshcipher_ctx *ciphercontext = NULL;
const struct sshcipher *cipher;
const char *kdfname = KDFNAME;
struct sshbuf *encoded = NULL, *encrypted = NULL, *kdf = NULL;
if (rounds <= 0)
rounds = DEFAULT_ROUNDS;
if (passphrase == NULL || !strlen(passphrase)) {
ciphername = "none";
kdfname = "none";
} else if (ciphername == NULL)
ciphername = DEFAULT_CIPHERNAME;
if ((cipher = cipher_by_name(ciphername)) == NULL) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if ((kdf = sshbuf_new()) == NULL ||
(encoded = sshbuf_new()) == NULL ||
(encrypted = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
blocksize = cipher_blocksize(cipher);
keylen = cipher_keylen(cipher);
ivlen = cipher_ivlen(cipher);
authlen = cipher_authlen(cipher);
if ((key = calloc(1, keylen + ivlen)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (strcmp(kdfname, "bcrypt") == 0) {
arc4random_buf(salt, SALT_LEN);
if (bcrypt_pbkdf(passphrase, strlen(passphrase),
salt, SALT_LEN, key, keylen + ivlen, rounds) < 0) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if ((r = sshbuf_put_string(kdf, salt, SALT_LEN)) != 0 ||
(r = sshbuf_put_u32(kdf, rounds)) != 0)
goto out;
} else if (strcmp(kdfname, "none") != 0) {
/* Unsupported KDF type */
r = SSH_ERR_KEY_UNKNOWN_CIPHER;
goto out;
}
if ((r = cipher_init(&ciphercontext, cipher, key, keylen,
key + keylen, ivlen, 1)) != 0)
goto out;
if ((r = sshbuf_put(encoded, AUTH_MAGIC, sizeof(AUTH_MAGIC))) != 0 ||
(r = sshbuf_put_cstring(encoded, ciphername)) != 0 ||
(r = sshbuf_put_cstring(encoded, kdfname)) != 0 ||
(r = sshbuf_put_stringb(encoded, kdf)) != 0 ||
(r = sshbuf_put_u32(encoded, 1)) != 0 || /* number of keys */
(r = sshkey_to_blob(prv, &pubkeyblob, &pubkeylen)) != 0 ||
(r = sshbuf_put_string(encoded, pubkeyblob, pubkeylen)) != 0)
goto out;
/* set up the buffer that will be encrypted */
/* Random check bytes */
check = arc4random();
if ((r = sshbuf_put_u32(encrypted, check)) != 0 ||
(r = sshbuf_put_u32(encrypted, check)) != 0)
goto out;
/* append private key and comment*/
if ((r = sshkey_private_serialize_opt(prv, encrypted,
SSHKEY_SERIALIZE_FULL)) != 0 ||
(r = sshbuf_put_cstring(encrypted, comment)) != 0)
goto out;
/* padding */
i = 0;
while (sshbuf_len(encrypted) % blocksize) {
if ((r = sshbuf_put_u8(encrypted, ++i & 0xff)) != 0)
goto out;
}
/* length in destination buffer */
if ((r = sshbuf_put_u32(encoded, sshbuf_len(encrypted))) != 0)
goto out;
/* encrypt */
if ((r = sshbuf_reserve(encoded,
sshbuf_len(encrypted) + authlen, &cp)) != 0)
goto out;
if ((r = cipher_crypt(ciphercontext, 0, cp,
sshbuf_ptr(encrypted), sshbuf_len(encrypted), 0, authlen)) != 0)
goto out;
sshbuf_reset(blob);
/* assemble uuencoded key */
if ((r = sshbuf_put(blob, MARK_BEGIN, MARK_BEGIN_LEN)) != 0 ||
(r = sshbuf_dtob64(encoded, blob, 1)) != 0 ||
(r = sshbuf_put(blob, MARK_END, MARK_END_LEN)) != 0)
goto out;
/* success */
r = 0;
out:
sshbuf_free(kdf);
sshbuf_free(encoded);
sshbuf_free(encrypted);
cipher_free(ciphercontext);
explicit_bzero(salt, sizeof(salt));
if (key != NULL)
freezero(key, keylen + ivlen);
if (pubkeyblob != NULL)
freezero(pubkeyblob, pubkeylen);
return r;
}
static int
private2_uudecode(struct sshbuf *blob, struct sshbuf **decodedp)
{
const u_char *cp;
size_t encoded_len;
int r;
u_char last;
struct sshbuf *encoded = NULL, *decoded = NULL;
