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 | package connection |
| 8 | |
| 9 | import ( |
| 10 | "bytes" |
| 11 | "crypto/tls" |
| 12 | "crypto/x509" |
| 13 | "encoding/asn1" |
| 14 | "encoding/hex" |
| 15 | "encoding/pem" |
| 16 | "errors" |
| 17 | "fmt" |
| 18 | "io/ioutil" |
| 19 | "strings" |
| 20 | ) |
| 21 | |
| 22 | // TLSConfig contains options for configuring a TLS connection to the server. |
| 23 | type TLSConfig struct { |
| 24 | *tls.Config |
| 25 | clientCertPass func() string |
| 26 | } |
| 27 | |
| 28 | // NewTLSConfig creates a new TLSConfig. |
| 29 | func NewTLSConfig() *TLSConfig { |
| 30 | cfg := &TLSConfig{} |
| 31 | cfg.Config = new(tls.Config) |
| 32 | |
| 33 | return cfg |
| 34 | } |
| 35 | |
| 36 | // SetClientCertDecryptPassword sets a function to retrieve the decryption password |
| 37 | // necessary to read a certificate. This is a function instead of a string to |
| 38 | // provide greater flexibility when deciding how to retrieve and store the password. |
| 39 | func (c *TLSConfig) SetClientCertDecryptPassword(f func() string) { |
| 40 | c.clientCertPass = f |
| 41 | } |
| 42 | |
| 43 | // SetInsecure sets whether the client should verify the server's certificate |
| 44 | // chain and hostnames. |
| 45 | func (c *TLSConfig) SetInsecure(allow bool) { |
| 46 | c.InsecureSkipVerify = allow |
| 47 | } |
| 48 | |
| 49 | // AddCACertFromFile adds a root CA certificate to the configuration given a path |
| 50 | // to the containing file. |
| 51 | func (c *TLSConfig) AddCACertFromFile(file string) error { |
| 52 | data, err := ioutil.ReadFile(file) |
| 53 | if err != nil { |
| 54 | return err |
| 55 | } |
| 56 | |
| 57 | certBytes, err := loadCert(data) |
| 58 | if err != nil { |
| 59 | return err |
| 60 | } |
| 61 | |
| 62 | cert, err := x509.ParseCertificate(certBytes) |
| 63 | if err != nil { |
| 64 | return err |
| 65 | } |
| 66 | |
| 67 | if c.RootCAs == nil { |
| 68 | c.RootCAs = x509.NewCertPool() |
| 69 | } |
| 70 | |
| 71 | c.RootCAs.AddCert(cert) |
| 72 | |
| 73 | return nil |
| 74 | } |
| 75 | |
| 76 | // AddClientCertFromFile adds a client certificate to the configuration given a path to the |
| 77 | // containing file and returns the certificate's subject name. |
| 78 | func (c *TLSConfig) AddClientCertFromFile(clientFile string) (string, error) { |
| 79 | data, err := ioutil.ReadFile(clientFile) |
| 80 | if err != nil { |
| 81 | return "", err |
| 82 | } |
| 83 | |
| 84 | var currentBlock *pem.Block |
| 85 | var certBlock, certDecodedBlock, keyBlock []byte |
| 86 | |
| 87 | remaining := data |
| 88 | start := 0 |
| 89 | for { |
| 90 | currentBlock, remaining = pem.Decode(remaining) |
| 91 | if currentBlock == nil { |
| 92 | break |
| 93 | } |
| 94 | |
| 95 | if currentBlock.Type == "CERTIFICATE" { |
| 96 | certBlock = data[start : len(data)-len(remaining)] |
| 97 | certDecodedBlock = currentBlock.Bytes |
| 98 | start += len(certBlock) |
| 99 | } else if strings.HasSuffix(currentBlock.Type, "PRIVATE KEY") { |
| 100 | if c.clientCertPass != nil && x509.IsEncryptedPEMBlock(currentBlock) { |
| 101 | var encoded bytes.Buffer |
| 102 | buf, err := x509.DecryptPEMBlock(currentBlock, []byte(c.clientCertPass())) |
| 103 | if err != nil { |
| 104 | return "", err |
| 105 | } |
| 106 | |
| 107 | pem.Encode(&encoded, &pem.Block{Type: currentBlock.Type, Bytes: buf}) |
| 108 | keyBlock = encoded.Bytes() |
| 109 | start = len(data) - len(remaining) |
| 110 | } else { |
| 111 | keyBlock = data[start : len(data)-len(remaining)] |
| 112 | start += len(keyBlock) |
| 113 | } |
| 114 | } |
| 115 | } |
| 116 | if len(certBlock) == 0 { |
| 117 | return "", fmt.Errorf("failed to find CERTIFICATE") |
| 118 | } |
| 119 | if len(keyBlock) == 0 { |
| 120 | return "", fmt.Errorf("failed to find PRIVATE KEY") |
| 121 | } |
| 122 | |
| 123 | cert, err := tls.X509KeyPair(certBlock, keyBlock) |
| 124 | if err != nil { |
| 125 | return "", err |
| 126 | } |
| 127 | |
| 128 | c.Certificates = append(c.Certificates, cert) |
| 129 | |
| 130 | // The documentation for the tls.X509KeyPair indicates that the Leaf certificate is not |
| 131 | // retained. |
| 132 | crt, err := x509.ParseCertificate(certDecodedBlock) |
| 133 | if err != nil { |
| 134 | return "", err |
| 135 | } |
| 136 | |
| 137 | return x509CertSubject(crt), nil |
| 138 | } |
| 139 | |
| 140 | func loadCert(data []byte) ([]byte, error) { |
| 141 | var certBlock *pem.Block |
| 142 | |
| 143 | for certBlock == nil { |
| 144 | if data == nil || len(data) == 0 { |
| 145 | return nil, errors.New(".pem file must have both a CERTIFICATE and an RSA PRIVATE KEY section") |
| 146 | } |
| 147 | |
| 148 | block, rest := pem.Decode(data) |
| 149 | if block == nil { |
| 150 | return nil, errors.New("invalid .pem file") |
| 151 | } |
| 152 | |
| 153 | switch block.Type { |
| 154 | case "CERTIFICATE": |
| 155 | if certBlock != nil { |
| 156 | return nil, errors.New("multiple CERTIFICATE sections in .pem file") |
| 157 | } |
| 158 | |
| 159 | certBlock = block |
| 160 | } |
| 161 | |
| 162 | data = rest |
| 163 | } |
| 164 | |
| 165 | return certBlock.Bytes, nil |
| 166 | } |
| 167 | |
| 168 | // Because the functionality to convert a pkix.Name to a string wasn't added until Go 1.10, we |
| 169 | // need to copy the implementation (along with the attributeTypeNames map below). |
| 170 | func x509CertSubject(cert *x509.Certificate) string { |
| 171 | r := cert.Subject.ToRDNSequence() |
| 172 | |
| 173 | s := "" |
| 174 | for i := 0; i < len(r); i++ { |
| 175 | rdn := r[len(r)-1-i] |
| 176 | if i > 0 { |
| 177 | s += "," |
| 178 | } |
| 179 | for j, tv := range rdn { |
| 180 | if j > 0 { |
| 181 | s += "+" |
| 182 | } |
| 183 | |
| 184 | oidString := tv.Type.String() |
| 185 | typeName, ok := attributeTypeNames[oidString] |
| 186 | if !ok { |
| 187 | derBytes, err := asn1.Marshal(tv.Value) |
| 188 | if err == nil { |
| 189 | s += oidString + "=#" + hex.EncodeToString(derBytes) |
| 190 | continue // No value escaping necessary. |
| 191 | } |
| 192 | |
| 193 | typeName = oidString |
| 194 | } |
| 195 | |
| 196 | valueString := fmt.Sprint(tv.Value) |
| 197 | escaped := make([]rune, 0, len(valueString)) |
| 198 | |
| 199 | for k, c := range valueString { |
| 200 | escape := false |
| 201 | |
| 202 | switch c { |
| 203 | case ',', '+', '"', '\\', '<', '>', ';': |
| 204 | escape = true |
| 205 | |
| 206 | case ' ': |
| 207 | escape = k == 0 || k == len(valueString)-1 |
| 208 | |
| 209 | case '#': |
| 210 | escape = k == 0 |
| 211 | } |
| 212 | |
| 213 | if escape { |
| 214 | escaped = append(escaped, '\\', c) |
| 215 | } else { |
| 216 | escaped = append(escaped, c) |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | s += typeName + "=" + string(escaped) |
| 221 | } |
| 222 | } |
| 223 | |
| 224 | return s |
| 225 | } |
| 226 | |
| 227 | var attributeTypeNames = map[string]string{ |
| 228 | "2.5.4.6": "C", |
| 229 | "2.5.4.10": "O", |
| 230 | "2.5.4.11": "OU", |
| 231 | "2.5.4.3": "CN", |
| 232 | "2.5.4.5": "SERIALNUMBER", |
| 233 | "2.5.4.7": "L", |
| 234 | "2.5.4.8": "ST", |
| 235 | "2.5.4.9": "STREET", |
| 236 | "2.5.4.17": "POSTALCODE", |
| 237 | } |