]> git.ipfire.org Git - thirdparty/hostap.git/blobdiff - src/common/dpp.c
DPP: DPPEnvelopedData generation for Configurator backup
[thirdparty/hostap.git] / src / common / dpp.c
index abcd6bf289d30ab9b6ab0ff044279aa4afbb8801..f4f080cdba51db37d3ad91931e518c8e2b6783b6 100644 (file)
@@ -5170,11 +5170,488 @@ dpp_build_conf_obj(struct dpp_authentication *auth, enum dpp_netrole netrole,
 }
 
 
+#ifdef CONFIG_DPP2
+
+static struct wpabuf * dpp_build_conf_params(void)
+{
+       struct wpabuf *buf;
+       size_t len;
+       /* TODO: proper template values */
+       const char *conf_template = "{\"wi-fi_tech\":\"infra\",\"discovery\":{\"ssid\":\"test\"},\"cred\":{\"akm\":\"dpp\"}}";
+       const char *connector_template = NULL;
+
+       len = 100 + os_strlen(conf_template);
+       if (connector_template)
+               len += os_strlen(connector_template);
+       buf = wpabuf_alloc(len);
+       if (!buf)
+               return NULL;
+
+       /*
+        * DPPConfigurationParameters ::= SEQUENCE {
+        *    configurationTemplate     UTF8String,
+        *    connectorTemplate         UTF8String OPTIONAL}
+        */
+
+       asn1_put_utf8string(buf, conf_template);
+       if (connector_template)
+               asn1_put_utf8string(buf, conf_template);
+       return asn1_encaps(buf, ASN1_CLASS_UNIVERSAL, ASN1_TAG_SEQUENCE);
+}
+
+
+static struct wpabuf * dpp_build_attribute(void)
+{
+       struct wpabuf *conf_params, *attr;
+
+       /*
+        * aa-DPPConfigurationParameters ATTRIBUTE ::=
+        * { TYPE DPPConfigurationParameters IDENTIFIED BY id-DPPConfigParams }
+        *
+        * Attribute ::= SEQUENCE {
+        *    type OBJECT IDENTIFIER,
+        *    values SET SIZE(1..MAX) OF Type
+        */
+       conf_params = dpp_build_conf_params();
+       conf_params = asn1_encaps(conf_params, ASN1_CLASS_UNIVERSAL,
+                                 ASN1_TAG_SET);
+       if (!conf_params)
+               return NULL;
+
+       attr = wpabuf_alloc(100 + wpabuf_len(conf_params));
+       if (!attr) {
+               wpabuf_clear_free(conf_params);
+               return NULL;
+       }
+
+       asn1_put_oid(attr, &asn1_dpp_config_params_oid);
+       wpabuf_put_buf(attr, conf_params);
+       wpabuf_clear_free(conf_params);
+
+       return asn1_encaps(attr, ASN1_CLASS_UNIVERSAL, ASN1_TAG_SEQUENCE);
+}
+
+
+static struct wpabuf * dpp_build_key_alg(const struct dpp_curve_params *curve)
+{
+       const struct asn1_oid *oid;
+       struct wpabuf *params, *res;
+
+       switch (curve->ike_group) {
+       case 19:
+               oid = &asn1_prime256v1_oid;
+               break;
+       case 20:
+               oid = &asn1_secp384r1_oid;
+               break;
+       case 21:
+               oid = &asn1_secp521r1_oid;
+               break;
+       case 28:
+               oid = &asn1_brainpoolP256r1_oid;
+               break;
+       case 29:
+               oid = &asn1_brainpoolP384r1_oid;
+               break;
+       case 30:
+               oid = &asn1_brainpoolP512r1_oid;
+               break;
+       default:
+               return NULL;
+       }
+
+       params = wpabuf_alloc(20);
+       if (!params)
+               return NULL;
+       asn1_put_oid(params, oid); /* namedCurve */
+
