[llvm] [llvm-objdump][ELF]Add Shdr buildID check(#126418) (PR #126537)

[Ruoyu Qiu via llvm-commits]

https://github.com/cabbaken created https://github.com/llvm/llvm-project/pull/126537

Add Section Header check for getBuildID, fix crash with invalid Program Header.

>From fadd3aab66adb74fc76bed0b5c3c3ee73d716b52 Mon Sep 17 00:00:00 2001
From: Ruoyu Qiu <cabbaken at outlook.com>
Date: Mon, 10 Feb 2025 15:56:31 +0000
Subject: [PATCH] [llvm-objdump][ELF]Add Shdr buildID check(#126418)

Add Section Header check for getBuildID, fix crash
with invalid Program Header.

Signed-off-by: Ruoyu Qiu <cabbaken at outlook.com>
---
 llvm/lib/Object/BuildID.cpp | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/llvm/lib/Object/BuildID.cpp b/llvm/lib/Object/BuildID.cpp
index 89d6bc3ab550db8..8bb15c89e02e884 100644
--- a/llvm/lib/Object/BuildID.cpp
+++ b/llvm/lib/Object/BuildID.cpp
@@ -24,6 +24,22 @@ using namespace llvm::object;
 namespace {
 
 template <typename ELFT> BuildIDRef getBuildID(const ELFFile<ELFT> &Obj) {
+  auto ShdrsOrErr = Obj.sections();
+  if (!ShdrsOrErr) {
+    consumeError(ShdrsOrErr.takeError());
+    return {};
+  }
+  for (const auto &S : *ShdrsOrErr) {
+    if (S.sh_type != ELF::SHT_NOTE)
+      continue;
+    Error Err = Error::success();
+    for (auto N : Obj.notes(S, Err))
+      if (N.getType() == ELF::NT_GNU_BUILD_ID &&
+          N.getName() == ELF::ELF_NOTE_GNU)
+        return N.getDesc(S.sh_addralign);
+    consumeError(std::move(Err));
+  }
+
   auto PhdrsOrErr = Obj.program_headers();
   if (!PhdrsOrErr) {
     consumeError(PhdrsOrErr.takeError());