add experiment

BUILD

@@ -3384,6 +3384,7 @@ grpc_cc_library(
         "//src/core:arena_promise",
         "//src/core:closure",
         "//src/core:error",
+        "//src/core:experiments",
         "//src/core:gpr_manual_constructor",
         "//src/core:httpcli_ssl_credentials",
         "//src/core:iomgr_fwd",

bazel/experiments.bzl

@@ -17,6 +17,7 @@
 """Dictionary of tags to experiments so we know when to test different experiments."""
 
 EXPERIMENT_ENABLES = {
+    "absl_base64": "absl_base64",
     "call_status_override_on_cancellation": "call_status_override_on_cancellation",
     "call_v3": "call_v3",
     "canary_client_privacy": "canary_client_privacy",
@@ -124,6 +125,9 @@ EXPERIMENTS = {
                 "round_robin_delegate_to_pick_first",
                 "wrr_delegate_to_pick_first",
             ],
+            "credential_token_tests": [
+                "absl_base64",
+            ],
             "event_engine_listener_test": [
                 "event_engine_listener",
             ],
@@ -201,6 +205,9 @@ EXPERIMENTS = {
                 "round_robin_delegate_to_pick_first",
                 "wrr_delegate_to_pick_first",
             ],
+            "credential_token_tests": [
+                "absl_base64",
+            ],
             "flow_control_test": [
                 "write_size_cap",
                 "write_size_policy",
@@ -288,6 +295,9 @@ EXPERIMENTS = {
                 "round_robin_delegate_to_pick_first",
                 "wrr_delegate_to_pick_first",
             ],
+            "credential_token_tests": [
+                "absl_base64",
+            ],
             "event_engine_listener_test": [
                 "event_engine_listener",
             ],

src/core/client_channel/http_proxy_mapper.cc

@@ -46,11 +46,13 @@
 #include "src/core/lib/address_utils/parse_address.h"
 #include "src/core/lib/address_utils/sockaddr_utils.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/experiments/experiments.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/gprpp/env.h"
 #include "src/core/lib/gprpp/host_port.h"
 #include "src/core/lib/gprpp/memory.h"
 #include "src/core/lib/iomgr/resolve_address.h"
+#include "src/core/lib/slice/b64.h"
 #include "src/core/lib/transport/http_connect_handshaker.h"
 #include "src/core/lib/uri/uri_parser.h"
 
@@ -258,7 +260,14 @@ absl::optional<std::string> HttpProxyMapper::MapName(
                     MaybeAddDefaultPort(absl::StripPrefix(uri->path(), "/")));
   if (user_cred.has_value()) {
     // Use base64 encoding for user credentials as stated in RFC 7617
-    std::string encoded_user_cred = absl::Base64Escape(*user_cred);
+    std::string encoded_user_cred;
+    if (IsAbslBase64Enabled()) {
+      encoded_user_cred = absl::Base64Escape(*user_cred);
+    } else {
+      UniquePtr<char> tmp(
+          grpc_base64_encode(user_cred->data(), user_cred->length(), 0, 0));
+      encoded_user_cred = tmp.get();
+    }
     *args = args->Set(
         GRPC_ARG_HTTP_CONNECT_HEADERS,
         absl::StrCat("Proxy-Authorization:Basic ", encoded_user_cred));

src/core/lib/experiments/experiments.cc

@@ -24,6 +24,8 @@
 
 #if defined(GRPC_CFSTREAM)
 namespace {
+const char* const description_absl_base64 = "Use abseil base64 functions.";
+const char* const additional_constraints_absl_base64 = "{}";
 const char* const description_call_status_override_on_cancellation =
     "Avoid overriding call status of successfully finished calls if it races "
     "with cancellation.";
@@ -193,6 +195,8 @@ const bool kDefaultForDebugOnly = true;
 namespace grpc_core {
 
 const ExperimentMetadata g_experiment_metadata[] = {
+    {"absl_base64", description_absl_base64, additional_constraints_absl_base64,
+     nullptr, 0, true, true},
     {"call_status_override_on_cancellation",
      description_call_status_override_on_cancellation,
      additional_constraints_call_status_override_on_cancellation, nullptr, 0,
@@ -297,6 +301,8 @@ const ExperimentMetadata g_experiment_metadata[] = {
 
