Add more EEK variant tests and related fixes
- Test with deliberately-invalid EEK in request:
- corrupt signature
- missing initial self-signed cert
- Test with different sizes of EEK chain.
These tests will only really take effect when we have a valid GEEK to
test with.
Other changes:
- Fix encoding of KeyUsage bitset.
- Add a made-up allowed-root pubkey for prod mode. This needs to be
replaced with the real GEEK when available.
- Fix generateEek() so that the first private key isn't used for
all signing operations.
Test: VtsHalRemotelyProvisionedComponentTargetTest
Change-Id: I833894d33cd1757b7a0cfcf18f79b61e4e56a556
diff --git a/security/keymint/aidl/default/RemotelyProvisionedComponent.cpp b/security/keymint/aidl/default/RemotelyProvisionedComponent.cpp
index 4dbaa05..ca06abc 100644
--- a/security/keymint/aidl/default/RemotelyProvisionedComponent.cpp
+++ b/security/keymint/aidl/default/RemotelyProvisionedComponent.cpp
@@ -46,6 +46,14 @@
namespace {
+// Hard-coded set of acceptable public keys that can act as roots of EEK chains.
+inline const vector<bytevec> kAuthorizedEekRoots = {
+ // TODO(drysdale): replace this random value with real root pubkey(s).
+ {0x5c, 0xea, 0x4b, 0xd2, 0x31, 0x27, 0x15, 0x5e, 0x62, 0x94, 0x70,
+ 0x53, 0x94, 0x43, 0x0f, 0x9a, 0x89, 0xd5, 0xc5, 0x0f, 0x82, 0x9b,
+ 0xcd, 0x10, 0xe0, 0x79, 0xef, 0xf3, 0xfa, 0x40, 0xeb, 0x0a},
+};
+
constexpr auto STATUS_FAILED = RemotelyProvisionedComponent::STATUS_FAILED;
constexpr auto STATUS_INVALID_EEK = RemotelyProvisionedComponent::STATUS_INVALID_EEK;
constexpr auto STATUS_INVALID_MAC = RemotelyProvisionedComponent::STATUS_INVALID_MAC;
@@ -135,6 +143,13 @@
"Failed to validate EEK chain: " + cosePubKey.moveMessage());
}
lastPubKey = *std::move(cosePubKey);
+
+ // In prod mode the first pubkey should match a well-known Google public key.
+ if (!testMode && i == 0 &&
+ std::find(kAuthorizedEekRoots.begin(), kAuthorizedEekRoots.end(), lastPubKey) ==
+ kAuthorizedEekRoots.end()) {
+ return Status(STATUS_INVALID_EEK, "Unrecognized root of EEK chain");
+ }
}
auto eek = CoseKey::parseX25519(lastPubKey, true /* requireKid */);
@@ -417,8 +432,8 @@
.add(1 /* Issuer */, "Issuer")
.add(2 /* Subject */, "Subject")
.add(-4670552 /* Subject Pub Key */, coseKey)
- .add(-4670553 /* Key Usage */,
- std::vector<uint8_t>(0x05) /* Big endian order */)
+ .add(-4670553 /* Key Usage (little-endian order) */,
+ std::vector<uint8_t>{0x20} /* keyCertSign = 1<<5 */)
.canonicalize()
.encode();
auto coseSign1 = constructCoseSign1(privKey, /* signing key */
diff --git a/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp b/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp
index 51928c9..6c16ff4 100644
--- a/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp
+++ b/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp
@@ -128,6 +128,55 @@
}
}
+ErrMsgOr<cppbor::Array> corrupt_sig(const cppbor::Array* coseSign1) {
+ if (coseSign1->size() != kCoseSign1EntryCount) {
+ return "Invalid COSE_Sign1, wrong entry count";
+ }
+ 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: missing content";
+ }
+
+ auto corruptSig = cppbor::Array();
+ corruptSig.add(protectedParams->clone());
+ corruptSig.add(unprotectedParams->clone());
+ corruptSig.add(payload->clone());
+ vector<uint8_t> sigData = signature->value();
+ sigData[0] ^= 0x08;
+ corruptSig.add(cppbor::Bstr(sigData));
+
+ return std::move(corruptSig);
+}
+
+ErrMsgOr<EekChain> corrupt_sig_chain(const EekChain& eek, int which) {
+ auto [chain, _, parseErr] = cppbor::parse(eek.chain);
+ if (!chain || !chain->asArray()) {
+ return "EekChain parse failed";
+ }
+
+ cppbor::Array* eekChain = chain->asArray();
+ if (which >= eekChain->size()) {
+ return "selected sig out of range";
+ }
+ auto corruptChain = cppbor::Array();
+
+ for (int ii = 0; ii < eekChain->size(); ++ii) {
+ if (ii == which) {
+ auto sig = corrupt_sig(eekChain->get(which)->asArray());
+ if (!sig) {
+ return "Failed to build corrupted signature" + sig.moveMessage();
+ }
+ corruptChain.add(sig.moveValue());
+ } else {
+ corruptChain.add(eekChain->get(ii)->clone());
+ }
+ }
+ return EekChain{corruptChain.encode(), eek.last_pubkey, eek.last_privkey};
+}
+
} // namespace
class VtsRemotelyProvisionedComponentTests : public testing::TestWithParam<std::string> {
@@ -182,9 +231,14 @@
