Apple MacOS 32-Bit Syscall Exit Kernel Register Leak(CVE-2017-2509)

The XNU kernel, when compiled for a x86-64 CPU, can run 32-bit x86 binaries in compatibility mode. 32-bit binaries use partly separate syscall entry and exit paths. To return to userspace, unixsyscall in bsd/dev/i386/systemcalls.c calls threadexceptionreturn in osfmk/x8664/locore.s, which in turn...