Perform health check on all reseed operations not associated with
[openssl.git] / fips / rand / fips_drbg_lib.c
index 9b497b54cc6eab6fb5cb6db0e0213a97b1435bfc..9873742c4535967abebd6947ac80c589d0469a56 100644 (file)
 
 #include <string.h>
 #include <openssl/crypto.h>
-#include <openssl/evp.h>
-#include <openssl/aes.h>
+#include <openssl/err.h>
 #include <openssl/fips_rand.h>
 #include "fips_rand_lcl.h"
 
 /* Support framework for SP800-90 DRBGs */
 
-DRBG_CTX *FIPS_drbg_new(int type, unsigned int flags)
+int FIPS_drbg_init(DRBG_CTX *dctx, int type, unsigned int flags)
        {
        int rv;
-       DRBG_CTX *dctx;
-       dctx = OPENSSL_malloc(sizeof(DRBG_CTX));
        memset(dctx, 0, sizeof(DRBG_CTX));
        dctx->status = DRBG_STATUS_UNINITIALISED;
-       dctx->flags = flags;
+       dctx->xflags = flags;
        dctx->type = type;
+
+       dctx->iflags = 0;
+       dctx->entropy_blocklen = 0;
+       dctx->health_check_cnt = 0;
+       dctx->health_check_interval = DRBG_HEALTH_INTERVAL;
+
        rv = fips_drbg_hash_init(dctx);
+
        if (rv == -2)
                rv = fips_drbg_ctr_init(dctx);
+       if (rv == -2)
+               rv = fips_drbg_hmac_init(dctx);
+       if (rv == -2)
+               rv = fips_drbg_ec_init(dctx);
+
        if (rv <= 0)
                {
-               /* Fatal: cannot initialiase DRBG */
-               goto err;
+               if (rv == -2)
+                       FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_UNSUPPORTED_DRBG_TYPE);
+               else
+                       FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_ERROR_INITIALISING_DRBG);
                }
 
-       return dctx;
+       /* If not in test mode run selftests on DRBG of the same type */
 
-       err:
-       if (dctx)
+       if (!(dctx->xflags & DRBG_FLAG_TEST))
+               {
+               DRBG_CTX tctx;
+               if (!fips_drbg_kat(&tctx, type, flags | DRBG_FLAG_TEST))
+                       {
+                       FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_SELFTEST_FAILURE);
+                       dctx->status = DRBG_STATUS_ERROR;
+                       return 0;
+                       }
+               }
+
+       return rv;
+       }
+
+DRBG_CTX *FIPS_drbg_new(int type, unsigned int flags)
+       {
+       DRBG_CTX *dctx;
+       dctx = OPENSSL_malloc(sizeof(DRBG_CTX));
+       if (!dctx)
+               {
+               FIPSerr(FIPS_F_FIPS_DRBG_NEW, ERR_R_MALLOC_FAILURE);
+               return NULL;
+               }
+
+       if (type == 0)
+               {
+               memset(dctx, 0, sizeof(DRBG_CTX));
+               dctx->type = 0;
+               dctx->status = DRBG_STATUS_UNINITIALISED;
+               return dctx;
+               }
+
+       if (FIPS_drbg_init(dctx, type, flags) <= 0)
+               {
                OPENSSL_free(dctx);
-       return NULL;
+               return NULL;
+               }
+               
+       return dctx;
+       }
+
+void FIPS_drbg_free(DRBG_CTX *dctx)
+       {
+       if (dctx->uninstantiate)
+               dctx->uninstantiate(dctx);
+       OPENSSL_cleanse(&dctx->d, sizeof(dctx->d));
+       OPENSSL_free(dctx);
+       }
+
+static size_t fips_get_entropy(DRBG_CTX *dctx, unsigned char **pout,
+                               int entropy, size_t min_len, size_t max_len)
+       {
+       unsigned char *tout, *p;
+       size_t bl = dctx->entropy_blocklen, rv;
+       if (dctx->xflags & DRBG_FLAG_TEST || !bl)
+               return dctx->get_entropy(dctx, pout, entropy, min_len, max_len);
+       rv = dctx->get_entropy(dctx, &tout, entropy + bl,
+                               min_len + bl, max_len + bl);
+       *pout = tout + bl;
+       if (rv < (min_len + bl) || (rv % bl))
+               return 0;
+       /* Compare consecutive blocks for continuous PRNG test */
+       for (p = tout; p < tout + rv - bl; p += bl)
+               {
+               if (!memcmp(p, p + bl, bl))
+                       {
+                       FIPSerr(FIPS_F_FIPS_GET_ENTROPY, FIPS_R_ENTROPY_SOURCE_STUCK);
+                       return 0;
+                       }
+               }
+       rv -= bl;
+       if (rv > max_len)
+               return max_len;
+       return rv;
        }
 
