fix(oauth): bound anthropic OAuth token request response reads at 16 MiB

wangmiao0668000666 · wangmiao0668000666 · commit ccfe13afe153 · 2026-06-28T23:49:46.000+08:00
diff --git a/src/llm/utils/oauth/anthropic.test.ts b/src/llm/utils/oauth/anthropic.test.ts
@@ -79,4 +79,39 @@ describe("Anthropic OAuth token responses", () => {
       "Anthropic token refresh returned invalid token fields.",
     );
   });
+
+  it("caps oversized Anthropic OAuth responses at 16 MiB instead of buffering the full body", async () => {
+    // 18 MiB body in 1 MiB chunks exceeds the shared 16 MiB cap on
+    // readProviderTextResponse. The bounded reader must surface the cap
+    // with the per-surface label so logs can attribute the rejection to
+    // this call site, not github-copilot or chutes.
+    const CHUNK = 1024 * 1024;
+    const CHUNK_COUNT = 18;
+    let pulls = 0;
+    const encoder = new TextEncoder();
+    const stream = new ReadableStream<Uint8Array>({
+      pull(controller) {
+        if (pulls >= CHUNK_COUNT) {
+          controller.close();
+          return;
+        }
+        pulls += 1;
+        controller.enqueue(encoder.encode("{".repeat(CHUNK)));
+      },
+    });
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(
+        async () =>
+          new Response(stream, {
+            status: 200,
+            headers: { "content-type": "application/json" },
+          }),
+      ),
+    );
+
+    await expect(refreshAnthropicToken("old-refresh-token")).rejects.toThrow(
+      "Anthropic OAuth token request: text response exceeds 16777216 bytes",
+    );
+  });
 });
diff --git a/src/llm/utils/oauth/anthropic.ts b/src/llm/utils/oauth/anthropic.ts
@@ -6,6 +6,7 @@
  */
 
 import type { Server } from "node:http";
+import { readProviderTextResponse } from "../../../agents/provider-http-errors.js";
 import { toErrorObject } from "../../../infra/errors.js";
 import {
   generateOAuthState,
@@ -233,7 +234,9 @@ async function postJson(
     signal: buildOAuthRequestSignal({ signal: options.signal, timeoutMs }),
   });
 
-  const responseBody = await response.text();
+  // 16 MiB cap. A hostile or broken Anthropic OAuth endpoint cannot force
+  // the runtime to buffer an unbounded token-exchange body before parsing.
+  const responseBody = await readProviderTextResponse(response, "Anthropic OAuth token request");
 
   if (!response.ok) {
     throw new Error(
