crypto: drbg - reseed often if seedsource is degraded

[firefly-linux-kernel-4.4.55.git] / crypto / drbg.c

diff --git a/crypto/drbg.c b/crypto/drbg.c
index c6cbf1336d73857f83ca9b1079d859067ca824e2..5fad297424fcff08d4b56910a6de09c4641ee420 100644 (file)
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1088,6 +1088,9 @@ static void drbg_async_seed(struct work_struct *work)
 
        __drbg_seed(drbg, &seedlist, true);
 
+       if (drbg->seeded)
+               drbg->reseed_threshold = drbg_max_requests(drbg);
+
        mutex_unlock(&drbg->drbg_mutex);
 
        memzero_explicit(entropy, entropylen);
@@ -1334,7 +1337,7 @@ static int drbg_generate(struct drbg_state *drbg,
         * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
         * here. The spec is a bit convoluted here, we make it simpler.
         */
-       if ((drbg_max_requests(drbg)) < drbg->reseed_ctr)
+       if (drbg->reseed_threshold < drbg->reseed_ctr)
                drbg->seeded = false;
 
        if (drbg->pr || !drbg->seeded) {
@@ -1478,6 +1481,12 @@ static int drbg_prepare_hrng(struct drbg_state *drbg)
 
        drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
 
+       /*
+        * Require frequent reseeds until the seed source is fully
+        * initialized.
+        */
+       drbg->reseed_threshold = 50;
+
        return err;
 }
 
@@ -1522,6 +1531,7 @@ static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
                drbg->core = &drbg_cores[coreref];
                drbg->pr = pr;
                drbg->seeded = false;
+               drbg->reseed_threshold = drbg_max_requests(drbg);
 
                ret = drbg_alloc_state(drbg);
                if (ret)