• Prem Karat's avatar
    MIPS: Enable VDSO randomization · ccd39880
    Prem Karat authored
    Based on commit 1091458d (mmap randomization)
    
    For 32-bit address spaces randomize within a
    16MB space, for 64-bit within a 256MB space.
    
    Test Results:
    ------------
    Without Patch (VDSO is not randomized)
    ---------------------------------------
    root@Maleo:~# ./aslr vdso
    FAIL: ASLR not functional (vdso always at 0x7fff7000)
    
    root@Maleo:~# ./aslr rekey vdso
    pre_val==cur_val
    value=0x7fff7000
    
    With patch:(VDSO is randmoized and doesn't interfere with stack)
    ----------------------------------------------------------------
    root@cavium-octeon2:~# ./aslr rekey vdso
    pre_val!=cur_val
    previous_value=0x7f830ea2
    current_value=0x776e2000
    root@cavium-octeon2:~# ./aslr rekey vdso
    pre_val!=cur_val
    previous_value=0x7fb0cea2
    current_value=0x77209000
    root@cavium-octeon2:~# ./aslr rekey vdso
    pre_val!=cur_val
    previous_value=0x7f985ea2
    current_value=0x7770c000
    root@cavium-octeon2:~# ./aslr rekey vdso
    pre_val!=cur_val
    previous_value=0x7fbc6ea2
    current_value=0x7fe25000
    
    Maps file output:
    -------------------------
    root@cavium-octeon2:~# ./aslr rekey maps
    78584000-785a5000 rwxp 00000000 00:00 0                                  [heap]
    7f9d0000-7f9f1000 rw-p 00000000 00:00 0                                  [stack]
    7ffa5000-7ffa6000 r-xp 00000000 00:00 0                                  [vdso]
    
    root@cavium-octeon2:~# ./aslr rekey maps
    77de0000-77e01000 rwxp 00000000 00:00 0                                  [heap]
    7f91b000-7f93c000 rw-p 00000000 00:00 0                                  [stack]
    7ff99000-7ff9a000 r-xp 00000000 00:00 0                                  [vdso]
    
    root@cavium-octeon2:~# ./aslr rekey maps
    77d7f000-77da0000 rwxp 00000000 00:00 0                                  [heap]
    7fc2a000-7fc4b000 rw-p 00000000 00:00 0                                  [stack]
    7fe09000-7fe0a000 r-xp 00000000 00:00 0                                  [vdso]
    
    root@cavium-octeon2:~# ./aslr rekey maps
    7794c000-7794d000 r-xp 00000000 00:00 0                                  [vdso]
    77e4b000-77e6c000 rwxp 00000000 00:00 0                                  [heap]
    7f6e7000-7f708000 rw-p 00000000 00:00 0                                  [stack]
    root@cavium-octeon2:~#
    Signed-off-by: default avatarPrem Karat <pkarat@mvista.com>
    Cc: linux-mips@linux-mips.org
    Cc: sergei.shtylyov@cogentembedded.com
    Cc: ddaney.cavm@gmail.com
    Patchwork: https://patchwork.linux-mips.org/patch/6812Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
    ccd39880
vdso.c 2.64 KB