if (blob == NULL || decodedp == NULL)
return SSH_ERR_INVALID_ARGUMENT;
*decodedp = NULL;
if ((encoded = sshbuf_new()) == NULL ||
(decoded = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
/* check preamble */
cp = sshbuf_ptr(blob);
encoded_len = sshbuf_len(blob);
if (encoded_len < (MARK_BEGIN_LEN + MARK_END_LEN) ||
memcmp(cp, MARK_BEGIN, MARK_BEGIN_LEN) != 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
cp += MARK_BEGIN_LEN;
encoded_len -= MARK_BEGIN_LEN;
/* Look for end marker, removing whitespace as we go */
while (encoded_len > 0) {
if (*cp != '\n' && *cp != '\r') {
if ((r = sshbuf_put_u8(encoded, *cp)) != 0)
goto out;
}
last = *cp;
encoded_len--;
cp++;
if (last == '\n') {
if (encoded_len >= MARK_END_LEN &&
memcmp(cp, MARK_END, MARK_END_LEN) == 0) {
/* \0 terminate */
if ((r = sshbuf_put_u8(encoded, 0)) != 0)
goto out;
break;
}
}
}
if (encoded_len == 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* decode base64 */
if ((r = sshbuf_b64tod(decoded, (char *)sshbuf_ptr(encoded))) != 0)
goto out;
/* check magic */
if (sshbuf_len(decoded) < sizeof(AUTH_MAGIC) ||
memcmp(sshbuf_ptr(decoded), AUTH_MAGIC, sizeof(AUTH_MAGIC))) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* success */
*decodedp = decoded;
decoded = NULL;
r = 0;
out:
sshbuf_free(encoded);
sshbuf_free(decoded);
return r;
}
static int
private2_decrypt(struct sshbuf *decoded, const char *passphrase,
struct sshbuf **decryptedp, struct sshkey **pubkeyp)
{
char *ciphername = NULL, *kdfname = NULL;
const struct sshcipher *cipher = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
size_t keylen = 0, ivlen = 0, authlen = 0, slen = 0;
struct sshbuf *kdf = NULL, *decrypted = NULL;
struct sshcipher_ctx *ciphercontext = NULL;
struct sshkey *pubkey = NULL;
u_char *key = NULL, *salt = NULL, *dp;
u_int blocksize, rounds, nkeys, encrypted_len, check1, check2;
if (decoded == NULL || decryptedp == NULL || pubkeyp == NULL)
return SSH_ERR_INVALID_ARGUMENT;
*decryptedp = NULL;
*pubkeyp = NULL;
if ((decrypted = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
/* parse public portion of key */
if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 ||
(r = sshbuf_get_cstring(decoded, &ciphername, NULL)) != 0 ||
(r = sshbuf_get_cstring(decoded, &kdfname, NULL)) != 0 ||
(r = sshbuf_froms(decoded, &kdf)) != 0 ||
(r = sshbuf_get_u32(decoded, &nkeys)) != 0)
goto out;
if (nkeys != 1) {
/* XXX only one key supported at present */
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if ((r = sshkey_froms(decoded, &pubkey)) != 0 ||
(r = sshbuf_get_u32(decoded, &encrypted_len)) != 0)
goto out;
if ((cipher = cipher_by_name(ciphername)) == NULL) {
r = SSH_ERR_KEY_UNKNOWN_CIPHER;
goto out;
}
if (strcmp(kdfname, "none") != 0 && strcmp(kdfname, "bcrypt") != 0) {
r = SSH_ERR_KEY_UNKNOWN_CIPHER;
goto out;
}
if (strcmp(kdfname, "none") == 0 && strcmp(ciphername, "none") != 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if ((passphrase == NULL || strlen(passphrase) == 0) &&
strcmp(kdfname, "none") != 0) {
/* passphrase required */
r = SSH_ERR_KEY_WRONG_PASSPHRASE;
goto out;
}
/* check size of encrypted key blob */
blocksize = cipher_blocksize(cipher);
if (encrypted_len < blocksize || (encrypted_len % blocksize) != 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* setup key */
