fix unbalanced lock; test for non NULL before dereference;

diff --git a/lib/isc/random.c b/lib/isc/random.c
index 06640eec7eeb9cf3343c872b938e90d0b83134af..0979f3e68db80dc05f03111ce161c5e68dc2ff1e 100644 (file)
--- a/lib/isc/random.c
+++ b/lib/isc/random.c
@@ -231,6 +231,7 @@ isc_rng_create(isc_mem_t *mctx, isc_entropy_t *entropy, isc_rng_t **rngp) {
 
 void
 isc_rng_attach(isc_rng_t *source, isc_rng_t **targetp) {
+
        REQUIRE(VALID_RNG(source));
        REQUIRE(targetp != NULL && *targetp == NULL);
 
@@ -255,10 +256,13 @@ destroy(isc_rng_t **rngp) {
 
 void
 isc_rng_detach(isc_rng_t **rngp) {
-       isc_rng_t *rng = *rngp;
+       isc_rng_t *rng;
        isc_boolean_t dest = ISC_FALSE;
 
-       REQUIRE(VALID_RNG(rng));
+       REQUIRE(rngp != NULL && VALID_RNG(*rngp));
+
+       rng = *rngp;
+       *rngp = NULL;
 
        LOCK(&rng->lock);
 
@@ -266,13 +270,10 @@ isc_rng_detach(isc_rng_t **rngp) {
        rng->references--;
        if (rng->references == 0)
                dest = ISC_TRUE;
+       UNLOCK(&rng->lock);
 
        if (dest)
                destroy(rngp);
-       else {
-               UNLOCK(&rng->lock);
-               *rngp = NULL;
-       }
 }
 
 static void