Merge: + DNS: TLS handshake: terminate handshake on bad SNI

Close #1014

Squashed commit of the following:

commit 759248efc0587ff2f288996c47739e602c557a76
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Dec 12 19:26:46 2019 +0300

    support empty ServerName

commit 68afecd5eca5ae66262b12dcb414b50efe88dc02
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Wed Dec 11 14:40:22 2019 +0300

    + DNS: TLS handshake: terminate handshake on bad SNI
This commit is contained in:
Simon Zolin 2019-12-13 13:06:37 +03:00
parent aa202277fb
commit c8c76ae12b
2 changed files with 21 additions and 10 deletions

View File

@ -147,14 +147,16 @@ type FilteringConfig struct {
// TLSConfig is the TLS configuration for HTTPS, DNS-over-HTTPS, and DNS-over-TLS // TLSConfig is the TLS configuration for HTTPS, DNS-over-HTTPS, and DNS-over-TLS
type TLSConfig struct { type TLSConfig struct {
TLSListenAddr *net.TCPAddr `yaml:"-" json:"-"` TLSListenAddr *net.TCPAddr `yaml:"-" json:"-"`
ServerName string `yaml:"server_name" json:"server_name,omitempty"` // ServerName is the hostname of your HTTPS/TLS server
CertificateChain string `yaml:"certificate_chain" json:"certificate_chain"` // PEM-encoded certificates chain CertificateChain string `yaml:"certificate_chain" json:"certificate_chain"` // PEM-encoded certificates chain
PrivateKey string `yaml:"private_key" json:"private_key"` // PEM-encoded private key PrivateKey string `yaml:"private_key" json:"private_key"` // PEM-encoded private key
CertificatePath string `yaml:"certificate_path" json:"certificate_path"` // certificate file name CertificatePath string `yaml:"certificate_path" json:"certificate_path"` // certificate file name
PrivateKeyPath string `yaml:"private_key_path" json:"private_key_path"` // private key file name PrivateKeyPath string `yaml:"private_key_path" json:"private_key_path"` // private key file name
CertificateChainData []byte `yaml:"-" json:"-"` CertificateChainData []byte `yaml:"-" json:"-"`
PrivateKeyData []byte `yaml:"-" json:"-"` PrivateKeyData []byte `yaml:"-" json:"-"`
Cert tls.Certificate `yaml:"-" json:"-"`
} }
// ServerConfig represents server configuration. // ServerConfig represents server configuration.
@ -294,13 +296,13 @@ func (s *Server) Prepare(config *ServerConfig) error {
if s.conf.TLSListenAddr != nil && len(s.conf.CertificateChainData) != 0 && len(s.conf.PrivateKeyData) != 0 { if s.conf.TLSListenAddr != nil && len(s.conf.CertificateChainData) != 0 && len(s.conf.PrivateKeyData) != 0 {
proxyConfig.TLSListenAddr = s.conf.TLSListenAddr proxyConfig.TLSListenAddr = s.conf.TLSListenAddr
keypair, err := tls.X509KeyPair(s.conf.CertificateChainData, s.conf.PrivateKeyData) s.conf.Cert, err = tls.X509KeyPair(s.conf.CertificateChainData, s.conf.PrivateKeyData)
if err != nil { if err != nil {
return errorx.Decorate(err, "Failed to parse TLS keypair") return errorx.Decorate(err, "Failed to parse TLS keypair")
} }
proxyConfig.TLSConfig = &tls.Config{ proxyConfig.TLSConfig = &tls.Config{
Certificates: []tls.Certificate{keypair}, GetCertificate: s.onGetCertificate,
MinVersion: tls.VersionTLS12, MinVersion: tls.VersionTLS12,
} }
} }
@ -318,6 +320,16 @@ func (s *Server) Prepare(config *ServerConfig) error {
return nil return nil
} }
// Called by 'tls' package when Client Hello is received
// If the server name (from SNI) supplied by client is incorrect - we terminate the ongoing TLS handshake.
func (s *Server) onGetCertificate(ch *tls.ClientHelloInfo) (*tls.Certificate, error) {
if len(s.conf.ServerName) != 0 && ch.ServerName != s.conf.ServerName {
log.Info("DNS: TLS: unknown SNI in Client Hello: %s", ch.ServerName)
return nil, fmt.Errorf("Invalid SNI")
}
return &s.conf.Cert, nil
}
// Stop stops the DNS server // Stop stops the DNS server
func (s *Server) Stop() error { func (s *Server) Stop() error {
s.Lock() s.Lock()

View File

@ -111,11 +111,10 @@ type dnsConfig struct {
} }
type tlsConfigSettings struct { type tlsConfigSettings struct {
Enabled bool `yaml:"enabled" json:"enabled"` // Enabled is the encryption (DOT/DOH/HTTPS) status Enabled bool `yaml:"enabled" json:"enabled"` // Enabled is the encryption (DOT/DOH/HTTPS) status
ServerName string `yaml:"server_name" json:"server_name,omitempty"` // ServerName is the hostname of your HTTPS/TLS server ForceHTTPS bool `yaml:"force_https" json:"force_https,omitempty"` // ForceHTTPS: if true, forces HTTP->HTTPS redirect
ForceHTTPS bool `yaml:"force_https" json:"force_https,omitempty"` // ForceHTTPS: if true, forces HTTP->HTTPS redirect PortHTTPS int `yaml:"port_https" json:"port_https,omitempty"` // HTTPS port. If 0, HTTPS will be disabled
PortHTTPS int `yaml:"port_https" json:"port_https,omitempty"` // HTTPS port. If 0, HTTPS will be disabled PortDNSOverTLS int `yaml:"port_dns_over_tls" json:"port_dns_over_tls,omitempty"` // DNS-over-TLS port. If 0, DOT will be disabled
PortDNSOverTLS int `yaml:"port_dns_over_tls" json:"port_dns_over_tls,omitempty"` // DNS-over-TLS port. If 0, DOT will be disabled
dnsforward.TLSConfig `yaml:",inline" json:",inline"` dnsforward.TLSConfig `yaml:",inline" json:",inline"`
} }