Don Newton | 379ae25 | 2019-04-01 12:17:06 -0400 | [diff] [blame^] | 1 | // Copyright (C) MongoDB, Inc. 2017-present. |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); you may |
| 4 | // not use this file except in compliance with the License. You may obtain |
| 5 | // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 |
| 6 | |
| 7 | //+build gssapi |
| 8 | //+build linux darwin |
| 9 | |
| 10 | package gssapi |
| 11 | |
| 12 | /* |
| 13 | #cgo linux CFLAGS: -DGOOS_linux |
| 14 | #cgo linux LDFLAGS: -lgssapi_krb5 -lkrb5 |
| 15 | #cgo darwin CFLAGS: -DGOOS_darwin |
| 16 | #cgo darwin LDFLAGS: -framework GSS |
| 17 | #include "gss_wrapper.h" |
| 18 | */ |
| 19 | import "C" |
| 20 | import ( |
| 21 | "fmt" |
| 22 | "net" |
| 23 | "runtime" |
| 24 | "strings" |
| 25 | "unsafe" |
| 26 | ) |
| 27 | |
| 28 | // New creates a new SaslClient. |
| 29 | func New(target, username, password string, passwordSet bool, props map[string]string) (*SaslClient, error) { |
| 30 | serviceName := "mongodb" |
| 31 | |
| 32 | for key, value := range props { |
| 33 | switch strings.ToUpper(key) { |
| 34 | case "CANONICALIZE_HOST_NAME": |
| 35 | return nil, fmt.Errorf("CANONICALIZE_HOST_NAME is not supported when using gssapi on %s", runtime.GOOS) |
| 36 | case "SERVICE_REALM": |
| 37 | return nil, fmt.Errorf("SERVICE_REALM is not supported when using gssapi on %s", runtime.GOOS) |
| 38 | case "SERVICE_NAME": |
| 39 | serviceName = value |
| 40 | default: |
| 41 | return nil, fmt.Errorf("unknown mechanism property %s", key) |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | hostname, _, err := net.SplitHostPort(target) |
| 46 | if err != nil { |
| 47 | return nil, fmt.Errorf("invalid endpoint (%s) specified: %s", target, err) |
| 48 | } |
| 49 | |
| 50 | servicePrincipalName := fmt.Sprintf("%s@%s", serviceName, hostname) |
| 51 | |
| 52 | return &SaslClient{ |
| 53 | servicePrincipalName: servicePrincipalName, |
| 54 | username: username, |
| 55 | password: password, |
| 56 | passwordSet: passwordSet, |
| 57 | }, nil |
| 58 | } |
| 59 | |
| 60 | type SaslClient struct { |
| 61 | servicePrincipalName string |
| 62 | username string |
| 63 | password string |
| 64 | passwordSet bool |
| 65 | |
| 66 | // state |
| 67 | state C.gssapi_client_state |
| 68 | contextComplete bool |
| 69 | done bool |
| 70 | } |
| 71 | |
| 72 | func (sc *SaslClient) Close() { |
| 73 | C.gssapi_client_destroy(&sc.state) |
| 74 | } |
| 75 | |
| 76 | func (sc *SaslClient) Start() (string, []byte, error) { |
| 77 | const mechName = "GSSAPI" |
| 78 | |
| 79 | cservicePrincipalName := C.CString(sc.servicePrincipalName) |
| 80 | defer C.free(unsafe.Pointer(cservicePrincipalName)) |
| 81 | var cusername *C.char |
| 82 | var cpassword *C.char |
| 83 | if sc.username != "" { |
| 84 | cusername = C.CString(sc.username) |
| 85 | defer C.free(unsafe.Pointer(cusername)) |
| 86 | if sc.passwordSet { |
| 87 | cpassword = C.CString(sc.password) |
| 88 | defer C.free(unsafe.Pointer(cpassword)) |
| 89 | } |
| 90 | } |
| 91 | status := C.gssapi_client_init(&sc.state, cservicePrincipalName, cusername, cpassword) |
| 92 | |
| 93 | if status != C.GSSAPI_OK { |
| 94 | return mechName, nil, sc.getError("unable to initialize client") |
| 95 | } |
| 96 | |
| 97 | return mechName, nil, nil |
| 98 | } |
| 99 | |
| 100 | func (sc *SaslClient) Next(challenge []byte) ([]byte, error) { |
| 101 | |
| 102 | var buf unsafe.Pointer |
| 103 | var bufLen C.size_t |
| 104 | var outBuf unsafe.Pointer |
| 105 | var outBufLen C.size_t |
| 106 | |
| 107 | if sc.contextComplete { |
| 108 | if sc.username == "" { |
| 109 | var cusername *C.char |
| 110 | status := C.gssapi_client_username(&sc.state, &cusername) |
| 111 | if status != C.GSSAPI_OK { |
| 112 | return nil, sc.getError("unable to acquire username") |
| 113 | } |
| 114 | defer C.free(unsafe.Pointer(cusername)) |
| 115 | sc.username = C.GoString((*C.char)(unsafe.Pointer(cusername))) |
| 116 | } |
| 117 | |
| 118 | bytes := append([]byte{1, 0, 0, 0}, []byte(sc.username)...) |
| 119 | buf = unsafe.Pointer(&bytes[0]) |
| 120 | bufLen = C.size_t(len(bytes)) |
| 121 | status := C.gssapi_client_wrap_msg(&sc.state, buf, bufLen, &outBuf, &outBufLen) |
| 122 | if status != C.GSSAPI_OK { |
| 123 | return nil, sc.getError("unable to wrap authz") |
| 124 | } |
| 125 | |
| 126 | sc.done = true |
| 127 | } else { |
| 128 | if len(challenge) > 0 { |
| 129 | buf = unsafe.Pointer(&challenge[0]) |
| 130 | bufLen = C.size_t(len(challenge)) |
| 131 | } |
| 132 | |
| 133 | status := C.gssapi_client_negotiate(&sc.state, buf, bufLen, &outBuf, &outBufLen) |
| 134 | switch status { |
| 135 | case C.GSSAPI_OK: |
| 136 | sc.contextComplete = true |
| 137 | case C.GSSAPI_CONTINUE: |
| 138 | default: |
| 139 | return nil, sc.getError("unable to negotiate with server") |
| 140 | } |
| 141 | } |
| 142 | |
| 143 | if outBuf != nil { |
| 144 | defer C.free(outBuf) |
| 145 | } |
| 146 | |
| 147 | return C.GoBytes(outBuf, C.int(outBufLen)), nil |
| 148 | } |
| 149 | |
| 150 | func (sc *SaslClient) Completed() bool { |
| 151 | return sc.done |
| 152 | } |
| 153 | |
| 154 | func (sc *SaslClient) getError(prefix string) error { |
| 155 | var desc *C.char |
| 156 | |
| 157 | status := C.gssapi_error_desc(sc.state.maj_stat, sc.state.min_stat, &desc) |
| 158 | if status != C.GSSAPI_OK { |
| 159 | if desc != nil { |
| 160 | C.free(unsafe.Pointer(desc)) |
| 161 | } |
| 162 | |
| 163 | return fmt.Errorf("%s: (%v, %v)", prefix, sc.state.maj_stat, sc.state.min_stat) |
| 164 | } |
| 165 | defer C.free(unsafe.Pointer(desc)) |
| 166 | |
| 167 | return fmt.Errorf("%s: %v(%v,%v)", prefix, C.GoString(desc), int32(sc.state.maj_stat), int32(sc.state.min_stat)) |
| 168 | } |