Fix crypto/ec/ec_mult.c to work properly with scalars of value 0
[openssl.git] / crypto / ec / ec_mult.c
index a045139..2ba173e 100644 (file)
@@ -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);
@@ -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)
                {
@@ -425,7 +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 */
 
@@ -538,6 +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;
                                                }
@@ -564,7 +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 */