class CertificateRequestTest : public VtsRemotelyProvisionedComponentTests {
protected:
CertificateRequestTest() : eekId_(string_to_bytevec("eekid")), challenge_(randomBytes(32)) {
- auto chain = generateEekChain(3, eekId_);
+ generateEek(3);
+ }
+
+ void generateEek(size_t eekLength) {
+ auto chain = generateEekChain(eekLength, eekId_);
EXPECT_TRUE(chain) << chain.message();
if (chain) eekChain_ = chain.moveValue();
+ eekLength_ = eekLength;
}
void generateKeys(bool testMode, size_t numKeys) {
@@ -258,6 +312,7 @@
}
bytevec eekId_;
+ size_t eekLength_;
EekChain eekChain_;
bytevec challenge_;
std::vector<MacedPublicKey> keysToSign_;
@@ -270,15 +325,20 @@
*/
TEST_P(CertificateRequestTest, EmptyRequest_testMode) {
bool testMode = true;
- bytevec keysToSignMac;
- DeviceInfo deviceInfo;
- ProtectedData protectedData;
- auto status = provisionable_->generateCertificateRequest(
- testMode, {} /* keysToSign */, eekChain_.chain, challenge_, &deviceInfo, &protectedData,
- &keysToSignMac);
- ASSERT_TRUE(status.isOk()) << status.getMessage();
+ for (size_t eekLength : {2, 3, 7}) {
+ SCOPED_TRACE(testing::Message() << "EEK of length " << eekLength);
+ generateEek(eekLength);
- checkProtectedData(testMode, cppbor::Array(), keysToSignMac, protectedData);
+ bytevec keysToSignMac;
+ DeviceInfo deviceInfo;
+ ProtectedData protectedData;
+ auto status = provisionable_->generateCertificateRequest(
+ testMode, {} /* keysToSign */, eekChain_.chain, challenge_, &deviceInfo,
+ &protectedData, &keysToSignMac);
+ ASSERT_TRUE(status.isOk()) << status.getMessage();
+
+ checkProtectedData(testMode, cppbor::Array(), keysToSignMac, protectedData);
+ }
}
/**
@@ -290,14 +350,20 @@
*/
TEST_P(CertificateRequestTest, EmptyRequest_prodMode) {
bool testMode = false;
- bytevec keysToSignMac;
- DeviceInfo deviceInfo;
- ProtectedData protectedData;
- auto status = provisionable_->generateCertificateRequest(
- testMode, {} /* keysToSign */, eekChain_.chain, challenge_, &deviceInfo, &protectedData,
- &keysToSignMac);
- ASSERT_FALSE(status.isOk());
- ASSERT_EQ(status.getServiceSpecificError(), BnRemotelyProvisionedComponent::STATUS_INVALID_EEK);
+ for (size_t eekLength : {2, 3, 7}) {
+ SCOPED_TRACE(testing::Message() << "EEK of length " << eekLength);
+ generateEek(eekLength);
+
+ bytevec keysToSignMac;
+ DeviceInfo deviceInfo;
+ ProtectedData protectedData;
+ auto status = provisionable_->generateCertificateRequest(
+ testMode, {} /* keysToSign */, eekChain_.chain, challenge_, &deviceInfo,
+ &protectedData, &keysToSignMac);
+ EXPECT_FALSE(status.isOk());
+ EXPECT_EQ(status.getServiceSpecificError(),
+ BnRemotelyProvisionedComponent::STATUS_INVALID_EEK);
+ }
}
/**
@@ -307,15 +373,20 @@
bool testMode = true;
generateKeys(testMode, 4 /* numKeys */);
- bytevec keysToSignMac;
- DeviceInfo deviceInfo;
- ProtectedData protectedData;
- auto status = provisionable_->generateCertificateRequest(testMode, keysToSign_, eekChain_.chain,
- challenge_, &deviceInfo,
- &protectedData, &keysToSignMac);
- ASSERT_TRUE(status.isOk()) << status.getMessage();
+ for (size_t eekLength : {2, 3, 7}) {
+ SCOPED_TRACE(testing::Message() << "EEK of length " << eekLength);
+ generateEek(eekLength);
- checkProtectedData(testMode, cborKeysToSign_, keysToSignMac, protectedData);
+ bytevec keysToSignMac;
+ DeviceInfo deviceInfo;
+ ProtectedData protectedData;
+ auto status = provisionable_->generateCertificateRequest(
+ testMode, keysToSign_, eekChain_.chain, challenge_, &deviceInfo, &protectedData,
+ &keysToSignMac);
+ ASSERT_TRUE(status.isOk()) << status.getMessage();
+
+ checkProtectedData(testMode, cborKeysToSign_, keysToSignMac, protectedData);
+ }
}
/**
@@ -329,12 +400,77 @@
bool testMode = false;
generateKeys(testMode, 4 /* numKeys */);
+ for (size_t eekLength : {2, 3, 7}) {
+ SCOPED_TRACE(testing::Message() << "EEK of length " << eekLength);
+ generateEek(eekLength);
+
+ bytevec keysToSignMac;
+ DeviceInfo deviceInfo;
+ ProtectedData protectedData;
+ auto status = provisionable_->generateCertificateRequest(
+ testMode, keysToSign_, eekChain_.chain, challenge_, &deviceInfo, &protectedData,
+ &keysToSignMac);
+ EXPECT_FALSE(status.isOk());
+ EXPECT_EQ(status.getServiceSpecificError(),
+ BnRemotelyProvisionedComponent::STATUS_INVALID_EEK);
+ }
+}
+
+/**
+ * Generate a non-empty certificate request in prod mode that has a corrupt EEK chain.
