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| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "crypto/tls" |
| 6 | + "encoding/json" |
| 7 | + "errors" |
| 8 | + "flag" |
| 9 | + "fmt" |
| 10 | + "go/format" |
| 11 | + "io/ioutil" |
| 12 | + "log" |
| 13 | + "net/http" |
| 14 | + "path/filepath" |
| 15 | + "sort" |
| 16 | + "strings" |
| 17 | + |
| 18 | + "github.com/mozilla/tls-observatory/constants" |
| 19 | +) |
| 20 | + |
| 21 | +var ( |
| 22 | + pkg = flag.String("pkg", "rules", "package name to be added to the output file") |
| 23 | + outputFile = flag.String("outputFile", "tls_config.go", "name of the output file") |
| 24 | +) |
| 25 | + |
| 26 | +// TLSConfURL url where Mozilla publishes the TLS ciphers recommendations |
| 27 | +const TLSConfURL = "https://statics.tls.security.mozilla.org/server-side-tls-conf.json" |
| 28 | + |
| 29 | +// ServerSideTLSJson contains all the available configurations and the version of the current document. |
| 30 | +type ServerSideTLSJson struct { |
| 31 | + Configurations map[string]Configuration `json:"configurations"` |
| 32 | + Version float64 `json:"version"` |
| 33 | +} |
| 34 | + |
| 35 | +// Configuration represents configurations levels declared by the Mozilla server-side-tls |
| 36 | +// see https://wiki.mozilla.org/Security/Server_Side_TLS |
| 37 | +type Configuration struct { |
| 38 | + OpenSSLCiphersuites string `json:"openssl_ciphersuites"` |
| 39 | + Ciphersuites []string `json:"ciphersuites"` |
| 40 | + TLSVersions []string `json:"tls_versions"` |
| 41 | + TLSCurves []string `json:"tls_curves"` |
| 42 | + CertificateTypes []string `json:"certificate_types"` |
| 43 | + CertificateCurves []string `json:"certificate_curves"` |
| 44 | + CertificateSignatures []string `json:"certificate_signatures"` |
| 45 | + RsaKeySize float64 `json:"rsa_key_size"` |
| 46 | + DHParamSize float64 `json:"dh_param_size"` |
| 47 | + ECDHParamSize float64 `json:"ecdh_param_size"` |
| 48 | + HstsMinAge float64 `json:"hsts_min_age"` |
| 49 | + OldestClients []string `json:"oldest_clients"` |
| 50 | +} |
| 51 | + |
| 52 | +type goCipherConfiguration struct { |
| 53 | + Name string |
| 54 | + Ciphers []string |
| 55 | + MinVersion string |
| 56 | + MaxVersion string |
| 57 | +} |
| 58 | + |
| 59 | +type goTLSConfiguration struct { |
| 60 | + cipherConfigs []goCipherConfiguration |
| 61 | +} |
| 62 | + |
| 63 | +// getTLSConfFromURL retrieves the json containing the TLS configurations from the specified URL. |
| 64 | +func getTLSConfFromURL(url string) (*ServerSideTLSJson, error) { |
| 65 | + r, err := http.Get(url) |
| 66 | + if err != nil { |
| 67 | + return nil, err |
| 68 | + } |
| 69 | + defer r.Body.Close() |
| 70 | + |
| 71 | + var sstls ServerSideTLSJson |
| 72 | + err = json.NewDecoder(r.Body).Decode(&sstls) |
| 73 | + if err != nil { |
| 74 | + return nil, err |
| 75 | + } |
| 76 | + |
| 77 | + return &sstls, nil |
| 78 | +} |
| 79 | + |
| 80 | +func getGoCipherConfig(name string, sstls ServerSideTLSJson) (goCipherConfiguration, error) { |
| 81 | + cipherConf := goCipherConfiguration{Name: strings.Title(name)} |
| 82 | + conf, ok := sstls.Configurations[name] |
| 83 | + if !ok { |
| 84 | + return cipherConf, fmt.Errorf("TLS configuration '%s' not found", name) |
| 85 | + } |
| 86 | + |
| 87 | + for _, cipherName := range conf.Ciphersuites { |
| 88 | + cipherSuite, ok := constants.CipherSuites[cipherName] |
| 89 | + if !ok { |
| 90 | + log.Printf("Warning: cannot map cipher '%s'\n", cipherName) |
| 91 | + } |
| 92 | + if len(cipherSuite.IANAName) > 0 { |
| 93 | + cipherConf.Ciphers = append(cipherConf.Ciphers, cipherSuite.IANAName) |
| 94 | + } |
| 95 | + } |
| 96 | + |
| 97 | + versions := mapTLSVersions(conf.TLSVersions) |
| 98 | + if len(versions) > 0 { |
