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package ssh_config
import (
"fmt"
"strconv"
"strings"
)
// Default returns the default value for the given keyword, for example "22" if
// the keyword is "Port". Default returns the empty string if the keyword has no
// default, or if the keyword is unknown. Keyword matching is case-insensitive.
//
// Default values are provided by OpenSSH_7.4p1 on a Mac.
func Default(keyword string) string {
return defaults[strings.ToLower(keyword)]
}
// Arguments where the value must be "yes" or "no" and *only* yes or no.
var yesnos = map[string]bool{
strings.ToLower("BatchMode"): true,
strings.ToLower("CanonicalizeFallbackLocal"): true,
strings.ToLower("ChallengeResponseAuthentication"): true,
strings.ToLower("CheckHostIP"): true,
strings.ToLower("ClearAllForwardings"): true,
strings.ToLower("Compression"): true,
strings.ToLower("EnableSSHKeysign"): true,
strings.ToLower("ExitOnForwardFailure"): true,
strings.ToLower("ForwardAgent"): true,
strings.ToLower("ForwardX11"): true,
strings.ToLower("ForwardX11Trusted"): true,
strings.ToLower("GatewayPorts"): true,
strings.ToLower("GSSAPIAuthentication"): true,
strings.ToLower("GSSAPIDelegateCredentials"): true,
strings.ToLower("HostbasedAuthentication"): true,
strings.ToLower("IdentitiesOnly"): true,
strings.ToLower("KbdInteractiveAuthentication"): true,
strings.ToLower("NoHostAuthenticationForLocalhost"): true,
strings.ToLower("PasswordAuthentication"): true,
strings.ToLower("PermitLocalCommand"): true,
strings.ToLower("PubkeyAuthentication"): true,
strings.ToLower("RhostsRSAAuthentication"): true,
strings.ToLower("RSAAuthentication"): true,
strings.ToLower("StreamLocalBindUnlink"): true,
strings.ToLower("TCPKeepAlive"): true,
strings.ToLower("UseKeychain"): true,
strings.ToLower("UsePrivilegedPort"): true,
strings.ToLower("VisualHostKey"): true,
}
var uints = map[string]bool{
strings.ToLower("CanonicalizeMaxDots"): true,
strings.ToLower("CompressionLevel"): true, // 1 to 9
strings.ToLower("ConnectionAttempts"): true,
strings.ToLower("ConnectTimeout"): true,
strings.ToLower("NumberOfPasswordPrompts"): true,
strings.ToLower("Port"): true,
strings.ToLower("ServerAliveCountMax"): true,
strings.ToLower("ServerAliveInterval"): true,
}
func mustBeYesOrNo(lkey string) bool {
return yesnos[lkey]
}
func mustBeUint(lkey string) bool {
return uints[lkey]
}
func validate(key, val string) error {
lkey := strings.ToLower(key)
if mustBeYesOrNo(lkey) && (val != "yes" && val != "no") {
return fmt.Errorf("ssh_config: value for key %q must be 'yes' or 'no', got %q", key, val)
}
if mustBeUint(lkey) {
_, err := strconv.ParseUint(val, 10, 64)
if err != nil {
return fmt.Errorf("ssh_config: %v", err)
}
}
return nil
}
var defaults = map[string]string{
strings.ToLower("AddKeysToAgent"): "no",
strings.ToLower("AddressFamily"): "any",
strings.ToLower("BatchMode"): "no",
strings.ToLower("CanonicalizeFallbackLocal"): "yes",
strings.ToLower("CanonicalizeHostname"): "no",
strings.ToLower("CanonicalizeMaxDots"): "1",
strings.ToLower("ChallengeResponseAuthentication"): "yes",
strings.ToLower("CheckHostIP"): "yes",
// TODO is this still the correct cipher
strings.ToLower("Cipher"): "3des",
strings.ToLower("Ciphers"): "chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc",
strings.ToLower("ClearAllForwardings"): "no",
strings.ToLower("Compression"): "no",
strings.ToLower("CompressionLevel"): "6",
strings.ToLower("ConnectionAttempts"): "1",
strings.ToLower("ControlMaster"): "no",
strings.ToLower("EnableSSHKeysign"): "no",
strings.ToLower("EscapeChar"): "~",
strings.ToLower("ExitOnForwardFailure"): "no",
strings.ToLower("FingerprintHash"): "sha256",
strings.ToLower("ForwardAgent"): "no",
strings.ToLower("ForwardX11"): "no",
strings.ToLower("ForwardX11Timeout"): "20m",
strings.ToLower("ForwardX11Trusted"): "no",
strings.ToLower("GatewayPorts"): "no",
strings.ToLower("GlobalKnownHostsFile"): "/etc/ssh/ssh_known_hosts /etc/ssh/ssh_known_hosts2",
strings.ToLower("GSSAPIAuthentication"): "no",
strings.ToLower("GSSAPIDelegateCredentials"): "no",
strings.ToLower("HashKnownHosts"): "no",
strings.ToLower("HostbasedAuthentication"): "no",
strings.ToLower("HostbasedKeyTypes"): "ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,ssh-rsa",
strings.ToLower("HostKeyAlgorithms"): "ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,ssh-rsa",
// HostName has a dynamic default (the value passed at the command line).
