From: W.C.A. Wijngaards <wouter@nlnetlabs.nl>
Date: Fri, 17 Jul 2020 15:15:55 +0000 (+0200)
Subject: - Fix lock dependency cycle in rpz zone config setup.
X-Git-Tag: release-1.11.0~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b7b5952c3aaa22c89e69c8ef994cab1e0dc0076a;p=thirdparty%2Funbound.git

- Fix lock dependency cycle in rpz zone config setup.
---

diff --git a/doc/Changelog b/doc/Changelog
index a551a59d4..8d820ca92 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -1,6 +1,7 @@
 17 July 2020: Wouter
 	- Fix libnettle compile for session ticket key callback function
 	  changes.
+	- Fix lock dependency cycle in rpz zone config setup.
 
 17 July 2020: Ralph
 	- Merge PR #234 - Ensure proper alignment of cmsg buffers by Jérémie
diff --git a/services/authzone.c b/services/authzone.c
index 9b0568c8c..a26d1003a 100644
--- a/services/authzone.c
+++ b/services/authzone.c
@@ -1866,15 +1866,26 @@ auth_zones_cfg(struct auth_zones* az, struct config_auth* c)
 	struct auth_xfer* x = NULL;
 
 	/* create zone */
+	if(c->isrpz) {
+		/* if the rpz lock is needed, grab it before the other
+		 * locks to avoid a lock dependency cycle */
+		lock_rw_wrlock(&az->rpz_lock);
+	}
 	lock_rw_wrlock(&az->lock);
 	if(!(z=auth_zones_find_or_add_zone(az, c->name))) {
 		lock_rw_unlock(&az->lock);
+		if(c->isrpz) {
+			lock_rw_unlock(&az->rpz_lock);
+		}
 		return 0;
 	}
 	if(c->masters || c->urls) {
 		if(!(x=auth_zones_find_or_add_xfer(az, z))) {
 			lock_rw_unlock(&az->lock);
 			lock_rw_unlock(&z->lock);
+			if(c->isrpz) {
+				lock_rw_unlock(&az->rpz_lock);
+			}
 			return 0;
 		}
 	}
@@ -1889,6 +1900,9 @@ auth_zones_cfg(struct auth_zones* az, struct config_auth* c)
 			lock_basic_unlock(&x->lock);
 		}
 		lock_rw_unlock(&z->lock);
+		if(c->isrpz) {
+			lock_rw_unlock(&az->rpz_lock);
+		}
 		return 0;
 	}
 	z->for_downstream = c->for_downstream;
@@ -1900,11 +1914,13 @@ auth_zones_cfg(struct auth_zones* az, struct config_auth* c)
 			return 0;
 		}
 		lock_protect(&z->lock, &z->rpz->local_zones, sizeof(*z->rpz));
-		lock_rw_wrlock(&az->rpz_lock);
+		/* the az->rpz_lock is locked above */
 		z->rpz_az_next = az->rpz_first;
 		if(az->rpz_first)
 			az->rpz_first->rpz_az_prev = z;
 		az->rpz_first = z;
+	}
+	if(c->isrpz) {
 		lock_rw_unlock(&az->rpz_lock);
 	}