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-rw-r--r--crypto/rand/rand_lib.c136
1 files changed, 98 insertions, 38 deletions
diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c
index e9bc9522101c..d8639c4a03f3 100644
--- a/crypto/rand/rand_lib.c
+++ b/crypto/rand/rand_lib.c
@@ -31,7 +31,7 @@ int rand_fork_count;
static CRYPTO_RWLOCK *rand_nonce_lock;
static int rand_nonce_count;
-static int rand_cleaning_up = 0;
+static int rand_inited = 0;
#ifdef OPENSSL_RAND_SEED_RDTSC
/*
@@ -146,17 +146,13 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
return 0;
}
- pool = rand_pool_new(entropy, min_len, max_len);
- if (pool == NULL)
- return 0;
-
- if (drbg->pool) {
- rand_pool_add(pool,
- rand_pool_buffer(drbg->pool),
- rand_pool_length(drbg->pool),
- rand_pool_entropy(drbg->pool));
- rand_pool_free(drbg->pool);
- drbg->pool = NULL;
+ if (drbg->seed_pool != NULL) {
+ pool = drbg->seed_pool;
+ pool->entropy_requested = entropy;
+ } else {
+ pool = rand_pool_new(entropy, min_len, max_len);
+ if (pool == NULL)
+ return 0;
}
if (drbg->parent) {
@@ -178,6 +174,8 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
prediction_resistance,
NULL, 0) != 0)
bytes = bytes_needed;
+ drbg->reseed_next_counter
+ = tsan_load(&drbg->parent->reseed_prop_counter);
rand_drbg_unlock(drbg->parent);
rand_pool_add_end(pool, bytes, 8 * bytes);
@@ -206,7 +204,8 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
}
err:
- rand_pool_free(pool);
+ if (drbg->seed_pool == NULL)
+ rand_pool_free(pool);
return ret;
}
@@ -217,7 +216,8 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
unsigned char *out, size_t outlen)
{
- OPENSSL_secure_clear_free(out, outlen);
+ if (drbg->seed_pool == NULL)
+ OPENSSL_secure_clear_free(out, outlen);
}
@@ -279,14 +279,9 @@ void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
* On success it allocates a buffer at |*pout| and returns the length of
* the data. The buffer should get freed using OPENSSL_secure_clear_free().
*/
-size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len)
+size_t rand_drbg_get_additional_data(RAND_POOL *pool, unsigned char **pout)
{
size_t ret = 0;
- RAND_POOL *pool;
-
- pool = rand_pool_new(0, 0, max_len);
- if (pool == NULL)
- return 0;
if (rand_pool_add_additional_data(pool) == 0)
goto err;
@@ -295,14 +290,12 @@ size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len)
*pout = rand_pool_detach(pool);
err:
- rand_pool_free(pool);
-
return ret;
}
-void rand_drbg_cleanup_additional_data(unsigned char *out, size_t outlen)
+void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out)
{
- OPENSSL_secure_clear_free(out, outlen);
+ rand_pool_reattach(pool, out);
}
void rand_fork(void)
@@ -326,13 +319,15 @@ DEFINE_RUN_ONCE_STATIC(do_rand_init)
if (rand_nonce_lock == NULL)
goto err2;
- if (!rand_cleaning_up && !rand_pool_init())
+ if (!rand_pool_init())
goto err3;
+ rand_inited = 1;
return 1;
err3:
- rand_pool_cleanup();
+ CRYPTO_THREAD_lock_free(rand_nonce_lock);
+ rand_nonce_lock = NULL;
err2:
CRYPTO_THREAD_lock_free(rand_meth_lock);
rand_meth_lock = NULL;
@@ -348,7 +343,8 @@ void rand_cleanup_int(void)
{
const RAND_METHOD *meth = default_RAND_meth;
- rand_cleaning_up = 1;
+ if (!rand_inited)
+ return;
if (meth != NULL && meth->cleanup != NULL)
meth->cleanup();
@@ -362,6 +358,7 @@ void rand_cleanup_int(void)
rand_meth_lock = NULL;
CRYPTO_THREAD_lock_free(rand_nonce_lock);
rand_nonce_lock = NULL;
+ rand_inited = 0;
}
/*
@@ -370,7 +367,8 @@ void rand_cleanup_int(void)
*/
void RAND_keep_random_devices_open(int keep)
{
- rand_pool_keep_random_devices_open(keep);
+ if (RUN_ONCE(&rand_init, do_rand_init))
+ rand_pool_keep_random_devices_open(keep);
}
/*
@@ -405,7 +403,7 @@ int RAND_poll(void)
/* fill random pool and seed the current legacy RNG */
pool = rand_pool_new(RAND_DRBG_STRENGTH,
RAND_DRBG_STRENGTH / 8,
- DRBG_MINMAX_FACTOR * (RAND_DRBG_STRENGTH / 8));
+ RAND_POOL_MAX_LENGTH);
if (pool == NULL)
return 0;
@@ -430,17 +428,18 @@ err:
* Allocate memory and initialize a new random pool
*/
-RAND_POOL *rand_pool_new(int entropy, size_t min_len, size_t max_len)
+RAND_POOL *rand_pool_new(int entropy_requested, size_t min_len, size_t max_len)
{
RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
if (pool == NULL) {
RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
- goto err;
+ return NULL;
}
pool->min_len = min_len;
- pool->max_len = max_len;
+ pool->max_len = (max_len > RAND_POOL_MAX_LENGTH) ?
+ RAND_POOL_MAX_LENGTH : max_len;
pool->buffer = OPENSSL_secure_zalloc(pool->max_len);
if (pool->buffer == NULL) {
@@ -448,7 +447,7 @@ RAND_POOL *rand_pool_new(int entropy, size_t min_len, size_t max_len)
goto err;
}
- pool->requested_entropy = entropy;
+ pool->entropy_requested = entropy_requested;
return pool;
@@ -458,6 +457,38 @@ err:
}
/*
+ * Attach new random pool to the given buffer
+ *
+ * This function is intended to be used only for feeding random data
+ * provided by RAND_add() and RAND_seed() into the <master> DRBG.
+ */
+RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
+ size_t entropy)
+{
+ RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
+
+ if (pool == NULL) {
+ RANDerr(RAND_F_RAND_POOL_ATTACH, ERR_R_MALLOC_FAILURE);
+ return NULL;
+ }
+
+ /*
+ * The const needs to be cast away, but attached buffers will not be
+ * modified (in contrary to allocated buffers which are zeroed and
+ * freed in the end).
+ */
+ pool->buffer = (unsigned char *) buffer;
+ pool->len = len;
+
+ pool->attached = 1;
+
+ pool->min_len = pool->max_len = pool->len;
+ pool->entropy = entropy;
+
+ return pool;
+}
+
+/*
* Free |pool|, securely erasing its buffer.
*/
void rand_pool_free(RAND_POOL *pool)
@@ -465,7 +496,14 @@ void rand_pool_free(RAND_POOL *pool)
if (pool == NULL)
return;
- OPENSSL_secure_clear_free(pool->buffer, pool->max_len);
+ /*
+ * Although it would be advisable from a cryptographical viewpoint,
+ * we are not allowed to clear attached buffers, since they are passed
+ * to rand_pool_attach() as `const unsigned char*`.
+ * (see corresponding comment in rand_pool_attach()).
+ */
+ if (!pool->attached)
+ OPENSSL_secure_clear_free(pool->buffer, pool->max_len);
OPENSSL_free(pool);
}
@@ -496,15 +534,27 @@ size_t rand_pool_length(RAND_POOL *pool)
/*
* Detach the |pool| buffer and return it to the caller.
* It's the responsibility of the caller to free the buffer
- * using OPENSSL_secure_clear_free().
+ * using OPENSSL_secure_clear_free() or to re-attach it
+ * again to the pool using rand_pool_reattach().
*/
unsigned char *rand_pool_detach(RAND_POOL *pool)
{
unsigned char *ret = pool->buffer;
pool->buffer = NULL;
+ pool->entropy = 0;
return ret;
}
+/*
+ * Re-attach the |pool| buffer. It is only allowed to pass
+ * the |buffer| which was previously detached from the same pool.
+ */
+void rand_pool_reattach(RAND_POOL *pool, unsigned char *buffer)
+{
+ pool->buffer = buffer;
+ OPENSSL_cleanse(pool->buffer, pool->len);
+ pool->len = 0;
+}
/*
* If |entropy_factor| bits contain 1 bit of entropy, how many bytes does one
@@ -524,7 +574,7 @@ unsigned char *rand_pool_detach(RAND_POOL *pool)
*/
size_t rand_pool_entropy_available(RAND_POOL *pool)
{
- if (pool->entropy < pool->requested_entropy)
+ if (pool->entropy < pool->entropy_requested)
return 0;
if (pool->len < pool->min_len)
@@ -540,8 +590,8 @@ size_t rand_pool_entropy_available(RAND_POOL *pool)
size_t rand_pool_entropy_needed(RAND_POOL *pool)
{
- if (pool->entropy < pool->requested_entropy)
- return pool->requested_entropy - pool->entropy;
+ if (pool->entropy < pool->entropy_requested)
+ return pool->entropy_requested - pool->entropy;
return 0;
}
@@ -601,6 +651,11 @@ int rand_pool_add(RAND_POOL *pool,
return 0;
}
+ if (pool->buffer == NULL) {
+ RANDerr(RAND_F_RAND_POOL_ADD, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
if (len > 0) {
memcpy(pool->buffer + pool->len, buffer, len);
pool->len += len;
@@ -632,6 +687,11 @@ unsigned char *rand_pool_add_begin(RAND_POOL *pool, size_t len)
return NULL;
}
+ if (pool->buffer == NULL) {
+ RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
return pool->buffer + pool->len;
}