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44 lines
1.1 KiB
44 lines
1.1 KiB
7 years ago
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From 38d600147331d36e74174ebbd4008b63188b321b Mon Sep 17 00:00:00 2001
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From: Andy Polyakov <appro@openssl.org>
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Date: Thu, 17 Aug 2017 21:08:57 +0200
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Subject: [PATCH] bn/asm/x86_64-mont5.pl: fix carry bug in bn_sqrx8x_internal.
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Credit to OSS-Fuzz for finding this.
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CVE-2017-3736
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Reviewed-by: Rich Salz <rsalz@openssl.org>
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---
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crypto/bn/asm/x86_64-mont5.pl | 12 ++++++++++--
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1 file changed, 10 insertions(+), 2 deletions(-)
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diff --git a/crypto/bn/asm/x86_64-mont5.pl b/crypto/bn/asm/x86_64-mont5.pl
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index 3bb0cdf..42178e4 100755
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--- a/crypto/bn/asm/x86_64-mont5.pl
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+++ b/crypto/bn/asm/x86_64-mont5.pl
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@@ -3090,11 +3090,19 @@ $code.=<<___;
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.align 32
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.Lsqrx8x_break:
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- sub 16+8(%rsp),%r8 # consume last carry
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+ xor $zero,$zero
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+ sub 16+8(%rsp),%rbx # mov 16(%rsp),%cf
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+ adcx $zero,%r8
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mov 24+8(%rsp),$carry # initial $tptr, borrow $carry
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+ adcx $zero,%r9
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mov 0*8($aptr),%rdx # a[8], modulo-scheduled
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- xor %ebp,%ebp # xor $zero,$zero
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+ adc \$0,%r10
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mov %r8,0*8($tptr)
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+ adc \$0,%r11
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+ adc \$0,%r12
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+ adc \$0,%r13
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+ adc \$0,%r14
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+ adc \$0,%r15
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cmp $carry,$tptr # cf=0, of=0
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je .Lsqrx8x_outer_loop
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--
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2.9.5
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