static int rand_status(void)
{
CRYPTO_THREAD_ID cur;
int ret;
int do_not_lock;
if (!RUN_ONCE(&rand_lock_init, do_rand_lock_init))
return 0;
cur = CRYPTO_THREAD_get_current_id();
/*
* check if we already have the lock (could happen if a RAND_poll()
* implementation calls RAND_status())
*/
if (crypto_lock_rand) {
CRYPTO_THREAD_read_lock(rand_tmp_lock);
do_not_lock = CRYPTO_THREAD_compare_id(locking_threadid, cur);
CRYPTO_THREAD_unlock(rand_tmp_lock);
} else
do_not_lock = 0;
if (!do_not_lock) {
CRYPTO_THREAD_write_lock(rand_lock);
/*
* Prevent deadlocks in case we end up in an async engine
*/
ASYNC_block_pause();
/*
* prevent rand_bytes() from trying to obtain the lock again
*/
CRYPTO_THREAD_write_lock(rand_tmp_lock);
locking_threadid = cur;
CRYPTO_THREAD_unlock(rand_tmp_lock);
crypto_lock_rand = 1;
}
if (!initialized) {
RAND_poll();
initialized = 1;
}
ret = entropy >= ENTROPY_NEEDED;
if (!do_not_lock) {
/* before unlocking, we must clear 'crypto_lock_rand' */
crypto_lock_rand = 0;
ASYNC_unblock_pause();
CRYPTO_THREAD_unlock(rand_lock);
}
return ret;
}
int BN_BLINDING_is_current_thread(BN_BLINDING *b)
{
return CRYPTO_THREAD_compare_id(CRYPTO_THREAD_get_current_id(), b->tid);
}
static int rand_add(const void *buf, int num, double add)
{
int i, j, k, st_idx;
long md_c[2];
unsigned char local_md[MD_DIGEST_LENGTH];
EVP_MD_CTX *m;
int do_not_lock;
int rv = 0;
if (!num)
return 1;
/*
* (Based on the rand(3) manpage)
*
* The input is chopped up into units of 20 bytes (or less for
* the last block). Each of these blocks is run through the hash
* function as follows: The data passed to the hash function
* is the current 'md', the same number of bytes from the 'state'
* (the location determined by in incremented looping index) as
* the current 'block', the new key data 'block', and 'count'
* (which is incremented after each use).
* The result of this is kept in 'md' and also xored into the
* 'state' at the same locations that were used as input into the
* hash function.
*/
m = EVP_MD_CTX_new();
if (m == NULL)
goto err;
if (!RUN_ONCE(&rand_lock_init, do_rand_lock_init))
goto err;
/* check if we already have the lock */
if (crypto_lock_rand) {
CRYPTO_THREAD_ID cur = CRYPTO_THREAD_get_current_id();
CRYPTO_THREAD_read_lock(rand_tmp_lock);
do_not_lock = CRYPTO_THREAD_compare_id(locking_threadid, cur);
CRYPTO_THREAD_unlock(rand_tmp_lock);
} else
do_not_lock = 0;
if (!do_not_lock)
CRYPTO_THREAD_write_lock(rand_lock);
st_idx = state_index;
/*
* use our own copies of the counters so that even if a concurrent thread
* seeds with exactly the same data and uses the same subarray there's
* _some_ difference
*/
md_c[0] = md_count[0];
md_c[1] = md_count[1];
memcpy(local_md, md, sizeof md);
/* state_index <= state_num <= STATE_SIZE */
state_index += num;
if (state_index >= STATE_SIZE) {
state_index %= STATE_SIZE;
state_num = STATE_SIZE;
} else if (state_num < STATE_SIZE) {
if (state_index > state_num)
state_num = state_index;
}
/* state_index <= state_num <= STATE_SIZE */
/*
* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE] are what we
* will use now, but other threads may use them as well
*/
md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
if (!do_not_lock)
CRYPTO_THREAD_unlock(rand_lock);
for (i = 0; i < num; i += MD_DIGEST_LENGTH) {
j = (num - i);
j = (j > MD_DIGEST_LENGTH) ? MD_DIGEST_LENGTH : j;
if (!MD_Init(m))
goto err;
if (!MD_Update(m, local_md, MD_DIGEST_LENGTH))
goto err;
k = (st_idx + j) - STATE_SIZE;
if (k > 0) {
if (!MD_Update(m, &(state[st_idx]), j - k))
goto err;
if (!MD_Update(m, &(state[0]), k))
goto err;
} else if (!MD_Update(m, &(state[st_idx]), j))
goto err;
/* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
if (!MD_Update(m, buf, j))
goto err;
/*
* We know that line may cause programs such as purify and valgrind
* to complain about use of uninitialized data. The problem is not,
* it's with the caller. Removing that line will make sure you get
* really bad randomness and thereby other problems such as very
* insecure keys.
*/
if (!MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c)))
goto err;
if (!MD_Final(m, local_md))
goto err;
md_c[1]++;
buf = (const char *)buf + j;
for (k = 0; k < j; k++) {
/*
* Parallel threads may interfere with this, but always each byte
* of the new state is the XOR of some previous value of its and
* local_md (intermediate values may be lost). Alway using locking
* could hurt performance more than necessary given that
* conflicts occur only when the total seeding is longer than the
* random state.
*/
state[st_idx++] ^= local_md[k];
if (st_idx >= STATE_SIZE)
st_idx = 0;
}
}
if (!do_not_lock)
CRYPTO_THREAD_write_lock(rand_lock);
/*
* Don't just copy back local_md into md -- this could mean that other
* thread's seeding remains without effect (except for the incremented
* counter). By XORing it we keep at least as much entropy as fits into
* md.
*/
for (k = 0; k < (int)sizeof(md); k++) {
md[k] ^= local_md[k];
}
if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
entropy += add;
if (!do_not_lock)
CRYPTO_THREAD_unlock(rand_lock);
rv = 1;
err:
EVP_MD_CTX_free(m);
return rv;
}
