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authorAndy Polyakov <appro@openssl.org>2017-08-17 21:08:57 +0200
committerMatt Caswell <matt@openssl.org>2017-11-02 11:05:15 +0000
commit4443cf7aa0099e5ce615c18cee249fff77fb0871 (patch)
treed3b8cfd39cc201031701dc6561da09a46114a33a /crypto
parentb701fa8340944c2a0481457f96e7f38b03180c24 (diff)
bn/asm/x86_64-mont5.pl: fix carry bug in bn_sqrx8x_internal.
Credit to OSS-Fuzz for finding this. CVE-2017-3736 Reviewed-by: Rich Salz <rsalz@openssl.org>
Diffstat (limited to 'crypto')
-rwxr-xr-xcrypto/bn/asm/x86_64-mont5.pl12
1 files changed, 10 insertions, 2 deletions
diff --git a/crypto/bn/asm/x86_64-mont5.pl b/crypto/bn/asm/x86_64-mont5.pl
index 6807ab5cfe..5779059ea2 100755
--- a/crypto/bn/asm/x86_64-mont5.pl
+++ b/crypto/bn/asm/x86_64-mont5.pl
@@ -3099,11 +3099,19 @@ $code.=<<___;
.align 32
.Lsqrx8x_break:
- sub 16+8(%rsp),%r8 # consume last carry
+ xor $zero,$zero
+ sub 16+8(%rsp),%rbx # mov 16(%rsp),%cf
+ adcx $zero,%r8
mov 24+8(%rsp),$carry # initial $tptr, borrow $carry
+ adcx $zero,%r9
mov 0*8($aptr),%rdx # a[8], modulo-scheduled
- xor %ebp,%ebp # xor $zero,$zero
+ adc \$0,%r10
mov %r8,0*8($tptr)
+ adc \$0,%r11
+ adc \$0,%r12
+ adc \$0,%r13
+ adc \$0,%r14
+ adc \$0,%r15
cmp $carry,$tptr # cf=0, of=0
je .Lsqrx8x_outer_loop