Add RemotelyProvisionedComponent HAL.
Test: VtsHalRemotelyProvisionedComponentTargetTest
Change-Id: I51fb01f4c52949c81f3ad2d694a4afdf0fa67788
diff --git a/security/keymint/support/Android.bp b/security/keymint/support/Android.bp
index fde6b57..efdff2b 100644
--- a/security/keymint/support/Android.bp
+++ b/security/keymint/support/Android.bp
@@ -37,3 +37,40 @@
"libutils",
],
}
+
+cc_library {
+ name: "libkeymint_remote_prov_support",
+ vendor_available: true,
+ srcs: [
+ "remote_prov_utils.cpp",
+ ],
+ export_include_dirs: [
+ "include",
+ ],
+ shared_libs: [
+ "libcppcose",
+ "libcppbor_external",
+ "libcrypto",
+ ],
+}
+
+cc_library {
+ name: "libcppcose",
+ vendor_available: true,
+ srcs: [
+ "cppcose.cpp",
+ ],
+ export_include_dirs: [
+ "include",
+ ],
+ shared_libs: [
+ "libbinder_ndk",
+ "libcppbor_external",
+ "libcrypto",
+ "liblog",
+ ],
+ static_libs: [
+ // TODO(swillden): Remove keymint NDK
+ "android.hardware.security.keymint-unstable-ndk_platform",
+ ],
+}
diff --git a/security/keymint/support/cppcose.cpp b/security/keymint/support/cppcose.cpp
new file mode 100644
index 0000000..c626ade
--- /dev/null
+++ b/security/keymint/support/cppcose.cpp
@@ -0,0 +1,467 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cppcose/cppcose.h>
+
+#include <stdio.h>
+#include <iostream>
+
+#include <cppbor.h>
+#include <cppbor_parse.h>
+
+#include <openssl/err.h>
+
+namespace cppcose {
+
+namespace {
+
+ErrMsgOr<bssl::UniquePtr<EVP_CIPHER_CTX>> aesGcmInitAndProcessAad(const bytevec& key,
+ const bytevec& nonce,
+ const bytevec& aad,
+ bool encrypt) {
+ if (key.size() != kAesGcmKeySize) return "Invalid key size";
+
+ bssl::UniquePtr<EVP_CIPHER_CTX> ctx(EVP_CIPHER_CTX_new());
+ if (!ctx) return "Failed to allocate cipher context";
+
+ if (!EVP_CipherInit_ex(ctx.get(), EVP_aes_256_gcm(), nullptr /* engine */, key.data(),
+ nonce.data(), encrypt ? 1 : 0)) {
+ return "Failed to initialize cipher";
+ }
+
+ int outlen;
+ if (!aad.empty() && !EVP_CipherUpdate(ctx.get(), nullptr /* out; null means AAD */, &outlen,
+ aad.data(), aad.size())) {
+ return "Failed to process AAD";
+ }
+
+ return std::move(ctx);
+}
+
+} // namespace
+
+ErrMsgOr<bytevec> generateCoseMac0Mac(const bytevec& macKey, const bytevec& externalAad,
+ const bytevec& payload) {
+ auto macStructure = cppbor::Array()
+ .add("MAC0")
+ .add(cppbor::Map().add(ALGORITHM, HMAC_256).canonicalize().encode())
+ .add(externalAad)
+ .add(payload)
+ .encode();
+
+ bytevec macTag(SHA256_DIGEST_LENGTH);
+ uint8_t* out = macTag.data();
+ unsigned int outLen;
+ out = HMAC(EVP_sha256(), //
+ macKey.data(), macKey.size(), //
+ macStructure.data(), macStructure.size(), //
+ out, &outLen);
+
+ assert(out != nullptr && outLen == macTag.size());
+ if (out == nullptr || outLen != macTag.size()) {
+ return "Error computing public key MAC";
+ }
+
+ return macTag;
+}
+
+ErrMsgOr<cppbor::Array> constructCoseMac0(const bytevec& macKey, const bytevec& externalAad,
+ const bytevec& payload) {
+ auto tag = generateCoseMac0Mac(macKey, externalAad, payload);
+ if (!tag) return tag.moveMessage();
+
+ return cppbor::Array()
+ .add(cppbor::Map().add(ALGORITHM, HMAC_256).canonicalize().encode())
+ .add(cppbor::Bstr() /* unprotected */)
+ .add(payload)
+ .add(tag.moveValue());
+}
+
+ErrMsgOr<bytevec /* payload */> parseCoseMac0(const cppbor::Item* macItem) {
+ auto mac = macItem ? macItem->asArray() : nullptr;
+ if (!mac || mac->size() != kCoseMac0EntryCount) {
+ return "Invalid COSE_Mac0";
+ }
+
+ auto protectedParms = mac->get(kCoseMac0ProtectedParams)->asBstr();
+ auto unprotectedParms = mac->get(kCoseMac0UnprotectedParams)->asBstr();
+ auto payload = mac->get(kCoseMac0Payload)->asBstr();
+ auto tag = mac->get(kCoseMac0Tag)->asBstr();
+ if (!protectedParms || !unprotectedParms || !payload || !tag) {
+ return "Invalid COSE_Mac0 contents";
+ }
+
+ return payload->value();
+}
+
+ErrMsgOr<bytevec /* payload */> verifyAndParseCoseMac0(const cppbor::Item* macItem,
