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  • Hash : 78556561
    Author : hjl-tools
    Date : 2020-02-21T19:08:06

    x86: Add indirect branch tracking support (#540) Intel Control-flow Enforcement Technology (CET): https://software.intel.com/en-us/articles/intel-sdm contains shadow stack (SHSTK) and indirect branch tracking (IBT). When CET is enabled, ELF object files must be marked with .note.gnu.property section. When Intel CET is enabled, include <cet.h> in assembly codes to mark Intel CET support. Also when IBT is enabled, all indirect branch targets must start with ENDBR instruction and notrack prefix can be used to disable IBT on indirect branch. <cet.h> defines _CET_ENDBR which can be used in assembly codes for ENDBR instruction. If <cet.h> isn't included, define _CET_ENDBR as empty so that _CET_ENDBR can be used in assembly codes. Trampoline must be enlarged to add ENDBR instruction unconditionally, which is NOP on non-CET processors. This is required regardless if libffi is enabled with CET since libffi.so will be marked in legacy bitmap, but trampoline won't. Update library version for larger FFI_TRAMPOLINE_SIZE. This fixed: https://github.com/libffi/libffi/issues/474 Tested with $ CC="gcc -Wl,-z,cet-report=error -fcf-protection" CXX="g++ -Wl,-z,cet-report=error -fcf-protection" .../configure on Linux CET machines in i686, x32 and x86-64 modes.