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Merge pull request #927 from hashicorp/f-tls 

Add new `verify_server_hostname` to mitigate possibility of MITM
This commit is contained in:
Armon Dadgar 2015-05-11 18:15:16 -07:00
parent 03a307dd38 97c87f4e4d
commit 430100a0c8
16 changed files with 389 additions and 52 deletions
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2
command/agent/agent.go
View File

@ -288,10 +288,12 @@ func (a *Agent) consulConfig() *consul.Config {
// Copy the TLS configuration
base.VerifyIncoming = a.config.VerifyIncoming
base.VerifyOutgoing = a.config.VerifyOutgoing
base.VerifyServerHostname = a.config.VerifyServerHostname
base.CAFile = a.config.CAFile
base.CertFile = a.config.CertFile
base.KeyFile = a.config.KeyFile
base.ServerName = a.config.ServerName
base.Domain = a.config.Domain
// Setup the ServerUp callback
base.ServerUp = a.state.ConsulServerUp

11
command/agent/config.go
View File

@ -188,6 +188,14 @@ type Config struct {
// certificate authority. This is used to verify authenticity of server nodes.
VerifyOutgoing bool `mapstructure:"verify_outgoing"`
// VerifyServerHostname is used to enable hostname verification of servers. This
// ensures that the certificate presented is valid for server.<datacenter>.<domain>.
// This prevents a compromised client from being restarted as a server, and then
// intercepting request traffic as well as being added as a raft peer. This should be
// enabled by default with VerifyOutgoing, but for legacy reasons we cannot break
// existing clients.
VerifyServerHostname bool `mapstructure:"verify_server_hostname"`
// CAFile is a path to a certificate authority file. This is used with VerifyIncoming
// or VerifyOutgoing to verify the TLS connection.
CAFile string `mapstructure:"ca_file"`
@ -838,6 +846,9 @@ func MergeConfig(a, b *Config) *Config {
if b.VerifyOutgoing {
result.VerifyOutgoing = true
}
if b.VerifyServerHostname {
result.VerifyServerHostname = true
}
if b.CAFile != "" {
result.CAFile = b.CAFile
}

6
command/agent/config_test.go
View File

@ -245,7 +245,7 @@ func TestDecodeConfig(t *testing.T) {
}
// TLS
input = `{"verify_incoming": true, "verify_outgoing": true}`
input = `{"verify_incoming": true, "verify_outgoing": true, "verify_server_hostname": true}`
config, err = DecodeConfig(bytes.NewReader([]byte(input)))
if err != nil {
t.Fatalf("err: %s", err)
@ -259,6 +259,10 @@ func TestDecodeConfig(t *testing.T) {
t.Fatalf("bad: %#v", config)
}
if config.VerifyServerHostname != true {
t.Fatalf("bad: %#v", config)
}
// TLS keys
input = `{"ca_file": "my/ca/file", "cert_file": "my.cert", "key_file": "key.pem", "server_name": "example.com"}`
config, err = DecodeConfig(bytes.NewReader([]byte(input)))

12
consul/client.go
View File

@ -1,7 +1,6 @@
package consul
import (
"crypto/tls"
"fmt"
"log"
"math/rand"
@ -91,10 +90,9 @@ func NewClient(config *Config) (*Client, error) {
config.LogOutput = os.Stderr
}
// Create the tlsConfig
var tlsConfig *tls.Config
var err error
if tlsConfig, err = config.tlsConfig().OutgoingTLSConfig(); err != nil {
// Create the tls Wrapper
tlsWrap, err := config.tlsConfig().OutgoingTLSWrapper()
if err != nil {
return nil, err
}
@ -104,7 +102,7 @@ func NewClient(config *Config) (*Client, error) {
// Create server
c := &Client{
config: config,
connPool: NewPool(config.LogOutput, clientRPCCache, clientMaxStreams, tlsConfig),
connPool: NewPool(config.LogOutput, clientRPCCache, clientMaxStreams, tlsWrap),
eventCh: make(chan serf.Event, 256),
logger: logger,
shutdownCh: make(chan struct{}),
@ -357,7 +355,7 @@ func (c *Client) RPC(method string, args interface{}, reply interface{}) error {
// Forward to remote Consul
TRY_RPC:
if err := c.connPool.RPC(server.Addr, server.Version, method, args, reply); err != nil {
if err := c.connPool.RPC(c.config.Datacenter, server.Addr, server.Version, method, args, reply); err != nil {
c.lastServer = nil
c.lastRPCTime = time.Time{}
return err

