Update dependencies.

[oweals/openssl.git] / crypto / bn / bn_exp.c

diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c
index 44f47e7eb20e89264676949fe62f155236da8156..cc4528247e486d05ed731641eaa7fac29cb30890 100644 (file)
--- a/crypto/bn/bn_exp.c
+++ b/crypto/bn/bn_exp.c
@@ -106,7 +106,7 @@ BN_CTX *ctx;
 
        if (BN_is_odd(p))
                { if (BN_copy(r,a) == NULL) goto err; }
-       else    { if (BN_one(r)) goto err; }
+       else    { if (!BN_one(r)) goto err; }
 
        for (i=1; i<bits; i++)
                {
@@ -131,30 +131,35 @@ int BN_exp(r,a,p,ctx)
 BIGNUM *r,*a,*p;
 BN_CTX *ctx;
        {
-       int i,bits,ret=0;
-       BIGNUM *v,*tmp;
+       int i,bits,ret=0,tos;
+       BIGNUM *v,*rr;
 
+       tos=ctx->tos;
        v= &(ctx->bn[ctx->tos++]);
-       tmp= &(ctx->bn[ctx->tos++]);
+       if ((r == a) || (r == p))
+               rr= &(ctx->bn[ctx->tos++]);
+       else
+               rr=r;
 
        if (BN_copy(v,a) == NULL) goto err;
        bits=BN_num_bits(p);
 
        if (BN_is_odd(p))
-               { if (BN_copy(r,a) == NULL) goto err; }
-       else    { if (BN_one(r)) goto err; }
+               { if (BN_copy(rr,a) == NULL) goto err; }
+       else    { if (!BN_one(rr)) goto err; }
 
        for (i=1; i<bits; i++)
                {
-               if (!BN_sqr(tmp,v,ctx)) goto err;
+               if (!BN_sqr(v,v,ctx)) goto err;
                if (BN_is_bit_set(p,i))
                        {
-                       if (!BN_mul(tmp,r,v,ctx)) goto err;
+                       if (!BN_mul(rr,rr,v,ctx)) goto err;
                        }
                }
        ret=1;
 err:
-       ctx->tos-=2;
+       ctx->tos=tos;
+       if (r != rr) BN_copy(r,rr);
        return(ret);
        }