Add possibility to set environment variables for specific services

Add possibility of persistent connections

Author: cyrilst

.cirrus.yml

@@ -2,9 +2,9 @@ task:
   env:
     GOPROXY: https://proxy.golang.org
     matrix:
-      VERSION: 1.13
       VERSION: 1.14
       VERSION: 1.15
+      VERSION: 1.16
 
   container:
     image: golang:$VERSION

Makefile

@@ -11,7 +11,7 @@ bashcompdir	?= /etc/bash_completion.d
 GO		?= go
 
 ASCIIDOC_OPTS	= -asshproxy_version=$(SSHPROXY_VERSION)
-GO_OPTS		= $(GO_OPTS_EXTRA) -ldflags "-X main.SshproxyVersion=$(SSHPROXY_VERSION)"
+GO_OPTS		= $(GO_OPTS_EXTRA) -mod=vendor -ldflags "-X main.SshproxyVersion=$(SSHPROXY_VERSION)"
 
 SSHPROXY_SRC		= $(wildcard cmd/sshproxy/*.go)
 SSHPROXY_DUMPD_SRC	= $(wildcard cmd/sshproxy-dumpd/*.go)

cmd/sshproxy/sshproxy.go

@@ -93,23 +93,24 @@ func (c *etcdChecker) doCheck(hostport string) utils.State {
 // findDestination finds a reachable destination for the sshd server according
 // to the etcd database if available or the routes and route_select algorithm.
 // It returns a string with the service name, a string with host:port, a string
-// containing ForceCommand value and a bool containing CommandMustMatch; a
+// containing ForceCommand value, a bool containing CommandMustMatch, an int64
+// with etcd_keyttl and a map of strings with the environment variables; a
 // string with the service name and an empty string if no destination is found
 // or an error if any.
-func findDestination(cli *utils.Client, username string, routes map[string]*utils.RouteConfig, sshdHostport string, checkInterval utils.Duration) (string, string, string, bool, error) {
+func findDestination(cli *utils.Client, username string, routes map[string]*utils.RouteConfig, sshdHostport string, checkInterval utils.Duration) (string, string, string, bool, int64, map[string]string, error) {
 	checker := &etcdChecker{
 		checkInterval: checkInterval,
 		cli:           cli,
 	}
 
 	service, err := findService(routes, sshdHostport)
 	if err != nil {
-		return "", "", "", false, err
+		return "", "", "", false, 0, nil, err
 	}
 	key := fmt.Sprintf("%s@%s", username, service)
 
 	if routes[service].Mode == "sticky" && cli != nil && cli.IsAlive() {
-		dest, err := cli.GetDestination(key)
+		dest, err := cli.GetDestination(key, routes[service].EtcdKeyTTL)
 		if err != nil {
 			if err != utils.ErrKeyNotFound {
 				log.Errorf("problem with etcd: %v", err)
@@ -118,7 +119,7 @@ func findDestination(cli *utils.Client, username string, routes map[string]*util
 			if utils.IsDestinationInRoutes(dest, routes[service].Dest) {
 				if checker.Check(dest) {
 					log.Debugf("found destination in etcd: %s", dest)
-					return service, dest, routes[service].ForceCommand, routes[service].CommandMustMatch, nil
+					return service, dest, routes[service].ForceCommand, routes[service].CommandMustMatch, routes[service].EtcdKeyTTL, routes[service].Environment, nil
 				}
 				log.Infof("cannot connect %s to already existing connection(s) to %s: host %s", key, dest, checker.LastState)
 			} else {
@@ -129,10 +130,10 @@ func findDestination(cli *utils.Client, username string, routes map[string]*util
 
 	if len(routes[service].Dest) > 0 {
 		selected, err := utils.SelectRoute(routes[service].RouteSelect, routes[service].Dest, checker, cli, key)
-		return service, selected, routes[service].ForceCommand, routes[service].CommandMustMatch, err
+		return service, selected, routes[service].ForceCommand, routes[service].CommandMustMatch, routes[service].EtcdKeyTTL, routes[service].Environment, err
 	}
 
-	return service, "", "", false, fmt.Errorf("no destination set for service %s", service)
+	return service, "", "", false, 0, nil, fmt.Errorf("no destination set for service %s", service)
 }
 
 // findService finds the first service containing a suitable source in the conf,
@@ -326,7 +327,7 @@ func mainExitCode() int {
 		log.Errorf("Cannot contact etcd cluster to update state: %v", err)
 	}
 
-	service, hostport, forceCommand, commandMustMatch, err := findDestination(cli, username, config.Routes, sshInfos.Dst(), config.CheckInterval)
+	service, hostport, forceCommand, commandMustMatch, etcdKeyTTL, environment, err := findDestination(cli, username, config.Routes, sshInfos.Dst(), config.CheckInterval)
 	switch {
 	case err != nil:
 		log.Fatalf("Finding destination: %s", err)
@@ -345,6 +346,8 @@ func mainExitCode() int {
 		log.Fatalf("Invalid destination '%s': %s", hostport, err)
 	}
 
