* fix: prevent `crypto/ssh` to block on dialing
`crypto/ssh` dialing doesn't support timeouts or context cancellation
propagation by default. Although `ssh.ClientConfig` has a field
`Timeout`, this field is only used when establishing a new TCP
connection but it's never used for ssh handshake.
This means that if the target server never replies and no intermediary
closes the connection, the connecton will be kept alive forever causing
Teleport dialer to deadlock and never recover.
Although teleport `ssh` package has `NewClientConnWithDeadline`, not all
every Teleport implementation of `net.Conn` supports read deadlines,
which means we can have cases where the system also deadlocks when using
`NewClientConnWithDeadline` and a timeout.
This PR tries to solve it by closing the underlying connection when the
minimum time between the context's deadline, the timeout and if none set
30s.
Signed-off-by: Tiago Silva <tiago.silva@goteleport.com>
* Apply suggestion from @espadolini
Co-authored-by: Edoardo Spadolini <edoardo.spadolini@goteleport.com>
* fix code
* rename methods to correctly describe the behavior
Signed-off-by: Tiago Silva <tiago.silva@goteleport.com>
* handle code review comment
---------
Signed-off-by: Tiago Silva <tiago.silva@goteleport.com>
Co-authored-by: Edoardo Spadolini <edoardo.spadolini@goteleport.com>
