Remove HKDF implementation from WebRTC.
We no longer have a need for a HKDF implementation in WebRTC. To keep
code quality high it makes sense to delete this dead code path.
Bug: webrtc:9600
Change-Id: Ibe6ee9150acd9dbf59452372242d857c5ffa65c4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/132802
Reviewed-by: Peter Slatala <psla@webrtc.org>
Reviewed-by: Qingsi Wang <qingsi@webrtc.org>
Reviewed-by: Seth Hampson <shampson@webrtc.org>
Commit-Queue: Benjamin Wright <benwright@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27604}diff --git a/pc/jsep_transport_controller.cc b/pc/jsep_transport_controller.cc
index e92dab5..fd9551a 100644
--- a/pc/jsep_transport_controller.cc
+++ b/pc/jsep_transport_controller.cc
@@ -21,7 +21,6 @@
#include "pc/srtp_filter.h"
#include "rtc_base/bind.h"
#include "rtc_base/checks.h"
-#include "rtc_base/key_derivation.h"
#include "rtc_base/thread.h"
using webrtc::SdpType;
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index 05cecd1..59eca29 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -825,8 +825,6 @@
"ip_address.cc",
"ip_address.h",
"keep_ref_until_done.h",
- "key_derivation.cc",
- "key_derivation.h",
"mdns_responder_interface.h",
"message_digest.cc",
"message_digest.h",
@@ -855,8 +853,6 @@
"openssl_digest.h",
"openssl_identity.cc",
"openssl_identity.h",
- "openssl_key_derivation_hkdf.cc",
- "openssl_key_derivation_hkdf.h",
"openssl_session_cache.cc",
"openssl_session_cache.h",
"openssl_stream_adapter.cc",
@@ -1363,7 +1359,6 @@
if (is_posix || is_fuchsia) {
sources += [
"openssl_adapter_unittest.cc",
- "openssl_key_derivation_hkdf_unittest.cc",
"openssl_session_cache_unittest.cc",
"openssl_utility_unittest.cc",
"ssl_adapter_unittest.cc",
diff --git a/rtc_base/key_derivation.cc b/rtc_base/key_derivation.cc
deleted file mode 100644
index 6c9a254..0000000
--- a/rtc_base/key_derivation.cc
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright 2018 The WebRTC Project Authors. All rights reserved.
- *
- * Use of this source code is governed by a BSD-style license
- * that can be found in the LICENSE file in the root of the source
- * tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
- * be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "rtc_base/key_derivation.h"
-
-#include "absl/memory/memory.h"
-#include "rtc_base/checks.h"
-#include "rtc_base/openssl_key_derivation_hkdf.h"
-
-namespace rtc {
-
-KeyDerivation::KeyDerivation() = default;
-KeyDerivation::~KeyDerivation() = default;
-
-// static
-std::unique_ptr<KeyDerivation> KeyDerivation::Create(
- KeyDerivationAlgorithm key_derivation_algorithm) {
- switch (key_derivation_algorithm) {
- case KeyDerivationAlgorithm::HKDF_SHA256:
- return absl::make_unique<OpenSSLKeyDerivationHKDF>();
- }
- RTC_NOTREACHED();
-}
-
-} // namespace rtc
diff --git a/rtc_base/key_derivation.h b/rtc_base/key_derivation.h
deleted file mode 100644
index f35e7ff..0000000
--- a/rtc_base/key_derivation.h
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * Copyright 2018 The WebRTC Project Authors. All rights reserved.
- *
- * Use of this source code is governed by a BSD-style license
- * that can be found in the LICENSE file in the root of the source
- * tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
- * be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef RTC_BASE_KEY_DERIVATION_H_
-#define RTC_BASE_KEY_DERIVATION_H_
-
-#include <stddef.h>
-#include <stdint.h>
-#include <memory>
-
-#include "absl/types/optional.h"
-#include "api/array_view.h"
-#include "rtc_base/buffer.h"
-#include "rtc_base/constructor_magic.h"
-
-namespace rtc {
-
-// Defines the set of key derivation algorithms that are supported. It is ideal
-// to keep this list as small as possible.
-enum class KeyDerivationAlgorithm {
- // This algorithm is not suitable to generate a key from a password. Please
- // only use with a cryptographically random master secret.
- HKDF_SHA256
-};
-
-// KeyDerivation provides a generic interface for deriving keys in WebRTC. This
-// class should be used over directly accessing openssl or boringssl primitives
-// so that we can maintain seperate implementations.
-// Example:
-// auto kd = KeyDerivation::Create(KeyDerivationAlgorithm::HDKF_SHA526);
-// if (kd == nullptr) return;
-// auto derived_key_or = kd->DeriveKey(secret, salt, label);
-// if (!derived_key_or.ok()) return;
-// DoSomethingWithKey(derived_key_or.value());
-class KeyDerivation {
- public:
- KeyDerivation();
- virtual ~KeyDerivation();
-
- // Derives a new key from existing key material.
- // secret - The random secret value you wish to derive a key from.
- // salt - Optional but recommended (non secret) cryptographically random.
- // label - A non secret but unique label value to determine the derivation.
- // derived_key_byte_size - This must be at least 128 bits.
- // return - An optional ZeroOnFreeBuffer containing the derived key or
- // absl::nullopt. Nullopt indicates a failure in derivation.
- virtual absl::optional<ZeroOnFreeBuffer<uint8_t>> DeriveKey(
- rtc::ArrayView<const uint8_t> secret,
- rtc::ArrayView<const uint8_t> salt,
- rtc::ArrayView<const uint8_t> label,
- size_t derived_key_byte_size) = 0;
-
- // Static factory that will return an implementation that is capable of
- // handling the key derivation with the requested algorithm. If no
- // implementation is available nullptr will be returned.
- static std::unique_ptr<KeyDerivation> Create(
- KeyDerivationAlgorithm key_derivation_algorithm);
-
- private:
- RTC_DISALLOW_COPY_AND_ASSIGN(KeyDerivation);
-};
-
-} // namespace rtc
-
-#endif // RTC_BASE_KEY_DERIVATION_H_
diff --git a/rtc_base/openssl_key_derivation_hkdf.cc b/rtc_base/openssl_key_derivation_hkdf.cc
deleted file mode 100644
index d82f07b..0000000
--- a/rtc_base/openssl_key_derivation_hkdf.cc
+++ /dev/null
@@ -1,108 +0,0 @@
-/*
- * Copyright 2018 The WebRTC Project Authors. All rights reserved.
- *
- * Use of this source code is governed by a BSD-style license
- * that can be found in the LICENSE file in the root of the source
- * tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
- * be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "rtc_base/openssl_key_derivation_hkdf.h"
-
-#include <utility>
-
-#include <openssl/ossl_typ.h>
-#ifdef OPENSSL_IS_BORINGSSL
-#include <openssl/digest.h>
-#include <openssl/hkdf.h>
-#else
-#include <openssl/evp.h>
-#include <openssl/kdf.h>
-#endif
-#include <openssl/err.h>
-#include <openssl/sha.h>
-
-#include "absl/algorithm/container.h"
-#include "rtc_base/buffer.h"
-#include "rtc_base/openssl.h"
-
-namespace rtc {
-
-#ifndef OPENSSL_IS_BORINGSSL
-namespace {
-
-// HKDF is static within OpenSSL and hence not accessible to the caller.
-// This internal implementation allows for compatibility with BoringSSL.
-static int HKDF(uint8_t* out_key,
- size_t out_len,
- const EVP_MD* digest,
- const uint8_t* secret,
- size_t secret_len,
- const uint8_t* salt,
- size_t salt_len,
- const uint8_t* info,
- size_t info_len) {
- EVP_PKEY_CTX* pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
-
- if (EVP_PKEY_derive_init(pctx) <= 0 ||
- EVP_PKEY_CTX_set_hkdf_md(pctx, digest) <= 0 ||
- EVP_PKEY_CTX_set1_hkdf_salt(pctx, salt, salt_len) <= 0 ||
- EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, secret_len) <= 0 ||
- EVP_PKEY_CTX_add1_hkdf_info(pctx, info, info_len) <= 0 ||
- EVP_PKEY_derive(pctx, out_key, &out_len) <= 0) {
- EVP_PKEY_CTX_free(pctx);
- return 0;
- }
- EVP_PKEY_CTX_free(pctx);
- return 1;
-}
-
-} // namespace
-#endif
-
-OpenSSLKeyDerivationHKDF::OpenSSLKeyDerivationHKDF() = default;
-OpenSSLKeyDerivationHKDF::~OpenSSLKeyDerivationHKDF() = default;
-
-const size_t OpenSSLKeyDerivationHKDF::kMinKeyByteSize = 16;
-const size_t OpenSSLKeyDerivationHKDF::kMaxKeyByteSize =
- 255 * SHA256_DIGEST_LENGTH;
-const size_t OpenSSLKeyDerivationHKDF::kMinSecretByteSize = 16;
-
-absl::optional<ZeroOnFreeBuffer<uint8_t>> OpenSSLKeyDerivationHKDF::DeriveKey(
- rtc::ArrayView<const uint8_t> secret,
- rtc::ArrayView<const uint8_t> salt,
- rtc::ArrayView<const uint8_t> label,
- size_t derived_key_byte_size) {
- // Prevent deriving less than 128 bits of key material or more than the max.
- if (derived_key_byte_size < kMinKeyByteSize ||
- derived_key_byte_size > kMaxKeyByteSize) {
- return absl::nullopt;
- }
- // The secret must reach the minimum number of bits to be secure.
- if (secret.data() == nullptr || secret.size() < kMinSecretByteSize) {
- return absl::nullopt;
- }
- // Empty labels are always invalid in derivation.
- if (label.data() == nullptr || label.size() == 0) {
- return absl::nullopt;
- }
- // If a random salt is not provided use all zeros.
- rtc::Buffer salt_buffer;
- if (salt.data() == nullptr || salt.size() == 0) {
- salt_buffer.SetSize(SHA256_DIGEST_LENGTH);
- absl::c_fill(salt_buffer, 0);
- salt = salt_buffer;
- }
- // This buffer will erase itself on release.
- ZeroOnFreeBuffer<uint8_t> derived_key_buffer(derived_key_byte_size, 0);
- if (!HKDF(derived_key_buffer.data(), derived_key_buffer.size(), EVP_sha256(),
- secret.data(), secret.size(), salt.data(), salt.size(),
- label.data(), label.size())) {
- return absl::nullopt;
- }
- return absl::optional<ZeroOnFreeBuffer<uint8_t>>(
- std::move(derived_key_buffer));
-}
-
-} // namespace rtc
diff --git a/rtc_base/openssl_key_derivation_hkdf.h b/rtc_base/openssl_key_derivation_hkdf.h
deleted file mode 100644
index 7f88252..0000000
--- a/rtc_base/openssl_key_derivation_hkdf.h
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Copyright 2018 The WebRTC Project Authors. All rights reserved.
- *
- * Use of this source code is governed by a BSD-style license
- * that can be found in the LICENSE file in the root of the source
- * tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
- * be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef RTC_BASE_OPENSSL_KEY_DERIVATION_HKDF_H_
-#define RTC_BASE_OPENSSL_KEY_DERIVATION_HKDF_H_
-
-#include "rtc_base/constructor_magic.h"
-#include "rtc_base/key_derivation.h"
-
-namespace rtc {
-
-// OpenSSLKeyDerivationHKDF provides a concrete implementation of the
-// KeyDerivation interface to support the HKDF algorithm using the
-// OpenSSL/BoringSSL internal implementation.
-class OpenSSLKeyDerivationHKDF final : public KeyDerivation {
- public:
- OpenSSLKeyDerivationHKDF();
- ~OpenSSLKeyDerivationHKDF() override;
-
- // General users shouldn't be generating keys smaller than 128 bits.
- static const size_t kMinKeyByteSize;
- // The maximum available derivation size 255*DIGEST_LENGTH
- static const size_t kMaxKeyByteSize;
- // The minimum acceptable secret size.
- static const size_t kMinSecretByteSize;
-
- // Derives a new key from existing key material using HKDF.
- // secret - The random secret value you wish to derive a key from.
- // salt - Optional (non secret) cryptographically random value.
- // label - A non secret but unique label value to determine the derivation.
- // derived_key_byte_size - The size of the derived key.
- // return - A ZeroOnFreeBuffer containing the derived key or an error
- // condition. Checking error codes is explicit in the API and error should
- // never be ignored.
- absl::optional<ZeroOnFreeBuffer<uint8_t>> DeriveKey(
- rtc::ArrayView<const uint8_t> secret,
- rtc::ArrayView<const uint8_t> salt,
- rtc::ArrayView<const uint8_t> label,
- size_t derived_key_byte_size) override;
-
- private:
- RTC_DISALLOW_COPY_AND_ASSIGN(OpenSSLKeyDerivationHKDF);
-};
-
-} // namespace rtc
-
-#endif // RTC_BASE_OPENSSL_KEY_DERIVATION_HKDF_H_
diff --git a/rtc_base/openssl_key_derivation_hkdf_unittest.cc b/rtc_base/openssl_key_derivation_hkdf_unittest.cc
deleted file mode 100644
index 92df42f..0000000
--- a/rtc_base/openssl_key_derivation_hkdf_unittest.cc
+++ /dev/null
@@ -1,107 +0,0 @@
-/*
- * Copyright 2018 The WebRTC Project Authors. All rights reserved.
- *
- * Use of this source code is governed by a BSD-style license
- * that can be found in the LICENSE file in the root of the source
- * tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
- * be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "rtc_base/openssl_key_derivation_hkdf.h"
-
-#include <utility>
-
-#include "test/gmock.h"
-
-namespace rtc {
-namespace {
-
-// Validates that a basic valid call works correctly.
-TEST(OpenSSLKeyDerivationHKDF, DerivationBasicTest) {
- rtc::Buffer secret(32);
- rtc::Buffer salt(32);
- rtc::Buffer label(32);
- const size_t derived_key_byte_size = 16;
-
- OpenSSLKeyDerivationHKDF hkdf;
- auto key_or = hkdf.DeriveKey(secret, salt, label, derived_key_byte_size);
- EXPECT_TRUE(key_or.has_value());
- ZeroOnFreeBuffer<uint8_t> key = std::move(key_or.value());
- EXPECT_EQ(derived_key_byte_size, key.size());
-}
-
-// Derivation fails if output is too small.
-TEST(OpenSSLKeyDerivationHKDF, DerivationFailsIfOutputIsTooSmall) {
- rtc::Buffer secret(32);
- rtc::Buffer salt(32);
- rtc::Buffer label(32);
- const size_t derived_key_byte_size = 15;
-
- OpenSSLKeyDerivationHKDF hkdf;
- auto key_or = hkdf.DeriveKey(secret, salt, label, derived_key_byte_size);
- EXPECT_FALSE(key_or.has_value());
-}
-
-// Derivation fails if output is too large.
-TEST(OpenSSLKeyDerivationHKDF, DerivationFailsIfOutputIsTooLarge) {
- rtc::Buffer secret(32);
- rtc::Buffer salt(32);
- rtc::Buffer label(32);
- const size_t derived_key_byte_size = 256 * 32;
-
- OpenSSLKeyDerivationHKDF hkdf;
- auto key_or = hkdf.DeriveKey(secret, salt, label, derived_key_byte_size);
- EXPECT_FALSE(key_or.has_value());
-}
-
-// Validates that too little key material causes a failure.
-TEST(OpenSSLKeyDerivationHKDF, DerivationFailsWithInvalidSecret) {
- rtc::Buffer secret(15);
- rtc::Buffer salt(32);
- rtc::Buffer label(32);
- const size_t derived_key_byte_size = 16;
-
- OpenSSLKeyDerivationHKDF hkdf;
- auto key_or_0 = hkdf.DeriveKey(secret, salt, label, derived_key_byte_size);
- EXPECT_FALSE(key_or_0.has_value());
-
- auto key_or_1 = hkdf.DeriveKey(nullptr, salt, label, derived_key_byte_size);
- EXPECT_FALSE(key_or_1.has_value());
-
- rtc::Buffer secret_empty;
- auto key_or_2 =
- hkdf.DeriveKey(secret_empty, salt, label, derived_key_byte_size);
- EXPECT_FALSE(key_or_2.has_value());
-}
-
-// Validates that HKDF works without a salt being set.
-TEST(OpenSSLKeyDerivationHKDF, DerivationWorksWithNoSalt) {
- rtc::Buffer secret(32);
- rtc::Buffer label(32);
- const size_t derived_key_byte_size = 16;
-
- OpenSSLKeyDerivationHKDF hkdf;
- auto key_or = hkdf.DeriveKey(secret, nullptr, label, derived_key_byte_size);
- EXPECT_TRUE(key_or.has_value());
-}
-
-// Validates that a label is required to work correctly.
-TEST(OpenSSLKeyDerivationHKDF, DerivationRequiresLabel) {
- rtc::Buffer secret(32);
- rtc::Buffer salt(32);
- rtc::Buffer label(1);
- const size_t derived_key_byte_size = 16;
-
- OpenSSLKeyDerivationHKDF hkdf;
- auto key_or_0 = hkdf.DeriveKey(secret, salt, label, derived_key_byte_size);
- EXPECT_TRUE(key_or_0.has_value());
- ZeroOnFreeBuffer<uint8_t> key = std::move(key_or_0.value());
- EXPECT_EQ(key.size(), derived_key_byte_size);
-
- auto key_or_1 = hkdf.DeriveKey(secret, salt, nullptr, derived_key_byte_size);
- EXPECT_FALSE(key_or_1.has_value());
-}
-
-} // namespace
-} // namespace rtc
