From 7045a630996e08c18beb7c3d39e1b2752c8a4ba4 Mon Sep 17 00:00:00 2001
From: Aria <me@aria.rip>
Date: Sun, 1 Oct 2023 22:55:08 +0100
Subject: a working version with only changing passwords

---
 client/messages.go | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 client/messages.go

(limited to 'client/messages.go')

diff --git a/client/messages.go b/client/messages.go
new file mode 100644
index 0000000..b3d2c4f
--- /dev/null
+++ b/client/messages.go
@@ -0,0 +1,69 @@
+package client
+
+import (
+	"github.com/jcmturner/gokrb5/v8/crypto"
+	"github.com/jcmturner/gokrb5/v8/kadmin"
+	"github.com/jcmturner/gokrb5/v8/krberror"
+	"github.com/jcmturner/gokrb5/v8/messages"
+	"github.com/jcmturner/gokrb5/v8/types"
+)
+
+// ChangePasswdMsg generate a change password request and also return the key needed to decrypt the reply.
+func ChangePasswdMsg(targetName types.PrincipalName, cname types.PrincipalName, realm, password string, tkt messages.Ticket, sessionKey types.EncryptionKey) (r kadmin.Request, k types.EncryptionKey, err error) {
+	// Create change password data struct and marshal to bytes
+	chgpasswd := kadmin.ChangePasswdData{
+		NewPasswd: []byte(password),
+		TargName:  targetName,
+		TargRealm: realm,
+	}
+	chpwdb, err := chgpasswd.Marshal()
+	if err != nil {
+		err = krberror.Errorf(err, krberror.KRBMsgError, "error marshaling change passwd data")
+		return
+	}
+
+	// Generate authenticator
+	auth, err := types.NewAuthenticator(realm, cname)
+	if err != nil {
+		err = krberror.Errorf(err, krberror.KRBMsgError, "error generating new authenticator")
+		return
+	}
+	etype, err := crypto.GetEtype(sessionKey.KeyType)
+	if err != nil {
+		err = krberror.Errorf(err, krberror.KRBMsgError, "error generating subkey etype")
+		return
+	}
+	err = auth.GenerateSeqNumberAndSubKey(etype.GetETypeID(), etype.GetKeyByteSize())
+	if err != nil {
+		err = krberror.Errorf(err, krberror.KRBMsgError, "error generating subkey")
+		return
+	}
+	k = auth.SubKey
+
+	// Generate AP_REQ
+	APreq, err := messages.NewAPReq(tkt, sessionKey, auth)
+	if err != nil {
+		return
+	}
+
+	// Form the KRBPriv encpart data
+	kp := messages.EncKrbPrivPart{
+		UserData:       chpwdb,
+		Timestamp:      auth.CTime,
+		Usec:           auth.Cusec,
+		SequenceNumber: auth.SeqNumber,
+	}
+	kpriv := messages.NewKRBPriv(kp)
+
+	err = kpriv.EncryptEncPart(k)
+	if err != nil {
+		err = krberror.Errorf(err, krberror.EncryptingError, "error encrypting change passwd data")
+		return
+	}
+
+	r = kadmin.Request{
+		APREQ:   APreq,
+		KRBPriv: kpriv,
+	}
+	return
+}
-- 
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