499 lines
17 KiB
Go
499 lines
17 KiB
Go
package tlsutil
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import (
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"crypto/ecdsa"
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"crypto/rsa"
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"crypto/tls"
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"crypto/x509"
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"fmt"
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"io/ioutil"
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"net"
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"strings"
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"time"
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"github.com/hashicorp/nomad/nomad/structs/config"
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)
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// supportedTLSVersions are the current TLS versions that Nomad supports
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var supportedTLSVersions = map[string]uint16{
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"tls10": tls.VersionTLS10,
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"tls11": tls.VersionTLS11,
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"tls12": tls.VersionTLS12,
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}
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// supportedTLSCiphers are the complete list of TLS ciphers supported by Nomad
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var supportedTLSCiphers = map[string]uint16{
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"TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305": tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
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"TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305": tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
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"TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256": tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
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"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
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"TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384": tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
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"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384": tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
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"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256": tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
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"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
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"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
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"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA": tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
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"TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
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"TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA": tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
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"TLS_RSA_WITH_AES_128_GCM_SHA256": tls.TLS_RSA_WITH_AES_128_GCM_SHA256,
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"TLS_RSA_WITH_AES_256_GCM_SHA384": tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
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"TLS_RSA_WITH_AES_128_CBC_SHA256": tls.TLS_RSA_WITH_AES_128_CBC_SHA256,
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"TLS_RSA_WITH_AES_128_CBC_SHA": tls.TLS_RSA_WITH_AES_128_CBC_SHA,
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"TLS_RSA_WITH_AES_256_CBC_SHA": tls.TLS_RSA_WITH_AES_256_CBC_SHA,
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}
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// signatureAlgorithm is the string representation of a signing algorithm
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type signatureAlgorithm string
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const (
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rsaStringRepr signatureAlgorithm = "RSA"
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ecdsaStringRepr signatureAlgorithm = "ECDSA"
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)
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// supportedCipherSignatures is the supported cipher suites with their
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// corresponding signature algorithm
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var supportedCipherSignatures = map[string]signatureAlgorithm{
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"TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305": rsaStringRepr,
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"TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305": ecdsaStringRepr,
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"TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256": rsaStringRepr,
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"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256": ecdsaStringRepr,
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"TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384": rsaStringRepr,
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"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384": ecdsaStringRepr,
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"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256": rsaStringRepr,
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"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA": rsaStringRepr,
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"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256": ecdsaStringRepr,
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"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA": ecdsaStringRepr,
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"TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA": rsaStringRepr,
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"TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA": ecdsaStringRepr,
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"TLS_RSA_WITH_AES_128_GCM_SHA256": rsaStringRepr,
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"TLS_RSA_WITH_AES_256_GCM_SHA384": rsaStringRepr,
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"TLS_RSA_WITH_AES_128_CBC_SHA256": rsaStringRepr,
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"TLS_RSA_WITH_AES_128_CBC_SHA": rsaStringRepr,
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"TLS_RSA_WITH_AES_256_CBC_SHA": rsaStringRepr,
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}
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// defaultTLSCiphers are the TLS Ciphers that are supported by default
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var defaultTLSCiphers = []string{
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"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
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"TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
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"TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305",
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"TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305",
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"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
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"TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
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"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
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"TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
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"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
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"TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
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}
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// RegionSpecificWrapper is used to invoke a static Region and turns a
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// RegionWrapper into a Wrapper type.
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func RegionSpecificWrapper(region string, tlsWrap RegionWrapper) Wrapper {
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if tlsWrap == nil {
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return nil
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}
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return func(conn net.Conn) (net.Conn, error) {
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return tlsWrap(region, conn)
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}
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}
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// RegionWrapper is a function that is used to wrap a non-TLS connection and
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// returns an appropriate TLS connection or error. This takes a Region as an
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// argument.
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type RegionWrapper func(region string, conn net.Conn) (net.Conn, error)
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// Wrapper wraps a connection and enables TLS on it.
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type Wrapper func(conn net.Conn) (net.Conn, error)
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// Config used to create tls.Config
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type Config struct {
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// VerifyIncoming is used to verify the authenticity of incoming connections.
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// This means that TCP requests are forbidden, only allowing for TLS. TLS connections
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// must match a provided certificate authority. This can be used to force client auth.
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VerifyIncoming bool
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// VerifyOutgoing is used to verify the authenticity of outgoing connections.
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// This means that TLS requests are used, and TCP requests are not made. TLS connections
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// must match a provided certificate authority. This is used to verify authenticity of
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// server nodes.
