diff options
| author | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2019-08-25 03:47:01 +0200 |
|---|---|---|
| committer | Nicola Tuveri <nic.tuv@gmail.com> | 2020-01-05 08:39:23 +0200 |
| commit | ec7c1fd322ede90783b626facc5252133a6dfa90 (patch) | |
| tree | 3881bd71faf14c4c8b9be05c499ae36e8b728157 /crypto | |
| parent | 75738b9433185f44103073fd29ec63ae72e24e63 (diff) | |
Improve side channel fix in ecp_nistz256-x86_64.pl
Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9239)
(cherry picked from commit e9fe87950db2e6169029b2ecf3ed09d64265bc9c)
Diffstat (limited to 'crypto')
| -rwxr-xr-x | crypto/ec/asm/ecp_nistz256-x86_64.pl | 31 |
1 files changed, 6 insertions, 25 deletions
diff --git a/crypto/ec/asm/ecp_nistz256-x86_64.pl b/crypto/ec/asm/ecp_nistz256-x86_64.pl index 7b8329079e..676c908cff 100755 --- a/crypto/ec/asm/ecp_nistz256-x86_64.pl +++ b/crypto/ec/asm/ecp_nistz256-x86_64.pl @@ -3628,35 +3628,16 @@ $code.=<<___; or $acc0, $acc4 or $acc1, $acc4 # !is_equal(U1, U2) - movq %xmm2, $acc0 - movq %xmm3, $acc1 + movq %xmm2, $acc0 # in1infty | in2infty + movq %xmm3, $acc1 # !is_equal(S1, S2) or $acc0, $acc4 - .byte 0x3e # predict taken - jnz .Ladd_proceed$x # !is_equal(U1, U2) || in1infty || in2infty - - # We now know A = B or A = -B and neither is infinity. Compare the - # y-coordinates via S1 and S2. - test $acc1, $acc1 - jz .Ladd_double$x # is_equal(S1, S2) + or $acc1, $acc4 - # A = -B, so the result is infinity. - # - # TODO: see https://github.com/google/boringssl/blob/12d9ed670da3edd64ce8175cfe0e091982989c18/crypto/fipsmodule/ec/asm/p256-x86_64-asm.pl#L3128-L3132 - # Does .Ladd_proceed handle this case? It seems to, in - # which case we should eliminate this special-case and simplify the - # timing analysis. - movq %xmm0, $r_ptr # restore $r_ptr - pxor %xmm0, %xmm0 - movdqu %xmm0, 0x00($r_ptr) - movdqu %xmm0, 0x10($r_ptr) - movdqu %xmm0, 0x20($r_ptr) - movdqu %xmm0, 0x30($r_ptr) - movdqu %xmm0, 0x40($r_ptr) - movdqu %xmm0, 0x50($r_ptr) - jmp .Ladd_done$x + # if (!is_equal(U1, U2) | in1infty | in2infty | !is_equal(S1, S2)) + .byte 0x3e # predict taken + jnz .Ladd_proceed$x -.align 32 .Ladd_double$x: movq %xmm1, $a_ptr # restore $a_ptr movq %xmm0, $r_ptr # restore $r_ptr |