Add continuous RNG test to entropy source. Entropy callbacks now need

[openssl.git] / fips / rand / fips_drbg_lib.c

diff --git a/fips/rand/fips_drbg_lib.c b/fips/rand/fips_drbg_lib.c
index 6d983aaf4bdede5653a19ec2840f3d483a2eebe4..46e42e2947d521211925f70d0bfd51329ae7c3f6 100644 (file)
--- a/fips/rand/fips_drbg_lib.c
+++ b/fips/rand/fips_drbg_lib.c
@@ -71,6 +71,7 @@ int FIPS_drbg_init(DRBG_CTX *dctx, int type, unsigned int flags)
        dctx->flags = flags;
        dctx->type = type;
 
+       dctx->entropy_blocklen = 0;
        dctx->health_check_cnt = 0;
        dctx->health_check_interval = DRBG_HEALTH_INTERVAL;
 
@@ -131,6 +132,43 @@ void FIPS_drbg_free(DRBG_CTX *dctx)
        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->flags & 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; p += bl)
+               {
+               if (!memcmp(p, p + bl, bl))
+                       {
+                       FIPSerr(FIPS_F_FIPS_GET_ENTROPY, FIPS_R_ENTROPY_SOURCE_STUCK);
+                       return 0;
+                       }
+               }
+       return rv - bl;
+       }
+
+static void fips_cleanup_entropy(DRBG_CTX *dctx,
+                                       unsigned char *out, size_t olen)
+       {
+       size_t bl;
+       if (dctx->flags & 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,
                                const unsigned char *pers, size_t perslen)
        {
@@ -167,7 +205,7 @@ int FIPS_drbg_instantiate(DRBG_CTX *dctx,
 
        dctx->status = DRBG_STATUS_ERROR;
 
-       entlen = dctx->get_entropy(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)
@@ -206,7 +244,7 @@ int FIPS_drbg_instantiate(DRBG_CTX *dctx,
        end:
 
        if (entropy && dctx->cleanup_entropy)
-               dctx->cleanup_entropy(dctx, entropy, entlen);
+               fips_cleanup_entropy(dctx, entropy, entlen);
 
        if (nonce && dctx->cleanup_nonce)
                dctx->cleanup_nonce(dctx, nonce, noncelen);
@@ -252,7 +290,7 @@ int FIPS_drbg_reseed(DRBG_CTX *dctx,
 
        dctx->status = DRBG_STATUS_ERROR;
 
-       entlen = dctx->get_entropy(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)
@@ -269,7 +307,7 @@ int FIPS_drbg_reseed(DRBG_CTX *dctx,
        end:
 
        if (entropy && dctx->cleanup_entropy)
-               dctx->cleanup_entropy(dctx, entropy, entlen);
+               fips_cleanup_entropy(dctx, entropy, entlen);
 
        if (dctx->status == DRBG_STATUS_READY)
                return 1;
@@ -383,12 +421,14 @@ 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),
        void (*cleanup_nonce)(DRBG_CTX *ctx, unsigned char *out, size_t olen))
        {
        if (dctx->status != DRBG_STATUS_UNINITIALISED)
                return 0;
+       dctx->entropy_blocklen = entropy_blocklen;
        dctx->get_entropy = get_entropy;
        dctx->cleanup_entropy = cleanup_entropy;
        dctx->get_nonce = get_nonce;