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-rw-r--r--crypto/rand/drbg_lib.c225
1 files changed, 157 insertions, 68 deletions
diff --git a/crypto/rand/drbg_lib.c b/crypto/rand/drbg_lib.c
index 729b49c94372..a13282181d6d 100644
--- a/crypto/rand/drbg_lib.c
+++ b/crypto/rand/drbg_lib.c
@@ -82,6 +82,10 @@ static unsigned int slave_reseed_interval = SLAVE_RESEED_INTERVAL;
static time_t master_reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
static time_t slave_reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL;
+/* A logical OR of all used DRBG flag bits (currently there is only one) */
+static const unsigned int rand_drbg_used_flags =
+ RAND_DRBG_FLAG_CTR_NO_DF;
+
static RAND_DRBG *drbg_setup(RAND_DRBG *parent);
static RAND_DRBG *rand_drbg_new(int secure,
@@ -105,16 +109,27 @@ int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags)
flags = rand_drbg_flags;
}
+ /* If set is called multiple times - clear the old one */
+ if (drbg->type != 0 && (type != drbg->type || flags != drbg->flags)) {
+ drbg->meth->uninstantiate(drbg);
+ rand_pool_free(drbg->adin_pool);
+ drbg->adin_pool = NULL;
+ }
+
drbg->state = DRBG_UNINITIALISED;
drbg->flags = flags;
drbg->type = type;
switch (type) {
default:
+ drbg->type = 0;
+ drbg->flags = 0;
+ drbg->meth = NULL;
RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
return 0;
case 0:
/* Uninitialized; that's okay. */
+ drbg->meth = NULL;
return 1;
case NID_aes_128_ctr:
case NID_aes_192_ctr:
@@ -123,8 +138,10 @@ int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags)
break;
}
- if (ret == 0)
+ if (ret == 0) {
+ drbg->state = DRBG_ERROR;
RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
+ }
return ret;
}
@@ -147,7 +164,7 @@ int RAND_DRBG_set_defaults(int type, unsigned int flags)
break;
}
- if ((flags & ~RAND_DRBG_USED_FLAGS) != 0) {
+ if ((flags & ~rand_drbg_used_flags) != 0) {
RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS);
return 0;
}
@@ -224,11 +241,8 @@ static RAND_DRBG *rand_drbg_new(int secure,
return drbg;
-err:
- if (drbg->secure)
- OPENSSL_secure_free(drbg);
- else
- OPENSSL_free(drbg);
+ err:
+ RAND_DRBG_free(drbg);
return NULL;
}
@@ -253,6 +267,7 @@ void RAND_DRBG_free(RAND_DRBG *drbg)
if (drbg->meth != NULL)
drbg->meth->uninstantiate(drbg);
+ rand_pool_free(drbg->adin_pool);
CRYPTO_THREAD_lock_free(drbg->lock);
CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
@@ -312,11 +327,18 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg,
max_entropylen += drbg->max_noncelen;
}
+ drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
+ if (drbg->reseed_next_counter) {
+ drbg->reseed_next_counter++;
+ if(!drbg->reseed_next_counter)
+ drbg->reseed_next_counter = 1;
+ }
+
if (drbg->get_entropy != NULL)
entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
min_entropylen, max_entropylen, 0);
if (entropylen < min_entropylen
- || entropylen > max_entropylen) {
+ || entropylen > max_entropylen) {
RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
goto end;
}
@@ -337,29 +359,15 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg,
}
drbg->state = DRBG_READY;
- drbg->generate_counter = 0;
+ drbg->reseed_gen_counter = 1;
drbg->reseed_time = time(NULL);
- if (drbg->reseed_counter > 0) {
- if (drbg->parent == NULL)
- drbg->reseed_counter++;
- else
- drbg->reseed_counter = drbg->parent->reseed_counter;
- }
+ tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
-end:
+ end:
if (entropy != NULL && drbg->cleanup_entropy != NULL)
drbg->cleanup_entropy(drbg, entropy, entropylen);
- if (nonce != NULL && drbg->cleanup_nonce!= NULL )
+ if (nonce != NULL && drbg->cleanup_nonce != NULL)
drbg->cleanup_nonce(drbg, nonce, noncelen);
- if (drbg->pool != NULL) {
- if (drbg->state == DRBG_READY) {
- RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
- RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED);
- drbg->state = DRBG_ERROR;
- }
- rand_pool_free(drbg->pool);
- drbg->pool = NULL;
- }
if (drbg->state == DRBG_READY)
return 1;
return 0;
@@ -375,6 +383,7 @@ end:
int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
{
if (drbg->meth == NULL) {
+ drbg->state = DRBG_ERROR;
RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
return 0;
@@ -419,13 +428,21 @@ int RAND_DRBG_reseed(RAND_DRBG *drbg,
}
drbg->state = DRBG_ERROR;
+
+ drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
+ if (drbg->reseed_next_counter) {
+ drbg->reseed_next_counter++;
+ if(!drbg->reseed_next_counter)
+ drbg->reseed_next_counter = 1;
+ }
+
if (drbg->get_entropy != NULL)
entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
drbg->min_entropylen,
drbg->max_entropylen,
prediction_resistance);
if (entropylen < drbg->min_entropylen
