[PATCH] D25514: [Object/ELF] - Do not allow overflow when checking section size/offset.

[George Rimar via llvm-commits]

grimar created this revision.
grimar added reviewers: rafael, davide.
grimar added subscribers: llvm-commits, grimar, evgeny777.

Overflow was the reason of incorrect passing the check,
patch fixes the case.


https://reviews.llvm.org/D25514

Files:
  include/llvm/Object/ELF.h
  test/Object/Inputs/invalid-section-size2.elf
  test/Object/invalid.test


Index: test/Object/invalid.test
===================================================================
--- test/Object/invalid.test
+++ test/Object/invalid.test
@@ -64,3 +64,7 @@
 RUN: not llvm-readobj -r %p/Inputs/invalid-relocation-sec-sh_offset.elf-x86-64 2>&1 | \
 RUN:   FileCheck --check-prefix=INVALID-RELOC-SH-OFFSET %s
 INVALID-RELOC-SH-OFFSET: Invalid data was encountered while parsing the file
+
+RUN: not llvm-readobj -t %p/Inputs/invalid-section-size2.elf 2>&1 | \
+RUN:   FileCheck --check-prefix=INVALID-SECTION-SIZE2 %s
+INVALID-SECTION-SIZE2: Invalid data was encountered while parsing the file.
Index: include/llvm/Object/ELF.h
===================================================================
--- include/llvm/Object/ELF.h
+++ include/llvm/Object/ELF.h
@@ -226,7 +226,8 @@
 
   if (Size % sizeof(T))
     return object_error::parse_failed;
-  if (Offset + Size > Buf.size())
+  if ((std::numeric_limits<uintX_t>::max() - Offset < Size) ||
+      Offset + Size > Buf.size())
     return object_error::parse_failed;
 
   const T *Start = reinterpret_cast<const T *>(base() + Offset);


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