+static void fips_cleanup_entropy(DRBG_CTX *dctx,
+                                       unsigned char *out, size_t olen)
+       {
+       size_t bl;
+       if (dctx->xflags & DRBG_FLAG_TEST)
+               bl = 0;
+       else
+               bl = dctx->entropy_blocklen;
+       /* Call cleanup with original arguments */
+       dctx->cleanup_entropy(dctx, out - bl, olen + bl);
+       }
+
+
 int FIPS_drbg_instantiate(DRBG_CTX *dctx,
-                               int strength,
                                const unsigned char *pers, size_t perslen)
        {
-       size_t entlen, noncelen;
+       size_t entlen = 0, noncelen = 0;
+       unsigned char *nonce = NULL, *entropy = NULL;
+
+#if 0
+       /* Put here so error script picks them up */
+       FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE,
+                               FIPS_R_PERSONALISATION_STRING_TOO_LONG);
+       FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_IN_ERROR_STATE);
+       FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ALREADY_INSTANTIATED);
+       FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_ENTROPY);
+       FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_NONCE);
+       FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_INSTANTIATE_ERROR);
+#endif
+
+       int r = 0;
 
        if (perslen > dctx->max_pers)
-               return 0;
+               {
+               r = FIPS_R_PERSONALISATION_STRING_TOO_LONG;
+               goto end;
+               }
 
        if (dctx->status != DRBG_STATUS_UNINITIALISED)
                {
-               /* error */
-               return 0;
+               if (dctx->status == DRBG_STATUS_ERROR)
+                       r = FIPS_R_IN_ERROR_STATE;
+               else
+                       r = FIPS_R_ALREADY_INSTANTIATED;
+               goto end;
                }
 
        dctx->status = DRBG_STATUS_ERROR;
 
-       entlen = dctx->get_entropy(dctx, dctx->entropy, dctx->strength,
+       entlen = fips_get_entropy(dctx, &entropy, dctx->strength,
                                dctx->min_entropy, dctx->max_entropy);
 
        if (entlen < dctx->min_entropy || entlen > dctx->max_entropy)
+               {
+               r = FIPS_R_ERROR_RETRIEVING_ENTROPY;
                goto end;
+               }
 
        if (dctx->max_nonce > 0)
                {
-
-               noncelen = dctx->get_nonce(dctx, dctx->nonce,
+               noncelen = dctx->get_nonce(dctx, &nonce,
                                        dctx->strength / 2,
                                        dctx->min_nonce, dctx->max_nonce);
 
                if (noncelen < dctx->min_nonce || noncelen > dctx->max_nonce)
+                       {
+                       r = FIPS_R_ERROR_RETRIEVING_NONCE;
                        goto end;
+                       }
 
                }
-       else
-               noncelen = 0;
 
        if (!dctx->instantiate(dctx, 
-                               dctx->entropy, entlen,
-                               dctx->nonce, noncelen,
+                               entropy, entlen,
+                               nonce, noncelen,
                                pers, perslen))
+               {
+               r = FIPS_R_ERROR_INSTANTIATING_DRBG;
                goto end;
+               }
 
 
        dctx->status = DRBG_STATUS_READY;
-       dctx->reseed_counter = 1;
-       /* Initial test value for reseed interval */
-       dctx->reseed_interval = 1<<24;
+       if (!(dctx->iflags & DRBG_CUSTOM_RESEED))
+               dctx->reseed_counter = 1;
 
        end:
 
