static CRYPTO_RWLOCK *rand_meth_lock;
static const RAND_METHOD *default_RAND_meth;
static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT;
-RAND_BYTES_BUFFER rand_bytes;
+
int rand_fork_count;
#ifdef OPENSSL_RAND_SEED_RDTSC
# error "RDTSC enabled? Should not be possible!"
/*
+ * Acquire entropy from high-speed clock
+ *
* Since we get some randomness from the low-order bits of the
- * high-speec clock, it can help. But don't return a status since
- * it's not sufficient to indicate whether or not the seeding was
- * done.
+ * high-speed clock, it can help.
+ *
+ * Returns the total entropy count, if it exceeds the requested
+ * entropy count. Otherwise, returns an entropy count of 0.
*/
-void rand_read_tsc(RAND_poll_cb rand_add, void *arg)
+size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool)
{
unsigned char c;
int i;
if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
for (i = 0; i < TSC_READ_COUNT; i++) {
c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
- rand_add(arg, &c, 1, 0.5);
+ RAND_POOL_add(pool, &c, 1, 4);
}
}
+ return RAND_POOL_entropy_available(pool);
}
#endif
#ifdef OPENSSL_RAND_SEED_RDCPU
-size_t OPENSSL_ia32_rdseed_bytes(char *buf, size_t len);
-size_t OPENSSL_ia32_rdrand_bytes(char *buf, size_t len);
+size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);
+size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
extern unsigned int OPENSSL_ia32cap_P[];
-int rand_read_cpu(RAND_poll_cb rand_add, void *arg)
+/*
+ * Acquire entropy using Intel-specific cpu instructions
+ *
+ * Uses the RDSEED instruction if available, otherwise uses
+ * RDRAND if available.
+ *
+ * For the differences between RDSEED and RDRAND, and why RDSEED
+ * is the preferred choice, see https://goo.gl/oK3KcN
+ *
+ * Returns the total entropy count, if it exceeds the requested
+ * entropy count. Otherwise, returns an entropy count of 0.
+ */
+size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool)
{
- char buff[RANDOMNESS_NEEDED];
-
- /* If RDSEED is available, use that. */
- if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
- if (OPENSSL_ia32_rdseed_bytes(buff, sizeof(buff)) == sizeof(buff)) {
- rand_add(arg, buff, (int)sizeof(buff), sizeof(buff));
- return 1;
- }
- }
-
- /* Second choice is RDRAND. */
- if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
- if (OPENSSL_ia32_rdrand_bytes(buff, sizeof(buff)) == sizeof(buff)) {
- rand_add(arg, buff, (int)sizeof(buff), sizeof(buff));
- return 1;
+ size_t bytes_needed;
+ unsigned char *buffer;
+
+ bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/);
+ if (bytes_needed > 0) {
+ buffer = RAND_POOL_add_begin(pool, bytes_needed);
+
+ if (buffer != NULL) {
+
+ /* If RDSEED is available, use that. */
+ if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
+ if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed)
+ == bytes_needed)
+ return RAND_POOL_add_end(pool,
+ bytes_needed,
+ 8 * bytes_needed);
+ }
+
+ /* Second choice is RDRAND. */
+ if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
+ if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed)
+ == bytes_needed)
+ return RAND_POOL_add_end(pool,
+ bytes_needed,
+ 8 * bytes_needed);
+ }
+
+ return RAND_POOL_add_end(pool, 0, 0);
}
}
- return 0;
+ return RAND_POOL_entropy_available(pool);
}
#endif
/*
- * DRBG has two sets of callbacks; we only discuss the "entropy" one
- * here. When the DRBG needs additional randomness bits (called entropy
- * in the NIST document), it calls the get_entropy callback which fills in
- * a pointer and returns the number of bytes. When the DRBG is finished with
- * the buffer, it calls the cleanup_entropy callback, with the value of
- * the buffer that the get_entropy callback filled in.
+ * Implements the get_entropy() callback (see RAND_DRBG_set_callbacks())
+ *
+ * If the DRBG has a parent, then the required amount of entropy input
+ * is fetched using the parent's RAND_DRBG_generate().
*
- * Get entropy from the system, via RAND_poll if needed. The |entropy|
- * is the bits of randomness required, and is expected to fit into a buffer
- * of |min_len|..|max__len| size. We assume we're getting high-quality
- * randomness from the system, and that |min_len| bytes will do.
+ * Otherwise, the entropy is polled from the system entropy sources
+ * using RAND_POOL_acquire_entropy().
+ *
+ * If a random pool has been added to the DRBG using RAND_add(), then
+ * its entropy will be used up first.
