Revert the size_t modifications from HEAD that had led to more

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

diff --git a/crypto/bn/bn_recp.c b/crypto/bn/bn_recp.c
index 0700a0f06375265589911333ae2935ab11a3a0eb..2e8efb8dae29ac2f5473299ae2bcb9e4752c1f5c 100644 (file)
--- a/crypto/bn/bn_recp.c
+++ b/crypto/bn/bn_recp.c
@@ -93,7 +93,7 @@ void BN_RECP_CTX_free(BN_RECP_CTX *recp)
 
 int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx)
        {
-       BN_copy(&(recp->N),d);
+       if (!BN_copy(&(recp->N),d)) return 0;
        BN_zero(&(recp->Nr));
        recp->num_bits=BN_num_bits(d);
        recp->shift=0;
@@ -120,10 +120,10 @@ int BN_mod_mul_reciprocal(BIGNUM *r, const BIGNUM *x, const BIGNUM *y,
        else
                ca=x; /* Just do the mod */
 
-       BN_div_recp(NULL,r,ca,recp,ctx);
-       ret=1;
+       ret = BN_div_recp(NULL,r,ca,recp,ctx);
 err:
        BN_CTX_end(ctx);
+       bn_check_top(r);
        return(ret);
        }
 
@@ -149,7 +149,7 @@ int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
        if (BN_ucmp(m,&(recp->N)) < 0)
                {
                BN_zero(d);
-               BN_copy(r,m);
+               if (!BN_copy(r,m)) return 0;
                BN_CTX_end(ctx);
                return(1);
                }
@@ -159,21 +159,28 @@ int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
         * we need multiply ABCDEF by 3 digests of the reciprocal of ab
         *
         */
-       i=BN_num_bits(m);
 
+       /* i := max(BN_num_bits(m), 2*BN_num_bits(N)) */
+       i=BN_num_bits(m);
        j=recp->num_bits<<1;
        if (j>i) i=j;
-       j>>=1;
 
+       /* Nr := round(2^i / N) */
        if (i != recp->shift)
                recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N),
                        i,ctx); /* BN_reciprocal returns i, or -1 for an error */
        if (recp->shift == -1) goto err;
 
-       if (!BN_rshift(a,m,j)) goto err;
+       /* d := |round(round(m / 2^BN_num_bits(N)) * recp->Nr / 2^(i - BN_num_bits(N)))|
+        *    = |round(round(m / 2^BN_num_bits(N)) * round(2^i / N) / 2^(i - BN_num_bits(N)))|
+        *   <= |(m / 2^BN_num_bits(N)) * (2^i / N) * (2^BN_num_bits(N) / 2^i)|
+        *    = |m/N|
+        */
+       if (!BN_rshift(a,m,recp->num_bits)) goto err;
        if (!BN_mul(b,a,&(recp->Nr),ctx)) goto err;
-       if (!BN_rshift(d,b,i-j)) goto err;
+       if (!BN_rshift(d,b,i-recp->num_bits)) goto err;
        d->neg=0;
+
        if (!BN_mul(b,&(recp->N),d,ctx)) goto err;
        if (!BN_usub(r,m,b)) goto err;
        r->neg=0;
@@ -184,7 +191,7 @@ int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
                {
                if (j++ > 2)
                        {
-                       BNerr(BN_F_BN_MOD_MUL_RECIPROCAL,BN_R_BAD_RECIPROCAL);
+                       BNerr(BN_F_BN_DIV_RECP,BN_R_BAD_RECIPROCAL);
                        goto err;
                        }
                if (!BN_usub(r,r,&(recp->N))) goto err;
@@ -197,6 +204,8 @@ int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
        ret=1;
 err:
        BN_CTX_end(ctx);
+       bn_check_top(dv);
+       bn_check_top(rem);
        return(ret);
        } 
 
@@ -208,17 +217,18 @@ err:
 int BN_reciprocal(BIGNUM *r, const BIGNUM *m, int len, BN_CTX *ctx)
        {
        int ret= -1;
-       BIGNUM t;
+       BIGNUM *t;
 
-       BN_init(&t);
+       BN_CTX_start(ctx);
+       if((t = BN_CTX_get(ctx)) == NULL) goto err;
+
+       if (!BN_set_bit(t,len)) goto err;
 
-       BN_zero(&t);
-       if (!BN_set_bit(&t,len)) goto err;
+       if (!BN_div(r,NULL,t,m,ctx)) goto err;
 
-       if (!BN_div(r,NULL,&t,m,ctx)) goto err;
        ret=len;
 err:
-       BN_free(&t);
+       bn_check_top(r);
+       BN_CTX_end(ctx);
        return(ret);
        }
-