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/* Copyright (c) 2020, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <cstdint>
#include <limits>
#include <string>
#include <vector>
#include <gtest/gtest.h>
#include <openssl/base.h>
#include <openssl/curve25519.h>
#include <openssl/digest.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/sha.h>
#include <openssl/span.h>
#include "../test/file_test.h"
#include "../test/test_util.h"
#include "internal.h"
namespace bssl {
namespace {
enum class HPKEMode {
kBase = 0,
kPSK = 1,
};
// HPKETestVector corresponds to one array member in the published
// test-vectors.json.
class HPKETestVector {
public:
explicit HPKETestVector() = default;
~HPKETestVector() = default;
bool ReadFromFileTest(FileTest *t);
void Verify() const {
ScopedEVP_HPKE_CTX sender_ctx;
ScopedEVP_HPKE_CTX receiver_ctx;
switch (mode_) {
case HPKEMode::kBase:
ASSERT_GT(secret_key_e_.size(), 0u);
ASSERT_EQ(psk_.size(), 0u);
ASSERT_EQ(psk_id_.size(), 0u);
// Set up the sender.
ASSERT_TRUE(EVP_HPKE_CTX_setup_base_s_x25519_for_test(
sender_ctx.get(), kdf_id_, aead_id_, public_key_r_.data(),
info_.data(), info_.size(), secret_key_e_.data(),
public_key_e_.data()));
// Set up the receiver.
ASSERT_TRUE(EVP_HPKE_CTX_setup_base_r_x25519(
receiver_ctx.get(), kdf_id_, aead_id_, public_key_e_.data(),
public_key_r_.data(), secret_key_r_.data(), info_.data(),
info_.size()));
break;
case HPKEMode::kPSK:
ASSERT_GT(secret_key_e_.size(), 0u);
ASSERT_GT(psk_.size(), 0u);
ASSERT_GT(psk_id_.size(), 0u);
// Set up the sender.
ASSERT_TRUE(EVP_HPKE_CTX_setup_psk_s_x25519_for_test(
sender_ctx.get(), kdf_id_, aead_id_, public_key_r_.data(),
info_.data(), info_.size(), psk_.data(), psk_.size(),
psk_id_.data(), psk_id_.size(), secret_key_e_.data(),
public_key_e_.data()));
// Set up the receiver.
ASSERT_TRUE(EVP_HPKE_CTX_setup_psk_r_x25519(
receiver_ctx.get(), kdf_id_, aead_id_, public_key_e_.data(),
public_key_r_.data(), secret_key_r_.data(), info_.data(),
info_.size(), psk_.data(), psk_.size(), psk_id_.data(),
psk_id_.size()));
break;
default:
FAIL() << "Unsupported mode";
return;
}
VerifyEncryptions(sender_ctx.get(), receiver_ctx.get());
VerifyExports(sender_ctx.get());
VerifyExports(receiver_ctx.get());
}
private:
void VerifyEncryptions(EVP_HPKE_CTX *sender_ctx,
EVP_HPKE_CTX *receiver_ctx) const {
for (const Encryption &task : encryptions_) {
std::vector<uint8_t> encrypted(task.plaintext.size() +
EVP_HPKE_CTX_max_overhead(sender_ctx));
size_t encrypted_len;
ASSERT_TRUE(EVP_HPKE_CTX_seal(
sender_ctx, encrypted.data(), &encrypted_len, encrypted.size(),
task.plaintext.data(), task.plaintext.size(), task.aad.data(),
task.aad.size()));
ASSERT_EQ(Bytes(encrypted.data(), encrypted_len), Bytes(task.ciphertext));
std::vector<uint8_t> decrypted(task.ciphertext.size());
size_t decrypted_len;
ASSERT_TRUE(EVP_HPKE_CTX_open(
receiver_ctx, decrypted.data(), &decrypted_len, decrypted.size(),
task.ciphertext.data(), task.ciphertext.size(), task.aad.data(),
task.aad.size()));
ASSERT_EQ(Bytes(decrypted.data(), decrypted_len), Bytes(task.plaintext));
}
}
void VerifyExports(EVP_HPKE_CTX *ctx) const {
for (const Export &task : exports_) {
std::vector<uint8_t> exported_secret(task.exportLength);
ASSERT_TRUE(EVP_HPKE_CTX_export(
ctx, exported_secret.data(), exported_secret.size(),
task.exportContext.data(), task.exportContext.size()));
