Change RNG test to block oriented instead of request oriented, add option
[openssl.git] / fips / rand / fips_drbg_lib.c
index 5564538..920a61a 100644 (file)
@@ -268,8 +268,7 @@ int FIPS_drbg_reseed(DRBG_CTX *dctx,
        }
 
 
-static int fips_drbg_generate_internal(DRBG_CTX *dctx,
-                       unsigned char *out, size_t outlen,
+int FIPS_drbg_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,
                        int strength, int prediction_resistance,
                        const unsigned char *adin, size_t adinlen)
        {
@@ -323,76 +322,13 @@ static int fips_drbg_generate_internal(DRBG_CTX *dctx,
        if (r)
                {
                if (!(dctx->flags & DRBG_FLAG_NOERR))
-                       FIPSerr(FIPS_F_FIPS_DRBG_GENERATE_INTERNAL, r);
+                       FIPSerr(FIPS_F_FIPS_DRBG_GENERATE, r);
                return 0;
                }
 
        return 1;
        }
 
-/* external generate function: incorporates continuous RNG test if not
- * in test mode.
- */
-
-int FIPS_drbg_generate(DRBG_CTX *dctx,
-                       unsigned char *out, size_t outlen,
-                       int strength, int prediction_resistance,
-                       const unsigned char *adin, size_t adinlen)
-       {
-       unsigned char tmp[16], *pout;
-       size_t poutlen;
-       /* If test mode don't run continuous RNG test */
-       if (dctx->flags & DRBG_FLAG_TEST)
-               {
-               return fips_drbg_generate_internal(dctx, out, outlen,
-                                                       strength,
-                                                       prediction_resistance,
-                                                       adin, adinlen);
-               }
-       /* If this is the first call generate block and save buffer */
-       if (!dctx->lb_valid)
-               {
-               if (!fips_drbg_generate_internal(dctx, dctx->lb, 16,
-                                               strength, prediction_resistance,
-                                               adin, adinlen))
-                       return 0;
-               dctx->lb_valid = 1;
-               }
-
-       /* If request less that 16 bytes request 16 in temp buffer */
-
-       if (outlen < 16)
-               {
-               pout = tmp;
-               poutlen = 16;
-               }
-       else
-               {
-               pout = out;
-               poutlen = outlen;
-               }
-
-       /* Generate data */
-       if (!fips_drbg_generate_internal(dctx, pout, poutlen,
-                                               strength, prediction_resistance,
-                                               adin, adinlen))
-                       return 0;
-       /* Compare to last block for continuous PRNG test */
-       if (!memcmp(pout, dctx->lb, 16))
-               {
-               FIPSerr(FIPS_F_FIPS_DRBG_GENERATE, FIPS_R_DRBG_STUCK);
-               return 0;
-               }
-       /* Update last block */
-       memcpy(dctx->lb, pout, 16);
-       /* Copy to output buffer if needed */
-       if (outlen < 16)
-               memcpy(out, pout, outlen);
-
-       return 1;
-
-       }
-
 int FIPS_drbg_uninstantiate(DRBG_CTX *dctx)
        {
        int rv;
@@ -461,3 +397,37 @@ int FIPS_drbg_get_strength(DRBG_CTX *dctx)
        {
        return dctx->strength;
        }
+
+static int drbg_stick = 0;
+
+void FIPS_drbg_stick(void)
+       {
+       drbg_stick = 1;
+       }
+
+/* Continuous DRBG utility function */
+int drbg_cprng_test(DRBG_CTX *dctx, const unsigned char *out)
+       {
+       /* No CPRNG in test mode */
+       if (dctx->flags & DRBG_FLAG_TEST)
+               return 1;
+       /* Check block is valid: should never happen */
+       if (dctx->lb_valid == 0)
+               {
+               FIPSerr(FIPS_F_DRBG_CPRNG_TEST, FIPS_R_INTERNAL_ERROR);
+               fips_set_selftest_fail();
+               return 0;
+               }
+       if (drbg_stick)
+               memcpy(dctx->lb, out, dctx->blocklength);
+       /* Check against last block: fail if match */
+       if (!memcmp(dctx->lb, out, dctx->blocklength))
+               {
+               FIPSerr(FIPS_F_DRBG_CPRNG_TEST, FIPS_R_DRBG_STUCK);
+               fips_set_selftest_fail();
+               return 0;
+               }
+       /* Save last block for next comparison */
+       memcpy(dctx->lb, out, dctx->blocklength);
+       return 1;
+       }