keylen = cipher_keylen(cipher);
ivlen = cipher_ivlen(cipher);
authlen = cipher_authlen(cipher);
if ((key = calloc(1, keylen + ivlen)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (strcmp(kdfname, "bcrypt") == 0) {
if ((r = sshbuf_get_string(kdf, &salt, &slen)) != 0 ||
(r = sshbuf_get_u32(kdf, &rounds)) != 0)
goto out;
if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, slen,
key, keylen + ivlen, rounds) < 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
}
/* check that an appropriate amount of auth data is present */
if (sshbuf_len(decoded) < authlen ||
sshbuf_len(decoded) - authlen < encrypted_len) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* decrypt private portion of key */
if ((r = sshbuf_reserve(decrypted, encrypted_len, &dp)) != 0 ||
(r = cipher_init(&ciphercontext, cipher, key, keylen,
key + keylen, ivlen, 0)) != 0)
goto out;
if ((r = cipher_crypt(ciphercontext, 0, dp, sshbuf_ptr(decoded),
encrypted_len, 0, authlen)) != 0) {
/* an integrity error here indicates an incorrect passphrase */
if (r == SSH_ERR_MAC_INVALID)
r = SSH_ERR_KEY_WRONG_PASSPHRASE;
goto out;
}
if ((r = sshbuf_consume(decoded, encrypted_len + authlen)) != 0)
goto out;
/* there should be no trailing data */
if (sshbuf_len(decoded) != 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* check check bytes */
if ((r = sshbuf_get_u32(decrypted, &check1)) != 0 ||
(r = sshbuf_get_u32(decrypted, &check2)) != 0)
goto out;
if (check1 != check2) {
r = SSH_ERR_KEY_WRONG_PASSPHRASE;
goto out;
}
/* success */
*decryptedp = decrypted;
decrypted = NULL;
*pubkeyp = pubkey;
pubkey = NULL;
r = 0;
out:
cipher_free(ciphercontext);
free(ciphername);
free(kdfname);
sshkey_free(pubkey);
if (salt != NULL) {
explicit_bzero(salt, slen);
free(salt);
}
if (key != NULL) {
explicit_bzero(key, keylen + ivlen);
free(key);
}
sshbuf_free(kdf);
sshbuf_free(decrypted);
return r;
}
static int
sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase,
struct sshkey **keyp, char **commentp)
{
char *comment = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
struct sshbuf *decoded = NULL, *decrypted = NULL;
struct sshkey *k = NULL, *pubkey = NULL;
if (keyp != NULL)
*keyp = NULL;
if (commentp != NULL)
*commentp = NULL;
/* Undo base64 encoding and decrypt the private section */
if ((r = private2_uudecode(blob, &decoded)) != 0 ||
(r = private2_decrypt(decoded, passphrase,
&decrypted, &pubkey)) != 0)
goto out;
if (type != KEY_UNSPEC &&
sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) {
r = SSH_ERR_KEY_TYPE_MISMATCH;
goto out;
}
/* Load the private key and comment */
if ((r = sshkey_private_deserialize(decrypted, &k)) != 0 ||
(r = sshbuf_get_cstring(decrypted, &comment, NULL)) != 0)
goto out;
/* Check deterministic padding after private section */
if ((r = private2_check_padding(decrypted)) != 0)
goto out;
/* Check that the public key in the envelope matches the private key */
if (!sshkey_equal(pubkey, k)) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* success */
r = 0;
if (keyp != NULL) {
*keyp = k;
k = NULL;
}
if (commentp != NULL) {
*commentp = comment;
comment = NULL;
}
out:
free(comment);
sshbuf_free(decoded);
sshbuf_free(decrypted);
sshkey_free(k);
sshkey_free(pubkey);
return r;
}
static int