ASSERT_EQ(Bytes(exported_secret), Bytes(task.exportValue));
}
}
struct Encryption {
std::vector<uint8_t> aad;
std::vector<uint8_t> ciphertext;
std::vector<uint8_t> plaintext;
};
struct Export {
std::vector<uint8_t> exportContext;
size_t exportLength;
std::vector<uint8_t> exportValue;
};
HPKEMode mode_;
uint16_t kdf_id_;
uint16_t aead_id_;
std::vector<uint8_t> context_;
std::vector<uint8_t> info_;
std::vector<uint8_t> public_key_e_;
std::vector<uint8_t> secret_key_e_;
std::vector<uint8_t> public_key_r_;
std::vector<uint8_t> secret_key_r_;
std::vector<Encryption> encryptions_;
std::vector<Export> exports_;
std::vector<uint8_t> psk_; // Empty when mode is not PSK.
std::vector<uint8_t> psk_id_; // Empty when mode is not PSK.
};
// Match FileTest's naming scheme for duplicated attribute names.
std::string BuildAttrName(const std::string &name, int iter) {
return iter == 1 ? name : name + "/" + std::to_string(iter);
}
// Parses |s| as an unsigned integer of type T and writes the value to |out|.
// Returns true on success. If the integer value exceeds the maximum T value,
// returns false.
template <typename T>
bool ParseIntSafe(T *out, const std::string &s) {
T value = 0;
for (char c : s) {
if (c < '0' || c > '9') {
return false;
}
if (value > (std::numeric_limits<T>::max() - (c - '0')) / 10) {
return false;
}
value = 10 * value + (c - '0');
}
*out = value;
return true;
}
// Read the |key| attribute from |file_test| and convert it to an integer.
template <typename T>
bool FileTestReadInt(FileTest *file_test, T *out, const std::string &key) {
std::string s;
return file_test->GetAttribute(&s, key) && ParseIntSafe(out, s);
}
bool HPKETestVector::ReadFromFileTest(FileTest *t) {
uint8_t mode_tmp;
if (!FileTestReadInt(t, &mode_tmp, "mode")) {
return false;
}
mode_ = static_cast<HPKEMode>(mode_tmp);
if (!FileTestReadInt(t, &kdf_id_, "kdf_id") ||
!FileTestReadInt(t, &aead_id_, "aead_id") ||
!t->GetBytes(&info_, "info") ||
!t->GetBytes(&secret_key_r_, "skRm") ||
!t->GetBytes(&public_key_r_, "pkRm") ||
!t->GetBytes(&secret_key_e_, "skEm") ||
!t->GetBytes(&public_key_e_, "pkEm")) {
return false;
}
if (mode_ == HPKEMode::kPSK) {
if (!t->GetBytes(&psk_, "psk") ||
!t->GetBytes(&psk_id_, "psk_id")) {
return false;
}
}
for (int i = 1; t->HasAttribute(BuildAttrName("aad", i)); i++) {
Encryption encryption;
if (!t->GetBytes(&encryption.aad, BuildAttrName("aad", i)) ||
!t->GetBytes(&encryption.ciphertext, BuildAttrName("ciphertext", i)) ||
!t->GetBytes(&encryption.plaintext, BuildAttrName("plaintext", i))) {
return false;
}
encryptions_.push_back(std::move(encryption));
}
for (int i = 1; t->HasAttribute(BuildAttrName("exportContext", i)); i++) {
Export exp;
if (!t->GetBytes(&exp.exportContext, BuildAttrName("exportContext", i)) ||
!FileTestReadInt(t, &exp.exportLength,
BuildAttrName("exportLength", i)) ||
!t->GetBytes(&exp.exportValue, BuildAttrName("exportValue", i))) {
return false;
}
exports_.push_back(std::move(exp));
}
return true;
}
} // namespace
TEST(HPKETest, VerifyTestVectors) {
FileTestGTest("crypto/hpke/hpke_test_vectors.txt", [](FileTest *t) {
HPKETestVector test_vec;
EXPECT_TRUE(test_vec.ReadFromFileTest(t));
test_vec.Verify();
});
}
// The test vectors used fixed sender ephemeral keys, while HPKE itself
// generates new keys for each context. Test this codepath by checking we can
// decrypt our own messages.
