Merge "Use libcert_request_validator to check DICE chain" am: 8e8f82502b am: e734865baa
Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2370709
Change-Id: I8fee17ad196d4f213c3ae80120f9ff10f7bb6a2c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
diff --git a/security/keymint/support/Android.bp b/security/keymint/support/Android.bp
index 8d7731c..ce72c81 100644
--- a/security/keymint/support/Android.bp
+++ b/security/keymint/support/Android.bp
@@ -66,6 +66,9 @@
static_libs: [
"android.hardware.security.rkp-V3-ndk",
],
+ whole_static_libs: [
+ "libcert_request_validator_cxx",
+ ],
shared_libs: [
"libbase",
"libbinder_ndk",
diff --git a/security/keymint/support/include/remote_prov/remote_prov_utils.h b/security/keymint/support/include/remote_prov/remote_prov_utils.h
index 1b94c62..79189a1 100644
--- a/security/keymint/support/include/remote_prov/remote_prov_utils.h
+++ b/security/keymint/support/include/remote_prov/remote_prov_utils.h
@@ -108,15 +108,6 @@
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);
-
struct JsonOutput {
static JsonOutput Ok(std::string json) { return {std::move(json), ""}; }
static JsonOutput Error(std::string error) { return {"", std::move(error)}; }
diff --git a/security/keymint/support/remote_prov_utils.cpp b/security/keymint/support/remote_prov_utils.cpp
index ea0fbd8..3d8de28 100644
--- a/security/keymint/support/remote_prov_utils.cpp
+++ b/security/keymint/support/remote_prov_utils.cpp
@@ -23,6 +23,7 @@
#include <aidl/android/hardware/security/keymint/RpcHardwareInfo.h>
#include <android-base/properties.h>
+#include <cert_request_validator/cert_request_validator.h>
#include <cppbor.h>
#include <json/json.h>
#include <keymaster/km_openssl/ec_key.h>
@@ -289,129 +290,16 @@
return chain.encode();
}
-ErrMsgOr<bytevec> validatePayloadAndFetchPubKey(const cppbor::Map* payload) {
- const auto& issuer = payload->get(kBccPayloadIssuer);
- if (!issuer || !issuer->asTstr()) return "Issuer is not present or not a tstr.";
- const auto& subject = payload->get(kBccPayloadSubject);
- if (!subject || !subject->asTstr()) return "Subject is not present or not a tstr.";
- const auto& keyUsage = payload->get(kBccPayloadKeyUsage);
- if (!keyUsage || !keyUsage->asBstr()) return "Key usage is not present or not a bstr.";
- const auto& serializedKey = payload->get(kBccPayloadSubjPubKey);
- if (!serializedKey || !serializedKey->asBstr()) return "Key is not present or not a bstr.";
- return serializedKey->asBstr()->value();
-}
-
-ErrMsgOr<bytevec> verifyAndParseCoseSign1Cwt(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::Map* unprotectedParams = coseSign1->get(kCoseSign1UnprotectedParams)->asMap();
- 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 && algorithm->asInt()->value() != ES256)) {
- return "Unsupported signature algorithm";
- }
-
- auto [parsedPayload, __, payloadErrMsg] = cppbor::parse(payload);
- if (!parsedPayload) return payloadErrMsg + " when parsing key";
- if (!parsedPayload->asMap()) return "CWT must be a map";
- auto serializedKey = validatePayloadAndFetchPubKey(parsedPayload->asMap());
- if (!serializedKey) {
- return "CWT validation failed: " + serializedKey.moveMessage();
- }
-
- bool selfSigned = signingCoseKey.empty();
- bytevec signatureInput =
- cppbor::Array().add("Signature1").add(*protectedParams).add(aad).add(*payload).encode();
-
- if (algorithm->asInt()->value() == EDDSA) {
- auto key = CoseKey::parseEd25519(selfSigned ? *serializedKey : signingCoseKey);
-
- if (!key) return "Bad signing key: " + key.moveMessage();
-
- if (!ED25519_verify(signatureInput.data(), signatureInput.size(), signature->value().data(),
- key->getBstrValue(CoseKey::PUBKEY_X)->data())) {
- return "Signature verification failed";
- }
- } else { // P256
- auto key = CoseKey::parseP256(selfSigned ? *serializedKey : signingCoseKey);
- if (!key || key->getBstrValue(CoseKey::PUBKEY_X)->empty() ||
- key->getBstrValue(CoseKey::PUBKEY_Y)->empty()) {
- return "Bad signing key: " + key.moveMessage();
- }
- auto publicKey = key->getEcPublicKey();
- if (!publicKey) return publicKey.moveMessage();
-
- auto ecdsaDerSignature = ecdsaCoseSignatureToDer(signature->value());
- if (!ecdsaDerSignature) return ecdsaDerSignature.moveMessage();
-
- // convert public key to uncompressed form.
- publicKey->insert(publicKey->begin(), 0x04);
-
- if (!verifyEcdsaDigest(publicKey.moveValue(), sha256(signatureInput), *ecdsaDerSignature)) {
- return "Signature verification failed";
- }
- }
-
- return serializedKey.moveValue();
-}
-
ErrMsgOr<std::vector<BccEntryData>> validateBcc(const cppbor::Array* bcc) {
- if (!bcc || bcc->size() == 0) return "Invalid BCC";
-
+ auto encodedBcc = bcc->encode();
+ auto chain = cert_request_validator::DiceChain::verify(encodedBcc);
+ if (!chain.ok()) return chain.error().message();
+ auto keys = chain->cose_public_keys();
+ if (!keys.ok()) return keys.error().message();
std::vector<BccEntryData> result;
-
- const auto& devicePubKey = bcc->get(0);
- if (!devicePubKey->asMap()) return "Invalid device public key at the 1st entry in the BCC";
-
- bytevec prevKey;
-
- 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(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();
- if (i == 1) {
- auto [parsedRootKey, _, errMsg] = cppbor::parse(prevKey);
- if (!parsedRootKey || !parsedRootKey->asMap()) return "Invalid payload entry in BCC.";
- if (*parsedRootKey != *devicePubKey) {
- return "Device public key doesn't match BCC root.";
- }
- }
+ for (auto& key : *keys) {
+ result.push_back({std::move(key)});
}
-
return result;
}
@@ -685,9 +573,6 @@
if (!bccContents) {
return bccContents.message() + "\n" + prettyPrint(bcc.get());
}
- if (bccContents->size() == 0U) {
- return "The BCC is empty. It must contain at least one entry.";
- }
auto deviceInfoResult =
parseAndValidateDeviceInfo(deviceInfo.deviceInfo, provisionable, isFactory);
@@ -979,9 +864,6 @@
if (!diceContents) {
return diceContents.message() + "\n" + prettyPrint(diceCertChain);
}
- if (diceContents->size() == 0U) {
- return "The DICE chain is empty. It must contain at least one entry.";
- }
auto& udsPub = diceContents->back().pubKey;