sshkey_parse_private2_pubkey(struct sshbuf *blob, int type,
struct sshkey **keyp)
{
int r = SSH_ERR_INTERNAL_ERROR;
struct sshbuf *decoded = NULL;
struct sshkey *pubkey = NULL;
u_int nkeys = 0;
if (keyp != NULL)
*keyp = NULL;
if ((r = private2_uudecode(blob, &decoded)) != 0)
goto out;
/* parse public key from unencrypted envelope */
if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 ||
(r = sshbuf_skip_string(decoded)) != 0 || /* cipher */
(r = sshbuf_skip_string(decoded)) != 0 || /* KDF alg */
(r = sshbuf_skip_string(decoded)) != 0 || /* KDF hint */
(r = sshbuf_get_u32(decoded, &nkeys)) != 0)
goto out;
if (nkeys != 1) {
/* XXX only one key supported at present */
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* Parse the public key */
if ((r = sshkey_froms(decoded, &pubkey)) != 0)
goto out;
if (type != KEY_UNSPEC &&
sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) {
r = SSH_ERR_KEY_TYPE_MISMATCH;
goto out;
}
/* success */
r = 0;
if (keyp != NULL) {
*keyp = pubkey;
pubkey = NULL;
}
out:
sshbuf_free(decoded);
sshkey_free(pubkey);
return r;
}
#ifdef WITH_OPENSSL
/* convert SSH v2 key to PEM or PKCS#8 format */
static int
sshkey_private_to_blob_pem_pkcs8(struct sshkey *key, struct sshbuf *buf,
int format, const char *_passphrase, const char *comment)
{
int was_shielded = sshkey_is_shielded(key);
int success, r;
int blen, len = strlen(_passphrase);
u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL;
char *bptr;
BIO *bio = NULL;
struct sshbuf *blob;
EVP_PKEY *pkey = NULL;
if (len > 0 && len <= 4)
return SSH_ERR_PASSPHRASE_TOO_SHORT;
if ((blob = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((bio = BIO_new(BIO_s_mem())) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (format == SSHKEY_PRIVATE_PKCS8 && (pkey = EVP_PKEY_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshkey_unshield_private(key)) != 0)
goto out;
switch (key->type) {
#ifdef WITH_DSA
case KEY_DSA:
if (format == SSHKEY_PRIVATE_PEM) {
success = PEM_write_bio_DSAPrivateKey(bio, key->dsa,
cipher, passphrase, len, NULL, NULL);
} else {
success = EVP_PKEY_set1_DSA(pkey, key->dsa);
}
break;
#endif
#ifdef OPENSSL_HAS_ECC
case KEY_ECDSA:
if (format == SSHKEY_PRIVATE_PEM) {
success = PEM_write_bio_ECPrivateKey(bio, key->ecdsa,
cipher, passphrase, len, NULL, NULL);
} else {
success = EVP_PKEY_set1_EC_KEY(pkey, key->ecdsa);
}
break;
#endif
case KEY_RSA:
if (format == SSHKEY_PRIVATE_PEM) {
success = PEM_write_bio_RSAPrivateKey(bio, key->rsa,
cipher, passphrase, len, NULL, NULL);
} else {
success = EVP_PKEY_set1_RSA(pkey, key->rsa);
}
break;
default:
success = 0;
break;
}
if (success == 0) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (format == SSHKEY_PRIVATE_PKCS8) {
if ((success = PEM_write_bio_PrivateKey(bio, pkey, cipher,
passphrase, len, NULL, NULL)) == 0) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
}
if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0) {
r = SSH_ERR_INTERNAL_ERROR;
goto out;
}
if ((r = sshbuf_put(blob, bptr, blen)) != 0)
goto out;
r = 0;
out:
if (was_shielded)
r = sshkey_shield_private(key);
if (r == 0)
r = sshbuf_putb(buf, blob);
EVP_PKEY_free(pkey);
sshbuf_free(blob);
BIO_free(bio);
return r;
}
#endif /* WITH_OPENSSL */
/* Serialise "key" to buffer "blob" */
int
sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