17
consul/config.go
View File

@ -56,6 +56,9 @@ type Config struct {
// Node name is the name we use to advertise. Defaults to hostname.
NodeName string
// Domain is the DNS domain for the records. Defaults to "consul."
Domain string
// RaftConfig is the configuration used for Raft in the local DC
RaftConfig *raft.Config
@ -100,6 +103,14 @@ type Config struct {
// server nodes.
VerifyOutgoing bool
// VerifyServerHostname is used to enable hostname verification of servers. This
// ensures that the certificate presented is valid for server.<datacenter>.<domain>.
// This prevents a compromised client from being restarted as a server, and then
// intercepting request traffic as well as being added as a raft peer. This should be
// enabled by default with VerifyOutgoing, but for legacy reasons we cannot break
// existing clients.
VerifyServerHostname bool
// CAFile is a path to a certificate authority file. This is used with VerifyIncoming
// or VerifyOutgoing to verify the TLS connection.
CAFile string
@ -269,11 +280,13 @@ func (c *Config) tlsConfig() *tlsutil.Config {
tlsConf := &tlsutil.Config{
VerifyIncoming: c.VerifyIncoming,
VerifyOutgoing: c.VerifyOutgoing,
VerifyServerHostname: c.VerifyServerHostname,
CAFile: c.CAFile,
CertFile: c.CertFile,
KeyFile: c.KeyFile,
NodeName: c.NodeName,
ServerName: c.ServerName}
ServerName: c.ServerName,
Domain: c.Domain,
}
return tlsConf
}

