Fix crypto/ec/ec_mult.c to work properly with scalars of value 0

[openssl.git] / crypto / ec / ec_mult.c

diff --git a/crypto/ec/ec_mult.c b/crypto/ec/ec_mult.c
index c71a69ac0d45676304cb3b0b2ce0e4ee557c4a8e..2ba173ef36422ad1c715fe3ebd5b0dc9b17cb03d 100644 (file)
--- a/crypto/ec/ec_mult.c
+++ b/crypto/ec/ec_mult.c
@@ -3,7 +3,7 @@
  * Originally written by Bodo Moeller and Nils Larsch for the OpenSSL project.
  */
 /* ====================================================================
- * Copyright (c) 1998-2003 The OpenSSL Project.  All rights reserved.
+ * Copyright (c) 1998-2007 The OpenSSL Project.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -104,7 +104,10 @@ static EC_PRE_COMP *ec_pre_comp_new(const EC_GROUP *group)
 
        ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP));
        if (!ret)
+               {
+               ECerr(EC_F_EC_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE);
                return ret;
+               }
        ret->group = group;
        ret->blocksize = 8; /* default */
        ret->numblocks = 0;
@@ -194,6 +197,19 @@ static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len)
        int bit, next_bit, mask;
        size_t len = 0, j;
        
+       if (BN_is_zero(scalar))
+               {
+               r = OPENSSL_malloc(1);
+               if (!r)
+                       {
+                       ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE);
+                       goto err;
+                       }
+               r[0] = 0;
+               *ret_len = 1;
+               return r;
+               }
+               
        if (w <= 0 || w > 7) /* 'signed char' can represent integers with absolute values less than 2^7 */
                {
                ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
@@ -203,7 +219,7 @@ static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len)
        next_bit = bit << 1; /* at most 256 */
        mask = next_bit - 1; /* at most 255 */
 
-       if (BN_get_sign(scalar))
+       if (BN_is_negative(scalar))
                {
                sign = -1;
                }
@@ -212,7 +228,11 @@ static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len)
        r = OPENSSL_malloc(len + 1); /* modified wNAF may be one digit longer than binary representation
                                      * (*ret_len will be set to the actual length, i.e. at most
                                      * BN_num_bits(scalar) + 1) */
-       if (r == NULL) goto err;
+       if (r == NULL)
+               {
+               ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE);
+               goto err;
+               }
 
        if (scalar->d == NULL || scalar->top == 0)
                {
@@ -307,12 +327,13 @@ static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len)
  *       (thus the boundaries should be increased)
  */
 #define EC_window_bits_for_scalar_size(b) \
-               ((b) >= 2000 ? 6 : \
-                (b) >=  800 ? 5 : \
-                (b) >=  300 ? 4 : \
-                (b) >=   70 ? 3 : \
-                (b) >=   20 ? 2 : \
-                 1)
+               ((size_t) \
+                ((b) >= 2000 ? 6 : \
+                 (b) >=  800 ? 5 : \
+                 (b) >=  300 ? 4 : \
+                 (b) >=   70 ? 3 : \
+                 (b) >=   20 ? 2 : \
+                 1))
 
 /* Compute
  *      \sum scalars[i]*points[i],
@@ -324,7 +345,7 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
        size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx)
        {
        BN_CTX *new_ctx = NULL;
-       EC_POINT *generator = NULL;
+       const EC_POINT *generator = NULL;
        EC_POINT *tmp = NULL;
        size_t totalnum;
        size_t blocksize = 0, numblocks = 0; /* for wNAF splitting */
@@ -384,7 +405,7 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
                
                /* look if we can use precomputed multiples of generator */
 
-               pre_comp = EC_GROUP_get_extra_data(group, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
+               pre_comp = EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
 
                if (pre_comp && pre_comp->numblocks && (EC_POINT_cmp(group, generator, pre_comp->points[0], ctx) == 0))
                        {
@@ -424,7 +445,10 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
        val_sub  = OPENSSL_malloc(totalnum * sizeof val_sub[0]);
                 
        if (!wsize || !wNAF_len || !wNAF || !val_sub)
+               {
+               ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE);
                goto err;
+               }
 
        wNAF[0] = NULL; /* preliminary pivot */
 
@@ -537,6 +561,7 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
                                        wNAF[i] = OPENSSL_malloc(wNAF_len[i]);
                                        if (wNAF[i] == NULL)
                                                {
+                                               ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE);
                                                OPENSSL_free(tmp_wNAF);
                                                goto err;
                                                }
@@ -563,7 +588,11 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
         * 'val_sub[i]' is a pointer to the subarray for the i-th point,
         * or to a subarray of 'pre_comp->points' if we already have precomputation. */
        val = OPENSSL_malloc((num_val + 1) * sizeof val[0]);
-       if (val == NULL) goto err;
+       if (val == NULL)
+               {
+               ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE);
+               goto err;
+               }
        val[num_val] = NULL; /* pivot element */
 
        /* allocate points for precomputation */
@@ -743,7 +772,7 @@ int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
        int ret = 0;
 
        /* if there is an old EC_PRE_COMP object, throw it away */
-       EC_GROUP_free_extra_data(group, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
+       EC_EX_DATA_free_data(&group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
 
        if ((pre_comp = ec_pre_comp_new(group)) == NULL)
                return 0;
@@ -871,14 +900,15 @@ int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
        points = NULL;
        pre_comp->num = num;
 
-       if (!EC_GROUP_set_extra_data(group, pre_comp,
+       if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp,
                ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free))
                goto err;
        pre_comp = NULL;
 
        ret = 1;
  err:
-       BN_CTX_end(ctx);
+       if (ctx != NULL)
+               BN_CTX_end(ctx);
        if (new_ctx != NULL)
                BN_CTX_free(new_ctx);
        if (pre_comp)
@@ -901,7 +931,7 @@ int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
 
 int ec_wNAF_have_precompute_mult(const EC_GROUP *group)
        {
-       if (EC_GROUP_get_extra_data(group, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free) != NULL)
+       if (EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free) != NULL)
                return 1;
        else
                return 0;