/* $OpenBSD: sshkey.c,v 1.147 2024/09/22 12:56:21 jsg 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 #include #include #ifdef WITH_OPENSSL #include #include #include #endif #include "crypto_api.h" #include #include #include #include #include #include #include #ifdef HAVE_UTIL_H #include #endif /* HAVE_UTIL_H */ #include "ssh2.h" #include "ssherr.h" #include "misc.h" #include "sshbuf.h" #include "cipher.h" #include "digest.h" #define SSHKEY_INTERNAL #include "sshkey.h" #include "match.h" #include "ssh-sk.h" #ifdef WITH_XMSS #include "sshkey-xmss.h" #include "xmss_fast.h" #endif #include "openbsd-compat/openssl-compat.h" /* openssh private key file format */ #define MARK_BEGIN "-----BEGIN OPENSSH PRIVATE KEY-----\n" #define MARK_END "-----END OPENSSH PRIVATE KEY-----\n" #define MARK_BEGIN_LEN (sizeof(MARK_BEGIN) - 1) #define MARK_END_LEN (sizeof(MARK_END) - 1) #define KDFNAME "bcrypt" #define AUTH_MAGIC "openssh-key-v1" #define SALT_LEN 16 #define DEFAULT_CIPHERNAME "aes256-ctr" #define DEFAULT_ROUNDS 24 /* * Constants relating to "shielding" support; protection of keys expected * to remain in memory for long durations */ #define SSHKEY_SHIELD_PREKEY_LEN (16 * 1024) #define SSHKEY_SHIELD_CIPHER "aes256-ctr" /* XXX want AES-EME* */ #define SSHKEY_SHIELD_PREKEY_HASH SSH_DIGEST_SHA512 int sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf, enum sshkey_serialize_rep); static int sshkey_from_blob_internal(struct sshbuf *buf, struct sshkey **keyp, int allow_cert); /* Supported key types */ extern const struct sshkey_impl sshkey_ed25519_impl; extern const struct sshkey_impl sshkey_ed25519_cert_impl; extern const struct sshkey_impl sshkey_ed25519_sk_impl; extern const struct sshkey_impl sshkey_ed25519_sk_cert_impl; #ifdef WITH_OPENSSL # ifdef OPENSSL_HAS_ECC # ifdef ENABLE_SK extern const struct sshkey_impl sshkey_ecdsa_sk_impl; extern const struct sshkey_impl sshkey_ecdsa_sk_cert_impl; extern const struct sshkey_impl sshkey_ecdsa_sk_webauthn_impl; # endif /* ENABLE_SK */ extern const struct sshkey_impl sshkey_ecdsa_nistp256_impl; extern const struct sshkey_impl sshkey_ecdsa_nistp256_cert_impl; extern const struct sshkey_impl sshkey_ecdsa_nistp384_impl; extern const struct sshkey_impl sshkey_ecdsa_nistp384_cert_impl; # ifdef OPENSSL_HAS_NISTP521 extern const struct sshkey_impl sshkey_ecdsa_nistp521_impl; extern const struct sshkey_impl sshkey_ecdsa_nistp521_cert_impl; # endif /* OPENSSL_HAS_NISTP521 */ # endif /* OPENSSL_HAS_ECC */ extern const struct sshkey_impl sshkey_rsa_impl; extern const struct sshkey_impl sshkey_rsa_cert_impl; extern const struct sshkey_impl sshkey_rsa_sha256_impl; extern const struct sshkey_impl sshkey_rsa_sha256_cert_impl; extern const struct sshkey_impl sshkey_rsa_sha512_impl; extern const struct sshkey_impl sshkey_rsa_sha512_cert_impl; # ifdef WITH_DSA extern const struct sshkey_impl sshkey_dss_impl; extern const struct sshkey_impl sshkey_dsa_cert_impl; # endif #endif /* WITH_OPENSSL */ #ifdef WITH_XMSS extern const struct sshkey_impl sshkey_xmss_impl; extern const struct sshkey_impl sshkey_xmss_cert_impl; #endif const struct sshkey_impl * const keyimpls[] = { &sshkey_ed25519_impl, &sshkey_ed25519_cert_impl, #ifdef ENABLE_SK &sshkey_ed25519_sk_impl, &sshkey_ed25519_sk_cert_impl, #endif #ifdef WITH_OPENSSL # ifdef OPENSSL_HAS_ECC &sshkey_ecdsa_nistp256_impl, &sshkey_ecdsa_nistp256_cert_impl, &sshkey_ecdsa_nistp384_impl, &sshkey_ecdsa_nistp384_cert_impl, # ifdef OPENSSL_HAS_NISTP521 &sshkey_ecdsa_nistp521_impl, &sshkey_ecdsa_nistp521_cert_impl, # endif /* OPENSSL_HAS_NISTP521 */ # ifdef ENABLE_SK &sshkey_ecdsa_sk_impl, &sshkey_ecdsa_sk_cert_impl, &sshkey_ecdsa_sk_webauthn_impl, # endif /* ENABLE_SK */ # endif /* OPENSSL_HAS_ECC */ # ifdef WITH_DSA &sshkey_dss_impl, &sshkey_dsa_cert_impl, # endif &sshkey_rsa_impl, &sshkey_rsa_cert_impl, &sshkey_rsa_sha256_impl, &sshkey_rsa_sha256_cert_impl, &sshkey_rsa_sha512_impl, &sshkey_rsa_sha512_cert_impl, #endif /* WITH_OPENSSL */ #ifdef WITH_XMSS &sshkey_xmss_impl, &sshkey_xmss_cert_impl, #endif NULL }; static const struct sshkey_impl * sshkey_impl_from_type(int type) { int i; for (i = 0; keyimpls[i] != NULL; i++) { if (keyimpls[i]->type == type) return keyimpls[i]; } return NULL; } static const struct sshkey_impl * sshkey_impl_from_type_nid(int type, int nid) { int i; for (i = 0; keyimpls[i] != NULL; i++) { if (keyimpls[i]->type == type && (keyimpls[i]->nid == 0 || keyimpls[i]->nid == nid)) return keyimpls[i]; } return NULL; } static const struct sshkey_impl * sshkey_impl_from_key(const struct sshkey *k) { if (k == NULL) return NULL; return sshkey_impl_from_type_nid(k->type, k->ecdsa_nid); } const char * sshkey_type(const struct sshkey *k) { const struct sshkey_impl *impl; if ((impl = sshkey_impl_from_key(k)) == NULL) return "unknown"; return impl->shortname; } static const char * sshkey_ssh_name_from_type_nid(int type, int nid) { const struct sshkey_impl *impl; if ((impl = sshkey_impl_from_type_nid(type, nid)) == NULL) return "ssh-unknown"; return impl->name; } int sshkey_type_is_cert(int type) { const struct sshkey_impl *impl; if ((impl = sshkey_impl_from_type(type)) == NULL) return 0; return impl->cert; } const char * sshkey_ssh_name(const struct sshkey *k) { return sshkey_ssh_name_from_type_nid(k->type, k->ecdsa_nid); } const char * sshkey_ssh_name_plain(const struct sshkey *k) { return sshkey_ssh_name_from_type_nid(sshkey_type_plain(k->type), k->ecdsa_nid); } static int type_from_name(const char *name, int allow_short) { int i; const struct sshkey_impl *impl; for (i = 0; keyimpls[i] != NULL; i++) { impl = keyimpls[i]; if (impl->name != NULL && strcmp(name, impl->name) == 0) return impl->type; /* Only allow shortname matches for plain key types */ if (allow_short && !impl->cert && impl->shortname != NULL && strcasecmp(impl->shortname, name) == 0) return impl->type; } return KEY_UNSPEC; } int sshkey_type_from_name(const char *name) { return type_from_name(name, 0); } int sshkey_type_from_shortname(const char *name) { return type_from_name(name, 1); } static int key_type_is_ecdsa_variant(int type) { switch (type) { case KEY_ECDSA: case KEY_ECDSA_CERT: case KEY_ECDSA_SK: case KEY_ECDSA_SK_CERT: return 1; } return 0; } int sshkey_ecdsa_nid_from_name(const char *name) { int i; for (i = 0; keyimpls[i] != NULL; i++) { if (!key_type_is_ecdsa_variant(keyimpls[i]->type)) continue; if (keyimpls[i]->name != NULL && strcmp(name, keyimpls[i]->name) == 0) return keyimpls[i]->nid; } return -1; } int sshkey_match_keyname_to_sigalgs(const char *keyname, const char *sigalgs) { int ktype; if (sigalgs == NULL || *sigalgs == '\0' || (ktype = sshkey_type_from_name(keyname)) == KEY_UNSPEC) return 0; else if (ktype == KEY_RSA) { return match_pattern_list("ssh-rsa", sigalgs, 0) == 1 || match_pattern_list("rsa-sha2-256", sigalgs, 0) == 1 || match_pattern_list("rsa-sha2-512", sigalgs, 0) == 1; } else if (ktype == KEY_RSA_CERT) { return match_pattern_list("ssh-rsa-cert-v01@openssh.com", sigalgs, 0) == 1 || match_pattern_list("rsa-sha2-256-cert-v01@openssh.com", sigalgs, 0) == 1 || match_pattern_list("rsa-sha2-512-cert-v01@openssh.com", sigalgs, 0) == 1; } else return match_pattern_list(keyname, sigalgs, 0) == 1; } char * sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep) { char *tmp, *ret = NULL; size_t i, nlen, rlen = 0; const struct sshkey_impl *impl; for (i = 0; keyimpls[i] != NULL; i++) { impl = keyimpls[i]; if (impl->name == NULL) continue; if (!include_sigonly && impl->sigonly) continue; if ((certs_only && !impl->cert) || (plain_only && impl->cert)) continue; if (ret != NULL) ret[rlen++] = sep; nlen = strlen(impl->name); if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) { free(ret); return NULL; } ret = tmp; memcpy(ret + rlen, impl->name, nlen + 1); rlen += nlen; } return ret; } int sshkey_names_valid2(const char *names, int allow_wildcard, int plain_only) { char *s, *cp, *p; const struct sshkey_impl *impl; int i, type; if (names == NULL || strcmp(names, "") == 0) return 0; if ((s = cp = strdup(names)) == NULL) return 0; for ((p = strsep(&cp, ",")); p && *p != '\0'; (p = strsep(&cp, ","))) { type = sshkey_type_from_name(p); if (type == KEY_UNSPEC) { if (allow_wildcard) { /* * Try matching key types against the string. * If any has a positive or negative match then * the component is accepted. */ impl = NULL; for (i = 0; keyimpls[i] != NULL; i++) { if (match_pattern_list( keyimpls[i]->name, p, 0) != 0) { impl = keyimpls[i]; break; } } if (impl != NULL) continue; } free(s); return 0; } else if (plain_only && sshkey_type_is_cert(type)) { free(s); return 0; } } free(s); return 1; } u_int sshkey_size(const struct sshkey *k) { const struct sshkey_impl *impl; if ((impl = sshkey_impl_from_key(k)) == NULL) return 0; if (impl->funcs->size != NULL) return impl->funcs->size(k); return impl->keybits; } static int sshkey_type_is_valid_ca(int type) { const struct sshkey_impl *impl; if ((impl = sshkey_impl_from_type(type)) == NULL) return 0; /* All non-certificate types may act as CAs */ return !impl->cert; } int sshkey_is_cert(const struct sshkey *k) { if (k == NULL) return 0; return sshkey_type_is_cert(k->type); } int sshkey_is_sk(const struct sshkey *k) { if (k == NULL) return 0; switch (sshkey_type_plain(k->type)) { case KEY_ECDSA_SK: case KEY_ED25519_SK: return 1; default: return 0; } } /* Return the cert-less equivalent to a certified key type */ int sshkey_type_plain(int type) { switch (type) { case KEY_RSA_CERT: return KEY_RSA; case KEY_DSA_CERT: return KEY_DSA; case KEY_ECDSA_CERT: return KEY_ECDSA; case KEY_ECDSA_SK_CERT: return KEY_ECDSA_SK; case KEY_ED25519_CERT: return KEY_ED25519; case KEY_ED25519_SK_CERT: return KEY_ED25519_SK; case KEY_XMSS_CERT: return KEY_XMSS; default: return type; } } /* Return the cert equivalent to a plain key type */ static int sshkey_type_certified(int type) { switch (type) { case KEY_RSA: return KEY_RSA_CERT; case KEY_DSA: return KEY_DSA_CERT; case KEY_ECDSA: return KEY_ECDSA_CERT; case KEY_ECDSA_SK: return KEY_ECDSA_SK_CERT; case KEY_ED25519: return KEY_ED25519_CERT; case KEY_ED25519_SK: return KEY_ED25519_SK_CERT; case KEY_XMSS: return KEY_XMSS_CERT; default: return -1; } } #ifdef WITH_OPENSSL static const EVP_MD * ssh_digest_to_md(int hash_alg) { switch (hash_alg) { case SSH_DIGEST_SHA1: return EVP_sha1(); case SSH_DIGEST_SHA256: return EVP_sha256(); case SSH_DIGEST_SHA384: return EVP_sha384(); case SSH_DIGEST_SHA512: return EVP_sha512(); } return NULL; } int sshkey_pkey_digest_sign(EVP_PKEY *pkey, int hash_alg, u_char **sigp, size_t *lenp, const u_char *data, size_t datalen) { EVP_MD_CTX *ctx = NULL; u_char *sig = NULL; int ret; size_t slen; const EVP_MD *evpmd; *sigp = NULL; *lenp = 0; slen = EVP_PKEY_size(pkey); if (slen <= 0 || slen > SSHBUF_MAX_BIGNUM || (evpmd = ssh_digest_to_md(hash_alg)) == NULL) return SSH_ERR_INVALID_ARGUMENT; if ((sig = malloc(slen)) == NULL) return SSH_ERR_ALLOC_FAIL; if ((ctx = EVP_MD_CTX_new()) == NULL) { ret = SSH_ERR_ALLOC_FAIL; goto out; } if (EVP_DigestSignInit(ctx, NULL, evpmd, NULL, pkey) != 1 || EVP_DigestSign(ctx, sig, &slen, data, datalen) != 1) { ret = SSH_ERR_LIBCRYPTO_ERROR; goto out; } *sigp = sig; *lenp = slen; /* Now owned by the caller */ sig = NULL; ret = 0; out: EVP_MD_CTX_free(ctx); free(sig); return ret; } int sshkey_pkey_digest_verify(EVP_PKEY *pkey, int hash_alg, const u_char *data, size_t datalen, u_char *sigbuf, size_t siglen) { EVP_MD_CTX *ctx = NULL; int ret = SSH_ERR_INTERNAL_ERROR; const EVP_MD *evpmd; if ((evpmd = ssh_digest_to_md(hash_alg)) == NULL) return SSH_ERR_INVALID_ARGUMENT; if ((ctx = EVP_MD_CTX_new()) == NULL) return SSH_ERR_ALLOC_FAIL; if (EVP_DigestVerifyInit(ctx, NULL, evpmd, NULL, pkey) != 1) { ret = SSH_ERR_LIBCRYPTO_ERROR; goto out; } switch (EVP_DigestVerify(ctx, sigbuf, siglen, data, datalen)) { case 1: ret = 0; break; case 0: ret = SSH_ERR_SIGNATURE_INVALID; break; default: ret = SSH_ERR_LIBCRYPTO_ERROR; break; } out: EVP_MD_CTX_free(ctx); return ret; } /* 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; } #if defined(MAP_CONCEAL) # define PREKEY_MMAP_FLAG MAP_CONCEAL #elif defined(MAP_NOCORE) # define PREKEY_MMAP_FLAG MAP_NOCORE #else # define PREKEY_MMAP_FLAG 0 #endif static int sshkey_prekey_alloc(u_char **prekeyp, size_t len) { u_char *prekey; *prekeyp = NULL; if ((prekey = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE|PREKEY_MMAP_FLAG, -1, 0)) == MAP_FAILED) return SSH_ERR_SYSTEM_ERROR; #if defined(MADV_DONTDUMP) && !defined(MAP_CONCEAL) && !defined(MAP_NOCORE) (void)madvise(prekey, len, MADV_DONTDUMP); #endif *prekeyp = prekey; return 0; } static void sshkey_prekey_free(void *prekey, size_t len) { if (prekey == NULL) return; munmap(prekey, len); } 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); sshkey_prekey_free(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 int nbits; if (k == NULL || k->pkey == NULL || (k->type != KEY_RSA && k->type != KEY_RSA_CERT)) return 0; nbits = EVP_PKEY_bits(k->pkey); if (nbits < SSH_RSA_MINIMUM_MODULUS_SIZE || (min_size > 0 && nbits < min_size)) return SSH_ERR_KEY_LENGTH; #endif /* WITH_OPENSSL */ return 0; } #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) int sshkey_ecdsa_key_to_nid(const EC_KEY *k) { const EC_GROUP *g; int nid; if (k == NULL || (g = EC_KEY_get0_group(k)) == NULL) return -1; if ((nid = EC_GROUP_get_curve_name(g)) <= 0) return -1; return nid; } int sshkey_ecdsa_pkey_to_nid(EVP_PKEY *pkey) { return sshkey_ecdsa_key_to_nid(EVP_PKEY_get0_EC_KEY(pkey)); } #endif /* defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) */ 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 ((r = sshkey_prekey_alloc(&prekey, SSHKEY_SHIELD_PREKEY_LEN)) != 0) 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); sshkey_prekey_free(prekey, SSHKEY_SHIELD_PREKEY_LEN); sshkey_free(kswap); sshbuf_free(prvbuf); return r; } /* Check deterministic padding after private key */ static int private2_check_padding(struct sshbuf *decrypted) { u_char pad; size_t i; int r; i = 0; while (sshbuf_len(decrypted)) { if ((r = sshbuf_get_u8(decrypted, &pad)) != 0) goto out; if (pad != (++i & 0xff)) { r = SSH_ERR_INVALID_FORMAT; goto out; } } /* success */ r = 0; out: explicit_bzero(&pad, sizeof(pad)); explicit_bzero(&i, sizeof(i)); return r; } int sshkey_unshield_private(struct sshkey *k) { struct sshbuf *prvbuf = NULL; u_char *cp, keyiv[SSH_DIGEST_MAX_LENGTH]; struct sshcipher_ctx *cctx = NULL; const struct sshcipher *cipher; struct sshkey *kswap = NULL, tmp; int r = SSH_ERR_INTERNAL_ERROR; #ifdef DEBUG_PK fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k)); #endif if (!sshkey_is_shielded(k)) return 0; /* nothing to do */ if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) { r = SSH_ERR_INVALID_ARGUMENT; goto out; } if (cipher_keylen(cipher) + cipher_ivlen(cipher) > ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) { r = SSH_ERR_INTERNAL_ERROR; goto out; } /* check size of shielded key blob */ if (k->shielded_len < cipher_blocksize(cipher) || (k->shielded_len % cipher_blocksize(cipher)) != 0) { r = SSH_ERR_INVALID_FORMAT; goto out; } /* Calculate the ephemeral key from the prekey */ if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH, k->shield_prekey, k->shield_prekey_len, keyiv, SSH_DIGEST_MAX_LENGTH)) != 0) goto out; if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher), keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0)) != 0) goto out; #ifdef DEBUG_PK fprintf(stderr, "%s: key+iv\n", __func__); sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH), stderr); #endif /* Decrypt and parse the shielded private key using the ephemeral key */ if ((prvbuf = sshbuf_new()) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0) goto out; /* decrypt */ #ifdef DEBUG_PK fprintf(stderr, "%s: encrypted\n", __func__); sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr); #endif if ((r = cipher_crypt(cctx, 0, cp, k->shielded_private, k->shielded_len, 0, 0)) != 0) goto out; #ifdef DEBUG_PK fprintf(stderr, "%s: serialised\n", __func__); sshbuf_dump(prvbuf, stderr); #endif /* Parse private key */ if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0) goto out; if ((r = private2_check_padding(prvbuf)) != 0) goto out; /* Swap the parsed key back into place */ tmp = *kswap; *kswap = *k; *k = tmp; /* success */ r = 0; out: cipher_free(cctx); explicit_bzero(keyiv, sizeof(keyiv)); explicit_bzero(&tmp, sizeof(tmp)); sshkey_free(kswap); sshbuf_free(prvbuf); return r; } static int cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf) { struct sshbuf *principals = NULL, *crit = NULL; struct sshbuf *exts = NULL, *ca = NULL; u_char *sig = NULL; size_t signed_len = 0, slen = 0, kidlen = 0; int ret = SSH_ERR_INTERNAL_ERROR; /* Copy the entire key blob for verification and later serialisation */ if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0) return ret; /* Parse body of certificate up to signature */ if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 || (ret = sshbuf_get_u32(b, &key->cert->type)) != 0 || (ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 || (ret = sshbuf_froms(b, &principals)) != 0 || (ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 || (ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 || (ret = sshbuf_froms(b, &crit)) != 0 || (ret = sshbuf_froms(b, &exts)) != 0 || (ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || (ret = sshbuf_froms(b, &ca)) != 0) { /* XXX debug print error for ret */ ret = SSH_ERR_INVALID_FORMAT; goto out; } /* Signature is left in the buffer so we can calculate this length */ signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b); if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) { ret = SSH_ERR_INVALID_FORMAT; goto out; } if (key->cert->type != SSH2_CERT_TYPE_USER && key->cert->type != SSH2_CERT_TYPE_HOST) { ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE; goto out; } /* Parse principals section */ while (sshbuf_len(principals) > 0) { char *principal = NULL; char **oprincipals = NULL; if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) { ret = SSH_ERR_INVALID_FORMAT; goto out; } if ((ret = sshbuf_get_cstring(principals, &principal, NULL)) != 0) { ret = SSH_ERR_INVALID_FORMAT; goto out; } oprincipals = key->cert->principals; key->cert->principals = recallocarray(key->cert->principals, key->cert->nprincipals, key->cert->nprincipals + 1, sizeof(*key->cert->principals)); if (key->cert->principals == NULL) { free(principal); key->cert->principals = oprincipals; ret = SSH_ERR_ALLOC_FAIL; goto out; } key->cert->principals[key->cert->nprincipals++] = principal; } /* * Stash a copies of the critical options and extensions sections * for later use. */ if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 || (exts != NULL && (ret = sshbuf_putb(key->cert->extensions, exts)) != 0)) goto out; /* * Validate critical options and extensions sections format. */ while (sshbuf_len(crit) != 0) { if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 || (ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) { sshbuf_reset(key->cert->critical); ret = SSH_ERR_INVALID_FORMAT; goto out; } } while (exts != NULL && sshbuf_len(exts) != 0) { if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 || (ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) { sshbuf_reset(key->cert->extensions); ret = SSH_ERR_INVALID_FORMAT; goto out; } } /* Parse CA key and check signature */ if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0) != 0) { ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; goto out; } if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) { ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; goto out; } if ((ret = sshkey_verify(key->cert->signature_key, sig, slen, sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0, NULL)) != 0) goto out; if ((ret = sshkey_get_sigtype(sig, slen, &key->cert->signature_type)) != 0) goto out; /* Success */ ret = 0; out: sshbuf_free(ca); sshbuf_free(crit); sshbuf_free(exts); sshbuf_free(principals); free(sig); return ret; } int sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key) { /* Parse additional security-key application string */ if (sshbuf_get_cstring(b, &key->sk_application, NULL) != 0) return SSH_ERR_INVALID_FORMAT; return 0; } static int sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp, int allow_cert) { int type, ret = SSH_ERR_INTERNAL_ERROR; char *ktype = NULL; struct sshkey *key = NULL; struct sshbuf *copy; const struct sshkey_impl *impl; #ifdef DEBUG_PK /* XXX */ sshbuf_dump(b, stderr); #endif if (keyp != NULL) *keyp = NULL; if ((copy = sshbuf_fromb(b)) == NULL) { ret = SSH_ERR_ALLOC_FAIL; goto out; } if (sshbuf_get_cstring(b, &ktype, NULL) != 0) { ret = SSH_ERR_INVALID_FORMAT; goto out; } type = sshkey_type_from_name(ktype); if (!allow_cert && sshkey_type_is_cert(type)) { ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; goto out; } if ((impl = sshkey_impl_from_type(type)) == NULL) { ret = SSH_ERR_KEY_TYPE_UNKNOWN; goto out; } if ((key = sshkey_new(type)) == NULL) { ret = SSH_ERR_ALLOC_FAIL; goto out; } if (sshkey_type_is_cert(type)) { /* Skip nonce that precedes all certificates */ if (sshbuf_get_string_direct(b, NULL, NULL) != 0) { ret = SSH_ERR_INVALID_FORMAT; goto out; } } if ((ret = impl->funcs->deserialize_public(ktype, b, key)) != 0) goto out; /* Parse certificate potion */ if (sshkey_is_cert(key) && (ret = cert_parse(b, key, copy)) != 0) goto out; if (key != NULL && sshbuf_len(b) != 0) { ret = SSH_ERR_INVALID_FORMAT; goto out; } ret = 0; if (keyp != NULL) { *keyp = key; key = NULL; } out: sshbuf_free(copy); sshkey_free(key); free(ktype); return ret; } int sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp) { struct sshbuf *b; int r; if ((b = sshbuf_from(blob, blen)) == NULL) return SSH_ERR_ALLOC_FAIL; r = sshkey_from_blob_internal(b, keyp, 1); sshbuf_free(b); return r; } int sshkey_fromb(struct sshbuf *b, struct sshkey **keyp) { return sshkey_from_blob_internal(b, keyp, 1); } int sshkey_froms(struct sshbuf *buf, struct sshkey **keyp) { struct sshbuf *b; int r; if ((r = sshbuf_froms(buf, &b)) != 0) return r; r = sshkey_from_blob_internal(b, keyp, 1); sshbuf_free(b); return r; } int sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep) { int r; struct sshbuf *b = NULL; char *sigtype = NULL; if (sigtypep != NULL) *sigtypep = NULL; if ((b = sshbuf_from(sig, siglen)) == NULL) return SSH_ERR_ALLOC_FAIL; if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0) goto out; /* success */ if (sigtypep != NULL) { *sigtypep = sigtype; sigtype = NULL; } r = 0; out: free(sigtype); sshbuf_free(b); return r; } /* * * Checks whether a certificate's signature type is allowed. * Returns 0 (success) if the certificate signature type appears in the * "allowed" pattern-list, or the key is not a certificate to begin with. * Otherwise returns a ssherr.h code. */ int sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed) { if (key == NULL || allowed == NULL) return SSH_ERR_INVALID_ARGUMENT; if (!sshkey_type_is_cert(key->type)) return 0; if (key->cert == NULL || key->cert->signature_type == NULL) return SSH_ERR_INVALID_ARGUMENT; if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1) return SSH_ERR_SIGN_ALG_UNSUPPORTED; return 0; } /* * Returns the expected signature algorithm for a given public key algorithm. */ const char * sshkey_sigalg_by_name(const char *name) { const struct sshkey_impl *impl; int i; for (i = 0; keyimpls[i] != NULL; i++) { impl = keyimpls[i]; if (strcmp(impl->name, name) != 0) continue; if (impl->sigalg != NULL) return impl->sigalg; if (!impl->cert) return impl->name; return sshkey_ssh_name_from_type_nid( sshkey_type_plain(impl->type), impl->nid); } return NULL; } /* * Verifies that the signature algorithm appearing inside the signature blob * matches that which was requested. */ int sshkey_check_sigtype(const u_char *sig, size_t