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VerifyOutgoing bool
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// VerifyServerHostname is used to enable hostname verification of servers. This
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// ensures that the certificate presented is valid for server.<datacenter>.<domain>.
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// This prevents a compromised client from being restarted as a server, and then
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// intercepting request traffic as well as being added as a raft peer. This should be
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// enabled by default with VerifyOutgoing, but for legacy reasons we cannot break
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// existing clients.
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VerifyServerHostname bool
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// CAFile is a path to a certificate authority file. This is used with VerifyIncoming
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// or VerifyOutgoing to verify the TLS connection.
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CAFile string
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// CertFile is used to provide a TLS certificate that is used for serving TLS connections.
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// Must be provided to serve TLS connections.
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CertFile string
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// KeyFile is used to provide a TLS key that is used for serving TLS connections.
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// Must be provided to serve TLS connections.
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KeyFile string
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// KeyLoader dynamically reloads TLS configuration.
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KeyLoader *config.KeyLoader
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// CipherSuites have a default safe configuration, or operators can override
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// these values for acceptable safe alternatives.
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CipherSuites []uint16
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// PreferServerCipherSuites controls whether the server selects the
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// client's most preferred ciphersuite, or the server's most preferred
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// ciphersuite. If true then the server's preference, as expressed in
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// the order of elements in CipherSuites, is used.
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PreferServerCipherSuites bool
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// MinVersion contains the minimum SSL/TLS version that is accepted.
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MinVersion uint16
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}
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func NewTLSConfiguration(newConf *config.TLSConfig, verifyIncoming, verifyOutgoing bool) (*Config, error) {
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ciphers, err := ParseCiphers(newConf)
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if err != nil {
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return nil, err
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}
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minVersion, err := ParseMinVersion(newConf.TLSMinVersion)
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if err != nil {
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return nil, err
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}
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return &Config{
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VerifyIncoming: verifyIncoming,
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VerifyOutgoing: verifyOutgoing,
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VerifyServerHostname: newConf.VerifyServerHostname,
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CAFile: newConf.CAFile,
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CertFile: newConf.CertFile,
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KeyFile: newConf.KeyFile,
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KeyLoader: newConf.GetKeyLoader(),
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CipherSuites: ciphers,
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MinVersion: minVersion,
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PreferServerCipherSuites: newConf.TLSPreferServerCipherSuites,
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}, nil
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}
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// AppendCA opens and parses the CA file and adds the certificates to
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// the provided CertPool.
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func (c *Config) AppendCA(pool *x509.CertPool) error {
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if c.CAFile == "" {
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return nil
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}
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// Read the file
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data, err := ioutil.ReadFile(c.CAFile)
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if err != nil {
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return fmt.Errorf("Failed to read CA file: %v", err)
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}
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// Read certificates and return an error if no valid certificates were
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// found. Unfortunately it is very difficult to return meaningful
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// errors as PEM files are extremely permissive.
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if !pool.AppendCertsFromPEM(data) {
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return fmt.Errorf("Failed to parse any valid certificates in CA file: %s", c.CAFile)
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}
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return nil
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}
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// LoadKeyPair is used to open and parse a certificate and key file
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func (c *Config) LoadKeyPair() (*tls.Certificate, error) {
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if c.CertFile == "" || c.KeyFile == "" {
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return nil, nil
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}
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if c.KeyLoader == nil {
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return nil, fmt.Errorf("No Keyloader object to perform LoadKeyPair")
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}
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cert, err := c.KeyLoader.LoadKeyPair(c.CertFile, c.KeyFile)
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if err != nil {
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return nil, fmt.Errorf("Failed to load cert/key pair: %v", err)
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}
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return cert, err
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}
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// OutgoingTLSConfig generates a TLS configuration for outgoing
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// requests. It will return a nil config if this configuration should
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// not use TLS for outgoing connections. Provides a callback to
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// fetch certificates, allowing for reloading on the fly.
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func (c *Config) OutgoingTLSConfig() (*tls.Config, error) {
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// If VerifyServerHostname is true, that implies VerifyOutgoing
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if c.VerifyServerHostname {
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c.VerifyOutgoing = true
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}
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if !c.VerifyOutgoing {
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return nil, nil
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}
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// Create the tlsConfig
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tlsConfig := &tls.Config{
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RootCAs: x509.NewCertPool(),
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InsecureSkipVerify: true,
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CipherSuites: c.CipherSuites,
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MinVersion: c.MinVersion,
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PreferServerCipherSuites: c.PreferServerCipherSuites,
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}
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if c.VerifyServerHostname {
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tlsConfig.InsecureSkipVerify = false
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}
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// Ensure we have a CA if VerifyOutgoing is set
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if c.VerifyOutgoing && c.CAFile == "" {
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return nil, fmt.Errorf("VerifyOutgoing set, and no CA certificate provided!")
