From 29c504504f0c56c861d968ba2498590bf34714cd Mon Sep 17 00:00:00 2001 From: Greg Hudson Date: Tue, 18 Jul 2017 12:29:12 -0400 Subject: [PATCH] Prevent null dereference with keyboard master key If krb5_db_fetch_mkey() prompts for a master key and needs to determine the kvno, check that the master entry contains any key data before dereferencing the first element. Reported by Joshua Schaeffer. ticket: 8600 (new) target_version: 1.15-next target_version: 1.14-next tags: pullup --- src/lib/kdb/kdb5.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/src/lib/kdb/kdb5.c b/src/lib/kdb/kdb5.c index ad637b6d43..da5332217f 100644 --- a/src/lib/kdb/kdb5.c +++ b/src/lib/kdb/kdb5.c @@ -1215,11 +1215,12 @@ krb5_db_fetch_mkey(krb5_context context, krb5_principal mname, krb5_db_entry *master_entry; rc = krb5_db_get_principal(context, mname, 0, &master_entry); - if (rc == 0) { + if (rc == 0 && master_entry->n_key_data > 0) *kvno = (krb5_kvno) master_entry->key_data->key_data_kvno; - krb5_db_free_principal(context, master_entry); - } else + else *kvno = 1; + if (rc == 0) + krb5_db_free_principal(context, master_entry); } if (!salt) -- 2.47.2