[PATCH] Adding diversity for security

[Nadav Rotem]

Hi Stephen, 

Thanks for submitting the patch.  I have a few questions.  It is not clear to me why you need cryptographically strong randomization at *compile* time.  You absolutely do need this kind of randomization when distributing the binary, not when compiling it.  To the best of my understanding in order to predict a safe jump location you need to read the binary data anyway, so using a strong crypto is not better than any pseudo random number generator.  

Thanks,
Nadav



On Oct 15, 2013, at 1:40 PM, Stephen Crane <sjcrane at uci.edu> wrote:

>  Trying to convince arcanist to upload the correct diffs...
> 
> http://llvm-reviews.chandlerc.com/D1802
> 
> CHANGE SINCE LAST DIFF
>  http://llvm-reviews.chandlerc.com/D1802?vs=4928&id=4930#toc
> 
> Files:
>  CMakeLists.txt
>  Makefile.config.in
>  autoconf/configure.ac
>  cmake/config-ix.cmake
>  cmake/modules/LLVM-Config.cmake
>  configure
>  include/llvm/CodeGen/CommandFlags.h
>  include/llvm/CodeGen/MachineInstr.h
>  include/llvm/Config/config.h.cmake
>  include/llvm/Config/config.h.in
>  include/llvm/MC/MCRegisterInfo.h
>  include/llvm/Support/RandomNumberGenerator.h
>  include/llvm/Target/TargetOptions.h
>  lib/CodeGen/LLVMBuild.txt
>  lib/CodeGen/MachineBasicBlock.cpp
>  lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
>  lib/LTO/LTOCodeGenerator.cpp
>  lib/LTO/LTOModule.cpp
>  lib/Support/CMakeLists.txt
>  lib/Support/RandomNumberGenerator.cpp
>  lib/Target/X86/CMakeLists.txt
>  lib/Target/X86/NOPInsertion.cpp
>  lib/Target/X86/X86.h
>  lib/Target/X86/X86TargetMachine.cpp
>  test/CodeGen/X86/nop-insert-percentage.ll
>  test/CodeGen/X86/nop-insert.ll
>  test/CodeGen/X86/sched-rnd-test.ll
>  test/Makefile
>  test/lit.cfg
>  test/lit.site.cfg.in
>  tools/llc/llc.cpp
>  tools/llvm-lto/llvm-lto.cpp
>  tools/lto/lto.cpp
>  tools/opt/opt.cpp
> <D1802.6.patch>