27
consul/pool.go
View File

@ -2,7 +2,6 @@ package consul
import (
"container/list"
"crypto/tls"
"fmt"
"io"
"net"
@ -135,8 +134,8 @@ type ConnPool struct {
// Pool maps an address to a open connection
pool map[string]*Conn
// TLS settings
tlsConfig *tls.Config
// TLS wrapper
tlsWrap tlsutil.DCWrapper
// Used to indicate the pool is shutdown
shutdown bool
@ -148,13 +147,13 @@ type ConnPool struct {
// Set maxTime to 0 to disable reaping. maxStreams is used to control
// the number of idle streams allowed.
// If TLS settings are provided outgoing connections use TLS.
func NewPool(logOutput io.Writer, maxTime time.Duration, maxStreams int, tlsConfig *tls.Config) *ConnPool {
func NewPool(logOutput io.Writer, maxTime time.Duration, maxStreams int, tlsWrap tlsutil.DCWrapper) *ConnPool {
pool := &ConnPool{
logOutput: logOutput,
maxTime: maxTime,
maxStreams: maxStreams,
pool: make(map[string]*Conn),
tlsConfig: tlsConfig,
tlsWrap: tlsWrap,
shutdownCh: make(chan struct{}),
}
if maxTime > 0 {
@ -183,14 +182,14 @@ func (p *ConnPool) Shutdown() error {
// Acquire is used to get a connection that is
// pooled or to return a new connection
func (p *ConnPool) acquire(addr net.Addr, version int) (*Conn, error) {
func (p *ConnPool) acquire(dc string, addr net.Addr, version int) (*Conn, error) {
// Check for a pooled ocnn
if conn := p.getPooled(addr, version); conn != nil {
return conn, nil
}
// Create a new connection
return p.getNewConn(addr, version)
return p.getNewConn(dc, addr, version)
}
// getPooled is used to return a pooled connection
@ -206,7 +205,7 @@ func (p *ConnPool) getPooled(addr net.Addr, version int) *Conn {
}
// getNewConn is used to return a new connection
func (p *ConnPool) getNewConn(addr net.Addr, version int) (*Conn, error) {
func (p *ConnPool) getNewConn(dc string, addr net.Addr, version int) (*Conn, error) {
// Try to dial the conn
conn, err := net.DialTimeout("tcp", addr.String(), 10*time.Second)
if err != nil {
@ -220,7 +219,7 @@ func (p *ConnPool) getNewConn(addr net.Addr, version int) (*Conn, error) {
}
// Check if TLS is enabled
if p.tlsConfig != nil {
if p.tlsWrap != nil {
// Switch the connection into TLS mode
if _, err := conn.Write([]byte{byte(rpcTLS)}); err != nil {
conn.Close()
@ -228,7 +227,7 @@ func (p *ConnPool) getNewConn(addr net.Addr, version int) (*Conn, error) {
}
// Wrap the connection in a TLS client
tlsConn, err := tlsutil.WrapTLSClient(conn, p.tlsConfig)
tlsConn, err := p.tlsWrap(dc, conn)
if err != nil {
conn.Close()
return nil, err
@ -314,11 +313,11 @@ func (p *ConnPool) releaseConn(conn *Conn) {
}
// getClient is used to get a usable client for an address and protocol version
func (p *ConnPool) getClient(addr net.Addr, version int) (*Conn, *StreamClient, error) {
func (p *ConnPool) getClient(dc string, addr net.Addr, version int) (*Conn, *StreamClient, error) {
retries := 0
START:
// Try to get a conn first
conn, err := p.acquire(addr, version)
conn, err := p.acquire(dc, addr, version)
if err != nil {
return nil, nil, fmt.Errorf("failed to get conn: %v", err)
}
@ -340,9 +339,9 @@ START:
}
// RPC is used to make an RPC call to a remote host
func (p *ConnPool) RPC(addr net.Addr, version int, method string, args interface{}, reply interface{}) error {
func (p *ConnPool) RPC(dc string, addr net.Addr, version int, method string, args interface{}, reply interface{}) error {
// Get a usable client
conn, sc, err := p.getClient(addr, version)
conn, sc, err := p.getClient(dc, addr, version)
if err != nil {
return fmt.Errorf("rpc error: %v", err)
}

16
consul/raft_rpc.go
View File

@ -1,12 +1,12 @@
package consul
import (
"crypto/tls"
"fmt"
"github.com/hashicorp/consul/tlsutil"
"net"
"sync"
"time"
"github.com/hashicorp/consul/tlsutil"
)
// RaftLayer implements the raft.StreamLayer interface,
@ -18,8 +18,8 @@ type RaftLayer struct {
// connCh is used to accept connections
connCh chan net.Conn
// TLS configuration
tlsConfig *tls.Config
// TLS wrapper
tlsWrap tlsutil.Wrapper
// Tracks if we are closed
closed bool
@ -30,11 +30,11 @@ type RaftLayer struct {
// NewRaftLayer is used to initialize a new RaftLayer which can
// be used as a StreamLayer for Raft. If a tlsConfig is provided,
// then the connection will use TLS.
func NewRaftLayer(addr net.Addr, tlsConfig *tls.Config) *RaftLayer {
func NewRaftLayer(addr net.Addr, tlsWrap tlsutil.Wrapper) *RaftLayer {
layer := &RaftLayer{
addr: addr,
connCh: make(chan net.Conn),
tlsConfig: tlsConfig,
tlsWrap: tlsWrap,
closeCh: make(chan struct{}),
}
return layer
@ -87,7 +87,7 @@ func (l *RaftLayer) Dial(address string, timeout time.Duration) (net.Conn, error
}
// Check for tls mode
if l.tlsConfig != nil {
if l.tlsWrap != nil {
// Switch the connection into TLS mode
if _, err := conn.Write([]byte{byte(rpcTLS)}); err != nil {
conn.Close()
@ -95,7 +95,7 @@ func (l *RaftLayer) Dial(address string, timeout time.Duration) (net.Conn, error
}
// Wrap the connection in a TLS client
conn, err = tlsutil.WrapTLSClient(conn, l.tlsConfig)
conn, err = l.tlsWrap(conn)
if err != nil {
return nil, err
}