*/
-size_t drbg_entropy_from_system(RAND_DRBG *drbg,
- unsigned char **pout,
- int entropy, size_t min_len, size_t max_len)
+size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
+ unsigned char **pout,
+ int entropy, size_t min_len, size_t max_len)
{
- int i;
- unsigned char *randomness;
+ size_t ret = 0;
+ size_t entropy_available = 0;
+ RAND_POOL *pool = RAND_POOL_new(entropy, min_len, max_len);
- if (min_len > (size_t)drbg->size) {
- /* Should not happen. See comment near RANDOMNESS_NEEDED. */
- min_len = drbg->size;
+ 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;
}
- randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size)
- : OPENSSL_malloc(drbg->size);
+ if (drbg->parent) {
+ size_t bytes_needed = RAND_POOL_bytes_needed(pool, 8);
+ unsigned char *buffer = RAND_POOL_add_begin(pool, bytes_needed);
- /* If we don't have enough, try to get more. */
- CRYPTO_THREAD_write_lock(rand_bytes.lock);
- for (i = RAND_POLL_RETRIES; rand_bytes.curr < min_len && --i >= 0; ) {
- CRYPTO_THREAD_unlock(rand_bytes.lock);
- RAND_poll();
- CRYPTO_THREAD_write_lock(rand_bytes.lock);
- }
+ if (buffer != NULL) {
+ size_t bytes = 0;
- /* Get desired amount, but no more than we have. */
- if (min_len > rand_bytes.curr)
- min_len = rand_bytes.curr;
- if (min_len != 0) {
- memcpy(randomness, rand_bytes.buff, min_len);
- /* Update amount left and shift it down. */
- rand_bytes.curr -= min_len;
- if (rand_bytes.curr != 0)
- memmove(rand_bytes.buff, &rand_bytes.buff[min_len], rand_bytes.curr);
- }
- CRYPTO_THREAD_unlock(rand_bytes.lock);
- *pout = randomness;
- return min_len;
-}
+ /* Get entropy from parent, include our state as additional input */
+ if (RAND_DRBG_generate(drbg->parent,
+ buffer, bytes_needed,
+ 0,
+ (unsigned char *)drbg, sizeof(*drbg)) != 0)
+ bytes = bytes_needed;
-size_t drbg_entropy_from_parent(RAND_DRBG *drbg,
- unsigned char **pout,
- int entropy, size_t min_len, size_t max_len)
-{
- int st;
- unsigned char *randomness;
+ entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes);
+ }
- if (min_len > (size_t)drbg->size) {
- /* Should not happen. See comment near RANDOMNESS_NEEDED. */
- min_len = drbg->size;
+ } else {
+ /* Get entropy by polling system entropy sources. */
+ entropy_available = RAND_POOL_acquire_entropy(pool);
}
- randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size)
- : OPENSSL_malloc(drbg->size);
-
- /* Get random from parent, include our state as additional input. */
- st = RAND_DRBG_generate(drbg->parent, randomness, min_len, 0,
- (unsigned char *)drbg, sizeof(*drbg));
- if (st == 0) {
- drbg_release_entropy(drbg, randomness, min_len);
- return 0;
+ if (entropy_available > 0) {
+ ret = RAND_POOL_length(pool);
+ *pout = RAND_POOL_detach(pool);
}
- *pout = randomness;
- return min_len;
+
+ RAND_POOL_free(pool);
+ return ret;
}
-void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
+
+/*
+ * Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks())
+ *
+ */
+void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
+ unsigned char *out, size_t outlen)
{
- if (drbg->secure)
- OPENSSL_secure_clear_free(out, outlen);
- else
- OPENSSL_clear_free(out, outlen);
+ OPENSSL_secure_clear_free(out, outlen);
}
void rand_fork()
rand_meth_lock = CRYPTO_THREAD_glock_new("rand_meth");
ret &= rand_meth_lock != NULL;
- rand_bytes.lock = CRYPTO_THREAD_glock_new("rand_bytes");
- ret &= rand_bytes.lock != NULL;
- rand_bytes.curr = 0;
- rand_bytes.size = MAX_RANDOMNESS_HELD;
- rand_bytes.secure = CRYPTO_secure_malloc_initialized();
- rand_bytes.buff = rand_bytes.secure
- ? OPENSSL_secure_malloc(rand_bytes.size)
- : OPENSSL_malloc(rand_bytes.size);
- ret &= rand_bytes.buff != NULL;
return ret;
}
CRYPTO_THREAD_lock_free(rand_engine_lock);
#endif
CRYPTO_THREAD_lock_free(rand_meth_lock);
- CRYPTO_THREAD_lock_free(rand_bytes.lock);
- if (rand_bytes.secure)
- OPENSSL_secure_clear_free(rand_bytes.buff, rand_bytes.size);
- else
- OPENSSL_clear_free(rand_bytes.buff, rand_bytes.size);
}
/*
- * RAND_poll_ex() gets a function pointer to call when it has random bytes.
