fix(go): read inline build strings from ELF mappings

Fixes #6716

docs/go-binaries.md

@@ -132,6 +132,11 @@ includes sectionless PIE images with metadata in a later data segment. Named
 sections retain priority, and alignment, file mapping and record validation
 remain required.
 
+A named ELF build-info section selects the record's discovery range. For inline
+encoding, the following version and module strings may continue past that
+section into its file-backed load mapping; their bytes are still checked
+against the mapping and the existing aggregate string limit.
+
 Historical moduleless Go binaries can store their empty module-string header in
 declared zero-initialized virtual memory rather than file-backed bytes. The reader
 recognizes this only when the complete optional module header lies in that memory

src/go/GoBinaryImage.ts

@@ -104,10 +104,10 @@ export const readGoBinaryImage = (bytes: Buffer): GoBinaryImage => {
   const encoding = (flags & 2) !== 0 ? "inline" : "pointer";
   const readInline = (offset: number, remaining: number) =>
     readInlineString(reader, offset, remaining);
-  const sourceEnd = search.offset + search.size;
   let version: LocatedString;
   let module: LocatedString;
   if (encoding === "inline") {
+    const sourceEnd = inlineDataEnd(header, search, container);
     version = readInline(header + 32, sourceEnd - header - 32);
     const next = version.location.offset + version.location.bytes;
     module = readInline(next, sourceEnd - next);
@@ -178,6 +178,29 @@ export const readGoBinaryImage = (bytes: Buffer): GoBinaryImage => {
   };
 };
 
+/** Inline strings follow the header in mapped Go build-info data, even when
+ * the named ELF discovery section ends immediately after the header.
+ */
+const inlineDataEnd = (
+  header: number,
+  search: FileMapping,
+  container: BinaryContainer,
+): number => {
+  if (container.format !== "elf") return search.offset + search.size;
+  const address = search.address + BigInt(header - search.offset);
+  let end = search.offset + search.size;
+  for (const { mapping } of container.load_regions ?? []) {
+    const delta = address - mapping.address;
+    if (
+      delta >= 0n &&
+      delta < BigInt(mapping.size) &&
+      mapping.offset + Number(delta) === header
+    )
+      end = Math.max(end, mapping.offset + mapping.size);
+  }
+  return Math.min(end, header + 32 + MAX_BUILD_INFO_BYTES);
+};
+
 const observedText = (bytes: Buffer): string | null => {
   try {
     return observedUtf8(bytes, "Go build string");

tests/boundary/go/goBinaryImage.test.ts

@@ -191,6 +191,24 @@ it.each([
   },
 );
 
+it("reads inline build strings past the ELF build-info discovery section", () => {
+  const fixture = createGoBinaryFixture();
+  const buildInfoSection = 256 + 64 * 2;
+  fixture.bytes.writeBigUInt64LE(32n, buildInfoSection + 32);
+
+  expect(readGoBinaryImage(fixture.bytes).build_info).toMatchObject({
+    header_offset: fixture.headerOffset,
+    encoding: "inline",
+    go_version: "go1.26.0",
+    module_text: GO_MODULE_TEXT,
+    version_location: { offset: fixture.versionOffset, bytes: 8 },
+    module_location: {
+      offset: fixture.moduleOffset,
+      bytes: fixture.moduleBytes.length,
+    },
+  });
+});
+
 it.each(["elf", "pe", "macho"] as const)(
   "follows mapped pointers in legacy %s metadata",
   (format) => {