-       OPENSSL_cleanse(dctx->entropy, sizeof(dctx->entropy));
-       OPENSSL_cleanse(dctx->nonce, sizeof(dctx->nonce));
+       if (entropy && dctx->cleanup_entropy)
+               fips_cleanup_entropy(dctx, entropy, entlen);
+
+       if (nonce && dctx->cleanup_nonce)
+               dctx->cleanup_nonce(dctx, nonce, noncelen);
 
        if (dctx->status == DRBG_STATUS_READY)
                return 1;
 
+       if (r && !(dctx->iflags & DRBG_FLAG_NOERR))
+               FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, r);
+
        return 0;
 
        }
 
-int FIPS_drbg_reseed(DRBG_CTX *dctx,
-                       const unsigned char *adin, size_t adinlen)
+static int drbg_reseed(DRBG_CTX *dctx,
+                       const unsigned char *adin, size_t adinlen, int hcheck)
        {
+       unsigned char *entropy = NULL;
        size_t entlen;
+       int r = 0;
+
+#if 0
+       FIPSerr(FIPS_F_FIPS_DRBG_RESEED, FIPS_R_NOT_INSTANTIATED);
+       FIPSerr(FIPS_F_FIPS_DRBG_RESEED, FIPS_R_ADDITIONAL_INPUT_TOO_LONG);
+#endif
        if (dctx->status != DRBG_STATUS_READY
                && dctx->status != DRBG_STATUS_RESEED)
                {
-               /* error */
-               return 0;
+               if (dctx->status == DRBG_STATUS_ERROR)
+                       r = FIPS_R_IN_ERROR_STATE;
+               else if(dctx->status == DRBG_STATUS_UNINITIALISED)
+                       r = FIPS_R_NOT_INSTANTIATED;
+               goto end;
                }
 
        if (!adin)
                adinlen = 0;
        else if (adinlen > dctx->max_adin)
                {
-               /* error */
-               return 0;
+               r = FIPS_R_ADDITIONAL_INPUT_TOO_LONG;
+               goto end;
                }
 
        dctx->status = DRBG_STATUS_ERROR;
+       /* Peform health check on all reseed operations if not a prediction
+        * resistance request and not in test mode.
+        */
+       if (hcheck && !(dctx->xflags & DRBG_FLAG_TEST))
+               {
+               if (!FIPS_drbg_test(dctx))
+                       {
+                       r = FIPS_R_SELFTEST_FAILURE;
+                       goto end;
+                       }
+               }
 
-       entlen = dctx->get_entropy(dctx, dctx->entropy, dctx->strength,
+       entlen = fips_get_entropy(dctx, &entropy, dctx->strength,
                                dctx->min_entropy, dctx->max_entropy);
 
        if (entlen < dctx->min_entropy || entlen > dctx->max_entropy)
+               {
+               r = FIPS_R_ERROR_RETRIEVING_ENTROPY;
                goto end;
+               }
 
-       if (!dctx->reseed(dctx, dctx->entropy, entlen, adin, adinlen))
+       if (!dctx->reseed(dctx, entropy, entlen, adin, adinlen))
                goto end;
 
