From 615506789cc7299e4e7b859d163f680228f1b724 Mon Sep 17 00:00:00 2001 From: Greg Hudson Date: Tue, 18 Jul 2017 12:29:12 -0400 Subject: 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. (cherry picked from commit 29c504504f0c56c861d968ba2498590bf34714cd) ticket: 8600 version_fixed: 1.15.2 --- 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 4adf0fc..6907257 100644 --- a/src/lib/kdb/kdb5.c +++ b/src/lib/kdb/kdb5.c @@ -1220,11 +1220,12 @@ 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) -- cgit v1.1