Merge "Add sanity check when loading public keys for OTA package" (6793f617) · Commits · e / os / android_bootable_recovery

tests/component/verifier_test.cpp

+32 −0

Original line number	Diff line number	Diff line
		@@ -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 @@ TEST(VerifierTest, LoadCertificateFromBuffer_sha256_ec256bits) {
		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());

verifier.cpp

+46 −6

Original line number	Diff line number	Diff line
		@@ -500,6 +500,48 @@ std::vector<Certificate> LoadKeysFromZipfile(const std::string& zip_name) {
		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 @@ bool LoadCertificateFromBuffer(const std::vector<uint8_t>& pem_content, Certific
		}

		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 {

verifier.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -72,6 +72,12 @@ int verify_file(const unsigned char* addr, size_t length, const std::vector<Cert

		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);