[llvm] r283740 - [Object/ELF] - Do not crash on invalid Header->e_shoff value.

[George Rimar via llvm-commits]

Author: grimar
Date: Mon Oct 10 05:51:38 2016
New Revision: 283740

URL: http://llvm.org/viewvc/llvm-project?rev=283740&view=rev
Log:
[Object/ELF] - Do not crash on invalid Header->e_shoff value.

sections_begin() may return unalignment pointer when Header->e_shoff isinvalid.
That may result in a crash in clients, for example we have one in LLD:

assert((PtrWord & ~PointerBitMask) == 0 &&
       "Pointer is not sufficiently aligned");
fails when trying to push_back Elf_Shdr* (unaligned) into TinyPtrVector.

Patch forces check for alignment of Header->e_shoff.

Differential revision: https://reviews.llvm.org/D25368

Added:
    llvm/trunk/test/Object/Inputs/invalid-sections-address-alignment.x86-64   (with props)
Modified:
    llvm/trunk/include/llvm/Object/ELF.h
    llvm/trunk/test/Object/invalid.test

Modified: llvm/trunk/include/llvm/Object/ELF.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/ELF.h?rev=283740&r1=283739&r2=283740&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Object/ELF.h (original)
+++ llvm/trunk/include/llvm/Object/ELF.h Mon Oct 10 05:51:38 2016
@@ -367,6 +367,8 @@ const typename ELFFile<ELFT>::Elf_Shdr *
   if (Header->e_shentsize != sizeof(Elf_Shdr))
     report_fatal_error(
         "Invalid section header entry size (e_shentsize) in ELF header");
+  if (Header->e_shoff & (AlignOf<Elf_Shdr>::Alignment - 1))
+    report_fatal_error("Invalid address alignment of section headers");
   return reinterpret_cast<const Elf_Shdr *>(base() + Header->e_shoff);
 }
 

Added: llvm/trunk/test/Object/Inputs/invalid-sections-address-alignment.x86-64
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/Inputs/invalid-sections-address-alignment.x86-64?rev=283740&view=auto
==============================================================================
Binary file - no diff available.

Propchange: llvm/trunk/test/Object/Inputs/invalid-sections-address-alignment.x86-64
------------------------------------------------------------------------------
    svn:mime-type = application/octet-stream

Modified: llvm/trunk/test/Object/invalid.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/invalid.test?rev=283740&r1=283739&r2=283740&view=diff
==============================================================================
--- llvm/trunk/test/Object/invalid.test (original)
+++ llvm/trunk/test/Object/invalid.test Mon Oct 10 05:51:38 2016
@@ -64,3 +64,7 @@ RUN:   FileCheck --check-prefix=INVALID-
 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-sections-address-alignment.x86-64 2>&1 | \
+RUN:   FileCheck --check-prefix=INVALID-SEC-ADDRESS-ALIGNMENT %s
+INVALID-SEC-ADDRESS-ALIGNMENT: Invalid address alignment of section headers