Fix possible NULL dereference in cd->dlz_destroy()

If the call to cd->dlz_create() in dlopen_dlz_create() fails, cd->dbdata
may be NULL when dlopen_dlz_destroy() gets called in the cleanup path
and passing NULL to the cd->dlz_destroy() callback may cause a NULL
dereference.  Ensure that does not happen by checking whether cd->dbdata
is non-NULL before calling the cd->dlz_destroy() callback.

diff --git a/bin/named/unix/dlz_dlopen_driver.c b/bin/named/unix/dlz_dlopen_driver.c
index df119849701381e6419f178e8438aac5b0cc0b8c..e88ea6fc52e973dbeea6b18918616ead94549ff1 100644 (file)
--- a/bin/named/unix/dlz_dlopen_driver.c
+++ b/bin/named/unix/dlz_dlopen_driver.c
@@ -339,7 +339,7 @@ dlopen_dlz_destroy(void *driverarg, void *dbdata) {
 
        UNUSED(driverarg);
 
-       if (cd->dlz_destroy) {
+       if (cd->dlz_destroy && cd->dbdata) {
                MAYBE_LOCK(cd);
                cd->dlz_destroy(cd->dbdata);
                MAYBE_UNLOCK(cd);