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}
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// Parse the CA cert if any
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err := c.AppendCA(tlsConfig.RootCAs)
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if err != nil {
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return nil, err
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}
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cert, err := c.LoadKeyPair()
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if err != nil {
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return nil, err
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} else if cert != nil {
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tlsConfig.GetCertificate = c.KeyLoader.GetOutgoingCertificate
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tlsConfig.GetClientCertificate = c.KeyLoader.GetClientCertificate
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}
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return tlsConfig, nil
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}
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// OutgoingTLSWrapper returns a a Wrapper based on the OutgoingTLS
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// configuration. If hostname verification is on, the wrapper
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// will properly generate the dynamic server name for verification.
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func (c *Config) OutgoingTLSWrapper() (RegionWrapper, error) {
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// Get the TLS config
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tlsConfig, err := c.OutgoingTLSConfig()
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if err != nil {
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return nil, err
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}
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// Check if TLS is not enabled
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if tlsConfig == nil {
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return nil, nil
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}
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// Generate the wrapper based on hostname verification
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if c.VerifyServerHostname {
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wrapper := func(region string, conn net.Conn) (net.Conn, error) {
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conf := tlsConfig.Clone()
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conf.ServerName = "server." + region + ".nomad"
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return WrapTLSClient(conn, conf)
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}
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return wrapper, nil
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} else {
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wrapper := func(dc string, c net.Conn) (net.Conn, error) {
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return WrapTLSClient(c, tlsConfig)
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}
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return wrapper, nil
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}
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}
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// WrapTLSClient wraps a net.Conn into a client tls connection, performing any
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// additional verification as needed.
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//
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// As of go 1.3, crypto/tls only supports either doing no certificate
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// verification, or doing full verification including of the peer's
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// DNS name. For consul, we want to validate that the certificate is
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// signed by a known CA, but because consul doesn't use DNS names for
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// node names, we don't verify the certificate DNS names. Since go 1.3
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// no longer supports this mode of operation, we have to do it
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// manually.
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func WrapTLSClient(conn net.Conn, tlsConfig *tls.Config) (net.Conn, error) {
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tlsConn := tls.Client(conn, tlsConfig)
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// If crypto/tls is doing verification, there's no need to do
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// our own.
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if !tlsConfig.InsecureSkipVerify {
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return tlsConn, nil
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}
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if err := tlsConn.Handshake(); err != nil {
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tlsConn.Close()
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return nil, err
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}
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// The following is lightly-modified from the doFullHandshake
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// method in crypto/tls's handshake_client.go.
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opts := x509.VerifyOptions{
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Roots: tlsConfig.RootCAs,
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CurrentTime: time.Now(),
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DNSName: "",
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Intermediates: x509.NewCertPool(),
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}
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certs := tlsConn.ConnectionState().PeerCertificates
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for i, cert := range certs {
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if i == 0 {
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continue
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}
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opts.Intermediates.AddCert(cert)
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}
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_, err := certs[0].Verify(opts)
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if err != nil {
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tlsConn.Close()
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return nil, err
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}
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return tlsConn, nil
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}
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// IncomingTLSConfig generates a TLS configuration for incoming requests
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func (c *Config) IncomingTLSConfig() (*tls.Config, error) {
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// Create the tlsConfig
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tlsConfig := &tls.Config{
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ClientCAs: x509.NewCertPool(),
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ClientAuth: tls.NoClientCert,
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CipherSuites: c.CipherSuites,
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MinVersion: c.MinVersion,
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PreferServerCipherSuites: c.PreferServerCipherSuites,
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}
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// Parse the CA cert if any
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err := c.AppendCA(tlsConfig.ClientCAs)
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if err != nil {
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return nil, err
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}
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// Add cert/key
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cert, err := c.LoadKeyPair()
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if err != nil {
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return nil, err
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} else if cert != nil {
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tlsConfig.GetCertificate = c.KeyLoader.GetOutgoingCertificate
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}
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// Check if we require verification
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if c.VerifyIncoming {
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tlsConfig.ClientAuth = tls.RequireAndVerifyClientCert
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if c.CAFile == "" {
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return nil, fmt.Errorf("VerifyIncoming set, and no CA certificate provided!")