- || entropylen > drbg->max_entropylen) {
+ || entropylen > drbg->max_entropylen) {
RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
goto end;
}
@@ -434,16 +451,11 @@ int RAND_DRBG_reseed(RAND_DRBG *drbg,
goto end;
drbg->state = DRBG_READY;
- drbg->generate_counter = 0;
+ drbg->reseed_gen_counter = 1;
drbg->reseed_time = time(NULL);
- if (drbg->reseed_counter > 0) {
- if (drbg->parent == NULL)
- drbg->reseed_counter++;
- else
- drbg->reseed_counter = drbg->parent->reseed_counter;
- }
+ tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
-end:
+ end:
if (entropy != NULL && drbg->cleanup_entropy != NULL)
drbg->cleanup_entropy(drbg, entropy, entropylen);
if (drbg->state == DRBG_READY)
@@ -475,10 +487,12 @@ int rand_drbg_restart(RAND_DRBG *drbg,
const unsigned char *adin = NULL;
size_t adinlen = 0;
- if (drbg->pool != NULL) {
+ if (drbg->seed_pool != NULL) {
RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
- rand_pool_free(drbg->pool);
- drbg->pool = NULL;
+ drbg->state = DRBG_ERROR;
+ rand_pool_free(drbg->seed_pool);
+ drbg->seed_pool = NULL;
+ return 0;
}
if (buffer != NULL) {
@@ -486,24 +500,25 @@ int rand_drbg_restart(RAND_DRBG *drbg,
if (drbg->max_entropylen < len) {
RANDerr(RAND_F_RAND_DRBG_RESTART,
RAND_R_ENTROPY_INPUT_TOO_LONG);
+ drbg->state = DRBG_ERROR;
return 0;
}
if (entropy > 8 * len) {
RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
+ drbg->state = DRBG_ERROR;
return 0;
}
/* will be picked up by the rand_drbg_get_entropy() callback */
- drbg->pool = rand_pool_new(entropy, len, len);
- if (drbg->pool == NULL)
+ drbg->seed_pool = rand_pool_attach(buffer, len, entropy);
+ if (drbg->seed_pool == NULL)
return 0;
-
- rand_pool_add(drbg->pool, buffer, len, entropy);
} else {
if (drbg->max_adinlen < len) {
RANDerr(RAND_F_RAND_DRBG_RESTART,
RAND_R_ADDITIONAL_INPUT_TOO_LONG);
+ drbg->state = DRBG_ERROR;
return 0;
}
adin = buffer;
@@ -543,14 +558,8 @@ int rand_drbg_restart(RAND_DRBG *drbg,
}
}
- /* check whether a given entropy pool was cleared properly during reseed */
- if (drbg->pool != NULL) {
- drbg->state = DRBG_ERROR;
- RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
- rand_pool_free(drbg->pool);
- drbg->pool = NULL;
- return 0;
- }
+ rand_pool_free(drbg->seed_pool);
+ drbg->seed_pool = NULL;
return drbg->state == DRBG_READY;
}
@@ -600,7 +609,7 @@ int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
}
if (drbg->reseed_interval > 0) {
- if (drbg->generate_counter >= drbg->reseed_interval)
+ if (drbg->reseed_gen_counter >= drbg->reseed_interval)
reseed_required = 1;
}
if (drbg->reseed_time_interval > 0) {
@@ -609,8 +618,11 @@ int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
|| now - drbg->reseed_time >= drbg->reseed_time_interval)
reseed_required = 1;
}
- if (drbg->reseed_counter > 0 && drbg->parent != NULL) {
- if (drbg->reseed_counter != drbg->parent->reseed_counter)
+ if (drbg->parent != NULL) {
+ unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
+ if (reseed_counter > 0
+ && tsan_load(&drbg->parent->reseed_prop_counter)
+ != reseed_counter)
reseed_required = 1;
}
@@ -629,7 +641,7 @@ int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
return 0;
}
- drbg->generate_counter++;
+ drbg->reseed_gen_counter++;
return 1;
}
@@ -647,9 +659,18 @@ int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
unsigned char *additional = NULL;
size_t additional_len;
size_t chunk;
- size_t ret;
+ size_t ret = 0;
+
+ if (drbg->adin_pool == NULL) {
+ if (drbg->type == 0)
+ goto err;
+ drbg->adin_pool = rand_pool_new(0, 0, drbg->max_adinlen);
+ if (drbg->adin_pool == NULL)
+ goto err;
+ }
- additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen);
+ additional_len = rand_drbg_get_additional_data(drbg->adin_pool,
+ &additional);
for ( ; outlen > 0; outlen -= chunk, out += chunk) {
chunk = outlen;
@@ -661,9 +682,9 @@ int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
}
ret = 1;
-err:
- if (additional_len != 0)
- OPENSSL_secure_clear_free(additional, additional_len);
+ err:
+ if (additional != NULL)
+ rand_drbg_cleanup_additional_data(drbg->adin_pool, additional);
return ret;
}
@@ -682,7 +703,8 @@ int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
RAND_DRBG_get_nonce_fn get_nonce,
RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
{
- if (drbg->state != DRBG_UNINITIALISED)
+ if (drbg->state != DRBG_UNINITIALISED
+ || drbg->parent != NULL)
return 0;
drbg->get_entropy = get_entropy;
drbg->cleanup_entropy = cleanup_entropy;
@@ -859,7 +881,7 @@ static RAND_DRBG *drbg_setup(RAND_DRBG *parent)
goto err;
/* enable seed propagation */
- drbg->reseed_counter = 1;
+ tsan_store(&drbg->reseed_prop_counter, 1);
/*
* Ignore instantiation error to support just-in-time instantiation.