siglen, const char *requested_alg) { const char *expected_alg; char *sigtype = NULL; int r; if (requested_alg == NULL) return 0; if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL) return SSH_ERR_INVALID_ARGUMENT; if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0) return r; r = strcmp(expected_alg, sigtype) == 0; free(sigtype); return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED; } int sshkey_sign(struct sshkey *key, u_char **sigp, size_t *lenp, const u_char *data, size_t datalen, const char *alg, const char *sk_provider, const char *sk_pin, u_int compat) { int was_shielded = sshkey_is_shielded(key); int r2, r = SSH_ERR_INTERNAL_ERROR; const struct sshkey_impl *impl; if (sigp != NULL) *sigp = NULL; if (lenp != NULL) *lenp = 0; if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE) return SSH_ERR_INVALID_ARGUMENT; if ((impl = sshkey_impl_from_key(key)) == NULL) return SSH_ERR_KEY_TYPE_UNKNOWN; if ((r = sshkey_unshield_private(key)) != 0) return r; if (sshkey_is_sk(key)) { r = sshsk_sign(sk_provider, key, sigp, lenp, data, datalen, compat, sk_pin); } else { if (impl->funcs->sign == NULL) r = SSH_ERR_SIGN_ALG_UNSUPPORTED; else { r = impl->funcs->sign(key, sigp, lenp, data, datalen, alg, sk_provider, sk_pin, compat); } } if (was_shielded && (r2 = sshkey_shield_private(key)) != 0) return r2; return r; } /* * ssh_key_verify returns 0 for a correct signature and < 0 on error. * If "alg" specified, then the signature must use that algorithm. */ int sshkey_verify(const struct sshkey *key, const u_char *sig, size_t siglen, const u_char *data, size_t dlen, const char *alg, u_int compat, struct sshkey_sig_details **detailsp) { const struct sshkey_impl *impl; if (detailsp != NULL) *detailsp = NULL; if (siglen == 0 || dlen > SSH_KEY_MAX_SIGN_DATA_SIZE) return SSH_ERR_INVALID_ARGUMENT; if ((impl = sshkey_impl_from_key(key)) == NULL) return SSH_ERR_KEY_TYPE_UNKNOWN; return impl->funcs->verify(key, sig, siglen, data, dlen, alg, compat, detailsp); } /* Convert a plain key to their _CERT equivalent */ int sshkey_to_certified(struct sshkey *k) { int newtype; if ((newtype = sshkey_type_certified(k->type)) == -1) return SSH_ERR_INVALID_ARGUMENT; if ((k->cert = cert_new()) == NULL) return SSH_ERR_ALLOC_FAIL; k->type = newtype; return 0; } /* Convert a certificate to its raw key equivalent */ int sshkey_drop_cert(struct sshkey *k) { if (!sshkey_type_is_cert(k->type)) return SSH_ERR_KEY_TYPE_UNKNOWN; cert_free(k->cert); k->cert = NULL; k->type = sshkey_type_plain(k->type); return 0; } /* Sign a certified key, (re-)generating the signed certblob. */ int sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg, const char *sk_provider, const char *sk_pin, sshkey_certify_signer *signer, void *signer_ctx) { const struct sshkey_impl *impl; struct sshbuf *principals = NULL; u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32]; size_t i, ca_len, sig_len; int ret = SSH_ERR_INTERNAL_ERROR; struct sshbuf *cert = NULL; char *sigtype = NULL; if (k == NULL || k->cert == NULL || k->cert->certblob == NULL || ca == NULL) return SSH_ERR_INVALID_ARGUMENT; if (!sshkey_is_cert(k)) return SSH_ERR_KEY_TYPE_UNKNOWN; if (!sshkey_type_is_valid_ca(ca->type)) return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; if ((impl = sshkey_impl_from_key(k)) == NULL) return SSH_ERR_INTERNAL_ERROR; /* * If no alg specified as argument but a signature_type was set, * then prefer that. If both were specified, then they must match. */ if (alg == NULL) alg = k->cert->signature_type; else if (k->cert->signature_type != NULL && strcmp(alg, k->cert->signature_type) != 0) return SSH_ERR_INVALID_ARGUMENT; /* * If no signing algorithm or signature_type was specified and we're * using a RSA key, then default to a good signature algorithm. */ if (alg == NULL && ca->type == KEY_RSA) alg = "rsa-sha2-512"; if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0) return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; cert = k->cert->certblob; /* for readability */ sshbuf_reset(cert); if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0) goto out; /* -v01 certs put nonce first */ arc4random_buf(&nonce, sizeof(nonce)); if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0) goto out; /* Public key next */ if ((ret = impl->funcs->serialize_public(k, cert, SSHKEY_SERIALIZE_DEFAULT)) != 0) goto out; /* Then remaining cert fields */ if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 || (ret = sshbuf_put_u32(cert, k->cert->type)) != 0 || (ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0) goto out; if ((principals = sshbuf_new()) == NULL) { ret = SSH_ERR_ALLOC_FAIL; goto out; } for (i = 0; i < k->cert->nprincipals; i++) { if ((ret = sshbuf_put_cstring(principals, k->cert->principals[i])) != 0) goto out; } if ((ret = sshbuf_put_stringb(cert, principals)) != 0 || (ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 || (ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 || (ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 || (ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 || (ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */ (ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0) goto out; /* Sign the whole mess */ if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert), sshbuf_len(cert), alg, sk_provider, sk_pin, 0, signer_ctx)) != 0) goto out; /* Check and update signature_type against what was actually used */ if ((ret = sshkey_get_sigtype(sig_blob, sig_len, &sigtype)) != 0) goto out; if (alg != NULL && strcmp(alg, sigtype) != 0) { ret = SSH_ERR_SIGN_ALG_UNSUPPORTED; goto out; } if (k->cert->signature_type == NULL) { k->cert->signature_type = sigtype; sigtype = NULL; } /* Append signature and we are done */ if ((ret = sshbuf_put_string(cert, sig_blob, sig_len)) != 0) goto out; ret = 0; out: if (ret != 0) sshbuf_reset(cert); free(sig_blob); free(ca_blob); free(sigtype); sshbuf_free(principals); return ret; } static int default_key_sign(struct sshkey *key, u_char **sigp, size_t *lenp, const u_char *data, size_t datalen, const char *alg, const char *sk_provider, const char *sk_pin, u_int compat, void *ctx) { if (ctx != NULL) return SSH_ERR_INVALID_ARGUMENT; return sshkey_sign(key, sigp, lenp, data, datalen, alg, sk_provider, sk_pin, compat); } int sshkey_certify(struct sshkey *k, struct sshkey *ca, const char *alg, const char *sk_provider, const char *sk_pin) { return sshkey_certify_custom(k, ca, alg, sk_provider, sk_pin, default_key_sign, NULL); } int sshkey_cert_check_authority(const struct sshkey *k, int want_host, int require_principal, int wildcard_pattern, uint64_t verify_time, const char *name, const char **reason) { u_int i, principal_matches; if (reason == NULL) return SSH_ERR_INVALID_ARGUMENT; if (!sshkey_is_cert(k)) { *reason = "Key is not a certificate"; return SSH_ERR_KEY_CERT_INVALID; } if (want_host) { if (k->cert->type != SSH2_CERT_TYPE_HOST) { *reason = "Certificate invalid: not a host certificate"; return SSH_ERR_KEY_CERT_INVALID; } } else { if (k->cert->type != SSH2_CERT_TYPE_USER) { *reason = "Certificate invalid: not a user certificate"; return SSH_ERR_KEY_CERT_INVALID; } } if (verify_time < k->cert->valid_after) { *reason = "Certificate invalid: not yet valid"; return SSH_ERR_KEY_CERT_INVALID; } if (verify_time >= k->cert->valid_before) { *reason = "Certificate invalid: expired"; return SSH_ERR_KEY_CERT_INVALID; } if (k->cert->nprincipals == 0) { if (require_principal) { *reason = "Certificate lacks principal list"; return SSH_ERR_KEY_CERT_INVALID; } } else if (name != NULL) { principal_matches = 0; for (i = 0; i < k->cert->nprincipals; i++) { if (wildcard_pattern) { if (match_pattern(k->cert->principals[i], name)) { principal_matches = 1; break; } } else if (strcmp(name, k->cert->principals[i]) == 0) { principal_matches = 1; break; } } if (!principal_matches) { *reason = "Certificate invalid: name is not a listed " "principal"; return SSH_ERR_KEY_CERT_INVALID; } } return 