 #elif defined(GPR_WINDOWS)
 namespace {
+const char* const description_absl_base64 = "Use abseil base64 functions.";
+const char* const additional_constraints_absl_base64 = "{}";
 const char* const description_call_status_override_on_cancellation =
     "Avoid overriding call status of successfully finished calls if it races "
     "with cancellation.";
@@ -466,6 +472,8 @@ const bool kDefaultForDebugOnly = true;
 namespace grpc_core {
 
 const ExperimentMetadata g_experiment_metadata[] = {
+    {"absl_base64", description_absl_base64, additional_constraints_absl_base64,
+     nullptr, 0, true, true},
     {"call_status_override_on_cancellation",
      description_call_status_override_on_cancellation,
      additional_constraints_call_status_override_on_cancellation, nullptr, 0,
@@ -570,6 +578,8 @@ const ExperimentMetadata g_experiment_metadata[] = {
 
 #else
 namespace {
+const char* const description_absl_base64 = "Use abseil base64 functions.";
+const char* const additional_constraints_absl_base64 = "{}";
 const char* const description_call_status_override_on_cancellation =
     "Avoid overriding call status of successfully finished calls if it races "
     "with cancellation.";
@@ -739,6 +749,8 @@ const bool kDefaultForDebugOnly = true;
 namespace grpc_core {
 
 const ExperimentMetadata g_experiment_metadata[] = {
+    {"absl_base64", description_absl_base64, additional_constraints_absl_base64,
+     nullptr, 0, true, true},
     {"call_status_override_on_cancellation",
      description_call_status_override_on_cancellation,
      additional_constraints_call_status_override_on_cancellation, nullptr, 0,

src/core/lib/experiments/experiments.h

@@ -57,6 +57,8 @@ namespace grpc_core {
 #ifdef GRPC_EXPERIMENTS_ARE_FINAL
 
 #if defined(GRPC_CFSTREAM)
+#define GRPC_EXPERIMENT_IS_INCLUDED_ABSL_BASE64
+inline bool IsAbslBase64Enabled() { return true; }
 #ifndef NDEBUG
 #define GRPC_EXPERIMENT_IS_INCLUDED_CALL_STATUS_OVERRIDE_ON_CANCELLATION
 #endif
@@ -119,6 +121,8 @@ inline bool IsWriteSizeCapEnabled() { return true; }
 inline bool IsWrrDelegateToPickFirstEnabled() { return true; }
 
 #elif defined(GPR_WINDOWS)
+#define GRPC_EXPERIMENT_IS_INCLUDED_ABSL_BASE64
+inline bool IsAbslBase64Enabled() { return true; }
 #ifndef NDEBUG
 #define GRPC_EXPERIMENT_IS_INCLUDED_CALL_STATUS_OVERRIDE_ON_CANCELLATION
 #endif
@@ -182,6 +186,8 @@ inline bool IsWriteSizeCapEnabled() { return true; }
 inline bool IsWrrDelegateToPickFirstEnabled() { return true; }
 
 #else
+#define GRPC_EXPERIMENT_IS_INCLUDED_ABSL_BASE64
+inline bool IsAbslBase64Enabled() { return true; }
 #ifndef NDEBUG
 #define GRPC_EXPERIMENT_IS_INCLUDED_CALL_STATUS_OVERRIDE_ON_CANCELLATION
 #endif
@@ -247,6 +253,7 @@ inline bool IsWrrDelegateToPickFirstEnabled() { return true; }
 
 #else
 enum ExperimentIds {
+  kExperimentIdAbslBase64,
   kExperimentIdCallStatusOverrideOnCancellation,
   kExperimentIdCallV3,
   kExperimentIdCanaryClientPrivacy,
@@ -289,6 +296,10 @@ enum ExperimentIds {
   kExperimentIdWrrDelegateToPickFirst,
   kNumExperiments
 };
+#define GRPC_EXPERIMENT_IS_INCLUDED_ABSL_BASE64
+inline bool IsAbslBase64Enabled() {
+  return IsExperimentEnabled(kExperimentIdAbslBase64);
+}
 #define GRPC_EXPERIMENT_IS_INCLUDED_CALL_STATUS_OVERRIDE_ON_CANCELLATION
 inline bool IsCallStatusOverrideOnCancellationEnabled() {
   return IsExperimentEnabled(kExperimentIdCallStatusOverrideOnCancellation);

src/core/lib/experiments/experiments.yaml

@@ -40,6 +40,11 @@
 
 # This file only defines the experiments. Refer to rollouts.yaml for the rollout
 # state of each experiment.
+- name: absl_base64
+  description: Use abseil base64 functions.
+  expiry: 2024/06/01
+  owner: roth@google.com
+  test_tags: ["credential_token_tests"]
 - name: call_status_override_on_cancellation
   description:
     Avoid overriding call status of successfully finished calls if it races with

src/core/lib/experiments/rollouts.yaml

@@ -40,6 +40,8 @@
 #
 # Supported platforms: ios, windows, posix
 
+- name: absl_base64
+  default: true
 - name: call_status_override_on_cancellation
   default: debug
 - name: call_v3

src/core/lib/security/credentials/jwt/json_token.cc

@@ -42,10 +42,12 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/time.h>
 
+#include "src/core/lib/experiments/experiments.h"
 #include "src/core/lib/iomgr/error.h"
 #include "src/core/lib/json/json_reader.h"
 #include "src/core/lib/json/json_writer.h"
 #include "src/core/lib/security/util/json_util.h"
+#include "src/core/lib/slice/b64.h"
 
 using grpc_core::Json;
 
@@ -181,6 +183,9 @@ static char* encoded_jwt_header(const char* key_id, const char* algorithm) {
       {"kid", Json::FromString(key_id)},
   });
   std::string json_str = grpc_core::JsonDump(json);
+  if (!grpc_core::IsAbslBase64Enabled()) {
+    return grpc_base64_encode(json_str.c_str(), json_str.size(), 1, 0);
+  }
   return gpr_strdup(absl::WebSafeBase64Escape(json_str).c_str());
 }
 
@@ -209,6 +214,9 @@ static char* encoded_jwt_claim(const grpc_auth_json_key* json_key,
 
   std::string json_str =
       grpc_core::JsonDump(Json::FromObject(std::move(object)));
+  if (!grpc_core::IsAbslBase64Enabled()) {
+    return grpc_base64_encode(json_str.c_str(), json_str.size(), 1, 0);
+  }
   return gpr_strdup(absl::WebSafeBase64Escape(json_str).c_str());
 }
 
@@ -281,10 +289,14 @@ char* compute_and_encode_signature(const grpc_auth_json_key* json_key,
     gpr_log(GPR_ERROR, "DigestFinal (signature compute) failed.");
     goto end;
   }
-  result =
-      gpr_strdup(absl::WebSafeBase64Escape(
-                     absl::string_view(reinterpret_cast<char*>(sig), sig_len))
-                     .c_str());
+  if (!grpc_core::IsAbslBase64Enabled()) {
+    result = grpc_base64_encode(sig, sig_len, 1, 0);
+  } else {
+    result =
+        gpr_strdup(absl::WebSafeBase64Escape(
+                       absl::string_view(reinterpret_cast<char*>(sig), sig_len))
+                       .c_str());
+  }
 
 end:
 #if OPENSSL_VERSION_NUMBER < 0x30000000L

src/core/lib/security/credentials/jwt/jwt_verifier.cc

@@ -53,6 +53,7 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/time.h>
 
+#include "src/core/lib/experiments/experiments.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/gprpp/manual_constructor.h"
 #include "src/core/lib/gprpp/memory.h"
@@ -67,6 +68,7 @@
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/json/json_reader.h"
 #include "src/core/lib/security/credentials/credentials.h"  // IWYU pragma: keep
+#include "src/core/lib/slice/b64.h"
 #include "src/core/lib/slice/slice.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/uri/uri_parser.h"
@@ -112,9 +114,19 @@ static const EVP_MD* evp_md_from_alg(const char* alg) {
 
