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| 1 | +package keyless |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "crypto/tls" |
| 6 | + "crypto/x509" |
| 7 | + "encoding/pem" |
| 8 | + "errors" |
| 9 | + "fmt" |
| 10 | + "net" |
| 11 | + "net/url" |
| 12 | + "strings" |
| 13 | + "time" |
| 14 | + |
| 15 | + keylesslib "github.com/gosuda/keyless_tls/keyless" |
| 16 | +) |
| 17 | + |
| 18 | +func BuildClientTLSConfig(relayURL string, domains []string) (*tls.Config, ioCloser, error) { |
| 19 | + parsed, err := url.Parse(strings.TrimSpace(relayURL)) |
| 20 | + if err != nil { |
| 21 | + return nil, nil, fmt.Errorf("parse relay url: %w", err) |
| 22 | + } |
| 23 | + serverName := parsed.Hostname() |
| 24 | + if serverName == "" { |
| 25 | + return nil, nil, errors.New("relay hostname is required") |
| 26 | + } |
| 27 | + |
| 28 | + certPEM, rootCAPEM, err := ResolveMaterials(context.Background(), relayURL, serverName) |
| 29 | + if err != nil { |
| 30 | + return nil, nil, fmt.Errorf("prepare keyless materials: %w", err) |
| 31 | + } |
| 32 | + for _, domain := range domains { |
| 33 | + domain = strings.TrimSpace(domain) |
| 34 | + if domain == "" { |
| 35 | + continue |
| 36 | + } |
| 37 | + verifyErr := VerifyCertificateHostname(certPEM, domain) |
| 38 | + if verifyErr != nil { |
| 39 | + return nil, nil, fmt.Errorf("keyless certificate does not cover %s: %w", domain, verifyErr) |
| 40 | + } |
| 41 | + } |
| 42 | + |
| 43 | + remoteSigner, err := keylesslib.NewRemoteSigner(keylesslib.RemoteSignerConfig{ |
| 44 | + Endpoint: relayURL, |
| 45 | + ServerName: serverName, |
| 46 | + KeyID: RelayKeyID, |
| 47 | + RootCAPEM: rootCAPEM, |
| 48 | + }, certPEM) |
| 49 | + if err != nil { |
| 50 | + return nil, nil, fmt.Errorf("create keyless remote signer: %w", err) |
| 51 | + } |
| 52 | + |
| 53 | + tlsConfig, err := keylesslib.NewServerTLSConfig(keylesslib.ServerTLSConfig{ |
| 54 | + CertPEM: certPEM, |
| 55 | + Signer: remoteSigner, |
| 56 | + NextProtos: []string{"http/1.1"}, |
| 57 | + MinVersion: tls.VersionTLS12, |
| 58 | + }) |
| 59 | + if err != nil { |
| 60 | + _ = remoteSigner.Close() |
| 61 | + return nil, nil, fmt.Errorf("create keyless tls config: %w", err) |
| 62 | + } |
| 63 | + return tlsConfig, remoteSigner, nil |
| 64 | +} |
| 65 | + |
| 66 | +type ioCloser interface { |
| 67 | + Close() error |
| 68 | +} |
| 69 | + |
| 70 | +func ResolveMaterials(ctx context.Context, endpoint, serverName string) ([]byte, []byte, error) { |
| 71 | + chainPEM, err := FetchEndpointCertificateChain(ctx, endpoint, serverName) |
| 72 | + if err != nil { |
| 73 | + return nil, nil, fmt.Errorf("fetch signer certificate chain: %w", err) |
| 74 | + } |
| 75 | + if len(chainPEM) == 0 { |
| 76 | + return nil, nil, errors.New("keyless certificate chain is required") |
| 77 | + } |
| 78 | + return append([]byte(nil), chainPEM...), append([]byte(nil), chainPEM...), nil |
| 79 | +} |
| 80 | + |
| 81 | +func VerifyCertificateHostname(certPEM []byte, hostname string) error { |
| 82 | + _, leaf, err := ParseCertificateChainPEM(certPEM) |
| 83 | + if err != nil { |
| 84 | + return err |
| 85 | + } |
| 86 | + return leaf.VerifyHostname(hostname) |
| 87 | +} |
| 88 | + |
| 89 | +func ParseCertificateChainPEM(certPEM []byte) ([][]byte, *x509.Certificate, error) { |
| 90 | + if len(certPEM) == 0 { |
| 91 | + return nil, nil, errors.New("certificate PEM is empty") |
