From: Ondřej Surý <ondrej@isc.org>
Date: Tue, 27 Oct 2020 13:18:43 +0000 (+0100)
Subject: Fix possible NULL dereference in cd->dlz_destroy()
X-Git-Tag: v9.17.7~38^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=38f34c266dc204094812d9e901507a865d441a03;p=thirdparty%2Fbind9.git

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 df119849701..e88ea6fc52e 100644
--- 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);