+ const bytevec& macKey) {
+ auto mac = macItem ? macItem->asArray() : nullptr;
+ if (!mac || mac->size() != kCoseMac0EntryCount) {
+ return "Invalid COSE_Mac0";
+ }
+
+ auto protectedParms = mac->get(kCoseMac0ProtectedParams)->asBstr();
+ auto unprotectedParms = mac->get(kCoseMac0UnprotectedParams)->asBstr();
+ auto payload = mac->get(kCoseMac0Payload)->asBstr();
+ auto tag = mac->get(kCoseMac0Tag)->asBstr();
+ if (!protectedParms || !unprotectedParms || !payload || !tag) {
+ return "Invalid COSE_Mac0 contents";
+ }
+
+ auto [protectedMap, _, errMsg] = cppbor::parse(protectedParms);
+ if (!protectedMap || !protectedMap->asMap()) {
+ return "Invalid Mac0 protected: " + errMsg;
+ }
+ auto& algo = protectedMap->asMap()->get(ALGORITHM);
+ if (!algo || !algo->asInt() || algo->asInt()->value() != HMAC_256) {
+ return "Unsupported Mac0 algorithm";
+ }
+
+ auto macTag = generateCoseMac0Mac(macKey, {} /* external_aad */, payload->value());
+ if (!macTag) return macTag.moveMessage();
+
+ if (macTag->size() != tag->value().size() ||
+ CRYPTO_memcmp(macTag->data(), tag->value().data(), macTag->size()) != 0) {
+ return "MAC tag mismatch";
+ }
+
+ return payload->value();
+}
+
+ErrMsgOr<bytevec> createCoseSign1Signature(const bytevec& key, const bytevec& protectedParams,
+ const bytevec& payload, const bytevec& aad) {
+ bytevec signatureInput = cppbor::Array()
+ .add("Signature1") //
+ .add(protectedParams)
+ .add(aad)
+ .add(payload)
+ .encode();
+
+ if (key.size() != ED25519_PRIVATE_KEY_LEN) return "Invalid signing key";
+ bytevec signature(ED25519_SIGNATURE_LEN);
+ if (!ED25519_sign(signature.data(), signatureInput.data(), signatureInput.size(), key.data())) {
+ return "Signing failed";
+ }
+
+ return signature;
+}
+
+ErrMsgOr<cppbor::Array> constructCoseSign1(const bytevec& key, cppbor::Map protectedParams,
+ const bytevec& payload, const bytevec& aad) {
+ bytevec protParms = protectedParams.add(ALGORITHM, EDDSA).canonicalize().encode();
+ auto signature = createCoseSign1Signature(key, protParms, payload, aad);
+ if (!signature) return signature.moveMessage();
+
+ return cppbor::Array()
+ .add(protParms)
+ .add(bytevec{} /* unprotected parameters */)
+ .add(payload)
+ .add(*signature);
+}
+
+ErrMsgOr<cppbor::Array> constructCoseSign1(const bytevec& key, const bytevec& payload,
+ const bytevec& aad) {
+ return constructCoseSign1(key, {} /* protectedParams */, payload, aad);
+}
+
+ErrMsgOr<bytevec> verifyAndParseCoseSign1(bool ignoreSignature, const cppbor::Array* coseSign1,
+ const bytevec& signingCoseKey, const bytevec& aad) {
+ if (!coseSign1 || coseSign1->size() != kCoseSign1EntryCount) {
+ return "Invalid COSE_Sign1";
+ }
+
+ const cppbor::Bstr* protectedParams = coseSign1->get(kCoseSign1ProtectedParams)->asBstr();
+ const cppbor::Bstr* unprotectedParams = coseSign1->get(kCoseSign1UnprotectedParams)->asBstr();
+ const cppbor::Bstr* payload = coseSign1->get(kCoseSign1Payload)->asBstr();
+ const cppbor::Bstr* signature = coseSign1->get(kCoseSign1Signature)->asBstr();
+
+ if (!protectedParams || !unprotectedParams || !payload || !signature) {
+ return "Invalid COSE_Sign1";
+ }
+
+ auto [parsedProtParams, _, errMsg] = cppbor::parse(protectedParams);
+ if (!parsedProtParams) {
+ return errMsg + " when parsing protected params.";
+ }
+ if (!parsedProtParams->asMap()) {
+ return "Protected params must be a map";
+ }
+
+ auto& algorithm = parsedProtParams->asMap()->get(ALGORITHM);
+ if (!algorithm || !algorithm->asInt() || algorithm->asInt()->value() != EDDSA) {
+ return "Unsupported signature algorithm";
+ }
+
+ if (!ignoreSignature) {
+ bool selfSigned = signingCoseKey.empty();
+ auto key = CoseKey::parseEd25519(selfSigned ? payload->value() : signingCoseKey);
+ if (!key) return "Bad signing key: " + key.moveMessage();
+
+ bytevec signatureInput = cppbor::Array()
+ .add("Signature1")
+ .add(*protectedParams)