const char *passphrase, const char *comment,
int format, const char *openssh_format_cipher, int openssh_format_rounds)
{
switch (key->type) {
#ifdef WITH_OPENSSL
case KEY_DSA:
case KEY_ECDSA:
case KEY_RSA:
break; /* see below */
#endif /* WITH_OPENSSL */
case KEY_ED25519:
case KEY_ED25519_SK:
#ifdef WITH_XMSS
case KEY_XMSS:
#endif /* WITH_XMSS */
#ifdef WITH_OPENSSL
case KEY_ECDSA_SK:
#endif /* WITH_OPENSSL */
return sshkey_private_to_blob2(key, blob, passphrase,
comment, openssh_format_cipher, openssh_format_rounds);
default:
return SSH_ERR_KEY_TYPE_UNKNOWN;
}
#ifdef WITH_OPENSSL
switch (format) {
case SSHKEY_PRIVATE_OPENSSH:
return sshkey_private_to_blob2(key, blob, passphrase,
comment, openssh_format_cipher, openssh_format_rounds);
case SSHKEY_PRIVATE_PEM:
case SSHKEY_PRIVATE_PKCS8:
return sshkey_private_to_blob_pem_pkcs8(key, blob,
format, passphrase, comment);
default:
return SSH_ERR_INVALID_ARGUMENT;
}
#endif /* WITH_OPENSSL */
}
#ifdef WITH_OPENSSL
static int
translate_libcrypto_error(unsigned long pem_err)
{
int pem_reason = ERR_GET_REASON(pem_err);
switch (ERR_GET_LIB(pem_err)) {
case ERR_LIB_PEM:
switch (pem_reason) {
case PEM_R_BAD_PASSWORD_READ:
#ifdef PEM_R_PROBLEMS_GETTING_PASSWORD
case PEM_R_PROBLEMS_GETTING_PASSWORD:
#endif
#ifdef PEM_R_BAD_DECRYPT
case PEM_R_BAD_DECRYPT:
#endif
return SSH_ERR_KEY_WRONG_PASSPHRASE;
default:
return SSH_ERR_INVALID_FORMAT;
}
case ERR_LIB_EVP:
switch (pem_reason) {
#ifdef EVP_R_BAD_DECRYPT
case EVP_R_BAD_DECRYPT:
return SSH_ERR_KEY_WRONG_PASSPHRASE;
#endif
#ifdef EVP_R_BN_DECODE_ERROR
case EVP_R_BN_DECODE_ERROR:
#endif
case EVP_R_DECODE_ERROR:
#ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR
case EVP_R_PRIVATE_KEY_DECODE_ERROR:
#endif
return SSH_ERR_INVALID_FORMAT;
default:
return SSH_ERR_LIBCRYPTO_ERROR;
}
case ERR_LIB_ASN1:
return SSH_ERR_INVALID_FORMAT;
}
return SSH_ERR_LIBCRYPTO_ERROR;
}
static void
clear_libcrypto_errors(void)
{
while (ERR_get_error() != 0)
;
}
/*
* Translate OpenSSL error codes to determine whether
* passphrase is required/incorrect.
*/
static int
convert_libcrypto_error(void)
{
/*
* Some password errors are reported at the beginning
* of the error queue.
*/
if (translate_libcrypto_error(ERR_peek_error()) ==
SSH_ERR_KEY_WRONG_PASSPHRASE)
return SSH_ERR_KEY_WRONG_PASSPHRASE;
return translate_libcrypto_error(ERR_peek_last_error());
}
static int
pem_passphrase_cb(char *buf, int size, int rwflag, void *u)
{
char *p = (char *)u;
size_t len;
if (p == NULL || (len = strlen(p)) == 0)
return -1;
if (size < 0 || len > (size_t)size)
return -1;
memcpy(buf, p, len);
return (int)len;
}
static int
sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type,
const char *passphrase, struct sshkey **keyp)
{
EVP_PKEY *pk = NULL;
struct sshkey *prv = NULL;
BIO *bio = NULL;
int r;
if (keyp != NULL)
*keyp = NULL;
if ((bio = BIO_new(BIO_s_mem())) == NULL || sshbuf_len(blob) > INT_MAX)
return SSH_ERR_ALLOC_FAIL;
if (BIO_write(bio, sshbuf_ptr(blob), sshbuf_len(blob)) !=
(int)sshbuf_len(blob)) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
clear_libcrypto_errors();
if ((pk = PEM_read_bio_PrivateKey(bio, NULL, pem_passphrase_cb,
(char *)passphrase)) == NULL) {
/*
* libcrypto may return various ASN.1 errors when attempting
* to parse a key with an incorrect passphrase.
