From: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Date: Sat, 6 Jul 2019 11:24:43 +0000 (+1200)
Subject: ldb: do not allow adding a DN as a base to itself
X-Git-Tag: talloc-2.3.0~129
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=19a13cbe0681b3996c33f7449f69b0fb0dc5d640;p=thirdparty%2Fsamba.git

ldb: do not allow adding a DN as a base to itself

If you try to add a dn to itself, it expands as it goes. The resulting
loop cannot end well.

It looks like this in Python:

    dn = ldb.Dn(ldb.Ldb(), 'CN=y,DC=x')
    dn.add_base(dn)

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>
---

diff --git a/lib/ldb/common/ldb_dn.c b/lib/ldb/common/ldb_dn.c
index 2e98f391467..eccb4a0ce4b 100644
--- a/lib/ldb/common/ldb_dn.c
+++ b/lib/ldb/common/ldb_dn.c
@@ -1357,6 +1357,10 @@ bool ldb_dn_add_base(struct ldb_dn *dn, struct ldb_dn *base)
 		return false;
 	}
 
+	if (dn == base) {
+		return false; /* or we will visit infinity */
+	}
+
 	if (dn->components) {
 		unsigned int i;