introducing dsa_verify_key_ex

src/headers/tomcrypt_pk.h

@@ -479,7 +479,9 @@ int dsa_decrypt_key(const unsigned char *in,  unsigned long  inlen,
 int dsa_import(const unsigned char *in, unsigned long inlen, dsa_key *key);
 int dsa_export(unsigned char *out, unsigned long *outlen, int type, dsa_key *key);
 int dsa_verify_key(dsa_key *key, int *stat);
-
+#ifdef LTC_SOURCE
+int dsa_verify_key_ex(dsa_key *key, int *stat, int mode);
+#endif
 int dsa_shared_secret(void          *private_key, void *base,
                       dsa_key       *public_key,
                       unsigned char *out,         unsigned long *outlen);

src/pk/dsa/dsa_set.c

@@ -45,12 +45,6 @@ int dsa_set_pqg(const unsigned char *p,  unsigned long plen,
 
    key->qord = mp_unsigned_bin_size(key->q);
 
-   /* just a quick, basic test - use dsa_verify_key if you want more */
-   if (mp_cmp_d(key->p, 1) != LTC_MP_GT || mp_cmp_d(key->g, 1) != LTC_MP_GT || mp_cmp_d(key->q, 1) != LTC_MP_GT) {
-      err= CRYPT_INVALID_ARG;
-      goto LBL_ERR;
-   }
-
    if (key->qord >= LTC_MDSA_MAX_GROUP || key->qord <= 15 ||
       (unsigned long)key->qord >= mp_unsigned_bin_size(key->p) || (mp_unsigned_bin_size(key->p) - key->qord) >= LTC_MDSA_DELTA) {
       err = CRYPT_INVALID_PACKET;
@@ -76,7 +70,7 @@ LBL_ERR:
 */
 int dsa_set_key(const unsigned char *in, unsigned long inlen, int type, dsa_key *key)
 {
-   int err;
+   int err, stat = 0;
 
    LTC_ARGCHK(key         != NULL);
    LTC_ARGCHK(key->x      != NULL);
@@ -89,19 +83,17 @@ int dsa_set_key(const unsigned char *in, unsigned long inlen, int type, dsa_key
    if (type == PK_PRIVATE) {
       key->type = PK_PRIVATE;
       if ((err = mp_read_unsigned_bin(key->x, (unsigned char *)in, inlen)) != CRYPT_OK) { goto LBL_ERR; }
-      if (mp_cmp_d(key->x, 1) != LTC_MP_GT) {
-         err= CRYPT_INVALID_ARG;
-         goto LBL_ERR;
-      }
       if ((err = mp_exptmod(key->g, key->x, key->p, key->y)) != CRYPT_OK)               { goto LBL_ERR; }
    }
    else {
       key->type = PK_PUBLIC;
       if ((err = mp_read_unsigned_bin(key->y, (unsigned char *)in, inlen)) != CRYPT_OK) { goto LBL_ERR; }
-      if (mp_cmp_d(key->y, 1) != LTC_MP_GT || mp_cmp(key->y, key->p) != LTC_MP_LT) {
+   }
-         err= CRYPT_INVALID_ARG;
+
-         goto LBL_ERR;
+   if ((err = dsa_verify_key_ex(key, &stat, 0)) != CRYPT_OK)                            { goto LBL_ERR; }
-      }
+   if (stat == 0) {
+      err = CRYPT_INVALID_ARG;
+      goto LBL_ERR;
    }
 
    return CRYPT_OK;

src/pk/dsa/dsa_verify_key.c

@@ -22,6 +22,11 @@
    @return CRYPT_OK if successful
 */
 int dsa_verify_key(dsa_key *key, int *stat)
+{
+   return dsa_verify_key_ex(key, stat, 1); /* 1 = full check */
+}
+
+int dsa_verify_key_ex(dsa_key *key, int *stat, int mode)
 {
    void   *tmp, *tmp2;
    int    res, err;
@@ -32,19 +37,21 @@ int dsa_verify_key(dsa_key *key, int *stat)
    /* default to an invalid key */
    *stat = 0;
 
-   /* first make sure key->q and key->p are prime */
+   if (mode == 1) {
-   if ((err = mp_prime_is_prime(key->q, 8, &res)) != CRYPT_OK) {
+      /* first make sure key->q and key->p are prime */
-      return err;
+      if ((err = mp_prime_is_prime(key->q, 8, &res)) != CRYPT_OK) {
-   }
+         return err;
-   if (res == 0) {
+      }
-      return CRYPT_OK;
+      if (res == 0) {
-   }
+         return CRYPT_OK;
+      }
 
-   if ((err = mp_prime_is_prime(key->p, 8, &res)) != CRYPT_OK) {
+      if ((err = mp_prime_is_prime(key->p, 8, &res)) != CRYPT_OK) {
-      return err;
+         return err;
-   }
+      }
-   if (res == 0) {
+      if (res == 0) {
-      return CRYPT_OK;
+         return CRYPT_OK;
+      }
    }
 
    /* now make sure that g is not -1, 0 or 1 and <p */