4
consul/rpc.go
View File

@ -208,7 +208,7 @@ func (s *Server) forwardLeader(method string, args interface{}, reply interface{
if server == nil {
return structs.ErrNoLeader
}
return s.connPool.RPC(server.Addr, server.Version, method, args, reply)
return s.connPool.RPC(s.config.Datacenter, server.Addr, server.Version, method, args, reply)
}
// forwardDC is used to forward an RPC call to a remote DC, or fail if no servers
@ -229,7 +229,7 @@ func (s *Server) forwardDC(method, dc string, args interface{}, reply interface{
// Forward to remote Consul
metrics.IncrCounter([]string{"consul", "rpc", "cross-dc", dc}, 1)
return s.connPool.RPC(server.Addr, server.Version, method, args, reply)
return s.connPool.RPC(dc, server.Addr, server.Version, method, args, reply)
}
// globalRPC is used to forward an RPC request to one server in each datacenter.

16
consul/server.go
View File

@ -15,6 +15,7 @@ import (
"time"
"github.com/hashicorp/consul/acl"
"github.com/hashicorp/consul/tlsutil"
"github.com/hashicorp/golang-lru"
"github.com/hashicorp/raft"
"github.com/hashicorp/raft-boltdb"
@ -182,9 +183,9 @@ func NewServer(config *Config) (*Server, error) {
config.LogOutput = os.Stderr
}
// Create the tlsConfig for outgoing connections
// Create the tls wrapper for outgoing connections
tlsConf := config.tlsConfig()
tlsConfig, err := tlsConf.OutgoingTLSConfig()
tlsWrap, err := tlsConf.OutgoingTLSWrapper()
if err != nil {
return nil, err
}
@ -207,7 +208,7 @@ func NewServer(config *Config) (*Server, error) {
// Create server
s := &Server{
config: config,
connPool: NewPool(config.LogOutput, serverRPCCache, serverMaxStreams, tlsConfig),
connPool: NewPool(config.LogOutput, serverRPCCache, serverMaxStreams, tlsWrap),
eventChLAN: make(chan serf.Event, 256),
eventChWAN: make(chan serf.Event, 256),
localConsuls: make(map[string]*serverParts),
@ -242,7 +243,7 @@ func NewServer(config *Config) (*Server, error) {
}
// Initialize the RPC layer
if err := s.setupRPC(tlsConfig); err != nil {
if err := s.setupRPC(tlsWrap); err != nil {
s.Shutdown()
return nil, fmt.Errorf("Failed to start RPC layer: %v", err)
}
@ -410,7 +411,7 @@ func (s *Server) setupRaft() error {
}
// setupRPC is used to setup the RPC listener
func (s *Server) setupRPC(tlsConfig *tls.Config) error {
func (s *Server) setupRPC(tlsWrap tlsutil.DCWrapper) error {
// Create endpoints
s.endpoints.Status = &Status{s}
s.endpoints.Catalog = &Catalog{s}
@ -453,7 +454,10 @@ func (s *Server) setupRPC(tlsConfig *tls.Config) error {
return fmt.Errorf("RPC advertise address is not advertisable: %v", addr)
}
s.raftLayer = NewRaftLayer(advertise, tlsConfig)
// Provide a DC specific wrapper. Raft replication is only
// ever done in the same datacenter, so we can provide it as a constant.
wrapper := tlsutil.SpecificDC(s.config.Datacenter, tlsWrap)
s.raftLayer = NewRaftLayer(advertise, wrapper)
return nil
}