+       res = asn1_build_alg_id(&asn1_ec_public_key_oid, params);
+       wpabuf_free(params);
+       return res;
+}
+
+
+static struct wpabuf * dpp_build_key_pkg(struct dpp_authentication *auth)
+{
+       struct wpabuf *key = NULL, *attr, *alg, *priv_key = NULL;
+       EC_KEY *eckey;
+       unsigned char *der = NULL;
+       int der_len;
+
+       eckey = EVP_PKEY_get0_EC_KEY(auth->conf->csign);
+       if (!eckey)
+               return NULL;
+
+       EC_KEY_set_enc_flags(eckey, EC_PKEY_NO_PUBKEY);
+       der_len = i2d_ECPrivateKey(eckey, &der);
+       if (der_len > 0)
+               priv_key = wpabuf_alloc_copy(der, der_len);
+       OPENSSL_free(der);
+
+       alg = dpp_build_key_alg(auth->conf->curve);
+
+       /* Attributes ::= SET OF Attribute { { OneAsymmetricKeyAttributes } } */
+       attr = dpp_build_attribute();
+       attr = asn1_encaps(attr, ASN1_CLASS_UNIVERSAL, ASN1_TAG_SET);
+       if (!priv_key || !attr || !alg)
+               goto fail;
+
+       /*
+        * OneAsymmetricKey ::= SEQUENCE {
+        *    version                   Version,
+        *    privateKeyAlgorithm       PrivateKeyAlgorithmIdentifier,
+        *    privateKey                PrivateKey,
+        *    attributes                [0] Attributes OPTIONAL,
+        *    ...,
+        *    [[2: publicKey            [1] BIT STRING OPTIONAL ]],
+        *    ...
+        * }
+        */
+
+       key = wpabuf_alloc(100 + wpabuf_len(alg) + wpabuf_len(priv_key) +
+                          wpabuf_len(attr));
+       if (!key)
+               goto fail;
+
+       asn1_put_integer(key, 1); /* version = v2(1) */
+
+       /* PrivateKeyAlgorithmIdentifier */
+       wpabuf_put_buf(key, alg);
+
+       /* PrivateKey ::= OCTET STRING */
+       asn1_put_octet_string(key, priv_key);
+
+       /* [0] Attributes OPTIONAL */
+       asn1_put_hdr(key, ASN1_CLASS_CONTEXT_SPECIFIC, 1, 0, wpabuf_len(attr));
+       wpabuf_put_buf(key, attr);
+
+fail:
+       wpabuf_clear_free(attr);
+       wpabuf_clear_free(priv_key);
+       wpabuf_free(alg);
+
+       /*
+        * DPPAsymmetricKeyPackage ::= AsymmetricKeyPackage
+        *
+        * AsymmetricKeyPackage ::= SEQUENCE SIZE (1..MAX) OF OneAsymmetricKey
+        *
+        * OneAsymmetricKey ::= SEQUENCE
+        */
+       return asn1_encaps(asn1_encaps(key,
+                                      ASN1_CLASS_UNIVERSAL, ASN1_TAG_SEQUENCE),
+                          ASN1_CLASS_UNIVERSAL, ASN1_TAG_SEQUENCE);
+       return key;
+}
+
+
+static struct wpabuf * dpp_build_pbkdf2_alg_id(const struct wpabuf *salt,
+                                              size_t hash_len)
+{
+       struct wpabuf *params = NULL, *buf = NULL, *prf = NULL;
+       const struct asn1_oid *oid;
+
+       /*
+        * PBKDF2-params ::= SEQUENCE {
+        *    salt CHOICE {
+        *       specified OCTET STRING,
+        *       otherSource AlgorithmIdentifier}
+        *    iterationCount INTEGER (1..MAX),
+        *    keyLength INTEGER (1..MAX),
+        *    prf AlgorithmIdentifier}
+        *
+        * salt is an 64 octet value, iterationCount is 1000, keyLength is based
+        * on Configurator signing key length, prf is
+        * id-hmacWithSHA{256,384,512} based on Configurator signing key.
