From 2632e8ebae826a7305fe7d3948ee28b77d2ffbc0 Mon Sep 17 00:00:00 2001
From: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Date: Fri, 21 Aug 2020 17:10:22 +1200
Subject: [PATCH] CVE-2020-14383: s4/dns: Ensure variable initialization with
 NULL.
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Based on patches from Francis Brosnan Blázquez <francis@aspl.es>
and Jeremy Allison <jra@samba.org>

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14472
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12795

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Jeremy Allison <jra@samba.org>
(based on commit 7afe449e7201be92bed8e53cbb37b74af720ef4e)
---
 .../rpc_server/dnsserver/dcerpc_dnsserver.c   | 24 ++++++++++---------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/source4/rpc_server/dnsserver/dcerpc_dnsserver.c b/source4/rpc_server/dnsserver/dcerpc_dnsserver.c
index b6389f2328a..ec610168266 100644
--- a/source4/rpc_server/dnsserver/dcerpc_dnsserver.c
+++ b/source4/rpc_server/dnsserver/dcerpc_dnsserver.c
@@ -1759,15 +1759,17 @@ static WERROR dnsserver_enumerate_records(struct dnsserver_state *dsstate,
 	TALLOC_CTX *tmp_ctx;
 	char *name;
 	const char * const attrs[] = { "name", "dnsRecord", NULL };
-	struct ldb_result *res;
-	struct DNS_RPC_RECORDS_ARRAY *recs;
+	struct ldb_result *res = NULL;
+	struct DNS_RPC_RECORDS_ARRAY *recs = NULL;
 	char **add_names = NULL;
-	char *rname;
+	char *rname = NULL;
 	const char *preference_name = NULL;
 	int add_count = 0;
 	int i, ret, len;
 	WERROR status;
-	struct dns_tree *tree, *base, *node;
+	struct dns_tree *tree = NULL;
+	struct dns_tree *base = NULL;
+	struct dns_tree *node = NULL;
 
 	tmp_ctx = talloc_new(mem_ctx);
 	W_ERROR_HAVE_NO_MEMORY(tmp_ctx);
@@ -1850,9 +1852,9 @@ static WERROR dnsserver_enumerate_records(struct dnsserver_state *dsstate,
 		}
 	}
 
-	talloc_free(res);
-	talloc_free(tree);
-	talloc_free(name);
+	TALLOC_FREE(res);
+	TALLOC_FREE(tree);
+	TALLOC_FREE(name);
 
 	/* Add any additional records */
 	if (select_flag & DNS_RPC_VIEW_ADDITIONAL_DATA) {
@@ -1870,14 +1872,14 @@ static WERROR dnsserver_enumerate_records(struct dnsserver_state *dsstate,
 						LDB_SCOPE_ONELEVEL, attrs,
 						"(&(objectClass=dnsNode)(name=%s)(!(dNSTombstoned=TRUE)))",
 						encoded_name);
-				talloc_free(name);
+				TALLOC_FREE(name);
 				if (ret != LDB_SUCCESS) {
 					continue;
 				}
 				if (res->count == 1) {
 					break;
 				} else {
-					talloc_free(res);
+					TALLOC_FREE(res);
 					continue;
 				}
 			}
@@ -1892,8 +1894,8 @@ static WERROR dnsserver_enumerate_records(struct dnsserver_state *dsstate,
 							select_flag, rname,
 							res->msgs[0], 0, recs,
 							NULL, NULL);
-			talloc_free(rname);
-			talloc_free(res);
+			TALLOC_FREE(rname);
+			TALLOC_FREE(res);
 			if (!W_ERROR_IS_OK(status)) {
 				talloc_free(tmp_ctx);
 				return status;
-- 
2.29.2