mirror of
https://github.com/gravitational/teleport.git
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rosstimothy
3cca37fff6
* Fix web ssh session with proxy recording mode The agent was not being propagated when establishing an ssh session via the web which resulted in the error described in #18850. Providing the agent was straightforward, however, due to the changes from #18656 when using the forward server, as is required with proxy recording mode, the ssh connection is now being performed directly over a `net.Pipe`. Due to the synchronous nature of `net.Pipe` this causes a deadlock when performing the ssh handshake. To mitigate the deadlocks, `DualPipeNetConn` was changed to leverage `syscall.Socketpair` instead of `net.Pipe`. `TestTerminal` now has two cases, one for node recording mode and another for proxy recording mode. In order for the proxy recording mode test to pass the fake clock used in the test needed to be properly propagated to the `ssh.CertChecker` and `forward.ServerConfig`. Fixes #18850
94 lines
2.7 KiB
Go
94 lines
2.7 KiB
Go
/*
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Copyright 2021 Gravitational, Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package sshutils
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import (
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"github.com/gravitational/trace"
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"github.com/jonboulle/clockwork"
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"github.com/sirupsen/logrus"
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"golang.org/x/crypto/ssh"
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)
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// CheckersGetter defines a function that returns a list of ssh public keys.
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type CheckersGetter func() ([]ssh.PublicKey, error)
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// HostKeyCallbackConfig is the host key callback configuration.
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type HostKeyCallbackConfig struct {
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// GetHostCheckers is used to fetch host checking (public) keys.
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GetHostCheckers CheckersGetter
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// HostKeyFallback sets optional callback to check non-certificate keys.
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HostKeyFallback ssh.HostKeyCallback
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// FIPS allows to set FIPS mode which will validate algorithms.
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FIPS bool
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// OnCheckCert is called on SSH certificate validation.
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OnCheckCert func(*ssh.Certificate)
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// Clock is used to set the Checker Time
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Clock clockwork.Clock
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}
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// Check validates the config.
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func (c *HostKeyCallbackConfig) Check() error {
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if c.GetHostCheckers == nil {
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return trace.BadParameter("missing GetHostCheckers")
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}
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if c.Clock == nil {
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c.Clock = clockwork.NewRealClock()
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}
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return nil
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}
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// NewHostKeyCallback returns host key callback function with the specified parameters.
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func NewHostKeyCallback(conf HostKeyCallbackConfig) (ssh.HostKeyCallback, error) {
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if err := conf.Check(); err != nil {
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return nil, trace.Wrap(err)
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}
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checker := CertChecker{
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CertChecker: ssh.CertChecker{
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IsHostAuthority: makeIsHostAuthorityFunc(conf.GetHostCheckers),
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HostKeyFallback: conf.HostKeyFallback,
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Clock: conf.Clock.Now,
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},
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FIPS: conf.FIPS,
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OnCheckCert: conf.OnCheckCert,
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}
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return checker.CheckHostKey, nil
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}
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func makeIsHostAuthorityFunc(getCheckers CheckersGetter) func(key ssh.PublicKey, host string) bool {
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return func(key ssh.PublicKey, host string) bool {
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checkers, err := getCheckers()
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if err != nil {
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logrus.WithError(err).Errorf("Failed to get checkers for %v.", host)
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return false
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}
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for _, checker := range checkers {
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switch v := key.(type) {
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case *ssh.Certificate:
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if KeysEqual(v.SignatureKey, checker) {
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return true
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}
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default:
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if KeysEqual(key, checker) {
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return true
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}
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}
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}
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logrus.Debugf("No CA for host %v.", host)
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return false
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}
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}
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