+        */
+
+       if (hash_len == 32)
+               oid = &asn1_pbkdf2_hmac_sha256_oid;
+       else if (hash_len == 48)
+               oid = &asn1_pbkdf2_hmac_sha384_oid;
+       else if (hash_len == 64)
+               oid = &asn1_pbkdf2_hmac_sha512_oid;
+       else
+               goto fail;
+       prf = asn1_build_alg_id(oid, NULL);
+       if (!prf)
+               goto fail;
+       params = wpabuf_alloc(100 + wpabuf_len(salt) + wpabuf_len(prf));
+       if (!params)
+               goto fail;
+       asn1_put_octet_string(params, salt); /* salt.specified */
+       asn1_put_integer(params, 1000); /* iterationCount */
+       asn1_put_integer(params, hash_len); /* keyLength */
+       wpabuf_put_buf(params, prf);
+       params = asn1_encaps(params, ASN1_CLASS_UNIVERSAL, ASN1_TAG_SEQUENCE);
+       if (!params)
+               goto fail;
+       buf = asn1_build_alg_id(&asn1_pbkdf2_oid, params);
+fail:
+       wpabuf_free(params);
+       wpabuf_free(prf);
+       return buf;
+}
+
+
+static struct wpabuf *
+dpp_build_pw_recipient_info(struct dpp_authentication *auth, size_t hash_len,
+                           const struct wpabuf *cont_enc_key)
+{
+       struct wpabuf *pwri = NULL, *enc_key = NULL, *key_der_alg = NULL,
+               *key_enc_alg = NULL, *salt;
+       u8 kek[DPP_MAX_HASH_LEN];
+       const u8 *key;
+       size_t key_len;
+
+       salt = wpabuf_alloc(64);
+       if (!salt || os_get_random(wpabuf_put(salt, 64), 64) < 0)
+               goto fail;
+       wpa_hexdump_buf(MSG_DEBUG, "DPP: PBKDF2 salt", salt);
+
+       /* TODO: For initial testing, use ke as the key. Replace this with a
+        * new key once that has been defined. */
+       key = auth->ke;
+       key_len = auth->curve->hash_len;
+       wpa_hexdump_key(MSG_DEBUG, "DPP: PBKDF2 key", key, key_len);
+
+       if (dpp_pbkdf2(hash_len, key, key_len, wpabuf_head(salt), 64, 1000,
+                      kek, hash_len)) {
+               wpa_printf(MSG_DEBUG, "DPP: PBKDF2 failed");
+               goto fail;
+       }
+       wpa_hexdump_key(MSG_DEBUG, "DPP: key-encryption key from PBKDF2",
+                       kek, hash_len);
+
+       enc_key = wpabuf_alloc(hash_len + AES_BLOCK_SIZE);
+       if (!enc_key ||
+           aes_siv_encrypt(kek, hash_len, wpabuf_head(cont_enc_key),
+                           wpabuf_len(cont_enc_key), 0, NULL, NULL,
+                           wpabuf_put(enc_key, hash_len + AES_BLOCK_SIZE)) < 0)
+               goto fail;
+       wpa_hexdump_buf(MSG_DEBUG, "DPP: encryptedKey", enc_key);
+
+       /*
+        * PasswordRecipientInfo ::= SEQUENCE {
+        *    version                   CMSVersion,
+        *    keyDerivationAlgorithm [0] KeyDerivationAlgorithmIdentifier OPTIONAL,
+        *    keyEncryptionAlgorithm    KeyEncryptionAlgorithmIdentifier,
+        *    encryptedKey              EncryptedKey}
+        *
+        * version is 0, keyDerivationAlgorithm is id-PKBDF2, and the
+        * parameters contains PBKDF2-params SEQUENCE.
+        */
+
+       key_der_alg = dpp_build_pbkdf2_alg_id(salt, hash_len);
+       key_enc_alg = asn1_build_alg_id(&asn1_aes_siv_cmac_aead_256_oid, NULL);
+       if (!key_der_alg || !key_enc_alg)
+               goto fail;
+       pwri = wpabuf_alloc(100 + wpabuf_len(key_der_alg) +
+                           wpabuf_len(key_enc_alg) + wpabuf_len(enc_key));
+       if (!pwri)
+               goto fail;
+
+       /* version = 0 */
+       asn1_put_integer(pwri, 0);
+
+       /* [0] KeyDerivationAlgorithmIdentifier */
+       asn1_put_hdr(pwri, ASN1_CLASS_CONTEXT_SPECIFIC, 1, 0,
+                    wpabuf_len(key_der_alg));
+       wpabuf_put_buf(pwri, key_der_alg);
+
+       /* KeyEncryptionAlgorithmIdentifier */
+       wpabuf_put_buf(pwri, key_enc_alg);
+
+       /* EncryptedKey ::= OCTET STRING */
+       asn1_put_octet_string(pwri, enc_key);
+
+fail:
+       wpabuf_clear_free(key_der_alg);
+       wpabuf_free(key_enc_alg);
+       wpabuf_free(enc_key);
+       wpabuf_free(salt);
+       forced_memzero(kek, sizeof(kek));
+       return asn1_encaps(pwri, ASN1_CLASS_UNIVERSAL, ASN1_TAG_SEQUENCE);
+}
+
+
+static struct wpabuf *
+dpp_build_recipient_info(struct dpp_authentication *auth, size_t hash_len,
+                        const struct wpabuf *cont_enc_key)
+{
+       struct wpabuf *pwri;
+
+       /*
+        * RecipientInfo ::= CHOICE {
+        *    ktri              KeyTransRecipientInfo,
+        *    kari      [1]     KeyAgreeRecipientInfo,
+        *    kekri     [2]     KEKRecipientInfo,
+        *    pwri      [3]     PasswordRecipientInfo,
+        *    ori       [4]     OtherRecipientInfo}
+        *
+        * Shall always use the pwri CHOICE.
+        */
+
+       pwri = dpp_build_pw_recipient_info(auth, hash_len, cont_enc_key);
+       return asn1_encaps(pwri, ASN1_CLASS_CONTEXT_SPECIFIC, 3);
+}
+
+
+static struct wpabuf *
+dpp_build_enc_cont_info(struct dpp_authentication *auth, size_t hash_len,
+                       const struct wpabuf *cont_enc_key)
+{
+       struct wpabuf *key_pkg, *enc_cont_info = NULL, *enc_cont = NULL,
+               *enc_alg;
+       const struct asn1_oid *oid;
+       size_t enc_cont_len;
+
+       /*
+        * EncryptedContentInfo ::= SEQUENCE {
+        *    contentType                       ContentType,
+        *    contentEncryptionAlgorithm  ContentEncryptionAlgorithmIdentifier,
+        *    encryptedContent  [0] IMPLICIT    EncryptedContent OPTIONAL}
+        */
+
+       if (hash_len == 32)
+               oid = &asn1_aes_siv_cmac_aead_256_oid;
+       else if (hash_len == 48)
+               oid = &asn1_aes_siv_cmac_aead_384_oid;
+       else if (hash_len == 64)
+               oid = &asn1_aes_siv_cmac_aead_512_oid;
+       else
+               return NULL;
+
+       key_pkg = dpp_build_key_pkg(auth);
+       enc_alg = asn1_build_alg_id(oid, NULL);
+       if (!key_pkg || !enc_alg)
+               goto fail;
+
+       wpa_hexdump_buf_key(MSG_MSGDUMP, "DPP: DPPAsymmetricKeyPackage",
+                           key_pkg);
+
+       enc_cont_len = wpabuf_len(key_pkg) + AES_BLOCK_SIZE;
+       enc_cont = wpabuf_alloc(enc_cont_len);
+       if (!enc_cont ||