strings.ToLower("IdentitiesOnly"): "no",
strings.ToLower("IdentityFile"): "~/.ssh/identity",
// IPQoS has a dynamic default based on interactive or non-interactive
// sessions.
strings.ToLower("KbdInteractiveAuthentication"): "yes",
strings.ToLower("KexAlgorithms"): "curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1",
strings.ToLower("LogLevel"): "INFO",
strings.ToLower("MACs"): "umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1",
strings.ToLower("NoHostAuthenticationForLocalhost"): "no",
strings.ToLower("NumberOfPasswordPrompts"): "3",
strings.ToLower("PasswordAuthentication"): "yes",
strings.ToLower("PermitLocalCommand"): "no",
strings.ToLower("Port"): "22",
strings.ToLower("PreferredAuthentications"): "gssapi-with-mic,hostbased,publickey,keyboard-interactive,password",
strings.ToLower("Protocol"): "2",
strings.ToLower("ProxyUseFdpass"): "no",
strings.ToLower("PubkeyAcceptedKeyTypes"): "ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,ssh-rsa",
strings.ToLower("PubkeyAuthentication"): "yes",
strings.ToLower("RekeyLimit"): "default none",
strings.ToLower("RhostsRSAAuthentication"): "no",
strings.ToLower("RSAAuthentication"): "yes",
strings.ToLower("ServerAliveCountMax"): "3",
strings.ToLower("ServerAliveInterval"): "0",
strings.ToLower("StreamLocalBindMask"): "0177",
strings.ToLower("StreamLocalBindUnlink"): "no",
strings.ToLower("StrictHostKeyChecking"): "ask",
strings.ToLower("TCPKeepAlive"): "yes",
strings.ToLower("Tunnel"): "no",
strings.ToLower("TunnelDevice"): "any:any",
strings.ToLower("UpdateHostKeys"): "no",
strings.ToLower("UseKeychain"): "no",
strings.ToLower("UsePrivilegedPort"): "no",
strings.ToLower("UserKnownHostsFile"): "~/.ssh/known_hosts ~/.ssh/known_hosts2",
strings.ToLower("VerifyHostKeyDNS"): "no",
strings.ToLower("VisualHostKey"): "no",
strings.ToLower("XAuthLocation"): "/usr/X11R6/bin/xauth",
}
// these identities are used for SSH protocol 2
var defaultProtocol2Identities = []string{
"~/.ssh/id_dsa",
"~/.ssh/id_ecdsa",
"~/.ssh/id_ed25519",
"~/.ssh/id_rsa",
}
// these directives support multiple items that can be collected
// across multiple files
var pluralDirectives = map[string]bool{
"CertificateFile": true,
"IdentityFile": true,
"DynamicForward": true,
"RemoteForward": true,
"SendEnv": true,
"SetEnv": true,
}
// SupportsMultiple reports whether a directive can be specified multiple times.
func SupportsMultiple(key string) bool {
return pluralDirectives[strings.ToLower(key)]
}
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