+ .add(aad)
+ .add(*payload)
+ .encode();
+
+ if (!ED25519_verify(signatureInput.data(), signatureInput.size(), signature->value().data(),
+ key->getBstrValue(CoseKey::PUBKEY_X)->data())) {
+ return "Signature verification failed";
+ }
+ }
+
+ return payload->value();
+}
+
+ErrMsgOr<bytevec> createCoseEncryptCiphertext(const bytevec& key, const bytevec& nonce,
+ const bytevec& protectedParams,
+ const bytevec& plaintextPayload, const bytevec& aad) {
+ auto ciphertext = aesGcmEncrypt(key, nonce,
+ cppbor::Array() // Enc strucure as AAD
+ .add("Encrypt") // Context
+ .add(protectedParams) // Protected
+ .add(aad) // External AAD
+ .encode(),
+ plaintextPayload);
+
+ if (!ciphertext) return ciphertext.moveMessage();
+ return ciphertext.moveValue();
+}
+
+ErrMsgOr<cppbor::Array> constructCoseEncrypt(const bytevec& key, const bytevec& nonce,
+ const bytevec& plaintextPayload, const bytevec& aad,
+ cppbor::Array recipients) {
+ auto encryptProtectedHeader = cppbor::Map() //
+ .add(ALGORITHM, AES_GCM_256)
+ .canonicalize()
+ .encode();
+
+ auto ciphertext =
+ createCoseEncryptCiphertext(key, nonce, encryptProtectedHeader, plaintextPayload, aad);
+ if (!ciphertext) return ciphertext.moveMessage();
+
+ return cppbor::Array()
+ .add(encryptProtectedHeader) // Protected
+ .add(cppbor::Map().add(IV, nonce).canonicalize()) // Unprotected
+ .add(*ciphertext) // Payload
+ .add(std::move(recipients));
+}
+
+ErrMsgOr<std::pair<bytevec /* pubkey */, bytevec /* key ID */>> getSenderPubKeyFromCoseEncrypt(
+ const cppbor::Item* coseEncrypt) {
+ if (!coseEncrypt || !coseEncrypt->asArray() ||
+ coseEncrypt->asArray()->size() != kCoseEncryptEntryCount) {
+ return "Invalid COSE_Encrypt";
+ }
+
+ auto& recipients = coseEncrypt->asArray()->get(kCoseEncryptRecipients);
+ if (!recipients || !recipients->asArray() || recipients->asArray()->size() != 1) {
+ return "Invalid recipients list";
+ }
+
+ auto& recipient = recipients->asArray()->get(0);
+ if (!recipient || !recipient->asArray() || recipient->asArray()->size() != 3) {
+ return "Invalid COSE_recipient";
+ }
+
+ auto& ciphertext = recipient->asArray()->get(2);
+ if (!ciphertext->asSimple() || !ciphertext->asSimple()->asNull()) {
+ return "Unexpected value in recipients ciphertext field " +
+ cppbor::prettyPrint(ciphertext.get());
+ }
+
+ auto& protParms = recipient->asArray()->get(0);
+ if (!protParms || !protParms->asBstr()) return "Invalid protected params";
+ auto [parsedProtParms, _, errMsg] = cppbor::parse(protParms->asBstr());
+ if (!parsedProtParms) return "Failed to parse protected params: " + errMsg;
+ if (!parsedProtParms->asMap()) return "Invalid protected params";
+
+ auto& algorithm = parsedProtParms->asMap()->get(ALGORITHM);
+ if (!algorithm || !algorithm->asInt() || algorithm->asInt()->value() != ECDH_ES_HKDF_256) {
+ return "Invalid algorithm";
+ }
+
+ auto& unprotParms = recipient->asArray()->get(1);
+ if (!unprotParms || !unprotParms->asMap()) return "Invalid unprotected params";
+
+ auto& senderCoseKey = unprotParms->asMap()->get(COSE_KEY);
+ if (!senderCoseKey || !senderCoseKey->asMap()) return "Invalid sender COSE_Key";
+
+ auto& keyType = senderCoseKey->asMap()->get(CoseKey::KEY_TYPE);
+ if (!keyType || !keyType->asInt() || keyType->asInt()->value() != OCTET_KEY_PAIR) {
+ return "Invalid key type";
+ }
+
+ auto& curve = senderCoseKey->asMap()->get(CoseKey::CURVE);
+ if (!curve || !curve->asInt() || curve->asInt()->value() != X25519) {
+ return "Unsupported curve";
+ }
+
+ auto& pubkey = senderCoseKey->asMap()->get(CoseKey::PUBKEY_X);
+ if (!pubkey || !pubkey->asBstr() ||
+ pubkey->asBstr()->value().size() != X25519_PUBLIC_VALUE_LEN) {
+ return "Invalid X25519 public key";
+ }
+
+ auto& key_id = unprotParms->asMap()->get(KEY_ID);
+ if (key_id && key_id->asBstr()) {
+ return std::make_pair(pubkey->asBstr()->value(), key_id->asBstr()->value());
+ }
+
+ // If no key ID, just return an empty vector.