* Treat all format errors as "incorrect passphrase" if a
* passphrase was supplied.
*/
if (passphrase != NULL && *passphrase != '\0')
r = SSH_ERR_KEY_WRONG_PASSPHRASE;
else
r = convert_libcrypto_error();
goto out;
}
if (EVP_PKEY_base_id(pk) == EVP_PKEY_RSA &&
(type == KEY_UNSPEC || type == KEY_RSA)) {
if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
prv->rsa = EVP_PKEY_get1_RSA(pk);
prv->type = KEY_RSA;
#ifdef DEBUG_PK
RSA_print_fp(stderr, prv->rsa, 8);
#endif
if (RSA_blinding_on(prv->rsa, NULL) != 1) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if ((r = sshkey_check_rsa_length(prv, 0)) != 0)
goto out;
#ifdef WITH_DSA
} else if (EVP_PKEY_base_id(pk) == EVP_PKEY_DSA &&
(type == KEY_UNSPEC || type == KEY_DSA)) {
if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
prv->dsa = EVP_PKEY_get1_DSA(pk);
prv->type = KEY_DSA;
#ifdef DEBUG_PK
DSA_print_fp(stderr, prv->dsa, 8);
#endif
#endif
#ifdef OPENSSL_HAS_ECC
} else if (EVP_PKEY_base_id(pk) == EVP_PKEY_EC &&
(type == KEY_UNSPEC || type == KEY_ECDSA)) {
if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
prv->ecdsa = EVP_PKEY_get1_EC_KEY(pk);
prv->type = KEY_ECDSA;
prv->ecdsa_nid = sshkey_ecdsa_key_to_nid(prv->ecdsa);
if (prv->ecdsa_nid == -1 ||
sshkey_curve_nid_to_name(prv->ecdsa_nid) == NULL ||
sshkey_ec_validate_public(EC_KEY_get0_group(prv->ecdsa),
EC_KEY_get0_public_key(prv->ecdsa)) != 0 ||
sshkey_ec_validate_private(prv->ecdsa) != 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
# ifdef DEBUG_PK
if (prv != NULL && prv->ecdsa != NULL)
sshkey_dump_ec_key(prv->ecdsa);
# endif
#endif /* OPENSSL_HAS_ECC */
#ifdef OPENSSL_HAS_ED25519
} else if (EVP_PKEY_base_id(pk) == EVP_PKEY_ED25519 &&
(type == KEY_UNSPEC || type == KEY_ED25519)) {
size_t len;
if ((prv = sshkey_new(KEY_UNSPEC)) == NULL ||
(prv->ed25519_sk = calloc(1, ED25519_SK_SZ)) == NULL ||
(prv->ed25519_pk = calloc(1, ED25519_PK_SZ)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
prv->type = KEY_ED25519;
len = ED25519_PK_SZ;
if (!EVP_PKEY_get_raw_public_key(pk, prv->ed25519_pk, &len)) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (len != ED25519_PK_SZ) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
len = ED25519_SK_SZ - ED25519_PK_SZ;
if (!EVP_PKEY_get_raw_private_key(pk, prv->ed25519_sk, &len)) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (len != ED25519_SK_SZ - ED25519_PK_SZ) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* Append the public key to our private key */
memcpy(prv->ed25519_sk + (ED25519_SK_SZ - ED25519_PK_SZ),
prv->ed25519_pk, ED25519_PK_SZ);
# ifdef DEBUG_PK
sshbuf_dump_data(prv->ed25519_sk, ED25519_SK_SZ, stderr);
# endif
#endif /* OPENSSL_HAS_ED25519 */
} else {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
r = 0;
if (keyp != NULL) {
*keyp = prv;
prv = NULL;
}
out:
BIO_free(bio);
EVP_PKEY_free(pk);
sshkey_free(prv);
return r;
}
#endif /* WITH_OPENSSL */
int
sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
const char *passphrase, struct sshkey **keyp, char **commentp)
{
int r = SSH_ERR_INTERNAL_ERROR;
if (keyp != NULL)
*keyp = NULL;
if (commentp != NULL)
