[Object/ELF] - Do not crash if string table sh_size is equal to zero.

Revealed using "id_000038,sig_11,src_000015,op_havoc,rep_16" from PR30540,
when sh_size was 0, crash happened.

Differential revision: https://reviews.llvm.org/D25091

llvm-svn: 285282

3 files changed, 3 insertions, 0 deletions

diff --git a/llvm/include/llvm/Object/ELF.h b/llvm/include/llvm/Object/ELF.h
index 7aee6b17574..b6d4b804c27 100644
--- a/llvm/include/llvm/Object/ELF.h
+++ b/llvm/include/llvm/Object/ELF.h
@@ -428,6 +428,8 @@ ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
   if (std::error_code EC = V.getError())
     return EC;
   ArrayRef<char> Data = *V;
+  if (Data.empty())
+    return object_error::parse_failed;
   if (Data.back() != '\0')
     return object_error::string_table_non_null_end;
   return StringRef(Data.begin(), Data.size());
diff --git a/llvm/test/Object/Inputs/invalid-strtab-zero-size.elf b/llvm/test/Object/Inputs/invalid-strtab-zero-size.elf
new file mode 100644
index 00000000000..cb0d0d0d0f9
--- /dev/null
+++ b/llvm/test/Object/Inputs/invalid-strtab-zero-size.elf
diff --git a/llvm/test/Object/invalid.test b/llvm/test/Object/invalid.test
index fda5d6d66d6..352917987de 100644
--- a/llvm/test/Object/invalid.test
+++ b/llvm/test/Object/invalid.test
@@ -1,6 +1,7 @@
 RUN: not llvm-dwarfdump %p/Inputs/invalid-bad-rel-type.elf 2>&1 | FileCheck %s
 RUN: not llvm-objdump -s %p/Inputs/invalid-strtab-type.elf 2>&1 | FileCheck %s
 RUN: not llvm-objdump -s %p/Inputs/invalid-strtab-size.elf 2>&1 | FileCheck %s
+RUN: not llvm-objdump -s %p/Inputs/invalid-strtab-zero-size.elf 2>&1 | FileCheck %s
 CHECK: Invalid data was encountered while parsing the file
 
 RUN: not llvm-objdump -s %p/Inputs/invalid-strtab-non-null.elf 2>&1 | FileCheck --check-prefix=NON-NULL %s