+ return std::make_pair(pubkey->asBstr()->value(), bytevec{});
+}
+
+ErrMsgOr<bytevec> decryptCoseEncrypt(const bytevec& key, const cppbor::Item* coseEncrypt,
+ const bytevec& external_aad) {
+ if (!coseEncrypt || !coseEncrypt->asArray() ||
+ coseEncrypt->asArray()->size() != kCoseEncryptEntryCount) {
+ return "Invalid COSE_Encrypt";
+ }
+
+ auto& protParms = coseEncrypt->asArray()->get(kCoseEncryptProtectedParams);
+ auto& unprotParms = coseEncrypt->asArray()->get(kCoseEncryptUnprotectedParams);
+ auto& ciphertext = coseEncrypt->asArray()->get(kCoseEncryptPayload);
+ auto& recipients = coseEncrypt->asArray()->get(kCoseEncryptRecipients);
+
+ if (!protParms || !protParms->asBstr() || !unprotParms || !ciphertext || !recipients) {
+ return "Invalid COSE_Encrypt";
+ }
+
+ auto [parsedProtParams, _, errMsg] = cppbor::parse(protParms->asBstr()->value());
+ if (!parsedProtParams) {
+ return errMsg + " when parsing protected params.";
+ }
+ if (!parsedProtParams->asMap()) {
+ return "Protected params must be a map";
+ }
+
+ auto& algorithm = parsedProtParams->asMap()->get(ALGORITHM);
+ if (!algorithm || !algorithm->asInt() || algorithm->asInt()->value() != AES_GCM_256) {
+ return "Unsupported encryption algorithm";
+ }
+
+ if (!unprotParms->asMap() || unprotParms->asMap()->size() != 1) {
+ return "Invalid unprotected params";
+ }
+
+ auto& nonce = unprotParms->asMap()->get(IV);
+ if (!nonce || !nonce->asBstr() || nonce->asBstr()->value().size() != kAesGcmNonceLength) {
+ return "Invalid nonce";
+ }
+
+ if (!ciphertext->asBstr()) return "Invalid ciphertext";
+
+ auto aad = cppbor::Array() // Enc strucure as AAD
+ .add("Encrypt") // Context
+ .add(protParms->asBstr()->value()) // Protected
+ .add(external_aad) // External AAD
+ .encode();
+
+ return aesGcmDecrypt(key, nonce->asBstr()->value(), aad, ciphertext->asBstr()->value());
+}
+
+ErrMsgOr<bytevec> x25519_HKDF_DeriveKey(const bytevec& pubKeyA, const bytevec& privKeyA,
+ const bytevec& pubKeyB, bool senderIsA) {
+ bytevec rawSharedKey(X25519_SHARED_KEY_LEN);
+ if (!::X25519(rawSharedKey.data(), privKeyA.data(), pubKeyB.data())) {
+ return "ECDH operation failed";
+ }
+
+ bytevec kdfContext = cppbor::Array()
+ .add(AES_GCM_256)
+ .add(cppbor::Array() // Sender Info
+ .add(cppbor::Bstr("client"))
+ .add(bytevec{} /* nonce */)
+ .add(senderIsA ? pubKeyA : pubKeyB))
+ .add(cppbor::Array() // Recipient Info
+ .add(cppbor::Bstr("server"))
+ .add(bytevec{} /* nonce */)
+ .add(senderIsA ? pubKeyB : pubKeyA))
+ .add(cppbor::Array() // SuppPubInfo
+ .add(128) // output key length
+ .add(bytevec{})) // protected
+ .encode();
+
+ bytevec retval(SHA256_DIGEST_LENGTH);
+ bytevec salt{};
+ if (!HKDF(retval.data(), retval.size(), //
+ EVP_sha256(), //
+ rawSharedKey.data(), rawSharedKey.size(), //
+ salt.data(), salt.size(), //
+ kdfContext.data(), kdfContext.size())) {
+ return "ECDH HKDF failed";
+ }
+
+ return retval;
+}
+
+ErrMsgOr<bytevec> aesGcmEncrypt(const bytevec& key, const bytevec& nonce, const bytevec& aad,
+ const bytevec& plaintext) {
+ auto ctx = aesGcmInitAndProcessAad(key, nonce, aad, true /* encrypt */);
+ if (!ctx) return ctx.moveMessage();
+
+ bytevec ciphertext(plaintext.size() + kAesGcmTagSize);
+ int outlen;
+ if (!EVP_CipherUpdate(ctx->get(), ciphertext.data(), &outlen, plaintext.data(),
+ plaintext.size())) {
+ return "Failed to encrypt plaintext";
+ }
+ assert(plaintext.size() == outlen);
+
+ if (!EVP_CipherFinal_ex(ctx->get(), ciphertext.data() + outlen, &outlen)) {
+ return "Failed to finalize encryption";
+ }
+ assert(outlen == 0);
+
+ if (!EVP_CIPHER_CTX_ctrl(ctx->get(), EVP_CTRL_GCM_GET_TAG, kAesGcmTagSize,
+ ciphertext.data() + plaintext.size())) {
+ return "Failed to retrieve tag";
+ }
+
+ return ciphertext;
+}
+
+ErrMsgOr<bytevec> aesGcmDecrypt(const bytevec& key, const bytevec& nonce, const bytevec& aad,
+ const bytevec& ciphertextWithTag) {
+ auto ctx = aesGcmInitAndProcessAad(key, nonce, aad, false /* encrypt */);
+ if (!ctx) return ctx.moveMessage();
+
+ if (ciphertextWithTag.size() < kAesGcmTagSize) return "Missing tag";
+