- * RAND_poll() sets the function pointer to be a wrapper that calls RAND_add().
+ * RAND_poll() reseeds the default RNG using random input
+ *
+ * The random input is obtained from polling various entropy
+ * sources which depend on the operating system and are
+ * configurable via the --with-rand-seed configure option.
*/
-static void call_rand_add(void* arg, const void *buf, int num, double r)
+int RAND_poll(void)
{
- RAND_add(buf, num, r);
+ int ret = 0;
+
+ RAND_POOL *pool = NULL;
+
+ const RAND_METHOD *meth = RAND_get_rand_method();
+
+ if (meth == RAND_OpenSSL()) {
+ /* fill random pool and seed the default DRBG */
+ RAND_DRBG *drbg = RAND_DRBG_get0_global();
+
+ if (drbg == NULL)
+ return 0;
+
+ CRYPTO_THREAD_write_lock(drbg->lock);
+ ret = rand_drbg_restart(drbg, NULL, 0, 0);
+ CRYPTO_THREAD_unlock(drbg->lock);
+
+ return ret;
+
+ } else {
+ /* 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));
+ if (pool == NULL)
+ return 0;
+
+ if (RAND_POOL_acquire_entropy(pool) == 0)
+ goto err;
+
+ if (meth->add == NULL
+ || meth->add(RAND_POOL_buffer(pool),
+ RAND_POOL_length(pool),
+ (RAND_POOL_entropy(pool) / 8.0)) == 0)
+ goto err;
+
+ ret = 1;
+ }
+
+err:
+ RAND_POOL_free(pool);
+ return ret;
}
-int RAND_poll(void)
+/*
+ * The 'random pool' acts as a dumb container for collecting random
+ * input from various entropy sources. The pool has no knowledge about
+ * whether its randomness is fed into a legacy RAND_METHOD via RAND_add()
+ * or into a new style RAND_DRBG. It is the callers duty to 1) initialize the
+ * random pool, 2) pass it to the polling callbacks, 3) seed the RNG, and
+ * 4) cleanup the random pool again.
+ *
+ * The random pool contains no locking mechanism because its scope and
+ * lifetime is intended to be restricted to a single stack frame.
+ */
+struct rand_pool_st {
+ unsigned char *buffer; /* points to the beginning of the random pool */
+ size_t len; /* current number of random bytes contained in the pool */
+
+ size_t min_len; /* minimum number of random bytes requested */
+ size_t max_len; /* maximum number of random bytes (allocated buffer size) */
+ size_t entropy; /* current entropy count in bits */
+ size_t requested_entropy; /* requested entropy count in bits */
+};
+
+/*
+ * 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 *pool = OPENSSL_zalloc(sizeof(*pool));
+
+ if (pool == NULL) {
+ RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ pool->min_len = min_len;
+ pool->max_len = max_len;
+
+ pool->buffer = OPENSSL_secure_zalloc(pool->max_len);
+ if (pool->buffer == NULL) {
+ RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ pool->requested_entropy = entropy;
+
+ return pool;
+
+err:
+ OPENSSL_free(pool);
+ return NULL;
+}
+
+/*
+ * Free |pool|, securely erasing its buffer.
+ */
+void RAND_POOL_free(RAND_POOL *pool)
{
- return RAND_poll_ex(call_rand_add, NULL);
+ if (pool == NULL)
+ return;
+
+ OPENSSL_secure_clear_free(pool->buffer, pool->max_len);
+ OPENSSL_free(pool);
+}
+
+/*
+ * Return the |pool|'s buffer to the caller (readonly).
+ */
+const unsigned char *RAND_POOL_buffer(RAND_POOL *pool)
+{
+ return pool->buffer;
+}
+
+/*
+ * Return the |pool|'s entropy to the caller.
+ */
+size_t RAND_POOL_entropy(RAND_POOL *pool)
+{
+ return pool->entropy;
+}
+
+/*
+ * Return the |pool|'s buffer length to the caller.
+ */
+size_t RAND_POOL_length(RAND_POOL *pool)
+{
+ return pool->len;
+}
+
+/*
+ * 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().
+ */
+unsigned char *RAND_POOL_detach(RAND_POOL *pool)
+{
+ unsigned char *ret = pool->buffer;
+ pool->buffer = NULL;
+ return ret;
+}
+
+
+/*
+ * If every byte of the input contains |entropy_per_bytes| bits of entropy,
+ * how many bytes does one need to obtain at least |bits| bits of entropy?
+ */
+#define ENTROPY_TO_BYTES(bits, entropy_per_bytes) \
+ (((bits) + ((entropy_per_bytes) - 1))/(entropy_per_bytes))
+
+
+/*
+ * Checks whether the |pool|'s entropy is available to the caller.