TEST(HPKETest, RoundTrip) {
uint16_t kdf_ids[] = {EVP_HPKE_HKDF_SHA256, EVP_HPKE_HKDF_SHA384,
EVP_HPKE_HKDF_SHA512};
uint16_t aead_ids[] = {EVP_HPKE_AEAD_AES_GCM_128, EVP_HPKE_AEAD_AES_GCM_256,
EVP_HPKE_AEAD_CHACHA20POLY1305};
const uint8_t info_a[] = {1, 1, 2, 3, 5, 8};
const uint8_t info_b[] = {42, 42, 42};
const uint8_t ad_a[] = {1, 2, 4, 8, 16};
const uint8_t ad_b[] = {7};
Span<const uint8_t> info_values[] = {{nullptr, 0}, info_a, info_b};
Span<const uint8_t> ad_values[] = {{nullptr, 0}, ad_a, ad_b};
// Generate the receiver's keypair.
uint8_t secret_key_r[X25519_PRIVATE_KEY_LEN];
uint8_t public_key_r[X25519_PUBLIC_VALUE_LEN];
X25519_keypair(public_key_r, secret_key_r);
for (uint16_t kdf_id : kdf_ids) {
for (uint16_t aead_id : aead_ids) {
for (const Span<const uint8_t> &info : info_values) {
for (const Span<const uint8_t> &ad : ad_values) {
// Set up the sender.
ScopedEVP_HPKE_CTX sender_ctx;
uint8_t enc[X25519_PUBLIC_VALUE_LEN];
ASSERT_TRUE(EVP_HPKE_CTX_setup_base_s_x25519(
sender_ctx.get(), enc, kdf_id, aead_id, public_key_r, info.data(),
info.size()));
// Set up the receiver.
ScopedEVP_HPKE_CTX receiver_ctx;
ASSERT_TRUE(EVP_HPKE_CTX_setup_base_r_x25519(
receiver_ctx.get(), kdf_id, aead_id, enc, public_key_r,
secret_key_r, info.data(), info.size()));
const char kCleartextPayload[] = "foobar";
// Have sender encrypt message for the receiver.
std::vector<uint8_t> ciphertext(
sizeof(kCleartextPayload) +
EVP_HPKE_CTX_max_overhead(sender_ctx.get()));
size_t ciphertext_len;
ASSERT_TRUE(EVP_HPKE_CTX_seal(
sender_ctx.get(), ciphertext.data(), &ciphertext_len,
ciphertext.size(),
reinterpret_cast<const uint8_t *>(kCleartextPayload),
sizeof(kCleartextPayload), ad.data(), ad.size()));
// Have receiver decrypt the message.
std::vector<uint8_t> cleartext(ciphertext.size());
size_t cleartext_len;
ASSERT_TRUE(EVP_HPKE_CTX_open(receiver_ctx.get(), cleartext.data(),
&cleartext_len, cleartext.size(),
ciphertext.data(), ciphertext_len,
ad.data(), ad.size()));
// Verify that decrypted message matches the original.
ASSERT_EQ(Bytes(cleartext.data(), cleartext_len),
Bytes(kCleartextPayload, sizeof(kCleartextPayload)));
}
}
}
}
}
// Verify that the DH operations inside Encap() and Decap() both fail when the
// public key is on a small-order point in the curve.
TEST(HPKETest, X25519EncapSmallOrderPoint) {
// Borrowed from X25519Test.SmallOrder.
static const uint8_t kSmallOrderPoint[32] = {
0xe0, 0xeb, 0x7a, 0x7c, 0x3b, 0x41, 0xb8, 0xae, 0x16, 0x56, 0xe3,
0xfa, 0xf1, 0x9f, 0xc4, 0x6a, 0xda, 0x09, 0x8d, 0xeb, 0x9c, 0x32,
0xb1, 0xfd, 0x86, 0x62, 0x05, 0x16, 0x5f, 0x49, 0xb8,
};
// Generate a valid keypair for the receiver.
uint8_t secret_key_r[X25519_PRIVATE_KEY_LEN];
uint8_t public_key_r[X25519_PUBLIC_VALUE_LEN];
X25519_keypair(public_key_r, secret_key_r);
uint16_t kdf_ids[] = {EVP_HPKE_HKDF_SHA256, EVP_HPKE_HKDF_SHA384,
EVP_HPKE_HKDF_SHA512};
uint16_t aead_ids[] = {EVP_HPKE_AEAD_AES_GCM_128, EVP_HPKE_AEAD_AES_GCM_256,
EVP_HPKE_AEAD_CHACHA20POLY1305};
for (uint16_t kdf_id : kdf_ids) {
for (uint16_t aead_id : aead_ids) {
// Set up the sender, passing in kSmallOrderPoint as |peer_public_value|.
ScopedEVP_HPKE_CTX sender_ctx;
uint8_t enc[X25519_PUBLIC_VALUE_LEN];
ASSERT_FALSE(EVP_HPKE_CTX_setup_base_s_x25519(
sender_ctx.get(), enc, kdf_id, aead_id, kSmallOrderPoint, nullptr,
0));
// Set up the receiver, passing in kSmallOrderPoint as |enc|.
ScopedEVP_HPKE_CTX receiver_ctx;
ASSERT_FALSE(EVP_HPKE_CTX_setup_base_r_x25519(
receiver_ctx.get(), kdf_id, aead_id, kSmallOrderPoint, public_key_r,
secret_key_r, nullptr, 0));
}
}
}
// Test that Seal() fails when the context has been initialized as a receiver.
TEST(HPKETest, ReceiverInvalidSeal) {
const uint8_t kMockEnc[X25519_PUBLIC_VALUE_LEN] = {0xff};
const char kCleartextPayload[] = "foobar";
// Generate the receiver's keypair.
uint8_t secret_key_r[X25519_PRIVATE_KEY_LEN];
uint8_t public_key_r[X25519_PUBLIC_VALUE_LEN];
X25519_keypair(public_key_r, secret_key_r);
// Set up the receiver.
ScopedEVP_HPKE_CTX receiver_ctx;
ASSERT_TRUE(EVP_HPKE_CTX_setup_base_r_x25519(
receiver_ctx.get(), EVP_HPKE_HKDF_SHA256, EVP_HPKE_AEAD_AES_GCM_128,
kMockEnc, public_key_r, secret_key_r, nullptr, 0));
// Call Seal() on the receiver.
size_t ciphertext_len;
uint8_t ciphertext[100];
ASSERT_FALSE(EVP_HPKE_CTX_seal(
receiver_ctx.get(), ciphertext, &ciphertext_len, sizeof(ciphertext),
reinterpret_cast<const uint8_t *>(kCleartextPayload),
sizeof(kCleartextPayload), nullptr, 0));
}
// Test that Open() fails when the context has been initialized as a sender.
TEST(HPKETest, SenderInvalidOpen) {
const uint8_t kMockCiphertext[100] = {0xff};
const size_t kMockCiphertextLen = 80;
// Generate the receiver's keypair.
uint8_t secret_key_r[X25519_PRIVATE_KEY_LEN];
uint8_t public_key_r[X25519_PUBLIC_VALUE_LEN];
X25519_keypair(public_key_r, secret_key_r);
// Set up the sender.
ScopedEVP_HPKE_CTX sender_ctx;
uint8_t enc[X25519_PUBLIC_VALUE_LEN];
ASSERT_TRUE(EVP_HPKE_CTX_setup_base_s_x25519(
sender_ctx.get(), enc, EVP_HPKE_HKDF_SHA256, EVP_HPKE_AEAD_AES_GCM_128,
public_key_r, nullptr, 0));
// Call Open() on the sender.
uint8_t cleartext[128];
size_t cleartext_len;
ASSERT_FALSE(EVP_HPKE_CTX_open(sender_ctx.get(), cleartext, &cleartext_len,
sizeof(cleartext), kMockCiphertext,
kMockCiphertextLen, nullptr, 0));
}
// Test that the PSK variants of Setup functions fail when any of the PSK inputs
// are empty.
TEST(HPKETest, EmptyPSK) {
const uint8_t kMockEnc[X25519_PUBLIC_VALUE_LEN] = {0xff};
const uint8_t kMockPSK[100] = {0xff};
const bssl::Span<const uint8_t> kPSKValues[] = {
{kMockPSK, sizeof(kMockPSK)},
{nullptr, 0},
};
// Generate the receiver's keypair.
uint8_t secret_key_r[X25519_PRIVATE_KEY_LEN];
uint8_t public_key_r[X25519_PUBLIC_VALUE_LEN];
X25519_keypair(public_key_r, secret_key_r);
// Vary the PSK and PSKID inputs for the sender and receiver, trying all four
// permutations of empty and nonempty inputs.
for (const auto psk : kPSKValues) {
for (const auto psk_id : kPSKValues) {
const bool kExpectSuccess = psk.size() > 0 && psk_id.size() > 0;
ASSERT_EQ(ERR_get_error(), 0u);
ScopedEVP_HPKE_CTX sender_ctx;
uint8_t enc[X25519_PUBLIC_VALUE_LEN];
ASSERT_EQ(EVP_HPKE_CTX_setup_psk_s_x25519(
sender_ctx.get(), enc, EVP_HPKE_HKDF_SHA256,
EVP_HPKE_AEAD_AES_GCM_128, public_key_r, nullptr, 0,
psk.data(), psk.size(), psk_id.data(), psk_id.size()),
kExpectSuccess);
if (!kExpectSuccess) {
uint32_t err = ERR_get_error();
EXPECT_EQ(ERR_LIB_EVP, ERR_GET_LIB(err));
EXPECT_EQ(EVP_R_EMPTY_PSK, ERR_GET_REASON(err));
}
ERR_clear_error();
ScopedEVP_HPKE_CTX receiver_ctx;
ASSERT_EQ(
EVP_HPKE_CTX_setup_psk_r_x25519(
receiver_ctx.get(), EVP_HPKE_HKDF_SHA256,
EVP_HPKE_AEAD_AES_GCM_128, kMockEnc, public_key_r, secret_key_r,
nullptr, 0, psk.data(), psk.size(), psk_id.data(), psk_id.size()),
kExpectSuccess);
if (!kExpectSuccess) {
uint32_t err = ERR_get_error();
EXPECT_EQ(ERR_LIB_EVP, ERR_GET_LIB(err));
EXPECT_EQ(EVP_R_EMPTY_PSK, ERR_GET_REASON(err));
}
ERR_clear_error();
}
}
}
TEST(HPKETest, InternalParseIntSafe) {
uint8_t u8 = 0xff;
ASSERT_FALSE(ParseIntSafe(&u8, "-1"));
ASSERT_TRUE(ParseIntSafe(&u8, "0"));
ASSERT_EQ(u8, 0);
ASSERT_TRUE(ParseIntSafe(&u8, "255"));
ASSERT_EQ(u8, 255);
ASSERT_FALSE(ParseIntSafe(&u8, "256"));
uint16_t u16 = 0xffff;
ASSERT_TRUE(ParseIntSafe(&u16, "257"));
ASSERT_EQ(u16, 257);
ASSERT_TRUE(ParseIntSafe(&u16, "65535"));
ASSERT_EQ(u16, 65535);
ASSERT_FALSE(ParseIntSafe(&u16, "65536"));
}
} // namespace bssl