[tor-commits] [tor/master] Stop ed25519 8-bit signed left shift overflowing

[nickm@xxxxxxxxxxxxxx]

commit b7eab94a9078b18593a0d0d378d0ccdc07798178
Author: teor <teor2345@xxxxxxxxx>
Date:   Sun Sep 28 20:44:00 2014 -0400

    Stop ed25519 8-bit signed left shift overflowing
    
    Standardise usage in ge_scalarmult_base.c for 1 new fix.
---
 src/ext/ed25519/ref10/ge_scalarmult_base.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ext/ed25519/ref10/ge_scalarmult_base.c b/src/ext/ed25519/ref10/ge_scalarmult_base.c
index 3ede0ad..5292f83 100644
--- a/src/ext/ed25519/ref10/ge_scalarmult_base.c
+++ b/src/ext/ed25519/ref10/ge_scalarmult_base.c
@@ -39,7 +39,7 @@ static void select(ge_precomp *t,int pos,signed char b)
 {
   ge_precomp minust;
   unsigned char bnegative = negative(b);
-  unsigned char babs = b - (((-bnegative) & b) << 1);
+  unsigned char babs = b - SHL8( (-bnegative) & (unsigned char)b, 1);
 
   ge_precomp_0(t);
   cmov(t,&base[pos][0],equal(babs,1));



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