+ * Confirm that the request is rejected.
+ *
+ * TODO(drysdale): Update to use a valid GEEK, so that the test actually confirms that the
+ * implementation is checking signatures.
+ */
+TEST_P(CertificateRequestTest, NonEmptyCorruptEekRequest_prodMode) {
+ bool testMode = false;
+ generateKeys(testMode, 4 /* numKeys */);
+
+ for (size_t ii = 0; ii < eekLength_; ii++) {
+ auto chain = corrupt_sig_chain(eekChain_, ii);
+ ASSERT_TRUE(chain) << chain.message();
+ EekChain corruptEek = chain.moveValue();
+
+ bytevec keysToSignMac;
+ DeviceInfo deviceInfo;
+ ProtectedData protectedData;
+ auto status = provisionable_->generateCertificateRequest(
+ testMode, keysToSign_, corruptEek.chain, challenge_, &deviceInfo, &protectedData,
+ &keysToSignMac);
+ ASSERT_FALSE(status.isOk());
+ ASSERT_EQ(status.getServiceSpecificError(),
+ BnRemotelyProvisionedComponent::STATUS_INVALID_EEK);
+ }
+}
+
+/**
+ * Generate a non-empty certificate request in prod mode that has an incomplete EEK chain.
+ * Confirm that the request is rejected.
+ *
+ * TODO(drysdale): Update to use a valid GEEK, so that the test actually confirms that the
+ * implementation is checking signatures.
+ */
+TEST_P(CertificateRequestTest, NonEmptyIncompleteEekRequest_prodMode) {
+ bool testMode = false;
+ generateKeys(testMode, 4 /* numKeys */);
+
+ // Build an EEK chain that omits the first self-signed cert.
+ auto truncatedChain = cppbor::Array();
+ auto [chain, _, parseErr] = cppbor::parse(eekChain_.chain);
+ ASSERT_TRUE(chain);
+ auto eekChain = chain->asArray();
+ ASSERT_NE(eekChain, nullptr);
+ for (size_t ii = 1; ii < eekChain->size(); ii++) {
+ truncatedChain.add(eekChain->get(ii)->clone());
+ }
+
bytevec keysToSignMac;
DeviceInfo deviceInfo;
ProtectedData protectedData;
- auto status = provisionable_->generateCertificateRequest(testMode, keysToSign_, eekChain_.chain,
- challenge_, &deviceInfo,
- &protectedData, &keysToSignMac);
+ auto status = provisionable_->generateCertificateRequest(
+ testMode, keysToSign_, truncatedChain.encode(), challenge_, &deviceInfo, &protectedData,
+ &keysToSignMac);
ASSERT_FALSE(status.isOk());
ASSERT_EQ(status.getServiceSpecificError(), BnRemotelyProvisionedComponent::STATUS_INVALID_EEK);
}
diff --git a/security/keymint/support/remote_prov_utils.cpp b/security/keymint/support/remote_prov_utils.cpp
index 3e4f3f7..da10eb2 100644
--- a/security/keymint/support/remote_prov_utils.cpp
+++ b/security/keymint/support/remote_prov_utils.cpp
@@ -54,6 +54,8 @@
{} /* AAD */);
if (!coseSign1) return coseSign1.moveMessage();
eekChain.add(coseSign1.moveValue());
+
+ prev_priv_key = priv_key;
}
bytevec pub_key(X25519_PUBLIC_VALUE_LEN);