+ bytevec plaintext(ciphertextWithTag.size() - kAesGcmTagSize);
+ int outlen;
+ if (!EVP_CipherUpdate(ctx->get(), plaintext.data(), &outlen, ciphertextWithTag.data(),
+ ciphertextWithTag.size() - kAesGcmTagSize)) {
+ return "Failed to decrypt plaintext";
+ }
+ assert(plaintext.size() == outlen);
+
+ bytevec tag(ciphertextWithTag.end() - kAesGcmTagSize, ciphertextWithTag.end());
+ if (!EVP_CIPHER_CTX_ctrl(ctx->get(), EVP_CTRL_GCM_SET_TAG, kAesGcmTagSize, tag.data())) {
+ return "Failed to set tag: " + std::to_string(ERR_peek_last_error());
+ }
+
+ if (!EVP_CipherFinal_ex(ctx->get(), nullptr, &outlen)) {
+ return "Failed to finalize encryption";
+ }
+ assert(outlen == 0);
+
+ return plaintext;
+}
+
+} // namespace cppcose
diff --git a/security/keymint/support/include/cppcose/cppcose.h b/security/keymint/support/include/cppcose/cppcose.h
new file mode 100644
index 0000000..a936bfd
--- /dev/null
+++ b/security/keymint/support/include/cppcose/cppcose.h
@@ -0,0 +1,288 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <memory>
+#include <optional>
+#include <string>
+#include <vector>
+
+#include <cppbor.h>
+#include <cppbor_parse.h>
+
+#include <openssl/cipher.h>
+#include <openssl/curve25519.h>
+#include <openssl/digest.h>
+#include <openssl/hkdf.h>
+#include <openssl/hmac.h>
+#include <openssl/mem.h>
+#include <openssl/sha.h>
+
+namespace cppcose {
+
+using bytevec = std::vector<uint8_t>;
+
+constexpr int kCoseSign1EntryCount = 4;
+constexpr int kCoseSign1ProtectedParams = 0;
+constexpr int kCoseSign1UnprotectedParams = 1;
+constexpr int kCoseSign1Payload = 2;
+constexpr int kCoseSign1Signature = 3;
+
+constexpr int kCoseMac0EntryCount = 4;
+constexpr int kCoseMac0ProtectedParams = 0;
+constexpr int kCoseMac0UnprotectedParams = 1;
+constexpr int kCoseMac0Payload = 2;
+constexpr int kCoseMac0Tag = 3;
+
+constexpr int kCoseEncryptEntryCount = 4;
+constexpr int kCoseEncryptProtectedParams = 0;
+constexpr int kCoseEncryptUnprotectedParams = 1;
+constexpr int kCoseEncryptPayload = 2;
+constexpr int kCoseEncryptRecipients = 3;
+
+enum Label : int {
+ ALGORITHM = 1,
+ KEY_ID = 4,
+ IV = 5,
+ COSE_KEY = -1,
+};
+
+enum CoseKeyAlgorithm : int {
+ AES_GCM_256 = 3,
+ HMAC_256 = 5,
+ ES256 = -7, // ECDSA with SHA-256
+ EDDSA = -8,
+ ECDH_ES_HKDF_256 = -25,
+};
+
+enum CoseKeyCurve : int { P256 = 1, X25519 = 4, ED25519 = 6 };
+enum CoseKeyType : int { OCTET_KEY_PAIR = 1, EC2 = 2, SYMMETRIC_KEY = 4 };
+enum CoseKeyOps : int { SIGN = 1, VERIFY = 2, ENCRYPT = 3, DECRYPT = 4 };
+
+constexpr int kAesGcmNonceLength = 12;
+constexpr int kAesGcmTagSize = 16;
+constexpr int kAesGcmKeySize = 32;
+
+template <typename T>
+class ErrMsgOr {
+ public:
+ ErrMsgOr(std::string errMsg) : errMsg_(std::move(errMsg)) {}
+ ErrMsgOr(const char* errMsg) : errMsg_(errMsg) {}
+ ErrMsgOr(T val) : value_(std::move(val)) {}
+
+ operator bool() const { return value_.has_value(); }
+
+ T* operator->() & {
+ assert(value_);
+ return &value_.value();
+ }
+ T& operator*() & {
+ assert(value_);
+ return value_.value();
+ };
+ T&& operator*() && {
+ assert(value_);
+ return std::move(value_).value();
+ };
+
+ const std::string& message() { return errMsg_; }
+ std::string moveMessage() { return std::move(errMsg_); }
+
+ T moveValue() {
+ assert(value_);
+ return std::move(value_).value();
+ }
+
+ private:
+ std::string errMsg_;
+ std::optional<T> value_;
+};
+
+class CoseKey {
+ public:
+ CoseKey() {}
+ CoseKey(const CoseKey&) = delete;
+ CoseKey(CoseKey&&) = default;
+
+ enum Label : int {
+ KEY_TYPE = 1,
+ KEY_ID = 2,
+ ALGORITHM = 3,
+ KEY_OPS = 4,
+ CURVE = -1,
+ PUBKEY_X = -2,
+ PUBKEY_Y = -3,
+ PRIVATE_KEY = -4,
+ TEST_KEY = -70000 // Application-defined
+ };
+
+ static ErrMsgOr<CoseKey> parse(const bytevec& coseKey) {
+ auto [parsedKey, _, errMsg] = cppbor::parse(coseKey);
+ if (!parsedKey) return errMsg + " when parsing key";
+ if (!parsedKey->asMap()) return "CoseKey must be a map";
+ return CoseKey(static_cast<cppbor::Map*>(parsedKey.release()));
+ }
+
+ static ErrMsgOr<CoseKey> parse(const bytevec& coseKey, CoseKeyType expectedKeyType,
