[lld] [ELF] Reject certain unknown section types (PR #85173)

[Fangrui Song via llvm-commits]

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@@ -741,6 +741,31 @@ template <class ELFT> void ObjFile<ELFT>::initializeJustSymbols() {
   sections.resize(numELFShdrs);
 }
 
+static bool isKnownSpecificSectionType(uint32_t t, uint32_t flags) {
+  if (SHT_LOUSER <= t && t <= SHT_HIUSER && !(flags & SHF_ALLOC))
+    return true;
+  if (SHT_LOOS <= t && t <= SHT_HIOS && !(flags & SHF_OS_NONCONFORMING))
+    return true;
+  switch (config->emachine) {
+  case EM_ARM:
+    return t == SHT_ARM_EXIDX || t == SHT_ARM_ATTRIBUTES;
+  case EM_AARCH64:
+    return t == SHT_AARCH64_MEMTAG_GLOBALS_STATIC;
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MaskRay wrote:

Thanks. Sounds good to allow SHT_AARCH64_ATTRIBUTES as well even if it is unused now.
SHT_AARCH64_AUTH_RELR is for dynamic relocations only, so rejecting it here is fine. The test has a SHT_RELR example.

Shall we just allow all processor-specific relocation types?

https://github.com/llvm/llvm-project/pull/85173