 static Json parse_json_part_from_jwt(const char* str, size_t len) {
   std::string string;
-  if (!absl::WebSafeBase64Unescape(absl::string_view(str, len), &string)) {
-    gpr_log(GPR_ERROR, "Invalid base64.");
-    return Json();  // JSON null
+  if (!grpc_core::IsAbslBase64Enabled()) {
+    grpc_slice slice = grpc_base64_decode_with_len(str, len, 1);
+    if (GRPC_SLICE_IS_EMPTY(slice)) {
+      gpr_log(GPR_ERROR, "Invalid base64.");
+      return Json();  // JSON null
+    }
+    string = std::string(grpc_core::StringViewFromSlice(slice));
+    grpc_core::CSliceUnref(slice);
+  } else {
+    if (!absl::WebSafeBase64Unescape(absl::string_view(str, len), &string)) {
+      gpr_log(GPR_ERROR, "Invalid base64.");
+      return Json();  // JSON null
+    }
   }
   auto json = grpc_core::JsonParse(string);
   if (!json.ok()) {
@@ -479,6 +491,18 @@ end:
 
 static BIGNUM* bignum_from_base64(const char* b64) {
   if (b64 == nullptr) return nullptr;
+  if (!grpc_core::IsAbslBase64Enabled()) {
+    grpc_slice bin = grpc_base64_decode(b64, 1);
+    if (GRPC_SLICE_IS_EMPTY(bin)) {
+      gpr_log(GPR_ERROR, "Invalid base64 for big num.");
+      return nullptr;
+    }
+    BIGNUM* result =
+        BN_bin2bn(GRPC_SLICE_START_PTR(bin),
+                  TSI_SIZE_AS_SIZE(GRPC_SLICE_LENGTH(bin)), nullptr);
+    grpc_core::CSliceUnref(bin);
+    return result;
+  }
   std::string string;
   if (!absl::WebSafeBase64Unescape(b64, &string)) {
     gpr_log(GPR_ERROR, "Invalid base64 for big num.");
@@ -920,10 +944,10 @@ void grpc_jwt_verifier_verify(grpc_jwt_verifier* verifier,
   const char* dot = nullptr;
   jose_header* header = nullptr;
   grpc_jwt_claims* claims = nullptr;
+  grpc_slice signature;
   size_t signed_jwt_len;
   const char* cur = jwt;
   Json json;
-  std::string signature;
 
   GPR_ASSERT(verifier != nullptr && jwt != nullptr && audience != nullptr &&
              cb != nullptr);
@@ -945,11 +969,17 @@ void grpc_jwt_verifier_verify(grpc_jwt_verifier* verifier,
   signed_jwt_len = static_cast<size_t>(dot - jwt);
   cur = dot + 1;
 
-  if (!absl::WebSafeBase64Unescape(cur, &signature)) goto error;
+  if (!grpc_core::IsAbslBase64Enabled()) {
+    signature = grpc_base64_decode(cur, 1);
+    if (GRPC_SLICE_IS_EMPTY(signature)) goto error;
+  } else {
+    std::string signature_str;
+    if (!absl::WebSafeBase64Unescape(cur, &signature_str)) goto error;
+    signature = grpc_slice_from_cpp_string(std::move(signature_str));
+  }
   retrieve_key_and_verify(
       verifier_cb_ctx_create(verifier, pollset, header, claims, audience,
-                             grpc_slice_from_cpp_string(std::move(signature)),
-                             jwt, signed_jwt_len, user_data, cb));
+                             signature, jwt, signed_jwt_len, user_data, cb));
   return;
 
 error:

test/core/security/BUILD

@@ -140,6 +140,7 @@ grpc_cc_test(
     language = "C++",
     uses_event_engine = False,
     uses_polling = False,
+    tags = ["credential_token_tests"],
     deps = [
         "//:gpr",
         "//:grpc",
@@ -156,6 +157,7 @@ grpc_cc_test(
     language = "C++",
     uses_event_engine = False,
     uses_polling = False,
+    tags = ["credential_token_tests"],
     deps = [
         "//:gpr",
         "//:grpc",