Adjust various bignum functions to use BN_CTX for variables instead of

[openssl.git] / crypto / bn / bn_exp2.c

diff --git a/crypto/bn/bn_exp2.c b/crypto/bn/bn_exp2.c
index 0b3e13f6bc394f7e69c14820db8c4f3745a43b85..b3f43cec8c1c1cc949f24c051c5cb7934f65e443 100644 (file)
--- a/crypto/bn/bn_exp2.c
+++ b/crypto/bn/bn_exp2.c
@@ -115,14 +115,16 @@
 
 #define TABLE_SIZE     32
 
-int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
-            BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont)
+int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1,
+       const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
+       BN_CTX *ctx, BN_MONT_CTX *in_mont)
        {
        int i,j,bits,b,bits1,bits2,ret=0,wpos1,wpos2,window1,window2,wvalue1,wvalue2;
-       int r_is_one=1,ts1=0,ts2=0;
+       int r_is_one=1;
        BIGNUM *d,*r;
-       BIGNUM *a_mod_m;
-       BIGNUM val1[TABLE_SIZE], val2[TABLE_SIZE];
+       const BIGNUM *a_mod_m;
+       /* Tables of variables obtained from 'ctx' */
+       BIGNUM *val1[TABLE_SIZE], *val2[TABLE_SIZE];
        BN_MONT_CTX *mont=NULL;
 
        bn_check_top(a1);
@@ -140,15 +142,18 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
        bits2=BN_num_bits(p2);
        if ((bits1 == 0) && (bits2 == 0))
                {
-               BN_one(rr);
-               return(1);
+               ret = BN_one(rr);
+               return ret;
                }
+       
        bits=(bits1 > bits2)?bits1:bits2;
 
        BN_CTX_start(ctx);
        d = BN_CTX_get(ctx);
        r = BN_CTX_get(ctx);
-       if (d == NULL || r == NULL) goto err;
+       val1[0] = BN_CTX_get(ctx);
+       val2[0] = BN_CTX_get(ctx);
+       if(!d || !r || !val1[0] || !val2[0]) goto err;
 
        if (in_mont != NULL)
                mont=in_mont;
@@ -164,58 +169,67 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
        /*
         * Build table for a1:   val1[i] := a1^(2*i + 1) mod m  for i = 0 .. 2^(window1-1)
         */
-       BN_init(&val1[0]);
-       ts1=1;
-       if (BN_ucmp(a1,m) >= 0)
+       if (a1->neg || BN_ucmp(a1,m) >= 0)
                {
-               if (!BN_mod(&(val1[0]),a1,m,ctx))
+               if (!BN_mod(val1[0],a1,m,ctx))
                        goto err;
-               a_mod_m = &(val1[0]);
+               a_mod_m = val1[0];
                }
        else
                a_mod_m = a1;
-       if (!BN_to_montgomery(&(val1[0]),a_mod_m,mont,ctx)) goto err;
+       if (BN_is_zero(a_mod_m))
+               {
+               BN_zero(rr);
+               ret = 1;
+               goto err;
+               }
+
+       if (!BN_to_montgomery(val1[0],a_mod_m,mont,ctx)) goto err;
        if (window1 > 1)
                {
-               if (!BN_mod_mul_montgomery(d,&(val1[0]),&(val1[0]),mont,ctx)) goto err;
+               if (!BN_mod_mul_montgomery(d,val1[0],val1[0],mont,ctx)) goto err;
 
                j=1<<(window1-1);
                for (i=1; i<j; i++)
                        {
-                       BN_init(&(val1[i]));
-                       if (!BN_mod_mul_montgomery(&(val1[i]),&(val1[i-1]),d,mont,ctx))
+                       if(((val1[i] = BN_CTX_get(ctx)) == NULL) ||
+                                       !BN_mod_mul_montgomery(val1[i],val1[i-1],
+                                               d,mont,ctx))
                                goto err;
                        }
-               ts1=i;
                }
 
 
        /*
         * Build table for a2:   val2[i] := a2^(2*i + 1) mod m  for i = 0 .. 2^(window2-1)
         */
-       BN_init(&val2[0]);
-       ts2=1;
-       if (BN_ucmp(a2,m) >= 0)
+       if (a2->neg || BN_ucmp(a2,m) >= 0)
                {
-               if (!BN_mod(&(val2[0]),a2,m,ctx))
+               if (!BN_mod(val2[0],a2,m,ctx))
                        goto err;
-               a_mod_m = &(val2[0]);
+               a_mod_m = val2[0];
                }
        else
                a_mod_m = a2;
-       if (!BN_to_montgomery(&(val2[0]),a_mod_m,mont,ctx)) goto err;
+       if (BN_is_zero(a_mod_m))
+               {
+               BN_zero(rr);
+               ret = 1;
+               goto err;
+               }
+       if (!BN_to_montgomery(val2[0],a_mod_m,mont,ctx)) goto err;
        if (window2 > 1)
                {
-               if (!BN_mod_mul_montgomery(d,&(val2[0]),&(val2[0]),mont,ctx)) goto err;
+               if (!BN_mod_mul_montgomery(d,val2[0],val2[0],mont,ctx)) goto err;
 
                j=1<<(window2-1);
                for (i=1; i<j; i++)
                        {
-                       BN_init(&(val2[i]));
-                       if (!BN_mod_mul_montgomery(&(val2[i]),&(val2[i-1]),d,mont,ctx))
+                       if(((val2[i] = BN_CTX_get(ctx)) == NULL) ||
+                                       !BN_mod_mul_montgomery(val2[i],val2[i-1],
+                                               d,mont,ctx))
                                goto err;
                        }
-               ts2=i;
                }
 
 
@@ -240,7 +254,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
                                {
                                /* consider bits b-window1+1 .. b for this window */
                                i = b-window1+1;
-                               while (!BN_is_bit_set(p1, i))
+                               while (!BN_is_bit_set(p1, i)) /* works for i<0 */
                                        i++;
                                wpos1 = i;
                                wvalue1 = 1;
@@ -272,7 +286,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
                if (wvalue1 && b == wpos1)
                        {
                        /* wvalue1 is odd and < 2^window1 */
-                       if (!BN_mod_mul_montgomery(r,r,&(val1[wvalue1>>1]),mont,ctx))
+                       if (!BN_mod_mul_montgomery(r,r,val1[wvalue1>>1],mont,ctx))
                                goto err;
                        wvalue1 = 0;
                        r_is_one = 0;
@@ -281,7 +295,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
                if (wvalue2 && b == wpos2)
                        {
                        /* wvalue2 is odd and < 2^window2 */
-                       if (!BN_mod_mul_montgomery(r,r,&(val2[wvalue2>>1]),mont,ctx))
+                       if (!BN_mod_mul_montgomery(r,r,val2[wvalue2>>1],mont,ctx))
                                goto err;
                        wvalue2 = 0;
                        r_is_one = 0;
@@ -292,9 +306,6 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 err:
        if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont);
        BN_CTX_end(ctx);
-       for (i=0; i<ts1; i++)
-               BN_clear_free(&(val1[i]));
-       for (i=0; i<ts2; i++)
-               BN_clear_free(&(val2[i]));
+       bn_check_top(rr);
        return(ret);
        }