+	setEnvironment(environment)
+
 	// waitgroup and channel to stop our background command when exiting.
 	var wg sync.WaitGroup
 	ctx, cancel := context.WithCancel(context.Background())
@@ -366,7 +369,7 @@ func mainExitCode() int {
 	// Register destination in etcd and keep it alive while running.
 	if cli != nil && cli.IsAlive() {
 		key := fmt.Sprintf("%s@%s", username, service)
-		keepAliveChan, eP, err := cli.SetDestination(ctx, key, sshInfos.Dst(), hostport)
+		keepAliveChan, eP, err := cli.SetDestination(ctx, key, sshInfos.Dst(), hostport, etcdKeyTTL)
 		etcdPath = eP
 		if err != nil {
 			log.Warningf("setting destination in etcd: %v", err)

config/sshproxy.yaml

@@ -129,13 +129,16 @@
 # the selection is random. For "bandwidth", it's the same as "connections", but
 # based on the bandwidth used, with a rollback on connections (which is
 # frequent for new simultaneous connections). The mode value defines the
-# stickiness of a connection. It can be "sticky" or "balanced". If "sticky",
-# then all connections of a user will be made on the same destination host. If
-# "balanced", the route_select algorithm will be used for every connection.
-# Finally, the force_command can be set to override the command asked by the
-# user. If command_must_match is set to true, then the connection is closed if
-# the original command is not the same as the force_command. command_must_match
-# defaults to false.
+# stickiness of a connection. It can be "sticky" or "balanced" (defaults to
+# sticky). If "sticky", then all connections of a user will be made on the same
+# destination host. If "balanced", the route_select algorithm will be used for
+# every connection.  Finally, the force_command can be set to override the
+# command asked by the user. If command_must_match is set to true, then the
+# connection is closed if the original command is not the same as the
+# force_command. command_must_match defaults to false. etcd_keyttl defauts to
+# 0. If a value is set (in seconds), the chosen backen will be remembered for
+# this amount of time. Environment variables can be set if needed. The '{user}'
+# pattern will be replaced with the user login.
 #routes:
 #    service1:
 #        source: ["192.168.0.1"]
@@ -147,6 +150,9 @@
 #        mode: balanced
 #        force_command: "internal-sftp"
 #        command_must_match: true
+#        etcd_keyttl: 3600
+#        environment:
+#            XAUTHORITY: /dev/shm/.Xauthority_{user}
 #    default:
 #        dest: ["host5:4222"]
 

doc/sshproxy.yaml.txt

@@ -102,11 +102,14 @@ executed by the ssh forked by sshproxy. *translate_commands* is an associative
 array which keys are strings containing the exact user command. The value is
 an associative array containing:
 
-*ssh_args*::
-	an optional list of options that will be passed to ssh.
+An associative array *ssh* specifies the SSH options:
+
+*exe*::
+	path or command to use for the SSH client ('ssh' by default).
 
-*command*::
-	a mandatory string, the actual executed command.
+*args*::
+	a list of arguments for the SSH client. Its default value is: '["-q",
+	"-Y"]'.
 
 *disable_dump*::
 	false by default. If true, no dumps will be done for this command.
@@ -178,6 +181,9 @@ listening IP address of the SSH daemon:
 	        mode: balanced
 		force_command: "internal-sftp"
 		command_must_match: true
+		etcd_keyttl: 3600
+		environment:
+		    XAUTHORITY: /dev/shm/.Xauthority_{user}
 	    default:
 	        dest: ["host5:4222"]
 
@@ -195,28 +201,23 @@ priority, then the hosts with less global connections, and in case of a draw,
 the selection is random. For 'bandwidth', it's the same as 'connections', but
 based on the bandwidth used, with a rollback on connections (which is
 frequent for new simultaneous connections). The mode value defines the
-stickiness of a connection. It can be 'sticky' or 'balanced'. If 'sticky',
-then all connections of a user will be made on the same destination host. If
-'balanced', the route_select algorithm will be used for every connections.
-Finally, the force_command can be set to override the command asked by the
-user. If command_must_match is set to true, then the connection is closed if
-the original command is not the same as the force_command. command_must_match
-defaults to false.
+stickiness of a connection. It can be 'sticky' or 'balanced' (defaults to
+'sticky'). If 'sticky', then all connections of a user will be made on the
+same destination host. If 'balanced', the route_select algorithm will be used
+for every connections.  Finally, the force_command can be set to override the
+command asked by the user. If command_must_match is set to true, then the
+connection is closed if the original command is not the same as the
+force_command. command_must_match defaults to false. etcd_keyttl defauts to 0.
+If a value is set (in seconds), the chosen backen will be remembered for this
+amount of time. An associative array *environment* can be used to set
+environment variables. The pattern '\{user}' will be replaced with the user
+login.
 
 In the previous example, a client connected to '192.168.0.1' will be proxied
 to 'host1' and, if the host is not reachable, to 'host2'. If a client does not
 connect to '192.168.0.1' or '192.168.0.2' it will be proxied to the sshd
 daemon listening on port 4222 on 'host5'.
 
-An associative array *ssh* specifies the SSH options:
-
-*exe*::
-	path or command to use for the SSH client ('ssh' by default).
-
-*args*::
-	a list of arguments for the SSH client. Its default value is: '["-q",
-	"-Y"]'.
-
 Each of the previous parameters can be overridden for a group thanks to the
 *groups* associative array.
 

go.mod

@@ -0,0 +1,21 @@
+module github.com/cea-hpc/sshproxy
+
+go 1.14
+
+require (
+	github.com/BurntSushi/toml v1.0.0 // indirect
+	github.com/coreos/etcd v2.3.8+incompatible // indirect
+	github.com/docker/docker v20.10.13+incompatible
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/kr/pty v1.1.8
+	github.com/moby/term v0.0.0-20210619224110-3f7ff695adc6 // indirect
+	github.com/olekukonko/tablewriter v0.0.5
+	github.com/op/go-logging v0.0.0-20160315200505-970db520ece7
+	go.etcd.io/etcd v2.3.8+incompatible
+	golang.org/x/lint v0.0.0-20210508222113-6edffad5e616 // indirect
+	golang.org/x/sys v0.0.0-20220319134239-a9b59b0215f8 // indirect
+	golang.org/x/tools v0.1.10 // indirect
+	gopkg.in/yaml.v2 v2.4.0
+	honnef.co/go/tools v0.2.2 // indirect
+)