        dctx->status = DRBG_STATUS_READY;
-       dctx->reseed_counter = 1;
+       if (!(dctx->iflags & DRBG_CUSTOM_RESEED))
+               dctx->reseed_counter = 1;
        end:
-       OPENSSL_cleanse(dctx->entropy, sizeof(dctx->entropy));
+
+       if (entropy && dctx->cleanup_entropy)
+               fips_cleanup_entropy(dctx, entropy, entlen);
+
        if (dctx->status == DRBG_STATUS_READY)
                return 1;
+
+       if (r && !(dctx->iflags & DRBG_FLAG_NOERR))
+               FIPSerr(FIPS_F_FIPS_DRBG_RESEED, r);
+
        return 0;
        }
-       
+
+int FIPS_drbg_reseed(DRBG_CTX *dctx,
+                       const unsigned char *adin, size_t adinlen)
+       {
+       return drbg_reseed(dctx, adin, adinlen, 1);
+       }
+
+static int fips_drbg_check(DRBG_CTX *dctx)
+       {
+       if (dctx->xflags & DRBG_FLAG_TEST)
+               return 1;
+       dctx->health_check_cnt++;
+       if (dctx->health_check_cnt >= dctx->health_check_interval)
+               {
+               if (!FIPS_drbg_test(dctx))
+                       {
+                       FIPSerr(FIPS_F_FIPS_DRBG_CHECK, FIPS_R_SELFTEST_FAILURE);
+                       dctx->status = DRBG_STATUS_ERROR;
+                       return 0;
+                       }
+               dctx->health_check_cnt = 0;
+               }
+       return 1;
+       }
 
 int FIPS_drbg_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,
                        int prediction_resistance,
                        const unsigned char *adin, size_t adinlen)
        {
+       int r = 0;
+
+       if (!fips_drbg_check(dctx))
+               return 0;
+
+       if (dctx->status != DRBG_STATUS_READY
+               && dctx->status != DRBG_STATUS_RESEED)
+               {
+               if (dctx->status == DRBG_STATUS_ERROR)
+                       r = FIPS_R_IN_ERROR_STATE;
+               else if(dctx->status == DRBG_STATUS_UNINITIALISED)
+                       r = FIPS_R_NOT_INSTANTIATED;
+               goto end;
+               }
+
        if (outlen > dctx->max_request)
                {
-               /* Too large */
+               r = FIPS_R_REQUEST_TOO_LARGE_FOR_DRBG;
                return 0;
                }
+
+       if (adinlen > dctx->max_adin)
+               {
+               r = FIPS_R_ADDITIONAL_INPUT_TOO_LONG;
+               goto end;
+               }
+
+       if (dctx->iflags & DRBG_CUSTOM_RESEED)
+               dctx->generate(dctx, NULL, outlen, NULL, 0);
+       else if (dctx->reseed_counter >= dctx->reseed_interval)
+               dctx->status = DRBG_STATUS_RESEED;
+
        if (dctx->status == DRBG_STATUS_RESEED || prediction_resistance)
                {
-               if (!FIPS_drbg_reseed(dctx, adin, adinlen))
-                       return 0;
+               /* If prediction resistance request don't do health check */
+               int hcheck = prediction_resistance ? 0 : 1;
+               
+               if (!drbg_reseed(dctx, adin, adinlen, hcheck))
+                       {
+                       r = FIPS_R_RESEED_ERROR;
+                       goto end;
+                       }
                adin = NULL;
                adinlen = 0;
                }
-       if (dctx->status != DRBG_STATUS_READY)
-               {
-               /* Bad error */
-               return 0;
-               }
+
        if (!dctx->generate(dctx, out, outlen, adin, adinlen))
                {
-               /* Bad error */
+               r = FIPS_R_GENERATE_ERROR;
                dctx->status = DRBG_STATUS_ERROR;
+               goto end;
+               }
+       if (!(dctx->iflags & DRBG_CUSTOM_RESEED))
+               {
+               if (dctx->reseed_counter >= dctx->reseed_interval)
+                       dctx->status = DRBG_STATUS_RESEED;
+               else
+                       dctx->reseed_counter++;
+               }
+
+       end:
+       if (r)
+               {
+               if (!(dctx->iflags & DRBG_FLAG_NOERR))
+                       FIPSerr(FIPS_F_FIPS_DRBG_GENERATE, r);
                return 0;
                }
-       if (dctx->reseed_counter > dctx->reseed_interval)
-               dctx->status = DRBG_STATUS_RESEED;
-       else
-               dctx->reseed_counter++;
 
        return 1;
        }
 
+int FIPS_drbg_uninstantiate(DRBG_CTX *dctx)
+       {
+       int rv;
+       if (!dctx->uninstantiate)
+               rv = 1;
+       else
+               rv = dctx->uninstantiate(dctx);
+       /* Although we'd like to cleanse here we can't because we have to
+        * test the uninstantiate really zeroes the data.
+        */
+       memset(&dctx->d, 0, sizeof(dctx->d));
+       dctx->status = DRBG_STATUS_UNINITIALISED;
+       /* If method has problems uninstantiating, return error */
+       return rv;
+       }
 