| 92 | + } |
| 93 | + |
| 94 | + var chain [][]byte |
| 95 | + rest := certPEM |
| 96 | + for { |
| 97 | + block, next := pem.Decode(rest) |
| 98 | + if block == nil { |
| 99 | + break |
| 100 | + } |
| 101 | + if block.Type == "CERTIFICATE" { |
| 102 | + chain = append(chain, block.Bytes) |
| 103 | + } |
| 104 | + rest = next |
| 105 | + } |
| 106 | + if len(chain) == 0 { |
| 107 | + return nil, nil, errors.New("no certificate blocks found") |
| 108 | + } |
| 109 | + |
| 110 | + leaf, err := x509.ParseCertificate(chain[0]) |
| 111 | + if err != nil { |
| 112 | + return nil, nil, fmt.Errorf("parse leaf certificate: %w", err) |
| 113 | + } |
| 114 | + return chain, leaf, nil |
| 115 | +} |
| 116 | + |
| 117 | +func FetchEndpointCertificateChain(ctx context.Context, endpoint, serverName string) ([]byte, error) { |
| 118 | + raw := strings.TrimSpace(endpoint) |
| 119 | + if raw == "" { |
| 120 | + return nil, errors.New("endpoint is required") |
| 121 | + } |
| 122 | + if !strings.Contains(raw, "://") { |
| 123 | + raw = "https://" + raw |
| 124 | + } |
| 125 | + |
| 126 | + u, err := url.Parse(raw) |
| 127 | + if err != nil { |
| 128 | + return nil, fmt.Errorf("parse endpoint url: %w", err) |
| 129 | + } |
| 130 | + if !strings.EqualFold(u.Scheme, "https") { |
| 131 | + return nil, errors.New("keyless endpoint must use https") |
| 132 | + } |
| 133 | + |
| 134 | + host := u.Hostname() |
| 135 | + if host == "" { |
| 136 | + return nil, errors.New("endpoint hostname is empty") |
| 137 | + } |
| 138 | + port := u.Port() |
| 139 | + if port == "" { |
| 140 | + port = "443" |
| 141 | + } |
| 142 | + if serverName == "" { |
| 143 | + serverName = host |
| 144 | + } |
| 145 | + |
| 146 | + dialer := &net.Dialer{Timeout: 5 * time.Second} |
| 147 | + rawConn, err := dialer.DialContext(ctx, "tcp", net.JoinHostPort(host, port)) |
| 148 | + if err != nil { |
| 149 | + return nil, fmt.Errorf("dial signer endpoint: %w", err) |
| 150 | + } |
| 151 | + |
| 152 | + tlsConn := tls.Client(rawConn, &tls.Config{ |
| 153 | + MinVersion: tls.VersionTLS12, |
| 154 | + ServerName: serverName, |
| 155 | + InsecureSkipVerify: isLocalhost(host), |
| 156 | + NextProtos: []string{"http/1.1"}, |
| 157 | + }) |
| 158 | + defer tlsConn.Close() |
| 159 | + if err := tlsConn.HandshakeContext(ctx); err != nil { |
| 160 | + return nil, fmt.Errorf("tls handshake with signer endpoint: %w", err) |
| 161 | + } |
| 162 | + |
| 163 | + peerCerts := tlsConn.ConnectionState().PeerCertificates |
| 164 | + if len(peerCerts) == 0 { |
| 165 | + return nil, errors.New("no peer certificates from signer endpoint") |
| 166 | + } |
| 167 | + |
| 168 | + var chainPEM []byte |
| 169 | + for _, cert := range peerCerts { |
| 170 | + chainPEM = append(chainPEM, pem.EncodeToMemory(&pem.Block{ |
| 171 | + Type: "CERTIFICATE", |
| 172 | + Bytes: cert.Raw, |
| 173 | + })...) |
| 174 | + } |
| 175 | + return chainPEM, nil |
| 176 | +} |
| 177 | + |
| 178 | +func isLocalhost(host string) bool { |
| 179 | + host = strings.TrimSpace(strings.ToLower(host)) |
| 180 | + switch host { |
| 181 | + case "", "localhost": |
| 182 | + return true |
| 183 | + } |
| 184 | + if ip := net.ParseIP(host); ip != nil { |
| 185 | + return ip.IsLoopback() |
| 186 | + } |
| 187 | + return strings.HasSuffix(host, ".localhost") |
| 188 | +} |
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