Problem: bn_mul_normal() misbehaves if the size of b is 0.

Solution: multiply a with 0, putting the result in r, and return.

diff --git a/crypto/bn/bn_mul.c b/crypto/bn/bn_mul.c
index b4ed7e23e62daa6a0864c2e59f3117c011960cf1..94db7c05e61f609d83643ae43ff4c652755bc6d1 100644 (file)
--- a/crypto/bn/bn_mul.c
+++ b/crypto/bn/bn_mul.c
@@ -1110,7 +1110,13 @@ void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
 
                }
        rr= &(r[na]);
-       rr[0]=bn_mul_words(r,a,na,b[0]);
+       if (nb <= 0)
+               {
+               (void)bn_mul_words(r,a,na,0);
+               return;
+               }
+       else
+               rr[0]=bn_mul_words(r,a,na,b[0]);
 
        for (;;)
                {