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}
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if cert == nil {
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return nil, fmt.Errorf("VerifyIncoming set, and no Cert/Key pair provided!")
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}
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}
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return tlsConfig, nil
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}
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// ParseCiphers parses ciphersuites from the comma-separated string into
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// recognized slice
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func ParseCiphers(tlsConfig *config.TLSConfig) ([]uint16, error) {
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suites := []uint16{}
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cipherStr := strings.TrimSpace(tlsConfig.TLSCipherSuites)
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var parsedCiphers []string
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if cipherStr == "" {
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parsedCiphers = defaultTLSCiphers
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} else {
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parsedCiphers = strings.Split(tlsConfig.TLSCipherSuites, ",")
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}
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for _, cipher := range parsedCiphers {
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c, ok := supportedTLSCiphers[cipher]
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if !ok {
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return suites, fmt.Errorf("unsupported TLS cipher %q", cipher)
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}
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suites = append(suites, c)
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}
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// Ensure that the specified cipher suite list is supported by the TLS
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// Certificate signature algorithm. This is a check for user error, where a
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// TLS certificate could support RSA but a user has configured a cipher suite
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// list of ciphers where only ECDSA is supported.
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keyLoader := tlsConfig.GetKeyLoader()
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// Ensure that the keypair has been loaded before continuing
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keyLoader.LoadKeyPair(tlsConfig.CertFile, tlsConfig.KeyFile)
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if keyLoader.GetCertificate() != nil {
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supportedSignatureAlgorithm, err := getSignatureAlgorithm(keyLoader.GetCertificate())
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if err != nil {
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return []uint16{}, err
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}
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for _, cipher := range parsedCiphers {
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if supportedCipherSignatures[cipher] == supportedSignatureAlgorithm {
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// Positive case, return the matched cipher suites as the signature
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// algorithm is also supported
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return suites, nil
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}
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}
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// Negative case, if this is reached it means that none of the specified
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// cipher suites signature algorithms match the signature algorithm
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// for the certificate.
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return []uint16{}, fmt.Errorf("Specified cipher suites don't support the certificate signature algorithm %s, consider adding more cipher suites to match this signature algorithm.", supportedSignatureAlgorithm)
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}
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// Default in case this function is called but TLS is not actually configured
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// This is only reached if the TLS certificate is nil
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return []uint16{}, nil
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}
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// getSignatureAlgorithm returns the signature algorithm for a TLS certificate
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// This is determined by examining the type of the certificate's public key,
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// as Golang doesn't expose a more straightforward API which returns this
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// type
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func getSignatureAlgorithm(tlsCert *tls.Certificate) (signatureAlgorithm, error) {
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privKey := tlsCert.PrivateKey
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switch privKey.(type) {
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case *rsa.PrivateKey:
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return rsaStringRepr, nil
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case *ecdsa.PrivateKey:
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return ecdsaStringRepr, nil
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default:
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return "", fmt.Errorf("Unsupported signature algorithm %T; RSA and ECDSA only are supported.", privKey)
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}
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}
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// ParseMinVersion parses the specified minimum TLS version for the Nomad agent
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func ParseMinVersion(version string) (uint16, error) {
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if version == "" {
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return supportedTLSVersions["tls12"], nil
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}
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vers, ok := supportedTLSVersions[version]
|
|
if !ok {
|
|
return 0, fmt.Errorf("unsupported TLS version %q", version)
|
|
}
|
|
|
|
return vers, nil
|
|
}
|
|
|
|
// ShouldReloadRPCConnections compares two TLS Configurations and determines
|
|
// whether they differ such that RPC connections should be reloaded
|
|
func ShouldReloadRPCConnections(old, new *config.TLSConfig) (bool, error) {
|
|
var certificateInfoEqual bool
|
|
var rpcInfoEqual bool
|
|
|
|
// If already configured with TLS, compare with the new TLS configuration
|
|
if new != nil {
|
|
var err error
|
|
certificateInfoEqual, err = new.CertificateInfoIsEqual(old)
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
} else if new == nil && old == nil {
|
|
certificateInfoEqual = true
|
|
}
|
|
|
|
if new != nil && old != nil && new.EnableRPC == old.EnableRPC {
|
|
rpcInfoEqual = true
|
|
}
|
|
|
|
return (!rpcInfoEqual || !certificateInfoEqual), nil
|
|
}
|