+ CoseKeyAlgorithm expectedAlgorithm, CoseKeyCurve expectedCurve) {
+ auto key = parse(coseKey);
+ if (!key) return key;
+
+ if (!key->checkIntValue(CoseKey::KEY_TYPE, expectedKeyType) ||
+ !key->checkIntValue(CoseKey::ALGORITHM, expectedAlgorithm) ||
+ !key->checkIntValue(CoseKey::CURVE, expectedCurve)) {
+ return "Unexpected key type:";
+ }
+
+ return key;
+ }
+
+ static ErrMsgOr<CoseKey> parseEd25519(const bytevec& coseKey) {
+ auto key = parse(coseKey, OCTET_KEY_PAIR, EDDSA, ED25519);
+ if (!key) return key;
+
+ auto& pubkey = key->getMap().get(PUBKEY_X);
+ if (!pubkey || !pubkey->asBstr() ||
+ pubkey->asBstr()->value().size() != ED25519_PUBLIC_KEY_LEN) {
+ return "Invalid Ed25519 public key";
+ }
+
+ return key;
+ }
+
+ static ErrMsgOr<CoseKey> parseX25519(const bytevec& coseKey, bool requireKid) {
+ auto key = parse(coseKey, OCTET_KEY_PAIR, ECDH_ES_HKDF_256, X25519);
+ if (!key) return key;
+
+ auto& pubkey = key->getMap().get(PUBKEY_X);
+ if (!pubkey || !pubkey->asBstr() ||
+ pubkey->asBstr()->value().size() != X25519_PUBLIC_VALUE_LEN) {
+ return "Invalid X25519 public key";
+ }
+
+ auto& kid = key->getMap().get(KEY_ID);
+ if (requireKid && (!kid || !kid->asBstr())) {
+ return "Missing KID";
+ }
+
+ return key;
+ }
+
+ static ErrMsgOr<CoseKey> parseP256(const bytevec& coseKey) {
+ auto key = parse(coseKey, EC2, ES256, P256);
+ if (!key) return key;
+
+ auto& pubkey_x = key->getMap().get(PUBKEY_X);
+ auto& pubkey_y = key->getMap().get(PUBKEY_Y);
+ if (!pubkey_x || !pubkey_y || !pubkey_x->asBstr() || !pubkey_y->asBstr() ||
+ pubkey_x->asBstr()->value().size() != 32 || pubkey_y->asBstr()->value().size() != 32) {
+ return "Invalid P256 public key";
+ }
+
+ return key;
+ }
+
+ std::optional<int> getIntValue(Label label) {
+ const auto& value = key_->get(label);
+ if (!value || !value->asInt()) return {};
+ return value->asInt()->value();
+ }
+
+ std::optional<bytevec> getBstrValue(Label label) {
+ const auto& value = key_->get(label);
+ if (!value || !value->asBstr()) return {};
+ return value->asBstr()->value();
+ }
+
+ const cppbor::Map& getMap() const { return *key_; }
+ cppbor::Map&& moveMap() { return std::move(*key_); }
+
+ bool checkIntValue(Label label, int expectedValue) {
+ const auto& value = key_->get(label);
+ return value && value->asInt() && value->asInt()->value() == expectedValue;
+ }
+
+ void add(Label label, int value) { key_->add(label, value); }
+ void add(Label label, bytevec value) { key_->add(label, std::move(value)); }
+
+ bytevec encode() { return key_->canonicalize().encode(); }
+
+ private:
+ CoseKey(cppbor::Map* parsedKey) : key_(parsedKey) {}
+
+ // This is the full parsed key structure.
+ std::unique_ptr<cppbor::Map> key_;
+};
+
+ErrMsgOr<bytevec> generateCoseMac0Mac(const bytevec& macKey, const bytevec& externalAad,
+ const bytevec& payload);
+ErrMsgOr<cppbor::Array> constructCoseMac0(const bytevec& macKey, const bytevec& externalAad,
+ const bytevec& payload);
+ErrMsgOr<bytevec /* payload */> parseCoseMac0(const cppbor::Item* macItem);
+ErrMsgOr<bytevec /* payload */> verifyAndParseCoseMac0(const cppbor::Item* macItem,
+ const bytevec& macKey);
+
+ErrMsgOr<bytevec> createCoseSign1Signature(const bytevec& key, const bytevec& protectedParams,
+ const bytevec& payload, const bytevec& aad);
+ErrMsgOr<cppbor::Array> constructCoseSign1(const bytevec& key, const bytevec& payload,
+ const bytevec& aad);
+ErrMsgOr<cppbor::Array> constructCoseSign1(const bytevec& key, cppbor::Map extraProtectedFields,
+ const bytevec& payload, const bytevec& aad);
+/**
+ * Verify and parse a COSE_Sign1 message, returning the payload.
+ *
+ * @param ignoreSignature indicates whether signature verification should be skipped. If true, no
+ * verification of the signature will be done.
+ *
+ * @param coseSign1 is the COSE_Sign1 to verify and parse.
+ *
+ * @param signingCoseKey is a CBOR-encoded COSE_Key to use to verify the signature. The bytevec may
+ * be empty, in which case the function assumes that coseSign1's payload is the COSE_Key to
+ * use, i.e. that coseSign1 is a self-signed "certificate".