0; } int sshkey_cert_check_authority_now(const struct sshkey *k, int want_host, int require_principal, int wildcard_pattern, const char *name, const char **reason) { time_t now; if ((now = time(NULL)) < 0) { /* yikes - system clock before epoch! */ *reason = "Certificate invalid: not yet valid"; return SSH_ERR_KEY_CERT_INVALID; } return sshkey_cert_check_authority(k, want_host, require_principal, wildcard_pattern, (uint64_t)now, name, reason); } int sshkey_cert_check_host(const struct sshkey *key, const char *host, int wildcard_principals, const char *ca_sign_algorithms, const char **reason) { int r; if ((r = sshkey_cert_check_authority_now(key, 1, 0, wildcard_principals, host, reason)) != 0) return r; if (sshbuf_len(key->cert->critical) != 0) { *reason = "Certificate contains unsupported critical options"; return SSH_ERR_KEY_CERT_INVALID; } if (ca_sign_algorithms != NULL && (r = sshkey_check_cert_sigtype(key, ca_sign_algorithms)) != 0) { *reason = "Certificate signed with disallowed algorithm"; return SSH_ERR_KEY_CERT_INVALID; } return 0; } size_t sshkey_format_cert_validity(const struct sshkey_cert *cert, char *s, size_t l) { char from[32], to[32], ret[128]; *from = *to = '\0'; if (cert->valid_after == 0 && cert->valid_before == 0xffffffffffffffffULL) return strlcpy(s, "forever", l); if (cert->valid_after != 0) format_absolute_time(cert->valid_after, from, sizeof(from)); if (cert->valid_before != 0xffffffffffffffffULL) format_absolute_time(cert->valid_before, to, sizeof(to)); if (cert->valid_after == 0) snprintf(ret, sizeof(ret), "before %s", to); else if (cert->valid_before == 0xffffffffffffffffULL) snprintf(ret, sizeof(ret), "after %s", from); else snprintf(ret, sizeof(ret), "from %s to %s", from, to); return strlcpy(s, ret, l); } /* Common serialization for FIDO private keys */ int sshkey_serialize_private_sk(const struct sshkey *key, struct sshbuf *b) { int r; if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0 || (r = sshbuf_put_u8(b, key->sk_flags)) != 0 || (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 || (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0) return r; return 0; } int sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf, enum sshkey_serialize_rep opts) { int r = SSH_ERR_INTERNAL_ERROR; int was_shielded = sshkey_is_shielded(key); struct sshbuf *b = NULL; const struct sshkey_impl *impl; if ((impl = sshkey_impl_from_key(key)) == NULL) return SSH_ERR_INTERNAL_ERROR; if ((r = sshkey_unshield_private(key)) != 0) return r; if ((b = sshbuf_new()) == NULL) return SSH_ERR_ALLOC_FAIL; if ((r = sshbuf_put_cstring(b, sshkey_ssh_name(key))) != 0) goto out; if (sshkey_is_cert(key)) { if (key->cert == NULL || sshbuf_len(key->cert->certblob) == 0) { r = SSH_ERR_INVALID_ARGUMENT; goto out; } if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0) goto out; } if ((r = impl->funcs->serialize_private(key, b, opts)) != 0) goto out; /* * success (but we still need to append the output to buf after * possibly re-shielding the private key) */ r = 0; out: if (was_shielded) r = sshkey_shield_private(key); if (r == 0) r = sshbuf_putb(buf, b); sshbuf_free(b); return r; } int sshkey_private_serialize(struct sshkey *key, struct sshbuf *b) { return sshkey_private_serialize_opt(key, b, SSHKEY_SERIALIZE_DEFAULT); } /* Shared deserialization of FIDO private key components */ int sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k) { int r; if ((k->sk_key_handle = sshbuf_new()) == NULL || (k->sk_reserved = sshbuf_new()) == NULL) return SSH_ERR_ALLOC_FAIL; if ((r = sshbuf_get_cstring(buf, &k->sk_application, NULL)) != 0 || (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 || (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 || (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0) return r; return 0; } int sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp) { const struct sshkey_impl *impl; char *tname = NULL; char *expect_sk_application = NULL; u_char *expect_ed25519_pk = NULL; struct sshkey *k = NULL; int type, r = SSH_ERR_INTERNAL_ERROR; if (kp != NULL) *kp = NULL; if ((r = sshbuf_get_cstring(buf, &tname, NULL)) != 0) goto out; type = sshkey_type_from_name(tname); if (sshkey_type_is_cert(type)) { /* * Certificate key private keys begin with the certificate * itself. Make sure this matches the type of the enclosing * private key. */ if ((r = sshkey_froms(buf, &k)) != 0) goto out; if (k->type != type) { r = SSH_ERR_KEY_CERT_MISMATCH; goto out; } /* For ECDSA keys, the group must match too */ if (k->type == KEY_ECDSA && k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) { r = SSH_ERR_KEY_CERT_MISMATCH; goto out; } /* * Several fields are redundant between certificate and * private key body, we require these to match. */ expect_sk_application = k->sk_application; expect_ed25519_pk = k->ed25519_pk; k->sk_application = NULL; k->ed25519_pk = NULL; /* XXX xmss too or refactor */ } else { if ((k = sshkey_new(type)) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } } if ((impl = sshkey_impl_from_type(type)) == NULL) { r = SSH_ERR_INTERNAL_ERROR; goto out; } if ((r = impl->funcs->deserialize_private(tname, buf, k)) != 0) goto out; /* XXX xmss too or refactor */ if ((expect_sk_application != NULL && (k->sk_application == NULL || strcmp(expect_sk_application, k->sk_application) != 0)) || (expect_ed25519_pk != NULL && (k->ed25519_pk == NULL || memcmp(expect_ed25519_pk, k->ed25519_pk, ED25519_PK_SZ) != 0))) { r = SSH_ERR_KEY_CERT_MISMATCH; goto out; } /* success */ r = 0; if (kp != NULL) { *kp = k; k = NULL; } out: free(tname); sshkey_free(k); free(expect_sk_application); free(expect_ed25519_pk); return r; } #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) int sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public) { EC_POINT *nq = NULL; BIGNUM *order = NULL, *x = NULL, *y = NULL, *tmp = NULL; int ret = SSH_ERR_KEY_INVALID_EC_VALUE; /* * NB. This assumes OpenSSL has already verified that the public * point lies on the curve. This is done by EC_POINT_oct2point() * implicitly calling EC_POINT_is_on_curve(). If this code is ever * reachable with public points not unmarshalled using * EC_POINT_oct2point then the caller will need to explicitly check. */ /* * We shouldn't ever hit this case because bignum_get_ecpoint() * refuses to load GF2m points. */ if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) != NID_X9_62_prime_field) goto out; /* Q != infinity */ if (EC_POINT_is_at_infinity(group, public)) goto out; if ((x = BN_new()) == NULL || (y = BN_new()) == NULL || (order = BN_new()) == NULL || (tmp = BN_new()) == NULL) { ret = SSH_ERR_ALLOC_FAIL; goto out; } /* log2(x) > log2(order)/2, log2(y) > log2(order)/2 */ if (EC_GROUP_get_order(group, order, NULL) != 1 || EC_POINT_get_affine_coordinates_GFp(group, public, x, y, NULL) != 1) { ret = SSH_ERR_LIBCRYPTO_ERROR; goto out; } if (BN_num_bits(x) <= BN_num_bits(order) / 2 || BN_num_bits(y) <= BN_num_bits(order) / 2) goto out; /* nQ == infinity (n == order of subgroup) */ if ((nq = EC_POINT_new(group)) == NULL) { ret = SSH_ERR_ALLOC_FAIL; goto out; } if (EC_POINT_mul(group, nq, NULL, public, order, NULL) != 1) { ret = SSH_ERR_LIBCRYPTO_ERROR; goto out; } if (EC_POINT_is_at_infinity(group, nq) != 1) goto out; /* x < order - 1, y < order - 1 */ if (!BN_sub(tmp, order, BN_value_one())) { ret = SSH_ERR_LIBCRYPTO_ERROR; goto out; } if (BN_cmp(x, tmp) >= 0 || BN_cmp(y, tmp) >= 0) goto out; ret = 0; out: BN_clear_free(x); BN_clear_free(y); BN_clear_free(order); BN_clear_free(tmp); EC_POINT_free(nq); return ret; } int sshkey_ec_validate_private(const EC_KEY *key) { BIGNUM *order = NULL, *tmp = NULL; int ret = SSH_ERR_KEY_INVALID_EC_VALUE; if ((order = BN_new()) == NULL || (tmp = BN_new()) == NULL) { ret = SSH_ERR_ALLOC_FAIL; goto out; } /* log2(private) > log2(order)/2 */ if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, NULL) != 1) { ret = SSH_ERR_LIBCRYPTO_ERROR; goto out; } if (BN_num_bits(EC_KEY_get0_private_key(key)) <= BN_num_bits(order) / 2) goto out; /* private < order - 1 */ if (!BN_sub(tmp, order, BN_value_one())) { ret = SSH_ERR_LIBCRYPTO_ERROR; goto out; } if (BN_cmp(EC_KEY_get0_private_key(key), tmp) >= 0) goto out; ret = 0; out: BN_clear_free(order); BN_clear_free(tmp); return ret; } void sshkey_dump_ec_point(const EC_GROUP *group, const EC_POINT *point) { BIGNUM *x = NULL, *y = NULL; if (point == NULL) { fputs("point=(NULL)\n", stderr); return; } if ((x = BN_new()) == NULL || (y = BN_new()) == NULL) { fprintf(stderr, "%s: BN_new failed\n", __func__); goto out; } if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) != NID_X9_62_prime_field) { fprintf(stderr, "%s: group is not a prime field\n", __func__); goto out; } if (EC_POINT_get_affine_coordinates_GFp(group, point, x, y, NULL) != 1) { fprintf(stderr, "%s: EC_POINT_get_affine_coordinates_GFp\n", __func__); goto out; } fputs("x=", stderr); BN_print_fp(stderr, x); fputs("\ny=", stderr); BN_print_fp(stderr, y); fputs("\n", stderr); out: BN_clear_free(x); BN_clear_free(y); } void sshkey_dump_ec_key(const EC_KEY *key) { const BIGNUM *exponent; sshkey_dump_ec_point(EC_KEY_get0_group(key), EC_KEY_get0_public_key(key)); fputs("exponent=", stderr); if ((exponent = EC_KEY_get0_private_key(key)) == NULL) fputs("(NULL)", stderr); else BN_print_fp(stderr, EC_KEY_get0_private_key(key)); fputs("\n", stderr); } #endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */ static int sshkey_private_to_blob2(struct sshkey *prv, struct sshbuf *blob, const char *passphrase, const char *comment, const char *ciphername, int rounds) { u_char *cp, *key = NULL, *pubkeyblob = NULL; u_char salt[SALT_LEN]; size_t i, pubkeylen, keylen, ivlen, blocksize, authlen; u_int check; int r = SSH_ERR_INTERNAL_ERROR; struct sshcipher_ctx *ciphercontext = NULL; const struct sshcipher *cipher; const char *kdfname = KDFNAME; struct sshbuf *encoded = NULL, *encrypted = NULL, *kdf = NULL; if (rounds <= 0) rounds = DEFAULT_ROUNDS; if (passphrase == NULL || !strlen(passphrase)) { ciphername = "none"; kdfname = "none"; } else if (ciphername == NULL) ciphername = DEFAULT_CIPHERNAME; if ((cipher = cipher_by_name(ciphername)) == NULL) { r = SSH_ERR_INVALID_ARGUMENT; goto out; } if ((kdf = sshbuf_new()) == NULL || (encoded = sshbuf_new()) == NULL || (encrypted = sshbuf_new()) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } blocksize = cipher_blocksize(cipher); keylen = cipher_keylen(cipher); ivlen = cipher_ivlen(cipher); authlen = cipher_authlen(cipher); if ((key = calloc(1, keylen + ivlen)) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } if (strcmp(kdfname, "bcrypt") == 0) { arc4random_buf(salt, SALT_LEN); if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, SALT_LEN, key, keylen + ivlen, rounds) < 0) { r = SSH_ERR_INVALID_ARGUMENT; goto out; } if ((r = sshbuf_put_string(kdf, salt, SALT_LEN)) != 0 || (r = sshbuf_put_u32(kdf, rounds)) != 0) goto out; } else if (strcmp(kdfname, "none") != 0) { /* Unsupported KDF type */ r = SSH_ERR_KEY_UNKNOWN_CIPHER; goto out; } if ((r = cipher_init(&ciphercontext, cipher, key, keylen, key + keylen, ivlen, 1)) != 0) goto out; if ((r = sshbuf_put(encoded, AUTH_MAGIC, sizeof(AUTH_MAGIC))) != 0 || (r = sshbuf_put_cstring(encoded, ciphername)) != 0 || (r = sshbuf_put_cstring(encoded, kdfname)) != 0 || (r = sshbuf_put_stringb(encoded, kdf)) != 0 || (r = sshbuf_put_u32(encoded, 1)) != 0 || /* number of keys */ (r = sshkey_to_blob(prv, &pubkeyblob, &pubkeylen)) != 0 || (r = sshbuf_put_string(encoded, pubkeyblob, pubkeylen)) != 0) goto out; /* set up the buffer that will be encrypted */ /* Random check bytes */ check = arc4random(); if ((r = sshbuf_put_u32(encrypted, check)) != 0 || (r = sshbuf_put_u32(encrypted, check)) != 0) goto out; /* append private key and comment*/ if ((r = sshkey_private_serialize_opt(prv, encrypted, SSHKEY_SERIALIZE_FULL)) != 0 || (r = sshbuf_put_cstring(encrypted, comment)) != 0) goto out; /* padding */ i = 0; while (sshbuf_len(encrypted) % blocksize) { if ((r = sshbuf_put_u8(encrypted, ++i & 0xff)) != 0) goto out; } /* length in destination buffer */ if ((r = sshbuf_put_u32(encoded, sshbuf_len(encrypted))) != 0) goto out; /* encrypt */ if ((r = sshbuf_reserve(encoded, sshbuf_len(encrypted) + authlen, &cp)) != 0) goto out; if ((r = cipher_crypt(ciphercontext, 0, cp, sshbuf_ptr(encrypted), sshbuf_len(encrypted), 0, authlen)) != 0) goto out; sshbuf_reset(blob); /* assemble uuencoded key */ if ((r = sshbuf_put(blob, MARK_BEGIN, MARK_BEGIN_LEN)) != 0 || (r = sshbuf_dtob64(encoded, blob, 1)) != 0 || (r = sshbuf_put(blob, MARK_END, MARK_END_LEN)) != 0) goto out; /* success */ r = 0; out: sshbuf_free(kdf); sshbuf_free(encoded); sshbuf_free(encrypted); cipher_free(ciphercontext); explicit_bzero(salt, sizeof(salt)); if (key != NULL) freezero(key, keylen + ivlen); if (pubkeyblob != NULL) freezero(pubkeyblob, pubkeylen); return r; } static int private2_uudecode(struct sshbuf *blob, struct sshbuf **decodedp) { const u_char *cp; size_t encoded_len; int r; u_char last; struct sshbuf *encoded = NULL, *decoded = NULL; if (blob == NULL || decodedp == NULL) return SSH_ERR_INVALID_ARGUMENT; *decodedp = NULL; if ((encoded = sshbuf_new()) == NULL || (decoded = sshbuf_new()) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } /* check preamble */ cp = sshbuf_ptr(blob); encoded_len = sshbuf_len(blob); if (encoded_len < (MARK_BEGIN_LEN + MARK_END_LEN) || memcmp(cp, MARK_BEGIN, MARK_BEGIN_LEN) != 0) { r = SSH_ERR_INVALID_FORMAT; goto out; } cp += MARK_BEGIN_LEN; encoded_len -= MARK_BEGIN_LEN; /* Look for end marker, removing whitespace as we go */ while (encoded_len > 0) { if (*cp != '\n' && *cp != '\r') { if ((r = sshbuf_put_u8(encoded, *cp)) != 0) goto out; } last = *cp; encoded_len--; cp++; if (last == '\n') { if (encoded_len >= MARK_END_LEN && memcmp(cp, MARK_END, MARK_END_LEN) == 0) { /* \0 terminate */ if ((r = sshbuf_put_u8(encoded, 0)) != 0) goto out; break; } } } if (encoded_len == 0) { r = SSH_ERR_INVALID_FORMAT; goto out; } /* decode base64 */ if ((r = sshbuf_b64tod(decoded, (char *)sshbuf_ptr(encoded))) != 0) goto out; /* check magic */ if (sshbuf_len(decoded) < sizeof(AUTH_MAGIC) || memcmp(sshbuf_ptr(decoded), AUTH_MAGIC, sizeof(AUTH_MAGIC))) { r = SSH_ERR_INVALID_FORMAT; goto out; } /* success */ *decodedp = decoded; decoded = NULL; r = 0; out: sshbuf_free(encoded); sshbuf_free(decoded); return r; } static int private2_decrypt(struct sshbuf *decoded, const char *passphrase, struct sshbuf **decryptedp, struct sshkey **pubkeyp) { char *ciphername = NULL, *kdfname = NULL; const struct sshcipher *cipher = NULL; int r = SSH_ERR_INTERNAL_ERROR; size_t keylen = 0, ivlen = 0, authlen = 0, slen = 0; struct sshbuf *kdf = NULL, *decrypted = NULL; struct sshcipher_ctx *ciphercontext = NULL; struct sshkey *pubkey = NULL; u_char *key = NULL, *salt = NULL, *dp; u_int blocksize, rounds, nkeys, encrypted_len, check1, check2; if (decoded == NULL || decryptedp == NULL || pubkeyp == NULL) return SSH_ERR_INVALID_ARGUMENT; *decryptedp = NULL; *pubkeyp = NULL; if ((decrypted = sshbuf_new()) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } /* parse public portion of key */ if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 || (r = sshbuf_get_cstring(decoded, &ciphername, NULL)) != 0 || (r = sshbuf_get_cstring(decoded, &kdfname, NULL)) != 0 || (r = sshbuf_froms(decoded, &kdf)) != 0 || (r = sshbuf_get_u32(decoded, &nkeys)) != 0) goto out; if (nkeys != 1) { /* XXX only one key supported at present */ r = SSH_ERR_INVALID_FORMAT; goto out; } if ((r = sshkey_froms(decoded, &pubkey)) != 0 || (r = sshbuf_get_u32(decoded, &encrypted_len)) != 0) goto out; if ((cipher = cipher_by_name(ciphername)) == NULL) { r = SSH_ERR_KEY_UNKNOWN_CIPHER; goto out; } if (strcmp(kdfname, "none") != 0 && strcmp(kdfname, "bcrypt") != 0) { r = SSH_ERR_KEY_UNKNOWN_CIPHER; goto out; } if (strcmp(kdfname, "none") == 0 && strcmp(ciphername, "none") != 