status: Fix ASAN error in Status payload handling

bazel/repository_locations.bzl

@@ -43,10 +43,10 @@ REPOSITORY_LOCATIONS = dict(
         urls = ["https://commondatastorage.googleapis.com/chromium-boringssl-docs/fips/boringssl-66005f41fbc3529ffe8d007708756720529da20d.tar.xz"],
     ),
     com_google_absl = dict(
-        sha256 = "2693730730247afb0e7cb2d41664ac2af3ad75c79944efd266be40ba944179b9",
-        strip_prefix = "abseil-cpp-06f0e767d13d4d68071c4fc51e25724e0fc8bc74",
-        # 2020-03-03
-        urls = ["https://github.com/abseil/abseil-cpp/archive/06f0e767d13d4d68071c4fc51e25724e0fc8bc74.tar.gz"],
+        sha256 = "14ee08e2089c2a9b6bf27e1d10abc5629c69c4d0bab4b78ec5b65a29ea1c2af7",
+        strip_prefix = "abseil-cpp-cf3a1998e9d41709d4141e2f13375993cba1130e",
+        # 2020-03-05
+        urls = ["https://github.com/abseil/abseil-cpp/archive/cf3a1998e9d41709d4141e2f13375993cba1130e.tar.gz"],
     ),
     com_github_apache_thrift = dict(
         sha256 = "7d59ac4fdcb2c58037ebd4a9da5f9a49e3e034bf75b3f26d9fe48ba3d8806e6b",

source/common/http/status.cc

@@ -37,17 +37,27 @@ struct PrematureResponsePayload : public EnvoyStatusPayload {
 };
 
 template <typename T> void storePayload(absl::Status& status, const T& payload) {
-  status.SetPayload(
-      EnvoyPayloadUrl,
-      absl::Cord(absl::string_view(reinterpret_cast<const char*>(&payload), sizeof(payload))));
+  absl::Cord cord(absl::string_view(reinterpret_cast<const char*>(&payload), sizeof(payload)));
+  cord.Flatten(); // Flatten ahead of time for easier access later.
+  status.SetPayload(EnvoyPayloadUrl, std::move(cord));
 }
 
-template <typename T = EnvoyStatusPayload> const T* getPayload(const absl::Status& status) {
-  auto payload = status.GetPayload(EnvoyPayloadUrl);
-  ASSERT(payload.has_value(), "Must have payload");
-  auto data = payload.value().Flatten();
-  ASSERT(data.length() >= sizeof(T), "Invalid payload length");
-  return reinterpret_cast<const T*>(data.data());
+template <typename T = EnvoyStatusPayload> const T& getPayload(const absl::Status& status) {
+  // The only way to get a reference to the payload owned by the absl::Status is through the
+  // ForEachPayload method. All other methods create a copy of the payload, which is not convenient
+  // for peeking at the payload value.
+  const T* payload = nullptr;
+  status.ForEachPayload([&payload](absl::string_view url, const absl::Cord& cord) {
+    if (url == EnvoyPayloadUrl) {
+      ASSERT(!payload); // Status API guarantees to have one payload with given URL
+      auto data = cord.TryFlat();
+      ASSERT(data.has_value()); // EnvoyPayloadUrl cords are flattened ahead of time
+      ASSERT(data.value().length() >= sizeof(T), "Invalid payload length");
+      payload = reinterpret_cast<const T*>(data.value().data());
+    }
+  });
+  ASSERT(payload);
+  return *payload;
 }
 
 } // namespace
@@ -94,7 +104,7 @@ Status codecClientError(absl::string_view message) {
 
 // Methods for checking and extracting error information
 StatusCode getStatusCode(const Status& status) {
-  return status.ok() ? StatusCode::Ok : getPayload(status)->status_code_;
+  return status.ok() ? StatusCode::Ok : getPayload(status).status_code_;
 }
 
 bool isCodecProtocolError(const Status& status) {
@@ -110,10 +120,10 @@ bool isPrematureResponseError(const Status& status) {
 }
 
 Http::Code getPrematureResponseHttpCode(const Status& status) {
-  const auto* payload = getPayload<PrematureResponsePayload>(status);
-  ASSERT(payload->status_code_ == StatusCode::PrematureResponseError,
+  const auto& payload = getPayload<PrematureResponsePayload>(status);
+  ASSERT(payload.status_code_ == StatusCode::PrematureResponseError,
          "Must be PrematureResponseError");
-  return payload->http_code_;
+  return payload.http_code_;
 }
 
 bool isCodecClientError(const Status& status) {