+ */
+ErrMsgOr<bytevec /* payload */> verifyAndParseCoseSign1(bool ignoreSignature,
+ const cppbor::Array* coseSign1,
+ const bytevec& signingCoseKey,
+ const bytevec& aad);
+
+ErrMsgOr<bytevec> createCoseEncryptCiphertext(const bytevec& key, const bytevec& nonce,
+ const bytevec& protectedParams, const bytevec& aad);
+ErrMsgOr<cppbor::Array> constructCoseEncrypt(const bytevec& key, const bytevec& nonce,
+ const bytevec& plaintextPayload, const bytevec& aad,
+ cppbor::Array recipients);
+ErrMsgOr<std::pair<bytevec /* pubkey */, bytevec /* key ID */>> getSenderPubKeyFromCoseEncrypt(
+ const cppbor::Item* encryptItem);
+inline ErrMsgOr<std::pair<bytevec /* pubkey */, bytevec /* key ID */>>
+getSenderPubKeyFromCoseEncrypt(const std::unique_ptr<cppbor::Item>& encryptItem) {
+ return getSenderPubKeyFromCoseEncrypt(encryptItem.get());
+}
+
+ErrMsgOr<bytevec /* plaintextPayload */> decryptCoseEncrypt(const bytevec& key,
+ const cppbor::Item* encryptItem,
+ const bytevec& aad);
+
+ErrMsgOr<bytevec> x25519_HKDF_DeriveKey(const bytevec& senderPubKey, const bytevec& senderPrivKey,
+ const bytevec& recipientPubKey, bool senderIsA);
+
+ErrMsgOr<bytevec /* ciphertextWithTag */> aesGcmEncrypt(const bytevec& key, const bytevec& nonce,
+ const bytevec& aad,
+ const bytevec& plaintext);
+ErrMsgOr<bytevec /* plaintext */> aesGcmDecrypt(const bytevec& key, const bytevec& nonce,
+ const bytevec& aad,
+ const bytevec& ciphertextWithTag);
+
+} // namespace cppcose
diff --git a/security/keymint/support/include/remote_prov/remote_prov_utils.h b/security/keymint/support/include/remote_prov/remote_prov_utils.h
new file mode 100644
index 0000000..5e205a2
--- /dev/null
+++ b/security/keymint/support/include/remote_prov/remote_prov_utils.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2019, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <vector>
+
+#include <cppcose/cppcose.h>
+
+namespace aidl::android::hardware::security::keymint::remote_prov {
+
+using bytevec = std::vector<uint8_t>;
+using namespace cppcose;
+
+extern bytevec kTestMacKey;
+
+/**
+ * Generates random bytes.
+ */
+bytevec randomBytes(size_t numBytes);
+
+struct EekChain {
+ bytevec chain;
+ bytevec last_pubkey;
+ bytevec last_privkey;
+};
+
+/**
+ * Generates an X25518 EEK with the specified eekId and an Ed25519 chain of the
+ * specified length. All keys are generated randomly.
+ */
+ErrMsgOr<EekChain> generateEekChain(size_t length, const bytevec& eekId);
+
+struct BccEntryData {
+ bytevec pubKey;
+};
+
+/**
+ * Validates the provided CBOR-encoded BCC, returning a vector of BccEntryData
+ * structs containing the BCC entry contents. If an entry contains no firmware
+ * digest, the corresponding BccEntryData.firmwareDigest will have length zero
+ * (there's no way to distinguish between an empty and missing firmware digest,
+ * which seems fine).
+ */
+ErrMsgOr<std::vector<BccEntryData>> validateBcc(const cppbor::Array* bcc);
+
+} // namespace aidl::android::hardware::security::keymint::remote_prov
diff --git a/security/keymint/support/remote_prov_utils.cpp b/security/keymint/support/remote_prov_utils.cpp
new file mode 100644
index 0000000..111cb30
--- /dev/null
+++ b/security/keymint/support/remote_prov_utils.cpp
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2019, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <remote_prov/remote_prov_utils.h>
+
+#include <openssl/rand.h>
+
+#include <cppbor.h>
+
+namespace aidl::android::hardware::security::keymint::remote_prov {
+
+bytevec kTestMacKey(32 /* count */, 0 /* byte value */);
+
+bytevec randomBytes(size_t numBytes) {
+ bytevec retval(numBytes);
+ RAND_bytes(retval.data(), numBytes);
+ return retval;
+}
+
+ErrMsgOr<EekChain> generateEekChain(size_t length, const bytevec& eekId) {
+ auto eekChain = cppbor::Array();
+
+ bytevec prev_priv_key;
+ for (size_t i = 0; i < length - 1; ++i) {
+ bytevec pub_key(ED25519_PUBLIC_KEY_LEN);
+ bytevec priv_key(ED25519_PRIVATE_KEY_LEN);
+
+ ED25519_keypair(pub_key.data(), priv_key.data());
+
+ // The first signing key is self-signed.