+           aes_siv_encrypt(wpabuf_head(cont_enc_key), wpabuf_len(cont_enc_key),
+                           wpabuf_head(key_pkg), wpabuf_len(key_pkg),
+                           0, NULL, NULL,
+                           wpabuf_put(enc_cont, enc_cont_len)) < 0)
+               goto fail;
+
+       enc_cont_info = wpabuf_alloc(100 + wpabuf_len(enc_alg) +
+                                    wpabuf_len(enc_cont));
+       if (!enc_cont_info)
+               goto fail;
+
+       /* ContentType ::= OBJECT IDENTIFIER */
+       asn1_put_oid(enc_cont_info, &asn1_dpp_asymmetric_key_package_oid);
+
+       /* ContentEncryptionAlgorithmIdentifier ::= AlgorithmIdentifier */
+       wpabuf_put_buf(enc_cont_info, enc_alg);
+
+       /* encryptedContent [0] IMPLICIT EncryptedContent OPTIONAL
+        * EncryptedContent ::= OCTET STRING */
+       asn1_put_hdr(enc_cont_info, ASN1_CLASS_CONTEXT_SPECIFIC, 1, 0,
+                    wpabuf_len(enc_cont));
+       wpabuf_put_buf(enc_cont_info, enc_cont);
+
+fail:
+       wpabuf_clear_free(key_pkg);
+       wpabuf_free(enc_cont);
+       wpabuf_free(enc_alg);
+       return enc_cont_info;
+}
+
+
+static struct wpabuf * dpp_gen_random(size_t len)
+{
+       struct wpabuf *key;
+
+       key = wpabuf_alloc(len);
+       if (!key || os_get_random(wpabuf_put(key, len), len) < 0) {
+               wpabuf_free(key);
+               key = NULL;
+       }
+       wpa_hexdump_buf_key(MSG_DEBUG, "DPP: content-encryption key", key);
+       return key;
+}
+
+
+static struct wpabuf * dpp_build_enveloped_data(struct dpp_authentication *auth)
+{
+       struct wpabuf *env = NULL;
+       struct wpabuf *recipient_info = NULL, *enc_cont_info = NULL;
+       struct wpabuf *cont_enc_key = NULL;
+       size_t hash_len;
+
+       if (!auth->conf) {
+               wpa_printf(MSG_DEBUG,
+                          "DPP: No Configurator instance selected for the session - cannot build DPPEnvelopedData");
+               return NULL;
+       }
+
+       wpa_printf(MSG_DEBUG, "DPP: Building DPPEnvelopedData");
+
+       hash_len = auth->conf->curve->hash_len;
+       cont_enc_key = dpp_gen_random(hash_len);
+       if (!cont_enc_key)
+               goto fail;
+       recipient_info = dpp_build_recipient_info(auth, hash_len, cont_enc_key);
+       enc_cont_info = dpp_build_enc_cont_info(auth, hash_len, cont_enc_key);
+       if (!recipient_info || !enc_cont_info)
+               goto fail;
+
+       env = wpabuf_alloc(wpabuf_len(recipient_info) +
+                          wpabuf_len(enc_cont_info) +
+                          100);
+       if (!env)
+               goto fail;
+
+       /*
+        * DPPEnvelopedData ::= EnvelopedData
+        *
+        * EnvelopedData ::= SEQUENCE {
+        *    version                   CMSVersion,
+        *    originatorInfo    [0]     IMPLICIT OriginatorInfo OPTIONAL,
+        *    recipientInfos            RecipientInfos,
+        *    encryptedContentInfo      EncryptedContentInfo,
+        *    unprotectedAttrs  [1] IMPLICIT    UnprotectedAttributes OPTIONAL}
+        *
+        * For DPP, version is 3, both originatorInfo and
+        * unprotectedAttrs are omitted, and recipientInfos contains a single
+        * RecipientInfo.
