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//go:build cgo
package sshd
import (
"fmt"
"github.com/openshift/gssapi"
"gitlab.com/gitlab-org/gitlab-shell/v14/internal/config"
"gitlab.com/gitlab-org/labkit/log"
)
var lib *gssapi.Lib
func LoadGSSAPILib(config *config.GSSAPIConfig) error {
var err error
if config.Enabled {
options := &gssapi.Options{
Krb5Ktname: config.Keytab,
}
if config.LibPath != "" {
options.LibPath = config.LibPath
}
lib, err = gssapi.Load(options)
if err != nil {
log.WithError(err).Error("Unable to load GSSAPI library, gssapi-with-mic is disabled")
config.Enabled = false
}
}
return err
}
type OSGSSAPIServer struct {
Keytab string
ServicePrincipalName string
contextId *gssapi.CtxId
}
func (_ *OSGSSAPIServer) str2name(str string) (*gssapi.Name, error) {
strBuffer, err := lib.MakeBufferString(str)
if err != nil {
return nil, err
}
defer strBuffer.Release()
return strBuffer.Name(lib.GSS_C_NO_OID)
}
func (server *OSGSSAPIServer) AcceptSecContext(
token []byte,
) (
outputToken []byte,
srcName string,
needContinue bool,
err error,
) {
tokenBuffer, err := lib.MakeBufferBytes(token)
if err != nil {
return
}
defer tokenBuffer.Release()
var spn *gssapi.CredId = lib.GSS_C_NO_CREDENTIAL
if server.ServicePrincipalName != "" {
var name *gssapi.Name
name, err = server.str2name(server.ServicePrincipalName)
if err != nil {
return
}
defer name.Release()
var actualMech *gssapi.OIDSet
spn, actualMech, _, err = lib.AcquireCred(name, 0, lib.GSS_C_NO_OID_SET, gssapi.GSS_C_ACCEPT)
if err != nil {
return
}
defer spn.Release()
defer actualMech.Release()
}
ctxOut, srcNameName, _, outputTokenBuffer, _, _, _, err := lib.AcceptSecContext(
server.contextId,
spn,
tokenBuffer,
nil,
)
if err == gssapi.ErrContinueNeeded {
needContinue = true
err = nil
} else if err != nil {
return
}
defer outputTokenBuffer.Release()
defer srcNameName.Release()
outputToken = outputTokenBuffer.Bytes()
server.contextId = ctxOut
return outputToken, srcNameName.String(), needContinue, err
}
func (server *OSGSSAPIServer) VerifyMIC(
micField []byte,
micToken []byte,
) error {
if server.contextId == nil {
return fmt.Errorf("gssapi: uninitialized contextId")
}
micFieldBuffer, err := lib.MakeBufferBytes(micField)
if err != nil {
return err
}
defer micFieldBuffer.Release()
micTokenBuffer, err := lib.MakeBufferBytes(micToken)
if err != nil {
return err
}
defer micTokenBuffer.Release()
_, err = server.contextId.VerifyMIC(micFieldBuffer, micTokenBuffer)
return err
}
func (server *OSGSSAPIServer) DeleteSecContext() error {
if server.contextId == nil {
return nil
}
err := server.contextId.DeleteSecContext()
if err == nil {
server.contextId = nil
}
return err
}
|