*commentp = NULL;
switch (type) {
case KEY_XMSS:
/* No fallback for new-format-only keys */
return sshkey_parse_private2(blob, type, passphrase,
keyp, commentp);
default:
r = sshkey_parse_private2(blob, type, passphrase, keyp,
commentp);
/* Only fallback to PEM parser if a format error occurred. */
if (r != SSH_ERR_INVALID_FORMAT)
return r;
#ifdef WITH_OPENSSL
return sshkey_parse_private_pem_fileblob(blob, type,
passphrase, keyp);
#else
return SSH_ERR_INVALID_FORMAT;
#endif /* WITH_OPENSSL */
}
}
int
sshkey_parse_private_fileblob(struct sshbuf *buffer, const char *passphrase,
struct sshkey **keyp, char **commentp)
{
if (keyp != NULL)
*keyp = NULL;
if (commentp != NULL)
*commentp = NULL;
return sshkey_parse_private_fileblob_type(buffer, KEY_UNSPEC,
passphrase, keyp, commentp);
}
void
sshkey_sig_details_free(struct sshkey_sig_details *details)
{
freezero(details, sizeof(*details));
}
int
sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob, int type,
struct sshkey **pubkeyp)
{
int r = SSH_ERR_INTERNAL_ERROR;
if (pubkeyp != NULL)
*pubkeyp = NULL;
/* only new-format private keys bundle a public key inside */
if ((r = sshkey_parse_private2_pubkey(blob, type, pubkeyp)) != 0)
return r;
return 0;
}
#ifdef WITH_XMSS
/*
* serialize the key with the current state and forward the state
* maxsign times.
*/
int
sshkey_private_serialize_maxsign(struct sshkey *k, struct sshbuf *b,
u_int32_t maxsign, int printerror)
{
int r, rupdate;
if (maxsign == 0 ||
sshkey_type_plain(k->type) != KEY_XMSS)
return sshkey_private_serialize_opt(k, b,
SSHKEY_SERIALIZE_DEFAULT);
if ((r = sshkey_xmss_get_state(k, printerror)) != 0 ||
(r = sshkey_private_serialize_opt(k, b,
SSHKEY_SERIALIZE_STATE)) != 0 ||
(r = sshkey_xmss_forward_state(k, maxsign)) != 0)
goto out;
r = 0;
out:
if ((rupdate = sshkey_xmss_update_state(k, printerror)) != 0) {
if (r == 0)
r = rupdate;
}
return r;
}
u_int32_t
sshkey_signatures_left(const struct sshkey *k)
{
if (sshkey_type_plain(k->type) == KEY_XMSS)
return sshkey_xmss_signatures_left(k);
return 0;
}
int
sshkey_enable_maxsign(struct sshkey *k, u_int32_t maxsign)
{
if (sshkey_type_plain(k->type) != KEY_XMSS)
return SSH_ERR_INVALID_ARGUMENT;
return sshkey_xmss_enable_maxsign(k, maxsign);
}
int
sshkey_set_filename(struct sshkey *k, const char *filename)
{
if (k == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if (sshkey_type_plain(k->type) != KEY_XMSS)
return 0;
if (filename == NULL)
return SSH_ERR_INVALID_ARGUMENT;
if ((k->xmss_filename = strdup(filename)) == NULL)
return SSH_ERR_ALLOC_FAIL;
return 0;
}
#else
int
sshkey_private_serialize_maxsign(struct sshkey *k, struct sshbuf *b,
u_int32_t maxsign, int printerror)
{
return sshkey_private_serialize_opt(k, b, SSHKEY_SERIALIZE_DEFAULT);
}
u_int32_t
sshkey_signatures_left(const struct sshkey *k)
{
return 0;
}
int
sshkey_enable_maxsign(struct sshkey *k, u_int32_t maxsign)
{
return SSH_ERR_INVALID_ARGUMENT;
}
int
sshkey_set_filename(struct sshkey *k, const char *filename)
{
if (k == NULL)
return SSH_ERR_INVALID_ARGUMENT;
return 0;
}
#endif /* WITH_XMSS */
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