diff options
Diffstat (limited to 'sshkey.c')
| -rw-r--r-- | sshkey.c | 3663 |
1 files changed, 3663 insertions, 0 deletions
diff --git a/sshkey.c b/sshkey.c new file mode 100644 index 0000000..4371225 --- /dev/null +++ b/sshkey.c @@ -0,0 +1,3663 @@ +/* $OpenBSD: sshkey.c,v 1.134 2022/10/28 02:47:04 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 <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 16 + +/* 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; +extern const struct sshkey_impl sshkey_dss_impl; +extern const struct sshkey_impl sshkey_dsa_cert_impl; +#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 */ + &sshkey_dss_impl, + &sshkey_dsa_cert_impl, + &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) +{ + 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; + } + } + 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 preceeds 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]; + char *b64 = NULL; + 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); + if (b64 != NULL) + freezero(b64, strlen(b64)); + 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) { + 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; +#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: + case PEM_R_PROBLEMS_GETTING_PASSWORD: + case PEM_R_BAD_DECRYPT: + return SSH_ERR_KEY_WRONG_PASSPHRASE; + default: + return SSH_ERR_INVALID_FORMAT; + } + case ERR_LIB_EVP: + switch (pem_reason) { + case EVP_R_BAD_DECRYPT: + return SSH_ERR_KEY_WRONG_PASSPHRASE; +#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; + } 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 +#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 */ + } 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_ED25519: + 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 */ |