Harden dumpDebugLoc against malformed .debug_loc sections

未關閉
  • 哪裡不對？
#9,249 0 則留言 0 個 reaction 已指派 0 人 在 GitHub 檢視

維護者通常 1 天內回覆

還沒有人認領這個 Issue。

評估

難度
3/5
預估耗時
1-2 天
新手友好度
45/100
Issue 類型
缺陷
描述清晰度
基本清楚
活躍度
活躍
技術堆疊
cpp, wasm
領域
compilers

研究方向

Start in dumpDebugLoc in third_party/llvm-project/dwarf2yaml.cpp, where the exit(1) on a null list sits, and read parseOneLocationList to see how entry.Loc is sized before the copy. Check how the address size is taken from the first CU. Done means a malformed list prints a warning and skips the rest of the section instead of exiting, the entry.Loc length is bounded, and a debug-build assert covers the shared address size. The issue does not give the length limit, so that needs a maintainer decision.

由索引模型根據 Issue 內容生成。

描述

Background:

#6879 was a SIGSEGV in dumpDebugLoc for modules with empty .debug_loc
sections. Fixed by #7910 with a null-CU guard. While reviewing that fix,
three defensive improvements to the same function became apparent. None
is a regression, but each turns a malformed-input case into a hard
failure when it could fail gracefully.

Location: third_party/llvm-project/dwarf2yaml.cpp, dumpDebugLoc.

  1. exit(1) on parse failure.

    if (!list) {
  errs() << "debug_loc error\n";
  exit(1);
}

    A single malformed location list aborts the entire wasm-opt run. A
    warning plus break (skip the rest of the section) would let the tool
    finish processing the module with incomplete debug info, which is
    the behavior for every other diagnostic in wasm-opt.

  2. Unbounded copy of location expression bytes.

    entry.Loc is read from the section by parseOneLocationList. There is
    no upper bound on its length before the copy into loc.Location. A
    malformed length field causes unbounded allocation.

  3. Address-size heuristic.

    The comment "should be ok since they all have the same address size?"
    is a heuristic. All CUs in well-formed modules share the same
    AddrSize, so reading it from the first CU is safe in practice, but
    the assumption is not enforced.

Proposed changes:

  • Replace exit(1) with a warning and break.
  • Add a length sanity check before copying entry.Loc.
  • Promote the address-size comment from a question to an explicit
    assumption with a debug-build assert.

Refs #6879, #7910.

主要語言
WebAssembly
星號
8.7k
分支
903
平均合併
2 天 5 小時
30 天內合併 PR
106

環境準備

  • 沒有 Dockerfile 或 Docker Compose 檔案
  • 沒有 Pull Request 範本
  • 閱讀貢獻指南

從這裡開始

  1. 先讀完整個 Issue，再讀專案的貢獻指南。
  2. 在 Issue 下留言說明你要接手 —— 這能避免兩個人做同樣的事。
  3. Fork 儲存庫，在一個分支上完成修改。
  4. 送出 Pull Request，並在描述裡引用這個 Issue 編號。

WebAssembly/binaryen 的其他 Issue

查看 WebAssembly/binaryen 的全部 Issue

相似的 Issue

更多 Compilers Issue

把新 issue 寄到你的電子郵件信箱

精選適合新手參與的 GitHub issue 摘要。