| 99 | + cipherConf.MinVersion = fmt.Sprintf("0x%04x", versions[0]) |
| 100 | + cipherConf.MaxVersion = fmt.Sprintf("0x%04x", versions[len(versions)-1]) |
| 101 | + } else { |
| 102 | + return cipherConf, fmt.Errorf("No TLS versions found for configuration '%s'", name) |
| 103 | + } |
| 104 | + return cipherConf, nil |
| 105 | +} |
| 106 | + |
| 107 | +func mapTLSVersions(tlsVersions []string) []int { |
| 108 | + var versions []int |
| 109 | + for _, tlsVersion := range tlsVersions { |
| 110 | + switch tlsVersion { |
| 111 | + case "TLSv1.2": |
| 112 | + versions = append(versions, tls.VersionTLS12) |
| 113 | + case "TLSv1.1": |
| 114 | + versions = append(versions, tls.VersionTLS11) |
| 115 | + case "TLSv1": |
| 116 | + versions = append(versions, tls.VersionTLS10) |
| 117 | + case "SSLv3": |
| 118 | + versions = append(versions, tls.VersionSSL30) |
| 119 | + default: |
| 120 | + continue |
| 121 | + } |
| 122 | + } |
| 123 | + sort.Ints(versions) |
| 124 | + return versions |
| 125 | +} |
| 126 | + |
| 127 | +func getGoTLSConf() (goTLSConfiguration, error) { |
| 128 | + sstls, err := getTLSConfFromURL(TLSConfURL) |
| 129 | + if err != nil || sstls == nil { |
| 130 | + msg := fmt.Sprintf("Could not load the Server Side TLS configuration from Mozilla's website. Check the URL: %s. Error: %v\n", |
| 131 | + TLSConfURL, err) |
| 132 | + panic(msg) |
| 133 | + } |
| 134 | + |
| 135 | + tlsConfg := goTLSConfiguration{} |
| 136 | + |
| 137 | + modern, err := getGoCipherConfig("modern", *sstls) |
| 138 | + if err != nil { |
| 139 | + return tlsConfg, err |
| 140 | + } |
| 141 | + tlsConfg.cipherConfigs = append(tlsConfg.cipherConfigs, modern) |
| 142 | + |
| 143 | + intermediate, err := getGoCipherConfig("intermediate", *sstls) |
| 144 | + if err != nil { |
| 145 | + return tlsConfg, err |
| 146 | + } |
| 147 | + tlsConfg.cipherConfigs = append(tlsConfg.cipherConfigs, intermediate) |
| 148 | + |
| 149 | + old, err := getGoCipherConfig("old", *sstls) |
| 150 | + if err != nil { |
| 151 | + return tlsConfg, err |
| 152 | + } |
| 153 | + tlsConfg.cipherConfigs = append(tlsConfg.cipherConfigs, old) |
| 154 | + |
| 155 | + return tlsConfg, nil |
| 156 | +} |
| 157 | + |
| 158 | +func getCurrentDir() (string, error) { |
| 159 | + dir := "." |
| 160 | + if args := flag.Args(); len(args) == 1 { |
| 161 | + dir = args[0] |
| 162 | + } else if len(args) > 1 { |
| 163 | + return "", errors.New("only one directory at a time") |
| 164 | + } |
| 165 | + dir, err := filepath.Abs(dir) |
| 166 | + if err != nil { |
| 167 | + return "", err |
| 168 | + } |
| 169 | + return dir, nil |
| 170 | +} |
| 171 | + |
| 172 | +func main() { |
| 173 | + dir, err := getCurrentDir() |
| 174 | + if err != nil { |
| 175 | + log.Fatalln(err) |
| 176 | + } |
| 177 | + tlsConfig, err := getGoTLSConf() |
| 178 | + if err != nil { |
| 179 | + log.Fatalln(err) |
| 180 | + } |
| 181 | + |
| 182 | + var buf bytes.Buffer |
| 183 | + err = generatedHeaderTmpl.Execute(&buf, *pkg) |
| 184 | + if err != nil { |
| 185 | + log.Fatalf("Failed to generate the header: %v", err) |
| 186 | + } |
| 187 | + for _, cipherConfig := range tlsConfig.cipherConfigs { |
| 188 | + err := generatedRuleTmpl.Execute(&buf, cipherConfig) |
| 189 | + if err != nil { |
| 190 | + log.Fatalf("Failed to generated the cipher config: %v", err) |
| 191 | + } |
| 192 | + } |
| 193 | + |
| 194 | + src, err := format.Source(buf.Bytes()) |
| 195 | + if err != nil { |
| 196 | + log.Printf("warnings: Failed to format the code: %v", err) |
| 197 | + src = buf.Bytes() |
| 198 | + } |
| 199 | + |
| 200 | + outputPath := filepath.Join(dir, *outputFile) |
| 201 | + if err := ioutil.WriteFile(outputPath, src, 0644); err != nil { |
| 202 | + log.Fatalf("Writing output: %s", err) |
| 203 | + } |
| 204 | +} |
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