87 lines
2.8 KiB
Go
87 lines
2.8 KiB
Go
package pac
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import (
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"bytes"
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"errors"
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"fmt"
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"gopkg.in/jcmturner/gokrb5.v7/crypto"
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"gopkg.in/jcmturner/gokrb5.v7/iana/keyusage"
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"gopkg.in/jcmturner/gokrb5.v7/types"
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"gopkg.in/jcmturner/rpc.v1/mstypes"
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"gopkg.in/jcmturner/rpc.v1/ndr"
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)
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// https://msdn.microsoft.com/en-us/library/cc237931.aspx
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// CredentialsInfo implements https://msdn.microsoft.com/en-us/library/cc237953.aspx
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type CredentialsInfo struct {
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Version uint32 // A 32-bit unsigned integer in little-endian format that defines the version. MUST be 0x00000000.
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EType uint32
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PACCredentialDataEncrypted []byte // Key usage number for encryption: KERB_NON_KERB_SALT (16)
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PACCredentialData CredentialData
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}
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// Unmarshal bytes into the CredentialsInfo struct
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func (c *CredentialsInfo) Unmarshal(b []byte, k types.EncryptionKey) (err error) {
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//The CredentialsInfo structure is a simple structure that is not NDR-encoded.
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r := mstypes.NewReader(bytes.NewReader(b))
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c.Version, err = r.Uint32()
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if err != nil {
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return
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}
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if c.Version != 0 {
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err = errors.New("credentials info version is not zero")
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return
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}
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c.EType, err = r.Uint32()
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if err != nil {
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return
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}
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c.PACCredentialDataEncrypted, err = r.ReadBytes(len(b) - 8)
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err = c.DecryptEncPart(k)
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if err != nil {
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err = fmt.Errorf("error decrypting PAC Credentials Data: %v", err)
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return
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}
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return
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}
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// DecryptEncPart decrypts the encrypted part of the CredentialsInfo.
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func (c *CredentialsInfo) DecryptEncPart(k types.EncryptionKey) error {
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if k.KeyType != int32(c.EType) {
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return fmt.Errorf("key provided is not the correct type. Type needed: %d, type provided: %d", c.EType, k.KeyType)
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}
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pt, err := crypto.DecryptMessage(c.PACCredentialDataEncrypted, k, keyusage.KERB_NON_KERB_SALT)
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if err != nil {
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return err
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}
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err = c.PACCredentialData.Unmarshal(pt)
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if err != nil {
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return err
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}
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return nil
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}
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// CredentialData implements https://msdn.microsoft.com/en-us/library/cc237952.aspx
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// This structure is encrypted prior to being encoded in any other structures.
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// Encryption is performed by first serializing the data structure via Network Data Representation (NDR) encoding, as specified in [MS-RPCE].
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// Once serialized, the data is encrypted using the key and cryptographic system selected through the AS protocol and the KRB_AS_REP message
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// Fields (for capturing this information) and cryptographic parameters are specified in PAC_CREDENTIAL_INFO (section 2.6.1).
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type CredentialData struct {
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CredentialCount uint32
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Credentials []SECPKGSupplementalCred // Size is the value of CredentialCount
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}
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// Unmarshal converts the bytes provided into a CredentialData type.
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func (c *CredentialData) Unmarshal(b []byte) (err error) {
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dec := ndr.NewDecoder(bytes.NewReader(b))
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err = dec.Decode(c)
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if err != nil {
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err = fmt.Errorf("error unmarshaling KerbValidationInfo: %v", err)
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}
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return
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}
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