+        */
+
+       /* EnvelopedData.version = 3 */
+       asn1_put_integer(env, 3);
+
+       /* RecipientInfos ::= SET SIZE (1..MAX) OF RecipientInfo */
+       asn1_put_set(env, recipient_info);
+
+       /* EncryptedContentInfo ::= SEQUENCE */
+       asn1_put_sequence(env, enc_cont_info);
+
+       env = asn1_encaps(env, ASN1_CLASS_UNIVERSAL, ASN1_TAG_SEQUENCE);
+       wpa_hexdump_buf(MSG_MSGDUMP, "DPP: DPPEnvelopedData", env);
+out:
+       wpabuf_clear_free(cont_enc_key);
+       wpabuf_clear_free(recipient_info);
+       wpabuf_free(enc_cont_info);
+       return env;
+fail:
+       wpabuf_free(env);
+       env = NULL;
+       goto out;
+}
+
+#endif /* CONFIG_DPP2 */
+
+
 static struct wpabuf *
 dpp_build_conf_resp(struct dpp_authentication *auth, const u8 *e_nonce,
                    u16 e_nonce_len, enum dpp_netrole netrole)
 {
-       struct wpabuf *conf, *conf2 = NULL;
+       struct wpabuf *conf = NULL, *conf2 = NULL, *env_data = NULL;
        size_t clear_len, attr_len;
        struct wpabuf *clear = NULL, *msg = NULL;
        u8 *wrapped;
@@ -5182,13 +5659,21 @@ dpp_build_conf_resp(struct dpp_authentication *auth, const u8 *e_nonce,
        size_t len[1];
        enum dpp_status_error status;
 
-       conf = dpp_build_conf_obj(auth, netrole, 0);
-       if (conf) {
-               wpa_hexdump_ascii(MSG_DEBUG, "DPP: configurationObject JSON",
-                                 wpabuf_head(conf), wpabuf_len(conf));
-               conf2 = dpp_build_conf_obj(auth, netrole, 1);
+       if (netrole == DPP_NETROLE_CONFIGURATOR) {
+#ifdef CONFIG_DPP2
+               env_data = dpp_build_enveloped_data(auth);
+#endif /* CONFIG_DPP2 */
+       } else {
+               conf = dpp_build_conf_obj(auth, netrole, 0);
+               if (conf) {
+                       wpa_hexdump_ascii(MSG_DEBUG,
+                                         "DPP: configurationObject JSON",
+                                         wpabuf_head(conf), wpabuf_len(conf));
+                       conf2 = dpp_build_conf_obj(auth, netrole, 1);
+               }
        }
-       status = conf ? DPP_STATUS_OK : DPP_STATUS_CONFIGURE_FAILURE;
+       status = (conf || env_data) ? DPP_STATUS_OK :
+               DPP_STATUS_CONFIGURE_FAILURE;
        auth->conf_resp_status = status;
 
        /* { E-nonce, configurationObject[, sendConnStatus]}ke */
@@ -5197,6 +5682,8 @@ dpp_build_conf_resp(struct dpp_authentication *auth, const u8 *e_nonce,
                clear_len += 4 + wpabuf_len(conf);
        if (conf2)
                clear_len += 4 + wpabuf_len(conf2);
+       if (env_data)
+               clear_len += 4 + wpabuf_len(env_data);
        if (auth->peer_version >= 2 && auth->send_conn_status &&
            netrole == DPP_NETROLE_STA)
                clear_len += 4;
@@ -5255,6 +5742,11 @@ skip_e_nonce:
                wpa_printf(MSG_DEBUG,
                           "DPP: Second Config Object available, but peer does not support more than one");
        }
+       if (env_data) {
+               wpabuf_put_le16(clear, DPP_ATTR_ENVELOPED_DATA);
+               wpabuf_put_le16(clear, wpabuf_len(env_data));
+               wpabuf_put_buf(clear, env_data);
+       }
 
        if (auth->peer_version >= 2 && auth->send_conn_status &&
            netrole == DPP_NETROLE_STA) {
@@ -5309,9 +5801,10 @@ skip_wrapped_data:
        wpa_hexdump_buf(MSG_DEBUG,
                        "DPP: Configuration Response attributes", msg);
 out:
-       wpabuf_free(conf);
-       wpabuf_free(conf2);
-       wpabuf_free(clear);
+       wpabuf_clear_free(conf);
+       wpabuf_clear_free(conf2);
+       wpabuf_clear_free(env_data);
+       wpabuf_clear_free(clear);
 
        return msg;
 fail: