devices/fido: use base::as_string_view()

The bespoke fido_parsing_utils::ConvertToStringView() is not needed.

Bug: None
Change-Id: Id4c944e6ba474997726cd3f485e8f3d8e42c3239
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6442538
Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Commit-Queue: Martin Kreichgauer <martinkr@google.com>
Commit-Queue: Elly FJ <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1444462}

device/fido/cable/fido_cable_device_unittest.cc

@@ -100,7 +100,7 @@ class FakeCableAuthenticator {
 
     std::string ciphertext;
     aead.Seal(
-        message, fido_parsing_utils::ConvertToStringView(encryption_nonce),
+        message, base::as_string_view(encryption_nonce),
         std::string(1, base::strict_cast<uint8_t>(FidoBleDeviceCommand::kMsg)),
         &ciphertext);
     authenticator_counter_++;
@@ -121,8 +121,7 @@ class FakeCableAuthenticator {
 
     std::string ciphertext;
     aead.Open(
-        fido_parsing_utils::ConvertToStringView(message),
+        base::as_string_view(message), base::as_string_view(encryption_nonce),
-        fido_parsing_utils::ConvertToStringView(encryption_nonce),
         std::string(1, base::strict_cast<uint8_t>(FidoBleDeviceCommand::kMsg)),
         &ciphertext);
     expected_client_counter_++;

device/fido/cable/fido_cable_handshake_handler.cc

@@ -64,8 +64,8 @@ ConstructHandshakeMessage(std::string_view handshake_key,
     return std::nullopt;
 
   std::array<uint8_t, kCableHandshakeMacMessageSize> client_hello_mac;
-  if (!hmac.Sign(fido_parsing_utils::ConvertToStringView(*client_hello),
+  if (!hmac.Sign(base::as_string_view(*client_hello), client_hello_mac.data(),
-                 client_hello_mac.data(), client_hello_mac.size())) {
+                 client_hello_mac.size())) {
     return std::nullopt;
   }
 
@@ -90,11 +90,10 @@ FidoCableV1HandshakeHandler::FidoCableV1HandshakeHandler(
     : cable_device_(cable_device),
       nonce_(fido_parsing_utils::Materialize(nonce)),
       session_pre_key_(fido_parsing_utils::Materialize(session_pre_key)),
-      handshake_key_(crypto::HkdfSha256(
+      handshake_key_(crypto::HkdfSha256(base::as_string_view(session_pre_key_),
-          fido_parsing_utils::ConvertToStringView(session_pre_key_),
+                                        base::as_string_view(nonce_),
-          fido_parsing_utils::ConvertToStringView(nonce_),
+                                        kCableHandshakeKeyInfo,
-          kCableHandshakeKeyInfo,
+                                        /*derived_key_size=*/32)) {
-          /*derived_key_size=*/32)) {
   crypto::RandBytes(client_session_random_);
 }
 
@@ -128,9 +127,8 @@ bool FidoCableV1HandshakeHandler::ValidateAuthenticatorHandshakeMessage(
   const auto authenticator_hello = response.first(
       kCableAuthenticatorHandshakeMessageSize - kCableHandshakeMacMessageSize);
   if (!hmac.VerifyTruncated(
-          fido_parsing_utils::ConvertToStringView(authenticator_hello),
+          base::as_string_view(authenticator_hello),
-          fido_parsing_utils::ConvertToStringView(
+          base::as_string_view(response.subspan(authenticator_hello.size())))) {
-              response.subspan(authenticator_hello.size())))) {
     return false;
   }
 

device/fido/cable/fido_cable_handshake_handler_unittest.cc

@@ -148,7 +148,7 @@ std::vector<uint8_t> ConstructAuthenticatorHelloReply(
     return std::vector<uint8_t>();
 
   std::array<uint8_t, 32> authenticator_hello_mac;
-  if (!hmac.Sign(fido_parsing_utils::ConvertToStringView(hello_msg),
+  if (!hmac.Sign(base::as_string_view(hello_msg),
                  authenticator_hello_mac.data(),
                  authenticator_hello_mac.size())) {
     return std::vector<uint8_t>();
@@ -184,9 +184,8 @@ class FakeCableAuthenticator {
  public:
   FakeCableAuthenticator() {
     handshake_key_ = crypto::HkdfSha256(
-        fido_parsing_utils::ConvertToStringView(kTestSessionPreKey),
+        base::as_string_view(kTestSessionPreKey),
-        fido_parsing_utils::ConvertToStringView(kTestNonce),
+        base::as_string_view(kTestNonce), kCableHandshakeKeyInfo, 32);
-        kCableHandshakeKeyInfo, 32);
   }
 
   // Receives handshake message from the client, check its validity and if the
@@ -208,9 +207,8 @@ class FakeCableAuthenticator {
 
     const auto client_hello = handshake_message.first(42u);
     if (!hmac.VerifyTruncated(
-            fido_parsing_utils::ConvertToStringView(client_hello),
+            base::as_string_view(client_hello),
-            fido_parsing_utils::ConvertToStringView(
+            base::as_string_view(handshake_message.subspan<42>()))) {
-                handshake_message.subspan<42>()))) {
       return false;
     }
 

device/fido/fido_parsing_utils.cc

@@ -89,10 +89,6 @@ std::array<uint8_t, crypto::kSHA256Length> CreateSHA256Hash(
   return hashed_data;
 }
 
-std::string_view ConvertToStringView(base::span<const uint8_t> data) {
-  return {reinterpret_cast<const char*>(data.data()), data.size()};
-}
-
 std::string ConvertBytesToUuid(base::span<const uint8_t, 16> bytes) {
   uint64_t most_significant_bytes = 0;
   for (size_t i = 0; i < sizeof(uint64_t); i++) {

device/fido/fido_parsing_utils.h

@@ -115,9 +115,6 @@ COMPONENT_EXPORT(DEVICE_FIDO)
 std::array<uint8_t, crypto::kSHA256Length> CreateSHA256Hash(
     std::string_view data);
 
-COMPONENT_EXPORT(DEVICE_FIDO)
-std::string_view ConvertToStringView(base::span<const uint8_t> data);
-
 // Convert byte array into GUID formatted string as defined by RFC 4122.
 // As we are converting 128 bit UUID, |bytes| must be have length of 16.
 // https://tools.ietf.org/html/rfc4122

device/fido/fido_parsing_utils_unittest.cc

@@ -275,10 +275,5 @@ TEST(U2fParsingUtils, CreateSHA256Hash) {
               ::testing::ElementsAreArray(test_data::kApplicationParameter));
 }
 
-TEST(U2fParsingUtils, ConvertSpanToStringView) {
-  constexpr uint8_t kTestAsciiAbcd[] = {'a', 'b', 'c', 'd'};
-  EXPECT_EQ("abcd", ConvertToStringView(kTestAsciiAbcd));
-}
-
 }  // namespace fido_parsing_utils
 }  // namespace device