143 lines
3.7 KiB
Go
143 lines
3.7 KiB
Go
package sasl
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// #include "sasl_windows.h"
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import "C"
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import (
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"fmt"
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"strings"
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"sync"
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"unsafe"
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)
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type saslStepper interface {
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Step(serverData []byte) (clientData []byte, done bool, err error)
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Close()
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}
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type saslSession struct {
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// Credentials
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mech string
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service string
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host string
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userPlusRealm string
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target string
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domain string
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// Internal state
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authComplete bool
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errored bool
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step int
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// C internal state
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credHandle C.CredHandle
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context C.CtxtHandle
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hasContext C.int
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// Keep track of pointers we need to explicitly free
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stringsToFree []*C.char
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}
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var initError error
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var initOnce sync.Once
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func initSSPI() {
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rc := C.load_secur32_dll()
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if rc != 0 {
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initError = fmt.Errorf("Error loading libraries: %v", rc)
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}
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}
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func New(username, password, mechanism, service, host string) (saslStepper, error) {
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initOnce.Do(initSSPI)
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ss := &saslSession{mech: mechanism, hasContext: 0, userPlusRealm: username}
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if service == "" {
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service = "mongodb"
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}
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if i := strings.Index(host, ":"); i >= 0 {
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host = host[:i]
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}
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ss.service = service
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ss.host = host
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usernameComponents := strings.Split(username, "@")
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if len(usernameComponents) < 2 {
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return nil, fmt.Errorf("Username '%v' doesn't contain a realm!", username)
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}
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user := usernameComponents[0]
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ss.domain = usernameComponents[1]
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ss.target = fmt.Sprintf("%s/%s", ss.service, ss.host)
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var status C.SECURITY_STATUS
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// Step 0: call AcquireCredentialsHandle to get a nice SSPI CredHandle
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if len(password) > 0 {
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status = C.sspi_acquire_credentials_handle(&ss.credHandle, ss.cstr(user), ss.cstr(password), ss.cstr(ss.domain))
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} else {
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status = C.sspi_acquire_credentials_handle(&ss.credHandle, ss.cstr(user), nil, ss.cstr(ss.domain))
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}
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if status != C.SEC_E_OK {
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ss.errored = true
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return nil, fmt.Errorf("Couldn't create new SSPI client, error code %v", status)
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}
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return ss, nil
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}
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func (ss *saslSession) cstr(s string) *C.char {
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cstr := C.CString(s)
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ss.stringsToFree = append(ss.stringsToFree, cstr)
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return cstr
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}
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func (ss *saslSession) Close() {
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for _, cstr := range ss.stringsToFree {
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C.free(unsafe.Pointer(cstr))
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}
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}
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func (ss *saslSession) Step(serverData []byte) (clientData []byte, done bool, err error) {
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ss.step++
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if ss.step > 10 {
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return nil, false, fmt.Errorf("too many SSPI steps without authentication")
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}
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var buffer C.PVOID
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var bufferLength C.ULONG
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var outBuffer C.PVOID
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var outBufferLength C.ULONG
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if len(serverData) > 0 {
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buffer = (C.PVOID)(unsafe.Pointer(&serverData[0]))
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bufferLength = C.ULONG(len(serverData))
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}
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var status C.int
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if ss.authComplete {
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// Step 3: last bit of magic to use the correct server credentials
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status = C.sspi_send_client_authz_id(&ss.context, &outBuffer, &outBufferLength, ss.cstr(ss.userPlusRealm))
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} else {
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// Step 1 + Step 2: set up security context with the server and TGT
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status = C.sspi_step(&ss.credHandle, ss.hasContext, &ss.context, buffer, bufferLength, &outBuffer, &outBufferLength, ss.cstr(ss.target))
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}
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if outBuffer != C.PVOID(nil) {
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defer C.free(unsafe.Pointer(outBuffer))
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}
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if status != C.SEC_E_OK && status != C.SEC_I_CONTINUE_NEEDED {
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ss.errored = true
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return nil, false, ss.handleSSPIErrorCode(status)
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}
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clientData = C.GoBytes(unsafe.Pointer(outBuffer), C.int(outBufferLength))
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if status == C.SEC_E_OK {
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ss.authComplete = true
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return clientData, true, nil
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} else {
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ss.hasContext = 1
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return clientData, false, nil
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}
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}
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func (ss *saslSession) handleSSPIErrorCode(code C.int) error {
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switch {
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case code == C.SEC_E_TARGET_UNKNOWN:
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return fmt.Errorf("Target %v@%v not found", ss.target, ss.domain)
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}
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return fmt.Errorf("Unknown error doing step %v, error code %v", ss.step, code)
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}
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