25
test/hostname/Alice.crt Normal file
View File

@ -0,0 +1,25 @@
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

27
test/hostname/Alice.key Normal file
View File

@ -0,0 +1,27 @@
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

29
test/hostname/CertAuth.crt Normal file
View File

@ -0,0 +1,29 @@
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

75
tlsutil/config.go
View File

@ -6,9 +6,19 @@ import (
"fmt"
"io/ioutil"
"net"
"strings"
"time"
)
// DCWrapper is a function that is used to wrap a non-TLS connection
// and returns an appropriate TLS connection or error. This takes
// a datacenter as an argument.
type DCWrapper func(dc string, conn net.Conn) (net.Conn, error)
// Wrapper is a variant of DCWrapper, where the DC is provided as
// a constant value. This is usually done by currying DCWrapper.
type Wrapper func(conn net.Conn) (net.Conn, error)
// Config used to create tls.Config
type Config struct {
// VerifyIncoming is used to verify the authenticity of incoming connections.
@ -22,6 +32,14 @@ type Config struct {
// server nodes.
VerifyOutgoing bool
// VerifyServerHostname is used to enable hostname verification of servers. This
// ensures that the certificate presented is valid for server.<datacenter>.<domain>.
// This prevents a compromised client from being restarted as a server, and then
// intercepting request traffic as well as being added as a raft peer. This should be
// enabled by default with VerifyOutgoing, but for legacy reasons we cannot break
// existing clients.
VerifyServerHostname bool
// CAFile is a path to a certificate authority file. This is used with VerifyIncoming
// or VerifyOutgoing to verify the TLS connection.
CAFile string
@ -40,6 +58,9 @@ type Config struct {
// ServerName is used with the TLS certificate to ensure the name we
// provide matches the certificate
ServerName string
// Domain is the Consul TLD being used. Defaults to "consul."
Domain string
}
// AppendCA opens and parses the CA file and adds the certificates to
@ -78,6 +99,10 @@ func (c *Config) KeyPair() (*tls.Certificate, error) {
// requests. It will return a nil config if this configuration should
// not use TLS for outgoing connections.
func (c *Config) OutgoingTLSConfig() (*tls.Config, error) {
// If VerifyServerHostname is true, that implies VerifyOutgoing
if c.VerifyServerHostname {
c.VerifyOutgoing = true
}
if !c.VerifyOutgoing {
return nil, nil
}
@ -90,6 +115,11 @@ func (c *Config) OutgoingTLSConfig() (*tls.Config, error) {
tlsConfig.ServerName = c.ServerName
tlsConfig.InsecureSkipVerify = false
}
if c.VerifyServerHostname {
// ServerName is filled in dynamically based on the target DC
tlsConfig.ServerName = "VerifyServerHostname"
tlsConfig.InsecureSkipVerify = false
}
// Ensure we have a CA if VerifyOutgoing is set
if c.VerifyOutgoing && c.CAFile == "" {
@ -113,6 +143,51 @@ func (c *Config) OutgoingTLSConfig() (*tls.Config, error) {
return tlsConfig, nil
}
// OutgoingTLSWrapper returns a a DCWrapper based on the OutgoingTLS
// configuration. If hostname verification is on, the wrapper
// will properly generate the dynamic server name for verification.
func (c *Config) OutgoingTLSWrapper() (DCWrapper, error) {
// Get the TLS config
tlsConfig, err := c.OutgoingTLSConfig()
if err != nil {
return nil, err
}
// Check if TLS is not enabled
if tlsConfig == nil {
return nil, nil
}
// Strip the trailing '.' from the domain if any
domain := strings.TrimSuffix(c.Domain, ".")
// Generate the wrapper based on hostname verification
if c.VerifyServerHostname {
wrapper := func(dc string, conn net.Conn) (net.Conn, error) {
conf := *tlsConfig
conf.ServerName = "server." + dc + "." + domain
return WrapTLSClient(conn, &conf)
}
return wrapper, nil
} else {
wrapper := func(dc string, c net.Conn) (net.Conn, error) {
return WrapTLSClient(c, tlsConfig)
}
return wrapper, nil
}
}
// SpecificDC is used to invoke a static datacenter
// and turns a DCWrapper into a Wrapper type.
func SpecificDC(dc string, tlsWrap DCWrapper) Wrapper {
if tlsWrap == nil {
return nil
}
return func(conn net.Conn) (net.Conn, error) {
return tlsWrap(dc, conn)
}
}
// Wrap a net.Conn into a client tls connection, performing any
// additional verification as needed.
//

