From: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Date: Fri, 26 Apr 2024 03:24:47 +0000 (+1200)
Subject: ldb: avoid NULL deref in ldb_db_compare
X-Git-Tag: tdb-1.4.11~834
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=af7654331fb6a2d9cc41cf5bdffa74c81ff4ffee;p=thirdparty%2Fsamba.git

ldb: avoid NULL deref in ldb_db_compare

This also sorts NULLs after invalid DNs, which matches the comment
above.

CID 1596622.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15625

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
---

diff --git a/lib/ldb/common/ldb_dn.c b/lib/ldb/common/ldb_dn.c
index d2517089da5..cb4266dca91 100644
--- a/lib/ldb/common/ldb_dn.c
+++ b/lib/ldb/common/ldb_dn.c
@@ -1145,13 +1145,23 @@ int ldb_dn_compare(struct ldb_dn *dn0, struct ldb_dn *dn1)
 	 * | normal DNs, sorted | casefold failed DNs | invalid DNs | NULLs |
 	 */
 
-	if (dn0 == dn1 || (dn0->invalid && dn1->invalid)) {
+	if (dn0 == dn1) {
+		/* this includes the both-NULL case */
 		return 0;
 	}
-	if (dn0 == NULL || dn0->invalid) {
+	if (dn0 == NULL) {
 		return 1;
 	}
-	if (dn1 == NULL || dn1->invalid) {
+	if (dn1 == NULL) {
+		return -1;
+	}
+	if (dn0->invalid && dn1->invalid) {
+		return 0;
+	}
+	if (dn0->invalid) {
+		return 1;
+	}
+	if (dn1->invalid) {
 		return -1;
 	}