203 lines
7.1 KiB
Go
203 lines
7.1 KiB
Go
// Package gssapi implements Generic Security Services Application Program Interface required for SPNEGO kerberos authentication.
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package gssapi
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import (
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"context"
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"fmt"
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"github.com/jcmturner/gofork/encoding/asn1"
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)
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// GSS-API OID names
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const (
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// GSS-API OID names
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OIDKRB5 OIDName = "KRB5" // MechType OID for Kerberos 5
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OIDMSLegacyKRB5 OIDName = "MSLegacyKRB5" // MechType OID for Kerberos 5
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OIDSPNEGO OIDName = "SPNEGO"
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OIDGSSIAKerb OIDName = "GSSIAKerb" // Indicates the client cannot get a service ticket and asks the server to serve as an intermediate to the target KDC. http://k5wiki.kerberos.org/wiki/Projects/IAKERB#IAKERB_mech
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)
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// GSS-API status values
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const (
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StatusBadBindings = 1 << iota
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StatusBadMech
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StatusBadName
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StatusBadNameType
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StatusBadStatus
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StatusBadSig
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StatusBadMIC
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StatusContextExpired
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StatusCredentialsExpired
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StatusDefectiveCredential
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StatusDefectiveToken
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StatusFailure
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StatusNoContext
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StatusNoCred
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StatusBadQOP
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StatusUnauthorized
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StatusUnavailable
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StatusDuplicateElement
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StatusNameNotMN
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StatusComplete
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StatusContinueNeeded
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StatusDuplicateToken
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StatusOldToken
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StatusUnseqToken
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StatusGapToken
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)
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// ContextToken is an interface for a GSS-API context token.
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type ContextToken interface {
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Marshal() ([]byte, error)
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Unmarshal(b []byte) error
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Verify() (bool, Status)
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Context() context.Context
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}
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/*
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CREDENTIAL MANAGEMENT
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GSS_Acquire_cred acquire credentials for use
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GSS_Release_cred release credentials after use
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GSS_Inquire_cred display information about credentials
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GSS_Add_cred construct credentials incrementally
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GSS_Inquire_cred_by_mech display per-mechanism credential information
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CONTEXT-LEVEL CALLS
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GSS_Init_sec_context initiate outbound security context
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GSS_Accept_sec_context accept inbound security context
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GSS_Delete_sec_context flush context when no longer needed
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GSS_Process_context_token process received control token on context
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GSS_Context_time indicate validity time remaining on context
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GSS_Inquire_context display information about context
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GSS_Wrap_size_limit determine GSS_Wrap token size limit
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GSS_Export_sec_context transfer context to other process
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GSS_Import_sec_context import transferred context
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PER-MESSAGE CALLS
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GSS_GetMIC apply integrity check, receive as token separate from message
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GSS_VerifyMIC validate integrity check token along with message
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GSS_Wrap sign, optionally encrypt, encapsulate
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GSS_Unwrap decapsulate, decrypt if needed, validate integrity check
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SUPPORT CALLS
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GSS_Display_status translate status codes to printable form
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GSS_Indicate_mechs indicate mech_types supported on local system
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GSS_Compare_name compare two names for equality
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GSS_Display_name translate name to printable form
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GSS_Import_name convert printable name to normalized form
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GSS_Release_name free storage of normalized-form name
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GSS_Release_buffer free storage of general GSS-allocated object
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GSS_Release_OID_set free storage of OID set object
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GSS_Create_empty_OID_set create empty OID set
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GSS_Add_OID_set_member add member to OID set
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GSS_Test_OID_set_member test if OID is member of OID set
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GSS_Inquire_names_for_mech indicate name types supported by mechanism
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GSS_Inquire_mechs_for_name indicates mechanisms supporting name type
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GSS_Canonicalize_name translate name to per-mechanism form
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GSS_Export_name externalize per-mechanism name
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GSS_Duplicate_name duplicate name object
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*/
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// Mechanism is the GSS-API interface for authentication mechanisms.
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type Mechanism interface {
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OID() asn1.ObjectIdentifier
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AcquireCred() error // acquire credentials for use (eg. AS exchange for KRB5)
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InitSecContext() (ContextToken, error) // initiate outbound security context (eg TGS exchange builds AP_REQ to go into ContextToken to send to service)
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AcceptSecContext(ct ContextToken) (bool, context.Context, Status) // service verifies the token server side to establish a context
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MIC() MICToken // apply integrity check, receive as token separate from message
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VerifyMIC(mt MICToken) (bool, error) // validate integrity check token along with message
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Wrap(msg []byte) WrapToken // sign, optionally encrypt, encapsulate
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Unwrap(wt WrapToken) []byte // decapsulate, decrypt if needed, validate integrity check
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}
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// OIDName is the type for defined GSS-API OIDs.
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type OIDName string
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// OID returns the OID for the provided OID name.
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func (o OIDName) OID() asn1.ObjectIdentifier {
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switch o {
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case OIDSPNEGO:
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return asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 2}
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case OIDKRB5:
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return asn1.ObjectIdentifier{1, 2, 840, 113554, 1, 2, 2}
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case OIDMSLegacyKRB5:
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return asn1.ObjectIdentifier{1, 2, 840, 48018, 1, 2, 2}
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case OIDGSSIAKerb:
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return asn1.ObjectIdentifier{1, 3, 6, 1, 5, 2, 5}
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}
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return asn1.ObjectIdentifier{}
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}
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// Status is the GSS-API status and implements the error interface.
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type Status struct {
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Code int
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Message string
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}
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// Error returns the Status description.
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func (s Status) Error() string {
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var str string
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switch s.Code {
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case StatusBadBindings:
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str = "channel binding mismatch"
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case StatusBadMech:
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str = "unsupported mechanism requested"
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case StatusBadName:
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str = "invalid name provided"
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case StatusBadNameType:
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str = "name of unsupported type provided"
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case StatusBadStatus:
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str = "invalid input status selector"
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case StatusBadSig:
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str = "token had invalid integrity check"
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case StatusBadMIC:
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str = "preferred alias for GSS_S_BAD_SIG"
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case StatusContextExpired:
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str = "specified security context expired"
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case StatusCredentialsExpired:
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str = "expired credentials detected"
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case StatusDefectiveCredential:
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str = "defective credential detected"
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case StatusDefectiveToken:
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str = "defective token detected"
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case StatusFailure:
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str = "failure, unspecified at GSS-API level"
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case StatusNoContext:
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str = "no valid security context specified"
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case StatusNoCred:
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str = "no valid credentials provided"
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case StatusBadQOP:
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str = "unsupported QOP valu"
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case StatusUnauthorized:
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str = "operation unauthorized"
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case StatusUnavailable:
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str = "operation unavailable"
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case StatusDuplicateElement:
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str = "duplicate credential element requested"
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case StatusNameNotMN:
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str = "name contains multi-mechanism elements"
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case StatusComplete:
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str = "normal completion"
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case StatusContinueNeeded:
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str = "continuation call to routine required"
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case StatusDuplicateToken:
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str = "duplicate per-message token detected"
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case StatusOldToken:
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str = "timed-out per-message token detected"
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case StatusUnseqToken:
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str = "reordered (early) per-message token detected"
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case StatusGapToken:
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str = "skipped predecessor token(s) detected"
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default:
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str = "unknown GSS-API error status"
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}
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if s.Message != "" {
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return fmt.Sprintf("%s: %s", str, s.Message)
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}
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return str
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}
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