Merge "Add sanity check when loading public keys for OTA package" am: 6793f61795
am: accb42d1b3
Change-Id: I7d66b01eeb8c25339c323d306fc7b8fc4980f9c9
diff --git a/tests/component/verifier_test.cpp b/tests/component/verifier_test.cpp
index d110c37..14b6060 100644
--- a/tests/component/verifier_test.cpp
+++ b/tests/component/verifier_test.cpp
@@ -30,6 +30,9 @@
#include <android-base/test_utils.h>
#include <android-base/unique_fd.h>
#include <gtest/gtest.h>
+#include <openssl/bn.h>
+#include <openssl/ec.h>
+#include <openssl/nid.h>
#include <ziparchive/zip_writer.h>
#include "common/test_constants.h"
@@ -148,6 +151,35 @@
VerifyPackageWithSingleCertificate("otasigned_v5.zip", std::move(cert));
}
+TEST(VerifierTest, LoadCertificateFromBuffer_check_rsa_keys) {
+ std::unique_ptr<RSA, RSADeleter> rsa(RSA_new());
+ std::unique_ptr<BIGNUM, decltype(&BN_free)> exponent(BN_new(), BN_free);
+ BN_set_word(exponent.get(), 3);
+ RSA_generate_key_ex(rsa.get(), 2048, exponent.get(), nullptr);
+ ASSERT_TRUE(CheckRSAKey(rsa));
+
+ // Exponent is expected to be 3 or 65537
+ BN_set_word(exponent.get(), 17);
+ RSA_generate_key_ex(rsa.get(), 2048, exponent.get(), nullptr);
+ ASSERT_FALSE(CheckRSAKey(rsa));
+
+ // Modulus is expected to be 2048.
+ BN_set_word(exponent.get(), 3);
+ RSA_generate_key_ex(rsa.get(), 1024, exponent.get(), nullptr);
+ ASSERT_FALSE(CheckRSAKey(rsa));
+}
+
+TEST(VerifierTest, LoadCertificateFromBuffer_check_ec_keys) {
+ std::unique_ptr<EC_KEY, ECKEYDeleter> ec(EC_KEY_new_by_curve_name(NID_X9_62_prime256v1));
+ ASSERT_EQ(1, EC_KEY_generate_key(ec.get()));
+ ASSERT_TRUE(CheckECKey(ec));
+
+ // Expects 256-bit EC key with curve NIST P-256
+ ec.reset(EC_KEY_new_by_curve_name(NID_secp224r1));
+ ASSERT_EQ(1, EC_KEY_generate_key(ec.get()));
+ ASSERT_FALSE(CheckECKey(ec));
+}
+
TEST(VerifierTest, LoadKeysFromZipfile_empty_archive) {
TemporaryFile otacerts;
BuildCertificateArchive({}, otacerts.release());
diff --git a/verifier.cpp b/verifier.cpp
index 2101dcb..2dfc208 100644
--- a/verifier.cpp
+++ b/verifier.cpp
@@ -500,6 +500,48 @@
return result;
}
+bool CheckRSAKey(const std::unique_ptr<RSA, RSADeleter>& rsa) {
+ if (!rsa) {
+ return false;
+ }
+
+ const BIGNUM* out_n;
+ const BIGNUM* out_e;
+ RSA_get0_key(rsa.get(), &out_n, &out_e, nullptr /* private exponent */);
+ auto modulus_bits = BN_num_bits(out_n);
+ if (modulus_bits != 2048) {
+ LOG(ERROR) << "Modulus should be 2048 bits long, actual: " << modulus_bits;
+ return false;
+ }
+
+ BN_ULONG exponent = BN_get_word(out_e);
+ if (exponent != 3 && exponent != 65537) {
+ LOG(ERROR) << "Public exponent should be 3 or 65537, actual: " << exponent;
+ return false;
+ }
+
+ return true;
+}
+
+bool CheckECKey(const std::unique_ptr<EC_KEY, ECKEYDeleter>& ec_key) {
+ if (!ec_key) {
+ return false;
+ }
+
+ const EC_GROUP* ec_group = EC_KEY_get0_group(ec_key.get());
+ if (!ec_group) {
+ LOG(ERROR) << "Failed to get the ec_group from the ec_key";
+ return false;
+ }
+ auto degree = EC_GROUP_get_degree(ec_group);
+ if (degree != 256) {
+ LOG(ERROR) << "Field size of the ec key should be 256 bits long, actual: " << degree;
+ return false;
+ }
+
+ return true;
+}
+
bool LoadCertificateFromBuffer(const std::vector<uint8_t>& pem_content, Certificate* cert) {
std::unique_ptr<BIO, decltype(&BIO_free)> content(
BIO_new_mem_buf(pem_content.data(), pem_content.size()), BIO_free);
@@ -538,22 +580,20 @@
}
int key_type = EVP_PKEY_id(public_key.get());
- // TODO(xunchang) check the rsa key has exponent 3 or 65537 with RSA_get0_key; and ec key is
- // 256 bits.
if (key_type == EVP_PKEY_RSA) {
cert->key_type = Certificate::KEY_TYPE_RSA;
cert->ec.reset();
cert->rsa.reset(EVP_PKEY_get1_RSA(public_key.get()));
- if (!cert->rsa) {
- LOG(ERROR) << "Failed to get the rsa key info from public key";
+ if (!cert->rsa || !CheckRSAKey(cert->rsa)) {
+ LOG(ERROR) << "Failed to validate the rsa key info from public key";
return false;
}
} else if (key_type == EVP_PKEY_EC) {
cert->key_type = Certificate::KEY_TYPE_EC;
cert->rsa.reset();
cert->ec.reset(EVP_PKEY_get1_EC_KEY(public_key.get()));
- if (!cert->ec) {
- LOG(ERROR) << "Failed to get the ec key info from the public key";
+ if (!cert->ec || !CheckECKey(cert->ec)) {
+ LOG(ERROR) << "Failed to validate the ec key info from the public key";
return false;
}
} else {
diff --git a/verifier.h b/verifier.h
index b7924c7..9448232 100644
--- a/verifier.h
+++ b/verifier.h
@@ -72,6 +72,12 @@
bool load_keys(const char* filename, std::vector<Certificate>& certs);
+// Checks that the RSA key has a modulus of 2048 bits long, and public exponent is 3 or 65537.
+bool CheckRSAKey(const std::unique_ptr<RSA, RSADeleter>& rsa);
+
+// Checks that the field size of the curve for the EC key is 256 bits.
+bool CheckECKey(const std::unique_ptr<EC_KEY, ECKEYDeleter>& ec_key);
+
// Parses a PEM-encoded x509 certificate from the given buffer and saves it into |cert|. Returns
// false if there is a parsing failure or the signature's encryption algorithm is not supported.
bool LoadCertificateFromBuffer(const std::vector<uint8_t>& pem_content, Certificate* cert);