137
tlsutil/config_test.go
View File

@ -7,6 +7,8 @@ import (
"io/ioutil"
"net"
"testing"
"github.com/hashicorp/yamux"
)
func TestConfig_AppendCA_None(t *testing.T) {
@ -133,6 +135,29 @@ func TestConfig_OutgoingTLS_ServerName(t *testing.T) {
}
}
func TestConfig_OutgoingTLS_VerifyHostname(t *testing.T) {
conf := &Config{
VerifyServerHostname: true,
CAFile: "../test/ca/root.cer",
}
tls, err := conf.OutgoingTLSConfig()
if err != nil {
t.Fatalf("err: %v", err)
}
if tls == nil {
t.Fatalf("expected config")
}
if len(tls.RootCAs.Subjects()) != 1 {
t.Fatalf("expect root cert")
}
if tls.ServerName != "VerifyServerHostname" {
t.Fatalf("expect server name")
}
if tls.InsecureSkipVerify {
t.Fatalf("should not skip built-in verification")
}
}
func TestConfig_OutgoingTLS_WithKeyPair(t *testing.T) {
conf := &Config{
VerifyOutgoing: true,
@ -168,8 +193,16 @@ func startTLSServer(config *Config) (net.Conn, chan error) {
}
client, server := net.Pipe()
// Use yamux to buffer the reads, otherwise it's easy to deadlock
muxConf := yamux.DefaultConfig()
serverSession, _ := yamux.Server(server, muxConf)
clientSession, _ := yamux.Client(client, muxConf)
clientConn, _ := clientSession.Open()
serverConn, _ := serverSession.Accept()
go func() {
tlsServer := tls.Server(server, tlsConfigServer)
tlsServer := tls.Server(serverConn, tlsConfigServer)
if err := tlsServer.Handshake(); err != nil {
errc <- err
}
@ -183,7 +216,107 @@ func startTLSServer(config *Config) (net.Conn, chan error) {
io.Copy(ioutil.Discard, tlsServer)
tlsServer.Close()
}()
return client, errc
return clientConn, errc
}
func TestConfig_outgoingWrapper_OK(t *testing.T) {
config := &Config{
CAFile: "../test/hostname/CertAuth.crt",
CertFile: "../test/hostname/Alice.crt",
KeyFile: "../test/hostname/Alice.key",
VerifyServerHostname: true,
Domain: "consul",
}
client, errc := startTLSServer(config)
if client == nil {
t.Fatalf("startTLSServer err: %v", <-errc)
}
wrap, err := config.OutgoingTLSWrapper()
if err != nil {
t.Fatalf("OutgoingTLSWrapper err: %v", err)
}
tlsClient, err := wrap("dc1", client)
if err != nil {
t.Fatalf("wrapTLS err: %v", err)
}
defer tlsClient.Close()
if err := tlsClient.(*tls.Conn).Handshake(); err != nil {
t.Fatalf("write err: %v", err)
}
err = <-errc
if err != nil {
t.Fatalf("server: %v", err)
}
}
func TestConfig_outgoingWrapper_BadDC(t *testing.T) {
config := &Config{
CAFile: "../test/hostname/CertAuth.crt",
CertFile: "../test/hostname/Alice.crt",
KeyFile: "../test/hostname/Alice.key",
VerifyServerHostname: true,
Domain: "consul",
}
client, errc := startTLSServer(config)
if client == nil {
t.Fatalf("startTLSServer err: %v", <-errc)
}
wrap, err := config.OutgoingTLSWrapper()
if err != nil {
t.Fatalf("OutgoingTLSWrapper err: %v", err)
}
tlsClient, err := wrap("dc2", client)
if err != nil {
t.Fatalf("wrapTLS err: %v", err)
}
defer tlsClient.Close()
err = tlsClient.(*tls.Conn).Handshake()
if _, ok := err.(x509.HostnameError); !ok {
t.Fatalf("should get hostname err: %v", err)
}
<-errc
}
func TestConfig_outgoingWrapper_BadCert(t *testing.T) {
config := &Config{
CAFile: "../test/ca/root.cer",
CertFile: "../test/key/ourdomain.cer",
KeyFile: "../test/key/ourdomain.key",
VerifyServerHostname: true,
Domain: "consul",
}
client, errc := startTLSServer(config)
if client == nil {
t.Fatalf("startTLSServer err: %v", <-errc)
}
wrap, err := config.OutgoingTLSWrapper()
if err != nil {
t.Fatalf("OutgoingTLSWrapper err: %v", err)
}
tlsClient, err := wrap("dc1", client)
if err != nil {
t.Fatalf("wrapTLS err: %v", err)
}
defer tlsClient.Close()
err = tlsClient.(*tls.Conn).Handshake()
if _, ok := err.(x509.HostnameError); !ok {
t.Fatalf("should get hostname err: %v", err)
}
<-errc
}
func TestConfig_wrapTLS_OK(t *testing.T) {

