tsh: Add support for host:port combinations to tsh puttyconfig

docs/pages/connect-your-client/putty-winscp.mdx

@@ -54,6 +54,7 @@ Node Name                           Address        Labels
 ----------------------------------- -------------- ----------------------------
 ip-172-31-30-140                    127.0.0.1:3022 company=acmecorp,env=aws,...
 ip-172-31-34-128.us-east-2.compu... ⟵ Tunnel      access=open,enhanced_reco...
+ip-172-31-8-63                      172.31.8.63:22 type=openssh
 ```
 
 3. Add a saved session for a specific login on a specific node to the Windows registry.
@@ -68,6 +69,17 @@ Added PuTTY session for ubuntu@ip-172-31-30-140 [proxy:teleport.example.com]
 
 If you don't provide a login to this command, your local Windows username is used instead.
 
+If you are adding a session for a registered OpenSSH node within your cluster (added with
+[`teleport join openssh`](../server-access/guides/openssh/openssh.mdx)), you must specify the `sshd` port
+(usually 22) when adding a session with `tsh puttyconfig`:
+
+```bash
+C:\Users\gus>tsh puttyconfig --port 22 ubuntu@ip-172-31-8-63
+Added PuTTY session for ubuntu@ip-172-31-8-63 [proxy:teleport.example.com]
+```
+
+You can also use `tsh puttyconfig user@host:22` if you prefer.
+
 </TabItem>
 <TabItem scope={["cloud"]} label="Teleport Enterprise Cloud">
 
@@ -241,8 +253,8 @@ After a session has been added, you can make changes to it in the PuTTY UI by cl
 
 ### If I re-run `tsh puttyconfig` for a given host, will it overwrite any custom changes I've made to the saved session?
 
-Teleport only modifies the configuration parameters that it relies on, like the proxy name, proxy command, hostname, username, and so on.
-Any changes to font size, window size, and other parameters are left untouched.
+Teleport only modifies the configuration parameters that it relies on, like the proxy name, proxy command, hostname, username,
+port, and so on. Any changes to font size, window size, and other parameters are left untouched.
 
 ### Can I use other graphical clients like MobaXterm or SecureCRT?
 
@@ -285,6 +297,9 @@ The Teleport proxy is unable to connect to the given host/port provided in the s
 offline. Check that the node is visible in `tsh ls` and that you can connect to it with `tsh ssh login@hostname`. If this is
 successful, check the Teleport proxy logs for more detailed errors.
 
+If the node is running OpenSSH rather than Teleport, you must make sure to specify the `sshd` port when adding the session,
+for example using `tsh puttyconfig --port 22 user@host` or `tsh puttyconfig user@host:22`.
+
 ### `Unable to use certificate file "C:\Users\<username>\.tsh\keys\<proxy>\<user>-ssh\<cluster>-cert.pub" (unable to open file)`
 
 You are not logged into Teleport correctly. Run `tsh login --proxy=<proxy hostname>` to get valid certificates before

docs/pages/reference/cli/tsh.mdx

@@ -180,6 +180,9 @@ $ tsh puttyconfig [--leaf <leaf-cluster-name>] [login@]hostname
 # Add a saved PuTTY session on 'node' for the user 'ec2-user'
 $ tsh puttyconfig ec2-user@node
 
+# Add a saved PuTTY session for the Teleport-registered OpenSSH node 'openssh' for the user 'ubuntu'
+$ tsh puttyconfig --port 22 ubuntu@openssh
+
 # Add a saved PuTTY session on leaf-node for the user 'ec2-user' on the leaf cluster 'example.teleport.sh'
 $ tsh puttyconfig --leaf example.teleport.sh ec2-user@leaf-node
 ```

lib/puttyhosts/puttyhosts.go

@@ -142,7 +142,7 @@ func AddHostToHostList(hostList []string, hostname string) []string {
 	return outputHostList
 }
 
-var hostnameRegexp = regexp.MustCompile("^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9]).)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9-]*[A-Za-z0-9])$")
+var hostnameRegexp = regexp.MustCompile(`^([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])(\.([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9]))*$`)
 
 // NaivelyValidateHostname checks the provided hostname against a naive regex to ensure it doesn't contain obviously
 // illegal characters. It's not guaranteed to be perfect, just a simple sanity check. It returns true when the hostname validates.

lib/puttyhosts/puttyhosts_test.go

@@ -300,6 +300,14 @@ func TestNaivelyValidateHostname(t *testing.T) {
 			hostname:   "consecutive..dots",
 			shouldPass: false,
 		},
+		{
+			hostname:   "host:22",
+			shouldPass: false,
+		},
+		{
+			hostname:   "host with spaces",
+			shouldPass: false,
+		},
 	}
 
 	for _, tt := range tests {

tool/tsh/common/putty_config_windows.go

@@ -19,6 +19,7 @@ package common
 import (
 	"fmt"
 	"net"
+	"strconv"
 	"strings"
 	"syscall"
 
@@ -257,15 +258,25 @@ func onPuttyConfig(cf *CLIConf) error {
 		return trace.Wrap(err)
 	}
 
-	// remove any spaces from provided hostname and validate it against a naive regex to make sure it doesn't contain
-	// obviously illegal characters due to typos or similar. setting an "invalid" key in the registry makes it impossible
-	// to delete via the PuTTY UI and requires registry edits, so it's much better to error out early here.
-	hostname := strings.ReplaceAll(tc.Config.Host, " ", "")
+	// remove any spaces from the provided hostname. if the hostname contains a colon, it will be a
+	// hostname:port combination so we split it. this is useful as shorthand when adding OpenSSH hosts
+	// with `tsh puttyconfig user@host:22`, rather than using the longer `tsh puttyconfig --port 22 user@host`
+	hostname := strings.TrimSpace(tc.Config.Host)
+	port := tc.Config.HostPort
+	if splitHost, splitPort, err := net.SplitHostPort(hostname); err == nil {
+		hostname = splitHost
+		port, err = strconv.Atoi(splitPort)
+		if err != nil {
+			return trace.Wrap(err)
+		}
+	}
+	// validate the hostname against a naive regex to make sure it doesn't contain obviously illegal characters
+	// due to typos or similar. setting an "invalid" key in the registry makes it impossible to delete via the
+	// PuTTY UI and requires registry edits, so it's much better to error out early here.
 	if !puttyhosts.NaivelyValidateHostname(hostname) {
 		return trace.BadParameter("provided hostname %v does not look like a valid hostname. Make sure it doesn't contain illegal characters.", hostname)
 	}
 
-	port := tc.Config.HostPort
 	userHostString := hostname
 	login := ""
 	if tc.Config.HostLogin != "" {