+ * This is the case when entropy count and buffer length are high enough.
+ * Returns
+ *
+ * |entropy| if the entropy count and buffer size is large enough
+ * 0 otherwise
+ */
+size_t RAND_POOL_entropy_available(RAND_POOL *pool)
+{
+ if (pool->entropy < pool->requested_entropy)
+ return 0;
+
+ if (pool->len < pool->min_len)
+ return 0;
+
+ return pool->entropy;
+}
+
+/*
+ * Returns the (remaining) amount of entropy needed to fill
+ * the random pool.
+ */
+
+size_t RAND_POOL_entropy_needed(RAND_POOL *pool)
+{
+ if (pool->entropy < pool->requested_entropy)
+ return pool->requested_entropy - pool->entropy;
+
+ return 0;
+}
+
+/*
+ * Returns the number of bytes needed to fill the pool, assuming
+ * the input has 'entropy_per_byte' entropy bits per byte.
+ * In case of an error, 0 is returned.
+ */
+
+size_t RAND_POOL_bytes_needed(RAND_POOL *pool, unsigned int entropy_per_byte)
+{
+ size_t bytes_needed;
+ size_t entropy_needed = RAND_POOL_entropy_needed(pool);
+
+ if (entropy_per_byte < 1 || entropy_per_byte > 8) {
+ RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_ARGUMENT_OUT_OF_RANGE);
+ return 0;
+ }
+
+ bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_per_byte);
+
+ if (bytes_needed > pool->max_len - pool->len) {
+ /* not enough space left */
+ RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_RANDOM_POOL_OVERFLOW);
+ return 0;
+ }
+
+ if (pool->len < pool->min_len &&
+ bytes_needed < pool->min_len - pool->len)
+ /* to meet the min_len requirement */
+ bytes_needed = pool->min_len - pool->len;
+
+ return bytes_needed;
+}
+
+/* Returns the remaining number of bytes available */
+size_t RAND_POOL_bytes_remaining(RAND_POOL *pool)
+{
+ return pool->max_len - pool->len;
+}
+
+/*
+ * Add random bytes to the random pool.
+ *
+ * It is expected that the |buffer| contains |len| bytes of
+ * random input which contains at least |entropy| bits of
+ * randomness.
+ *
+ * Return available amount of entropy after this operation.
+ * (see RAND_POOL_entropy_available(pool))
+ */
+size_t RAND_POOL_add(RAND_POOL *pool,
+ const unsigned char *buffer, size_t len, size_t entropy)
+{
+ if (len > pool->max_len - pool->len) {
+ RANDerr(RAND_F_RAND_POOL_ADD, RAND_R_ENTROPY_INPUT_TOO_LONG);
+ return 0;
+ }
+
+ if (len > 0) {
+ memcpy(pool->buffer + pool->len, buffer, len);
+ pool->len += len;
+ pool->entropy += entropy;
+ }
+
+ return RAND_POOL_entropy_available(pool);
+}
+
+/*
+ * Start to add random bytes to the random pool in-place.
+ *
+ * Reserves the next |len| bytes for adding random bytes in-place
+ * and returns a pointer to the buffer.
+ * The caller is allowed to copy up to |len| bytes into the buffer.
+ * If |len| == 0 this is considered a no-op and a NULL pointer
+ * is returned without producing an error message.
+ *
+ * After updating the buffer, RAND_POOL_add_end() needs to be called
+ * to finish the udpate operation (see next comment).
+ */
+unsigned char *RAND_POOL_add_begin(RAND_POOL *pool, size_t len)
+{
+ if (len == 0)
+ return NULL;
+
+ if (len > pool->max_len - pool->len) {
+ RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, RAND_R_RANDOM_POOL_OVERFLOW);
+ return NULL;
+ }
+
+ return pool->buffer + pool->len;
+}
+
+/*
+ * Finish to add random bytes to the random pool in-place.
+ *
+ * Finishes an in-place update of the random pool started by
+ * RAND_POOL_add_begin() (see previous comment).
+ * It is expected that |len| bytes of random input have been added
+ * to the buffer which contain at least |entropy| bits of randomness.
+ * It is allowed to add less bytes than originally reserved.
+ */
+size_t RAND_POOL_add_end(RAND_POOL *pool, size_t len, size_t entropy)
+{
+ if (len > pool->max_len - pool->len) {
+ RANDerr(RAND_F_RAND_POOL_ADD_END, RAND_R_RANDOM_POOL_OVERFLOW);
+ return 0;
+ }
+
+ if (len > 0) {
+ pool->len += len;
+ pool->entropy += entropy;
+ }
+
+ return RAND_POOL_entropy_available(pool);
}
int RAND_set_rand_method(const RAND_METHOD *meth)
projects / openssl.git / blobdiff