+ if (prev_priv_key.empty()) prev_priv_key = priv_key;
+
+ auto coseSign1 = constructCoseSign1(prev_priv_key,
+ cppbor::Map() /* payload CoseKey */
+ .add(CoseKey::KEY_TYPE, OCTET_KEY_PAIR)
+ .add(CoseKey::ALGORITHM, EDDSA)
+ .add(CoseKey::CURVE, ED25519)
+ .add(CoseKey::PUBKEY_X, pub_key)
+ .canonicalize()
+ .encode(),
+ {} /* AAD */);
+ if (!coseSign1) return coseSign1.moveMessage();
+ eekChain.add(coseSign1.moveValue());
+ }
+
+ bytevec pub_key(X25519_PUBLIC_VALUE_LEN);
+ bytevec priv_key(X25519_PRIVATE_KEY_LEN);
+ X25519_keypair(pub_key.data(), priv_key.data());
+
+ auto coseSign1 = constructCoseSign1(prev_priv_key,
+ cppbor::Map() /* payload CoseKey */
+ .add(CoseKey::KEY_TYPE, OCTET_KEY_PAIR)
+ .add(CoseKey::KEY_ID, eekId)
+ .add(CoseKey::ALGORITHM, ECDH_ES_HKDF_256)
+ .add(CoseKey::CURVE, cppcose::X25519)
+ .add(CoseKey::PUBKEY_X, pub_key)
+ .canonicalize()
+ .encode(),
+ {} /* AAD */);
+ if (!coseSign1) return coseSign1.moveMessage();
+ eekChain.add(coseSign1.moveValue());
+
+ return EekChain{eekChain.encode(), pub_key, priv_key};
+}
+
+ErrMsgOr<bytevec> verifyAndParseCoseSign1Cwt(bool ignoreSignature, const cppbor::Array* coseSign1,
+ const bytevec& signingCoseKey, const bytevec& aad) {
+ if (!coseSign1 || coseSign1->size() != kCoseSign1EntryCount) {
+ return "Invalid COSE_Sign1";
+ }
+
+ const cppbor::Bstr* protectedParams = coseSign1->get(kCoseSign1ProtectedParams)->asBstr();
+ const cppbor::Bstr* unprotectedParams = coseSign1->get(kCoseSign1UnprotectedParams)->asBstr();
+ const cppbor::Bstr* payload = coseSign1->get(kCoseSign1Payload)->asBstr();
+ const cppbor::Bstr* signature = coseSign1->get(kCoseSign1Signature)->asBstr();
+
+ if (!protectedParams || !unprotectedParams || !payload || !signature) {
+ return "Invalid COSE_Sign1";
+ }
+
+ auto [parsedProtParams, _, errMsg] = cppbor::parse(protectedParams);
+ if (!parsedProtParams) {
+ return errMsg + " when parsing protected params.";
+ }
+ if (!parsedProtParams->asMap()) {
+ return "Protected params must be a map";
+ }
+
+ auto& algorithm = parsedProtParams->asMap()->get(ALGORITHM);
+ if (!algorithm || !algorithm->asInt() || algorithm->asInt()->value() != EDDSA) {
+ return "Unsupported signature algorithm";
+ }
+
+ // TODO(jbires): Handle CWTs as the CoseSign1 payload in a less hacky way. Since the CWT payload
+ // is extremely remote provisioning specific, probably just make a separate
+ // function there.
+ auto [parsedPayload, __, payloadErrMsg] = cppbor::parse(payload);
+ if (!parsedPayload) return payloadErrMsg + " when parsing key";
+ if (!parsedPayload->asMap()) return "CWT must be a map";
+ auto serializedKey = parsedPayload->asMap()->get(-4670552)->clone();
+ if (!serializedKey || !serializedKey->asBstr()) return "Could not find key entry";
+
+ if (!ignoreSignature) {
+ bool selfSigned = signingCoseKey.empty();
+ auto key = CoseKey::parseEd25519(selfSigned ? serializedKey->asBstr()->value()
+ : signingCoseKey);
+ if (!key) return "Bad signing key: " + key.moveMessage();
+
+ bytevec signatureInput = cppbor::Array()
+ .add("Signature1")
+ .add(*protectedParams)
+ .add(aad)
+ .add(*payload)
+ .encode();
+
+ if (!ED25519_verify(signatureInput.data(), signatureInput.size(), signature->value().data(),
+ key->getBstrValue(CoseKey::PUBKEY_X)->data())) {
+ return "Signature verification failed";
+ }
+ }
+
+ return serializedKey->asBstr()->value();
+}
+ErrMsgOr<std::vector<BccEntryData>> validateBcc(const cppbor::Array* bcc) {
+ if (!bcc || bcc->size() == 0) return "Invalid BCC";
+
+ std::vector<BccEntryData> result;
+
+ bytevec prevKey;
+ // TODO(jbires): Actually process the pubKey at the start of the new bcc entry
+ for (size_t i = 1; i < bcc->size(); ++i) {
+ const cppbor::Array* entry = bcc->get(i)->asArray();
+ if (!entry || entry->size() != kCoseSign1EntryCount) {
+ return "Invalid BCC entry " + std::to_string(i) + ": " + prettyPrint(entry);
+ }
+ auto payload = verifyAndParseCoseSign1Cwt(false /* ignoreSignature */, entry,
+ std::move(prevKey), bytevec{} /* AAD */);
+ if (!payload) {
+ return "Failed to verify entry " + std::to_string(i) + ": " + payload.moveMessage();
+ }
+
+ auto& certProtParms = entry->get(kCoseSign1ProtectedParams);
+ if (!certProtParms || !certProtParms->asBstr()) return "Invalid prot params";
+ auto [parsedProtParms, _, errMsg] = cppbor::parse(certProtParms->asBstr()->value());
+ if (!parsedProtParms || !parsedProtParms->asMap()) return "Invalid prot params";
+
+ result.push_back(BccEntryData{*payload});
+
+ // This entry's public key is the signing key for the next entry.
+ prevKey = payload.moveValue();
+ }
+
+ return result;
+}
+
+} // namespace aidl::android::hardware::security::keymint::remote_prov