Some 64 bit linux assembly for detecting and using specialized AES instructions.

README

A program designed to test operating system capabilities on 64 bit CPUs.
Currently supported operating systems: Linux, Mac OS X

In order to build, you need nasm: the netwide assembler.

$ make -f makefile.{your os} 

AUTHOR

Max DeLiso <[email protected]>

cpuid.asm

bits 64

;; exports
global aes_feature_check

section .text

aes_feature_check:
;; preconditions
; none
;; postconditions
; returns 0 on success, -1 or -2 on failure

  mov eax, 1
  cpuid ; feature bits returned int ecx/edx

  and ecx, 01a000000h
  cmp ecx, 01a000000h
  jne .fail ; check OSXSAVE AVX and AESNI

  mov ecx, 0
  xgetbv ; value returned in eax

  and eax, 06h
  cmp eax, 06h
  jne .fail2 ; check for XMM and YMM

  xor rax, rax ; return 0 for failure
  ret

  .fail:
  mov rax, -1 ; return -1 for no OSXSAVE AVX and AESNI
  ret

  .fail2:
  mov rax, -2 ; return -2 for missing XMM and YMM
  ret

exit_linux.asm

bits 64

;; exports
global exit

;; imports
; none

section .text

exit: ; rbx is return code from caller
    mov rax, 60
    syscall

exit_macosx.asm

bits 64

;; exports
global exit

;; imports
; none

section .text

exit: ; rbx is return code from caller,
      ; but mac os x's abi expects it in rdi,
      ; so copy it over
   mov rax, 0x2000001
   mov rdi, rbx
   syscall

exit_win64.asm

bits 64

;; exports
global exit

;; imports
; none

section .text

exit:
    xor rcx, rcx
    xor rdx, rdx
    mov rax, 0x29
    syscall ;TODO: fix this, it sould terminate the caller but doesn't
    
    ret ; as a fallback

makefile.linux

LD=ld
RM=rm
PROBE=probe
NASM=nasm
AFLAGS=-felf64
LDFLAGS =-e probe -pie --gc-sections --print-gc-sections
LDFLAGS+=-dynamic-linker /lib64/ld-linux-x86-64.so.2 # replace with your dynamic linker path
LDFLAGS+=-z execstack -z initfirst -z relro -z now
MODULES=probe.o cpuid.o print_linux.o exit_linux.o 
OBJDIR=obj
STRIP=strip

.PHONY: clean

probe: $(MODULES) makefile.linux
	$(LD) $(LDFLAGS) $(MODULES) -o $(PROBE)
#	$(STRIP) $(PROBE)

%.o : %.asm
	$(NASM) $(AFLAGS) -o $@ $<

clean:
	$(RM) -f $(PROBE) $(MODULES) *~

makefile.macosx

LD=ld
RM=rm
PROBE=probe
NASM=nasm
AFLAGS=-fmacho64
LDFLAGS=-e probe -macosx_version_min 10.6
MODULES=probe.o cpuid.o print_macosx.o exit_macosx.o 
OBJDIR=obj
STRIP=strip

.PHONY: clean

probe: $(MODULES)
	$(LD) $(LDFLAGS) $(MODULES) -o $(PROBE)
#	$(STRIP) $(PROBE)

%.o : %.asm
	$(NASM) $(AFLAGS) -o $@ $<

clean:
	$(RM) -f $(PROBE) $(MODULES) *~

makefile.win64

LD=link
RM=del
PROBE=probe

NASM=nasm

AFLAGS=-fwin64

LDFLAGS=/entry:probe /subsystem:console /release /nologo /tsaware\
/dynamicbase /errorReport:none /nxcompat /opt:ref /out:probe.exe
 
MODULES=probe.obj cpuid.obj print_win64.obj exit_win64.obj

probe: $(MODULES) makefile.win64
	$(LD) $(LDFLAGS) $(MODULES)

.asm.obj:
	$(NASM) -o $@ $(AFLAGS) $<

clean:
	$(RM) $(PROBE).exe $(MODULES) *~

print_linux.asm

bits 64

;;exports

global print

;;imports
;none

section .text
print:
;; preconditions 
; rsi contains pointer to string
; rdx contains number of bytes to write
;; postconditions
; none
    mov rax, 1
    mov rdi, 1
    syscall
    ret

print_macosx.asm

bits 64

;;exports

global print

;;imports
;none

section .text
print:
;; preconditions 
; rsi contains pointer to string
; rdx contains number of bytes to write
;; postconditions
; some stdio action

    mov rax, 0x2000004  ; UNIX class + SYS_write
    mov rdi, 1          ; write to stdout
    syscall             ; trap (rdx already contains length)
       
    ret                 

print_win64.asm

bits 64

;;exports

global print

;;imports
;none

section .text
print:
;; preconditions 
; rsi contains pointer to string
; rdx contains number of bytes to write
;; postconditions
; some stdio action

    ;mov rax, 0x2000004  ; UNIX class + SYS_write
    ;mov rdi, 1          ; write to stdout
    ;syscall             ; trap (rdx already contains length)
       
    ret                 

probe.asm

bits 64

;;exports

global probe ;entry point

;;imports

extern print ;; in (rsi, rdx) = (string address, string length)
extern exit  ;; in (rbx) = (return code)
extern aes_feature_check

section .text

probe:
  push rbp
  mov rbp, rsp ; build main stack frame

  mov rsi, probeMsg
  mov rdx, probeMsgLen
  call print ; display startup message

  call aes_feature_check
  cmp rax, rax
  jnz .done

  nop ; TODO: some cpu accelerated cipherage

  .done:

  pop rbp ; cleanup main stack frame

  xor rdi, rdi ; return 0 for success
  call exit
  ret ; added for windows case as fallback

section .rodata

probeMsg: db 'pr0be', 10, 0 ; hopefully this is 1337 enough
probeMsgLen: equ $-probeMsg