From 0574007d288a6743b5448b5f630be95ec4abb0e7 Mon Sep 17 00:00:00 2001
From: Aizal Khan <aizumusheer2@gmail.com>
Date: Wed, 24 Jun 2026 18:23:16 +0530
Subject: [PATCH] Avoid out-of-bounds section_starts_ read on invalid reloc
 index

An out-of-range reloc.* section index leaves reloc_section_ as BinarySection::Invalid; the details-mode OnRelocCount ignored the base error and let OnReloc index section_starts_ with the sentinel. Propagate the result so the section is rejected.
---
 src/binary-reader-objdump.cc | 2 +-
 test/binary/bad-relocs.txt   | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/binary-reader-objdump.cc b/src/binary-reader-objdump.cc
index b2ae365440..6c7039abb5 100644
--- a/src/binary-reader-objdump.cc
+++ b/src/binary-reader-objdump.cc
@@ -2161,7 +2161,7 @@ Result BinaryReaderObjdump::OnDylinkNeeded(std::string_view so_name) {
 }
 
 Result BinaryReaderObjdump::OnRelocCount(Index count, Index section_index) {
-  BinaryReaderObjdumpBase::OnRelocCount(count, section_index);
+  CHECK_RESULT(BinaryReaderObjdumpBase::OnRelocCount(count, section_index));
   PrintDetails("  - relocations for section: %d (" PRIstringview ") [%d]\n",
                section_index,
                WABT_PRINTF_STRING_VIEW_ARG(GetSectionName(section_index)),
diff --git a/test/binary/bad-relocs.txt b/test/binary/bad-relocs.txt
index 6240ced061..2ca701a611 100644
--- a/test/binary/bad-relocs.txt
+++ b/test/binary/bad-relocs.txt
@@ -4,7 +4,10 @@ magic
 version
 section("reloc.BAD") {
   reloc_section[99]
-  reloc_count[0]
+  reloc_count[1]
+  reloc_type[0]  ;; R_WASM_FUNCTION_INDEX_LEB
+  offset[0]
+  index[0]
 }
 (;; STDERR ;;;
 invalid relocation section index: 99
@@ -20,7 +23,6 @@ Section Details:
 
 Custom:
  - name: "reloc.BAD"
-  - relocations for section: 99 () [0]
 
 Code Disassembly: