[lld] r283533 - [ELF] - Do not crash on invalid size of dynamic section.

[George Rimar via llvm-commits]

Author: grimar
Date: Fri Oct  7 04:01:04 2016
New Revision: 283533

URL: http://llvm.org/viewvc/llvm-project?rev=283533&view=rev
Log:
[ELF] - Do not crash on invalid size of dynamic section.

Previously if sh_size of dynamic section was broken,
lld may crash. Or even may not crash if used 32 bits host.
(then value may be truncated to 32 bits when doing pointer arithmetic 
and could be just zero).
Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D25327

Added:
    lld/trunk/test/ELF/invalid/Inputs/dynamic-section-sh_size.elf   (with props)
    lld/trunk/test/ELF/invalid/dynamic-section-size.s
Modified:
    lld/trunk/ELF/InputFiles.cpp

Modified: lld/trunk/ELF/InputFiles.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputFiles.cpp?rev=283533&r1=283532&r2=283533&view=diff
==============================================================================
--- lld/trunk/ELF/InputFiles.cpp (original)
+++ lld/trunk/ELF/InputFiles.cpp Fri Oct  7 04:01:04 2016
@@ -523,11 +523,11 @@ template <class ELFT> void SharedFile<EL
 
   if (!DynamicSec)
     return;
-  auto *Begin =
-      reinterpret_cast<const Elf_Dyn *>(Obj.base() + DynamicSec->sh_offset);
-  const Elf_Dyn *End = Begin + DynamicSec->sh_size / sizeof(Elf_Dyn);
 
-  for (const Elf_Dyn &Dyn : make_range(Begin, End)) {
+  ArrayRef<Elf_Dyn> Arr =
+      check(Obj.template getSectionContentsAsArray<Elf_Dyn>(DynamicSec),
+            getFilename(this) + ": getSectionContentsAsArray failed");
+  for (const Elf_Dyn &Dyn : Arr) {
     if (Dyn.d_tag == DT_SONAME) {
       uintX_t Val = Dyn.getVal();
       if (Val >= this->StringTable.size())

Added: lld/trunk/test/ELF/invalid/Inputs/dynamic-section-sh_size.elf
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/invalid/Inputs/dynamic-section-sh_size.elf?rev=283533&view=auto
==============================================================================
Binary file - no diff available.

Propchange: lld/trunk/test/ELF/invalid/Inputs/dynamic-section-sh_size.elf
------------------------------------------------------------------------------
    svn:mime-type = application/octet-stream

Added: lld/trunk/test/ELF/invalid/dynamic-section-size.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/invalid/dynamic-section-size.s?rev=283533&view=auto
==============================================================================
--- lld/trunk/test/ELF/invalid/dynamic-section-size.s (added)
+++ lld/trunk/test/ELF/invalid/dynamic-section-size.s Fri Oct  7 04:01:04 2016
@@ -0,0 +1,4 @@
+## dynamic-section-sh_size.elf has incorrect sh_size of dynamic section.
+# RUN: not ld.lld %p/Inputs/dynamic-section-sh_size.elf -o %t2 2>&1 | \
+# RUN:   FileCheck %s
+# CHECK: getSectionContentsAsArray failed: Invalid data was encountered while parsing the file