11
website/source/docs/agent/encryption.html.markdown
View File

@ -64,7 +64,8 @@ using OpenSSL. Note: client certificates must have
for client and server authentication.
TLS can be used to verify the authenticity of the servers or verify the authenticity of clients.
These modes are controlled by the [`verify_outgoing`](/docs/agent/options.html#verify_outgoing)
These modes are controlled by the [`verify_outgoing`](/docs/agent/options.html#verify_outgoing),
[`verify_server_hostname`](/docs/agent/options.html#verify_server_hostname),
and [`verify_incoming`](/docs/agent/options.html#verify_incoming) options, respectively.
If [`verify_outgoing`](/docs/agent/options.html#verify_outgoing) is set, agents verify the
@ -74,6 +75,14 @@ by the certificate authority present on all agents, set via the agent's
appropriate key pair set using [`cert_file`](/docs/agent/options.html#cert_file) and
[`key_file`](/docs/agent/options.html#key_file).
If [`verify_server_hostname`](/docs/agent/options.html#verify_server_hostname) is set, then
outgoing connections perform hostname verification. All servers must have a certificate
valid for "server.\<datacenter\>.\<domain\>" or the client will reject the handshake. This is
a new configuration as of 0.5.1, and it is used to prevent a compromised client from being
able to restart in server mode and perform a MITM attack. New deployments should set this
to true, and generate the proper certificates, but this is defaulted to false to avoid breaking
existing deployments.
If [`verify_incoming`](/docs/agent/options.html#verify_incoming) is set, the servers verify the
authenticity of all incoming connections. All clients must have a valid key pair set using
[`cert_file`](/docs/agent/options.html#cert_file) and

8
website/source/docs/agent/options.html.markdown
View File

@ -584,6 +584,14 @@ definitions support being updated during a reload.
will not make use of TLS for outgoing connections. This applies to clients and servers
as both will make outgoing connections.
* <a name="verify_server_hostname"></a><a href="#verify_server_hostname">`verify_server_hostname`</a> - If set to
true, Consul verifies for all outgoing connections that the TLS certificate presented by the servers
matches "server.<datacenter>.<domain>" hostname. This implies `verify_outgoing`.
By default, this is false, and Consul does not verify the hostname of the certificate, only
that it is signed by a trusted CA. This setting is important to prevent a compromised
client from being restarted as a server, and thus being able to perform a MITM attack
or to be added as a Raft peer. This is new in 0.5.1.
* <a name="watches"></a><a href="#watches">`watches`</a> - Watches is a list of watch
specifications which allow an external process to be automatically invoked when a
particular data view is updated. See the