-int FIPS_drbg_set_test_mode(DRBG_CTX *dctx,
-       size_t (*get_entropy)(DRBG_CTX *ctx, unsigned char *out,
+int FIPS_drbg_set_callbacks(DRBG_CTX *dctx,
+       size_t (*get_entropy)(DRBG_CTX *ctx, unsigned char **pout,
+                               int entropy, size_t min_len, size_t max_len),
+       void (*cleanup_entropy)(DRBG_CTX *ctx, unsigned char *out, size_t olen),
+       size_t entropy_blocklen,
+       size_t (*get_nonce)(DRBG_CTX *ctx, unsigned char **pout,
                                int entropy, size_t min_len, size_t max_len),
-       size_t (*get_nonce)(DRBG_CTX *ctx, unsigned char *out,
-                               int entropy, size_t min_len, size_t max_len))
+       void (*cleanup_nonce)(DRBG_CTX *ctx, unsigned char *out, size_t olen))
        {
        if (dctx->status != DRBG_STATUS_UNINITIALISED)
                return 0;
-       dctx->flags |= DRBG_FLAG_TEST;
+       dctx->entropy_blocklen = entropy_blocklen;
        dctx->get_entropy = get_entropy;
+       dctx->cleanup_entropy = cleanup_entropy;
        dctx->get_nonce = get_nonce;
+       dctx->cleanup_nonce = cleanup_nonce;
+       return 1;
+       }
+
+int FIPS_drbg_set_rand_callbacks(DRBG_CTX *dctx,
+       size_t (*get_adin)(DRBG_CTX *ctx, unsigned char **pout),
+       void (*cleanup_adin)(DRBG_CTX *ctx, unsigned char *out, size_t olen),
+       int (*rand_seed_cb)(DRBG_CTX *ctx, const void *buf, int num),
+       int (*rand_add_cb)(DRBG_CTX *ctx,
+                               const void *buf, int num, double entropy))
+       {
+       if (dctx->status != DRBG_STATUS_UNINITIALISED)
+               return 0;
+       dctx->get_adin = get_adin;
+       dctx->cleanup_adin = cleanup_adin;
+       dctx->rand_seed_cb = rand_seed_cb;
+       dctx->rand_add_cb = rand_add_cb;
        return 1;
        }
 
@@ -253,3 +508,52 @@ size_t FIPS_drbg_get_blocklength(DRBG_CTX *dctx)
        {
        return dctx->blocklength;
        }
+
+int FIPS_drbg_get_strength(DRBG_CTX *dctx)
+       {
+       return dctx->strength;
+       }
+
+void FIPS_drbg_set_check_interval(DRBG_CTX *dctx, int interval)
+       {
+       dctx->health_check_interval = interval;
+       }
+
+void FIPS_drbg_set_reseed_interval(DRBG_CTX *dctx, int interval)
+       {
+       dctx->reseed_interval = interval;
+       }
+
+static int drbg_stick = 0;
+
+void FIPS_drbg_stick(void)
+       {
+       drbg_stick = 1;
+       }
+
+/* Continuous DRBG utility function */
+int fips_drbg_cprng_test(DRBG_CTX *dctx, const unsigned char *out)
+       {
+       /* No CPRNG in test mode */
+       if (dctx->xflags & DRBG_FLAG_TEST)
+               return 1;
+       /* Check block is valid: should never happen */
+       if (dctx->lb_valid == 0)
+               {
+               FIPSerr(FIPS_F_FIPS_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_FIPS_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;
+       }