[PATCH] D25016: [ELF] - Fixed assert fail when symbol table has invalid sh_info value.

[George Rimar via llvm-commits]

grimar updated this revision to Diff 72816.
grimar added a comment.

- Added testcase for sh_info == 0.
- Do verification check earlier.


https://reviews.llvm.org/D25016

Files:
  ELF/InputFiles.cpp
  ELF/Writer.cpp
  test/ELF/Inputs/invalid-symtab-sh_info2.elf
  test/ELF/Inputs/invalid-symtab-sh_info3.elf
  test/ELF/invalid-elf.test
  test/ELF/invalid-symtab-sh-info.s

Index: test/ELF/invalid-symtab-sh-info.s
===================================================================
--- test/ELF/invalid-symtab-sh-info.s
+++ test/ELF/invalid-symtab-sh-info.s
@@ -0,0 +1,13 @@
+## sh_info contains value greater than total amount of symbols.
+# RUN: not ld.lld %p/Inputs/invalid-symtab-sh_info.elf -o %t2 2>&1 | \
+# RUN:   FileCheck --check-prefix=INVALID-SYMTAB-SHINFO %s
+# INVALID-SYMTAB-SHINFO: invalid sh_info in symbol table
+
+## sh_info contains invalid value saying non-local symbol is local.
+# RUN: not ld.lld %p/Inputs/invalid-symtab-sh_info2.elf -o %t2 2>&1 | \
+# RUN:   FileCheck --check-prefix=INVALID-SYMTAB-SHINFO %s
+
+## sh_info contains zero value. First entry in a symbol table is always completely zeroed,
+## so sh_info should be at least 1 in a valid ELF.
+# RUN: not ld.lld %p/Inputs/invalid-symtab-sh_info3.elf -o %t2 2>&1 | \
+# RUN:   FileCheck --check-prefix=INVALID-SYMTAB-SHINFO %s
Index: test/ELF/invalid-elf.test
===================================================================
--- test/ELF/invalid-elf.test
+++ test/ELF/invalid-elf.test
@@ -8,10 +8,6 @@
 # RUN:   FileCheck --check-prefix=INVALID-FILE-CLASS %s
 # INVALID-FILE-CLASS: invalid file class: test.o
 
-# RUN: not ld.lld %p/Inputs/invalid-symtab-sh_info.elf -o %t2 2>&1 | \
-# RUN:   FileCheck --check-prefix=INVALID-SYMTAB-SHINFO %s
-# INVALID-SYMTAB-SHINFO: invalid sh_info in symbol table
-
 # RUN: not ld.lld %p/Inputs/invalid-binding.elf -o %t2 2>&1 | \
 # RUN:   FileCheck --check-prefix=INVALID-BINDING %s
 # INVALID-BINDING: unexpected binding
Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -381,6 +381,9 @@
   for (elf::ObjectFile<ELFT> *F : Symtab<ELFT>::X->getObjectFiles()) {
     const char *StrTab = F->getStringTable().data();
     for (SymbolBody *B : F->getLocalSymbols()) {
+      if (!B->IsLocal)
+        fatal(getFilename(F) + ": invalid sh_info in symbol table");
+
       auto *DR = dyn_cast<DefinedRegular<ELFT>>(B);
       // No reason to keep local undefined symbol in symtab.
       if (!DR)
Index: ELF/InputFiles.cpp
===================================================================
--- ELF/InputFiles.cpp
+++ ELF/InputFiles.cpp
@@ -81,7 +81,7 @@
   Elf_Sym_Range Syms = ELFObj.symbols(Symtab);
   uint32_t NumSymbols = std::distance(Syms.begin(), Syms.end());
   uint32_t FirstNonLocal = Symtab->sh_info;
-  if (FirstNonLocal > NumSymbols)
+  if (!FirstNonLocal || (FirstNonLocal > NumSymbols))
     fatal(getFilename(this) + ": invalid sh_info in symbol table");
 
   if (OnlyGlobals)


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