DRBG: make locking api truly private

In PR #5295 it was decided that the locking api should remain private
and used only inside libcrypto. However, the locking functions were added
back to `libcrypto.num` by `mkdef.pl`, because the function prototypes
were still listed in `internal/rand.h`. (This header contains functions
which are internal, but shared between libcrypto and libssl.)

This commit moves the prototypes to `rand_lcl.h` and changes the names
to lowercase, following the convention therein. It also corrects an
outdated documenting comment.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5375)

1 files changed, 21 insertions, 21 deletions

diff --git a/crypto/rand/drbg_lib.c b/crypto/rand/drbg_lib.c
index c592a7b9d0..c43f571d64 100644
--- a/crypto/rand/drbg_lib.c
+++ b/crypto/rand/drbg_lib.c
@@ -94,17 +94,17 @@ static RAND_DRBG *drbg_private;
  * LOCKING
  *
  * The three shared DRBGs are intended to be used concurrently, so they
- * support locking by default. It is the callers responsibility to wrap
- * calls to functions like RAND_DRBG_generate() which modify the DRBGs
- * internal state with calls to RAND_DRBG_lock() and RAND_DRBG_unlock().
- * The functions RAND_bytes() and RAND_priv_bytes() take the locks
- * automatically, so using the RAND api is thread safe as before.
- *
- * All other DRBG instances don't have locking enabled by default, because
- * they are intendended to be used by a single thread. If it is desired,
- * locking can be enabled using RAND_DRBG_enable_locking(). However, instead
- * of accessing a single DRBG instance concurrently from different threads,
- * it is recommended to instantiate a separate DRBG instance per thread.
+ * support locking. The RAND methods take the locks automatically, so using
+ * the RAND api (in particular RAND_bytes() and RAND_priv_bytes()) is
+ * thread-safe. Note however that accessing the shared DRBGs directly via
+ * the RAND_DRBG interface is *not* thread-safe.
+ *
+ * All other DRBG instances don't support locking, because they are
+ * intendended to be used by a single thread. Instead of accessing a single
+ * DRBG instance concurrently from different threads, it is recommended to
+ * instantiate a separate DRBG instance per thread. Using the same shared
+ * DRBG (preferrably the public DRBG) as parent of DRBG instances on
+ * different threads is safe.
  */
 
 
@@ -708,7 +708,7 @@ int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
  *
  * Returns 1 on success, 0 on failure.
  */
-int RAND_DRBG_lock(RAND_DRBG *drbg)
+int rand_drbg_lock(RAND_DRBG *drbg)
 {
     if (drbg->lock != NULL)
         return CRYPTO_THREAD_write_lock(drbg->lock);
@@ -722,7 +722,7 @@ int RAND_DRBG_lock(RAND_DRBG *drbg)
  *
  * Returns 1 on success, 0 on failure.
  */
-int RAND_DRBG_unlock(RAND_DRBG *drbg)
+int rand_drbg_unlock(RAND_DRBG *drbg)
 {
     if (drbg->lock != NULL)
         return CRYPTO_THREAD_unlock(drbg->lock);
@@ -738,7 +738,7 @@ int RAND_DRBG_unlock(RAND_DRBG *drbg)
  *
  * Returns 1 on success, 0 on failure.
  */
-int RAND_DRBG_enable_locking(RAND_DRBG *drbg)
+int rand_drbg_enable_locking(RAND_DRBG *drbg)
 {
     if (drbg->state != DRBG_UNINITIALISED) {
         RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
@@ -797,7 +797,7 @@ static RAND_DRBG *drbg_setup(RAND_DRBG *parent)
     if (drbg == NULL)
         return NULL;
 
-    if (RAND_DRBG_enable_locking(drbg) == 0)
+    if (rand_drbg_enable_locking(drbg) == 0)
         goto err;
 
     if (parent == NULL) {
@@ -869,9 +869,9 @@ static int drbg_bytes(unsigned char *out, int count)
     if (drbg == NULL)
         return 0;
 
-    RAND_DRBG_lock(drbg);
+    rand_drbg_lock(drbg);
     ret = RAND_DRBG_bytes(drbg, out, count);
-    RAND_DRBG_unlock(drbg);
+    rand_drbg_unlock(drbg);
 
     return ret;
 }
@@ -898,11 +898,11 @@ static int drbg_add(const void *buf, int num, double randomness)
         return 0;
     }
 
-    RAND_DRBG_lock(drbg);
+    rand_drbg_lock(drbg);
     ret = rand_drbg_restart(drbg, buf,
                             (size_t)(unsigned int)num,
                             (size_t)(8*randomness));
-    RAND_DRBG_unlock(drbg);
+    rand_drbg_unlock(drbg);
 
     return ret;
 }
@@ -922,9 +922,9 @@ static int drbg_status(void)
     if (drbg == NULL)
         return 0;
 
-    RAND_DRBG_lock(drbg);
+    rand_drbg_lock(drbg);
     ret = drbg->state == DRBG_READY ? 1 : 0;
-    RAND_DRBG_unlock(drbg);
+    rand_drbg_unlock(drbg);
     return ret;
 }