0) { r = SSH_ERR_INVALID_FORMAT; goto out; } if ((passphrase == NULL || strlen(passphrase) == 0) && strcmp(kdfname, "none") != 0) { /* passphrase required */ r = SSH_ERR_KEY_WRONG_PASSPHRASE; goto out; } /* check size of encrypted key blob */ blocksize = cipher_blocksize(cipher); if (encrypted_len < blocksize || (encrypted_len % blocksize) != 0) { r = SSH_ERR_INVALID_FORMAT; goto out; } /* setup key */ keylen = cipher_keylen(cipher); ivlen = cipher_ivlen(cipher); authlen = cipher_authlen(cipher); if ((key = calloc(1, keylen + ivlen)) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } if (strcmp(kdfname, "bcrypt") == 0) { if ((r = sshbuf_get_string(kdf, &salt, &slen)) != 0 || (r = sshbuf_get_u32(kdf, &rounds)) != 0) goto out; if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, slen, key, keylen + ivlen, rounds) < 0) { r = SSH_ERR_INVALID_FORMAT; goto out; } } /* check that an appropriate amount of auth data is present */ if (sshbuf_len(decoded) < authlen || sshbuf_len(decoded) - authlen < encrypted_len) { r = SSH_ERR_INVALID_FORMAT; goto out; } /* decrypt private portion of key */ if ((r = sshbuf_reserve(decrypted, encrypted_len, &dp)) != 0 || (r = cipher_init(&ciphercontext, cipher, key, keylen, key + keylen, ivlen, 0)) != 0) goto out; if ((r = cipher_crypt(ciphercontext, 0, dp, sshbuf_ptr(decoded), encrypted_len, 0, authlen)) != 0) { /* an integrity error here indicates an incorrect passphrase */ if (r == SSH_ERR_MAC_INVALID) r = SSH_ERR_KEY_WRONG_PASSPHRASE; goto out; } if ((r = sshbuf_consume(decoded, encrypted_len + authlen)) != 0) goto out; /* there should be no trailing data */ if (sshbuf_len(decoded) != 0) { r = SSH_ERR_INVALID_FORMAT; goto out; } /* check check bytes */ if ((r = sshbuf_get_u32(decrypted, &check1)) != 0 || (r = sshbuf_get_u32(decrypted, &check2)) != 0) goto out; if (check1 != check2) { r = SSH_ERR_KEY_WRONG_PASSPHRASE; goto out; } /* success */ *decryptedp = decrypted; decrypted = NULL; *pubkeyp = pubkey; pubkey = NULL; r = 0; out: cipher_free(ciphercontext); free(ciphername); free(kdfname); sshkey_free(pubkey); if (salt != NULL) { explicit_bzero(salt, slen); free(salt); } if (key != NULL) { explicit_bzero(key, keylen + ivlen); free(key); } sshbuf_free(kdf); sshbuf_free(decrypted); return r; } static int sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase, struct sshkey **keyp, char **commentp) { char *comment = NULL; int r = SSH_ERR_INTERNAL_ERROR; struct sshbuf *decoded = NULL, *decrypted = NULL; struct sshkey *k = NULL, *pubkey = NULL; if (keyp != NULL) *keyp = NULL; if (commentp != NULL) *commentp = NULL; /* Undo base64 encoding and decrypt the private section */ if ((r = private2_uudecode(blob, &decoded)) != 0 || (r = private2_decrypt(decoded, passphrase, &decrypted, &pubkey)) != 0) goto out; if (type != KEY_UNSPEC && sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) { r = SSH_ERR_KEY_TYPE_MISMATCH; goto out; } /* Load the private key and comment */ if ((r = sshkey_private_deserialize(decrypted, &k)) != 0 || (r = sshbuf_get_cstring(decrypted, &comment, NULL)) != 0) goto out; /* Check deterministic padding after private section */ if ((r = private2_check_padding(decrypted)) != 0) goto out; /* Check that the public key in the envelope matches the private key */ if (!sshkey_equal(pubkey, k)) { r = SSH_ERR_INVALID_FORMAT; goto out; } /* success */ r = 0; if (keyp != NULL) { *keyp = k; k = NULL; } if (commentp != NULL) { *commentp = comment; comment = NULL; } out: free(comment); sshbuf_free(decoded); sshbuf_free(decrypted); sshkey_free(k); sshkey_free(pubkey); return r; } static int sshkey_parse_private2_pubkey(struct sshbuf *blob, int type, struct sshkey **keyp) { int r = SSH_ERR_INTERNAL_ERROR; struct sshbuf *decoded = NULL; struct sshkey *pubkey = NULL; u_int nkeys = 0; if (keyp != NULL) *keyp = NULL; if ((r = private2_uudecode(blob, &decoded)) != 0) goto out; /* parse public key from unencrypted envelope */ if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 || (r = sshbuf_skip_string(decoded)) != 0 || /* cipher */ (r = sshbuf_skip_string(decoded)) != 0 || /* KDF alg */ (r = sshbuf_skip_string(decoded)) != 0 || /* KDF hint */ (r = sshbuf_get_u32(decoded, &nkeys)) != 0) goto out; if (nkeys != 1) { /* XXX only one key supported at present */ r = SSH_ERR_INVALID_FORMAT; goto out; } /* Parse the public key */ if ((r = sshkey_froms(decoded, &pubkey)) != 0) goto out; if (type != KEY_UNSPEC && sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) { r = SSH_ERR_KEY_TYPE_MISMATCH; goto out; } /* success */ r = 0; if (keyp != NULL) { *keyp = pubkey; pubkey = NULL; } out: sshbuf_free(decoded); sshkey_free(pubkey); return r; } #ifdef WITH_OPENSSL /* convert SSH v2 key to PEM or PKCS#8 format */ static int sshkey_private_to_blob_pem_pkcs8(struct sshkey *key, struct sshbuf *buf, int format, const char *_passphrase, const char *comment) { int was_shielded = sshkey_is_shielded(key); int success, r; int blen, len = strlen(_passphrase); u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL; const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL; char *bptr; BIO *bio = NULL; struct sshbuf *blob; EVP_PKEY *pkey = NULL; if (len > 0 && len <= 4) return SSH_ERR_PASSPHRASE_TOO_SHORT; if ((blob = sshbuf_new()) == NULL) return SSH_ERR_ALLOC_FAIL; if ((bio = BIO_new(BIO_s_mem())) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } if ((r = sshkey_unshield_private(key)) != 0) goto out; switch (key->type) { #ifdef WITH_DSA case KEY_DSA: if (format == SSHKEY_PRIVATE_PEM) { success = PEM_write_bio_DSAPrivateKey(bio, key->dsa, cipher, passphrase, len, NULL, NULL); } else { if ((pkey = EVP_PKEY_new()) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } success = EVP_PKEY_set1_DSA(pkey, key->dsa); } break; #endif #ifdef OPENSSL_HAS_ECC case KEY_ECDSA: if (format == SSHKEY_PRIVATE_PEM) { success = PEM_write_bio_ECPrivateKey(bio, EVP_PKEY_get0_EC_KEY(key->pkey), cipher, passphrase, len, NULL, NULL); } else { pkey = key->pkey; EVP_PKEY_up_ref(key->pkey); success = 1; } break; #endif case KEY_RSA: if (format == SSHKEY_PRIVATE_PEM) { success = PEM_write_bio_RSAPrivateKey(bio, EVP_PKEY_get0_RSA(key->pkey), cipher, passphrase, len, NULL, NULL); } else { pkey = key->pkey; EVP_PKEY_up_ref(key->pkey); success = 1; } break; default: success = 0; break; } if (success == 0) { r = SSH_ERR_LIBCRYPTO_ERROR; goto out; } if (format == SSHKEY_PRIVATE_PKCS8) { if ((success = PEM_write_bio_PrivateKey(bio, pkey, cipher, passphrase, len, NULL, NULL)) == 0) { r = SSH_ERR_LIBCRYPTO_ERROR; goto out; } } if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0) { r = SSH_ERR_INTERNAL_ERROR; goto out; } if ((r = sshbuf_put(blob, bptr, blen)) != 0) goto out; r = 0; out: if (was_shielded) r = sshkey_shield_private(key); if (r == 0) r = sshbuf_putb(buf, blob); EVP_PKEY_free(pkey); sshbuf_free(blob); BIO_free(bio); return r; } #endif /* WITH_OPENSSL */ /* Serialise "key" to buffer "blob" */ int sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob, const char *passphrase, const char *comment, int format, const char *openssh_format_cipher, int openssh_format_rounds) { switch (key->type) { #ifdef WITH_OPENSSL case KEY_DSA: case KEY_ECDSA: case KEY_RSA: break; /* see below */ #endif /* WITH_OPENSSL */ case KEY_ED25519: case KEY_ED25519_SK: #ifdef WITH_XMSS case KEY_XMSS: #endif /* WITH_XMSS */ #ifdef WITH_OPENSSL case KEY_ECDSA_SK: #endif /* WITH_OPENSSL */ return sshkey_private_to_blob2(key, blob, passphrase, comment, openssh_format_cipher, openssh_format_rounds); default: return SSH_ERR_KEY_TYPE_UNKNOWN; } #ifdef WITH_OPENSSL switch (format) { case SSHKEY_PRIVATE_OPENSSH: return sshkey_private_to_blob2(key, blob, passphrase, comment, openssh_format_cipher, openssh_format_rounds); case SSHKEY_PRIVATE_PEM: case SSHKEY_PRIVATE_PKCS8: return sshkey_private_to_blob_pem_pkcs8(key, blob, format, passphrase, comment); default: return SSH_ERR_INVALID_ARGUMENT; } #endif /* WITH_OPENSSL */ } #ifdef WITH_OPENSSL static int translate_libcrypto_error(unsigned long pem_err) { int pem_reason = ERR_GET_REASON(pem_err); switch (ERR_GET_LIB(pem_err)) { case ERR_LIB_PEM: switch (pem_reason) { case PEM_R_BAD_PASSWORD_READ: #ifdef PEM_R_PROBLEMS_GETTING_PASSWORD case PEM_R_PROBLEMS_GETTING_PASSWORD: #endif #ifdef PEM_R_BAD_DECRYPT case PEM_R_BAD_DECRYPT: #endif return SSH_ERR_KEY_WRONG_PASSPHRASE; default: return SSH_ERR_INVALID_FORMAT; } case ERR_LIB_EVP: switch (pem_reason) { #ifdef EVP_R_BAD_DECRYPT case EVP_R_BAD_DECRYPT: return SSH_ERR_KEY_WRONG_PASSPHRASE; #endif #ifdef EVP_R_BN_DECODE_ERROR case EVP_R_BN_DECODE_ERROR: #endif case EVP_R_DECODE_ERROR: #ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR case EVP_R_PRIVATE_KEY_DECODE_ERROR: #endif return SSH_ERR_INVALID_FORMAT; default: return SSH_ERR_LIBCRYPTO_ERROR; } case ERR_LIB_ASN1: return SSH_ERR_INVALID_FORMAT; } return SSH_ERR_LIBCRYPTO_ERROR; } static void clear_libcrypto_errors(void) { while (ERR_get_error() != 0) ; } /* * Translate OpenSSL error codes to determine whether * passphrase is required/incorrect. */ static int convert_libcrypto_error(void) { /* * Some password errors are reported at the beginning * of the error queue. */ if (translate_libcrypto_error(ERR_peek_error()) == SSH_ERR_KEY_WRONG_PASSPHRASE) return SSH_ERR_KEY_WRONG_PASSPHRASE; return translate_libcrypto_error(ERR_peek_last_error()); } static int pem_passphrase_cb(char *buf, int size, int rwflag, void *u) { char *p = (char *)u; size_t len; if (p == NULL || (len = strlen(p)) == 0) return -1; if (size < 0 || len > (size_t)size) return -1; memcpy(buf, p, len); return (int)len; } static int sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type, const char *passphrase, struct sshkey **keyp) { EVP_PKEY *pk = NULL; struct sshkey *prv = NULL; BIO *bio = NULL; int r; RSA *rsa = NULL; EC_KEY *ecdsa = NULL; 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; } if ((rsa = EVP_PKEY_get1_RSA(pk)) == NULL) { r = SSH_ERR_LIBCRYPTO_ERROR; goto out; } prv->type = KEY_RSA; #ifdef DEBUG_PK RSA_print_fp(stderr, rsa, 8); #endif if (RSA_blinding_on(rsa, NULL) != 1 || EVP_PKEY_set1_RSA(pk, rsa) != 1) { r = SSH_ERR_LIBCRYPTO_ERROR; goto out; } EVP_PKEY_up_ref(pk); prv->pkey = pk; if ((r = sshkey_check_rsa_length(prv, 0)) != 0) goto out; #ifdef WITH_DSA } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_DSA && (type == KEY_UNSPEC || type == KEY_DSA)) { if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } prv->dsa = EVP_PKEY_get1_DSA(pk); prv->type = KEY_DSA; #ifdef DEBUG_PK DSA_print_fp(stderr, prv->dsa, 8); #endif #endif #ifdef OPENSSL_HAS_ECC } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_EC && (type == KEY_UNSPEC || type == KEY_ECDSA)) { if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } if ((prv->ecdsa_nid = sshkey_ecdsa_fixup_group(pk)) == -1 || (ecdsa = EVP_PKEY_get1_EC_KEY(pk)) == NULL) { r = SSH_ERR_LIBCRYPTO_ERROR; goto out; } prv->type = KEY_ECDSA; if (sshkey_curve_nid_to_name(prv->ecdsa_nid) == NULL || sshkey_ec_validate_public(EC_KEY_get0_group(ecdsa), EC_KEY_get0_public_key(ecdsa)) != 0 || sshkey_ec_validate_private(ecdsa) != 0) { r = SSH_ERR_INVALID_FORMAT; goto out; } EVP_PKEY_up_ref(pk); prv->pkey = pk; #ifdef DEBUG_PK if (prv != NULL && prv->pkey != NULL) sshkey_dump_ec_key(EVP_PKEY_get0_EC_KEY(prv->pkey)); #endif #endif /* OPENSSL_HAS_ECC */ #ifdef OPENSSL_HAS_ED25519 } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_ED25519 && (type == KEY_UNSPEC || type == KEY_ED25519)) { size_t len; if ((prv = sshkey_new(KEY_UNSPEC)) == NULL || (prv->ed25519_sk = calloc(1, ED25519_SK_SZ)) == NULL || (prv->ed25519_pk = calloc(1, ED25519_PK_SZ)) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } prv->type = KEY_ED25519; len = ED25519_PK_SZ; if (!EVP_PKEY_get_raw_public_key(pk, prv->ed25519_pk, &len)) { r = SSH_ERR_LIBCRYPTO_ERROR; goto out; } if (len != ED25519_PK_SZ) { r = SSH_ERR_INVALID_FORMAT; goto out; } len = ED25519_SK_SZ - ED25519_PK_SZ; if (!EVP_PKEY_get_raw_private_key(pk, prv->ed25519_sk, &len)) { r = SSH_ERR_LIBCRYPTO_ERROR; goto out; } if (len != ED25519_SK_SZ - ED25519_PK_SZ) { r = SSH_ERR_INVALID_FORMAT; goto out; } /* Append the public key to our private key */ memcpy(prv->ed25519_sk + (ED25519_SK_SZ - ED25519_PK_SZ), prv->ed25519_pk, ED25519_PK_SZ); #ifdef DEBUG_PK sshbuf_dump_data(prv->ed25519_sk, ED25519_SK_SZ, stderr); #endif #endif /* OPENSSL_HAS_ED25519 */ } else { r = SSH_ERR_INVALID_FORMAT; goto out; } r = 0; if (keyp != NULL) { *keyp = prv; prv = NULL; } out: BIO_free(bio); EVP_PKEY_free(pk); RSA_free(rsa); #ifdef OPENSSL_HAS_ECC EC_KEY_free(ecdsa); #endif sshkey_free(prv); return r; } #endif /* WITH_OPENSSL */ int sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type, const char *passphrase, struct sshkey **keyp, char **commentp) { int r = SSH_ERR_INTERNAL_ERROR; if (keyp != NULL) *keyp = NULL; if (commentp != NULL) *commentp = NULL; switch (type) { case KEY_XMSS: /* No fallback for new-format-only keys */ return sshkey_parse_private2(blob, type, passphrase, keyp, commentp); default: r = sshkey_parse_private2(blob, type, passphrase, keyp, commentp); /* Only fallback to PEM parser if a format error occurred. */ if (r != SSH_ERR_INVALID_FORMAT) return r; #ifdef WITH_OPENSSL return sshkey_parse_private_pem_fileblob(blob, type, passphrase, keyp); #else return SSH_ERR_INVALID_FORMAT; #endif /* WITH_OPENSSL */ } } int sshkey_parse_private_fileblob(struct sshbuf *buffer, const char *passphrase, struct sshkey **keyp, char **commentp) { if (keyp != NULL) *keyp = NULL; if (commentp != NULL) *commentp = NULL; return sshkey_parse_private_fileblob_type(buffer, KEY_UNSPEC, passphrase, keyp, commentp); } void sshkey_sig_details_free(struct sshkey_sig_details *details) { freezero(details, sizeof(*details)); } int sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob, int type, struct sshkey **pubkeyp) { int r = SSH_ERR_INTERNAL_ERROR; if (pubkeyp != NULL) *pubkeyp = NULL; /* only new-format private keys bundle a public key inside */ if ((r = sshkey_parse_private2_pubkey(blob, type, pubkeyp)) != 0) return r; return 0; } #ifdef WITH_XMSS /* * serialize the key with the current state and forward the state * maxsign times. */ int sshkey_private_serialize_maxsign(struct sshkey *k, struct sshbuf *b, u_int32_t maxsign, int printerror) { int r, rupdate; if (maxsign == 0 || sshkey_type_plain(k->type) != KEY_XMSS) return sshkey_private_serialize_opt(k, b, SSHKEY_SERIALIZE_DEFAULT); if ((r = sshkey_xmss_get_state(k, printerror)) != 0 || (r = sshkey_private_serialize_opt(k, b, SSHKEY_SERIALIZE_STATE)) != 0 || (r = sshkey_xmss_forward_state(k, maxsign)) != 0) goto out; r = 0; out: if ((rupdate = sshkey_xmss_update_state(k, printerror)) != 0) { if (r == 0) r = rupdate; } return r; } u_int32_t sshkey_signatures_left(const struct sshkey *k) { if (sshkey_type_plain(k->type) == KEY_XMSS) return sshkey_xmss_signatures_left(k); return 0; } int sshkey_enable_maxsign(struct sshkey *k, u_int32_t maxsign) { if (sshkey_type_plain(k->type) != KEY_XMSS) return SSH_ERR_INVALID_ARGUMENT; return sshkey_xmss_enable_maxsign(k, maxsign); } int sshkey_set_filename(struct sshkey *k, const char *filename) { if (k == NULL) return SSH_ERR_INVALID_ARGUMENT; if (sshkey_type_plain(k->type) != KEY_XMSS) return 0; if (filename == NULL) return SSH_ERR_INVALID_ARGUMENT; if ((k->xmss_filename = strdup(filename)) == NULL) return SSH_ERR_ALLOC_FAIL; return 0; } #else int sshkey_private_serialize_maxsign(struct sshkey *k, struct sshbuf *b, u_int32_t maxsign, int printerror) { return sshkey_private_serialize_opt(k, b, SSHKEY_SERIALIZE_DEFAULT); } u_int32_t sshkey_signatures_left(const struct sshkey *k) { return 0; } int sshkey_enable_maxsign(struct sshkey *k, u_int32_t maxsign) { return SSH_ERR_INVALID_ARGUMENT; } int sshkey_set_filename(struct sshkey *k, const char *filename) { if (k == NULL) return SSH_ERR_INVALID_ARGUMENT; return 0; } #endif /* WITH_XMSS */