@@ -948,11 +970,49 @@ static int drbg_bytes(unsigned char *out, int count)
return ret;
}
+/*
+ * Calculates the minimum length of a full entropy buffer
+ * which is necessary to seed (i.e. instantiate) the DRBG
+ * successfully.
+ */
+size_t rand_drbg_seedlen(RAND_DRBG *drbg)
+{
+ /*
+ * If no os entropy source is available then RAND_seed(buffer, bufsize)
+ * is expected to succeed if and only if the buffer length satisfies
+ * the following requirements, which follow from the calculations
+ * in RAND_DRBG_instantiate().
+ */
+ size_t min_entropy = drbg->strength;
+ size_t min_entropylen = drbg->min_entropylen;
+
+ /*
+ * Extra entropy for the random nonce in the absence of a
+ * get_nonce callback, see comment in RAND_DRBG_instantiate().
+ */
+ if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
+ min_entropy += drbg->strength / 2;
+ min_entropylen += drbg->min_noncelen;
+ }
+
+ /*
+ * Convert entropy requirement from bits to bytes
+ * (dividing by 8 without rounding upwards, because
+ * all entropy requirements are divisible by 8).
+ */
+ min_entropy >>= 3;
+
+ /* Return a value that satisfies both requirements */
+ return min_entropy > min_entropylen ? min_entropy : min_entropylen;
+}
+
/* Implements the default OpenSSL RAND_add() method */
static int drbg_add(const void *buf, int num, double randomness)
{
int ret = 0;
RAND_DRBG *drbg = RAND_DRBG_get0_master();
+ size_t buflen;
+ size_t seedlen;
if (drbg == NULL)
return 0;
@@ -960,20 +1020,49 @@ static int drbg_add(const void *buf, int num, double randomness)
if (num < 0 || randomness < 0.0)
return 0;
- if (randomness > (double)drbg->max_entropylen) {
+ rand_drbg_lock(drbg);
+ seedlen = rand_drbg_seedlen(drbg);
+
+ buflen = (size_t)num;
+
+ if (buflen < seedlen || randomness < (double) seedlen) {
+#if defined(OPENSSL_RAND_SEED_NONE)
+ /*
+ * If no os entropy source is available, a reseeding will fail
+ * inevitably. So we use a trick to mix the buffer contents into
+ * the DRBG state without forcing a reseeding: we generate a
+ * dummy random byte, using the buffer content as additional data.
+ * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF.
+ */
+ unsigned char dummy[1];
+
+ ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
+ rand_drbg_unlock(drbg);
+ return ret;
+#else
+ /*
+ * If an os entropy source is avaible then we declare the buffer content
+ * as additional data by setting randomness to zero and trigger a regular
+ * reseeding.
+ */
+ randomness = 0.0;
+#endif
+ }
+
+
+ if (randomness > (double)seedlen) {
/*
* The purpose of this check is to bound |randomness| by a
* relatively small value in order to prevent an integer
* overflow when multiplying by 8 in the rand_drbg_restart()
- * call below.
+ * call below. Note that randomness is measured in bytes,
+ * not bits, so this value corresponds to eight times the
+ * security strength.
*/
- return 0;
+ randomness = (double)seedlen;
}
- rand_drbg_lock(drbg);
- ret = rand_drbg_restart(drbg, buf,
- (size_t)(unsigned int)num,
- (size_t)(8*randomness));
+ ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
rand_drbg_unlock(drbg);
return ret;