From: Tom Clegg <tom@tomclegg.ca>
Date: Thu, 2 Jul 2020 14:48:15 +0000 (-0400)
Subject: 15348: Look up hostname if not provided in config args.
X-Git-Tag: 2.1.0~169^2~2
X-Git-Url: https://git.arvados.org/arvados.git/commitdiff_plain/183f8c6feeb8d3adbf36a1a4adf122607fb55617

15348: Look up hostname if not provided in config args.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@tomclegg.ca>
---

diff --git a/lib/pam/README b/lib/pam/README
index 243a179e6c..aafff23a8c 100644
--- a/lib/pam/README
+++ b/lib/pam/README
@@ -1 +1,18 @@
 For configuration advice, please refer to https://doc.arvados.org/install/install-webshell.html
+
+Usage (in pam config):
+
+    pam_arvados.so arvados_api_host [my_vm_host_name] ["insecure"] ["debug"]
+
+pam_arvados.so passes authentication if (according to
+arvados_api_host) the supplied PAM token belongs to an Arvados user
+who is allowed to log in to my_vm_host_name with the supplied PAM
+username.
+
+If my_vm_host_name is omitted or "-", the current hostname is used.
+
+"insecure" -- continue even if the TLS certificate presented by
+arvados_api_host fails verification.
+
+"debug" -- enable debug-level log messages in syslog and (when not in
+"silent" mode) on the calling application's stderr.
diff --git a/lib/pam/docker_test.go b/lib/pam/docker_test.go
index 5b1755496b..fa16b313be 100644
--- a/lib/pam/docker_test.go
+++ b/lib/pam/docker_test.go
@@ -60,7 +60,6 @@ func (s *DockerSuite) SetUpSuite(c *check.C) {
 	}
 	s.proxysrv = &http.Server{Handler: proxy}
 	go s.proxysrv.ServeTLS(ln, "../../services/api/tmp/self-signed.pem", "../../services/api/tmp/self-signed.key")
-	proxyhost := ln.Addr().String()
 
 	// Build a pam module to install & configure in the docker
 	// container.
@@ -70,20 +69,6 @@ func (s *DockerSuite) SetUpSuite(c *check.C) {
 	err = cmd.Run()
 	c.Assert(err, check.IsNil)
 
-	// Write a PAM config file that uses our proxy as
-	// ARVADOS_API_HOST.
-	confdata := fmt.Sprintf(`Name: Arvados authentication
-Default: yes
-Priority: 256
-Auth-Type: Primary
-Auth:
-	[success=end default=ignore]	/usr/lib/pam_arvados.so %s testvm2.shell insecure
-Auth-Initial:
-	[success=end default=ignore]	/usr/lib/pam_arvados.so %s testvm2.shell insecure
-`, proxyhost, proxyhost)
-	err = ioutil.WriteFile(s.tmpdir+"/conffile", []byte(confdata), 0755)
-	c.Assert(err, check.IsNil)
-
 	// Build the testclient program that will (from inside the
 	// docker container) configure the system to use the above PAM
 	// config, and then try authentication.
@@ -103,9 +88,28 @@ func (s *DockerSuite) TearDownSuite(c *check.C) {
 	}
 }
 
+func (s *DockerSuite) SetUpTest(c *check.C) {
+	// Write a PAM config file that uses our proxy as
+	// ARVADOS_API_HOST.
+	proxyhost := s.proxyln.Addr().String()
+	confdata := fmt.Sprintf(`Name: Arvados authentication
+Default: yes
+Priority: 256
+Auth-Type: Primary
+Auth:
+	[success=end default=ignore]	/usr/lib/pam_arvados.so %s testvm2.shell insecure
+Auth-Initial:
+	[success=end default=ignore]	/usr/lib/pam_arvados.so %s testvm2.shell insecure
+`, proxyhost, proxyhost)
+	err := ioutil.WriteFile(s.tmpdir+"/conffile", []byte(confdata), 0755)
+	c.Assert(err, check.IsNil)
+}
+
 func (s *DockerSuite) runTestClient(c *check.C, args ...string) (stdout, stderr *bytes.Buffer, err error) {
+
 	cmd := exec.Command("docker", append([]string{
 		"run", "--rm",
+		"--hostname", "testvm2.shell",
 		"--add-host", "zzzzz.arvadosapi.com:" + s.hostip,
 		"-v", s.tmpdir + "/pam_arvados.so:/usr/lib/pam_arvados.so:ro",
 		"-v", s.tmpdir + "/conffile:/usr/share/pam-configs/arvados:ro",
@@ -147,3 +151,23 @@ func (s *DockerSuite) TestFailure(c *check.C) {
 		c.Check(stderr.String(), check.Matches, `(?ms).*authentication failed.*`)
 	}
 }
+
+func (s *DockerSuite) TestDefaultHostname(c *check.C) {
+	confdata := fmt.Sprintf(`Name: Arvados authentication
+Default: yes
+Priority: 256
+Auth-Type: Primary
+Auth:
+	[success=end default=ignore]	/usr/lib/pam_arvados.so %s - insecure debug
+Auth-Initial:
+	[success=end default=ignore]	/usr/lib/pam_arvados.so %s - insecure debug
+`, s.proxyln.Addr().String(), s.proxyln.Addr().String())
+	err := ioutil.WriteFile(s.tmpdir+"/conffile", []byte(confdata), 0755)
+	c.Assert(err, check.IsNil)
+
+	stdout, stderr, err := s.runTestClient(c, "try", "active", arvadostest.ActiveTokenV2)
+	c.Check(err, check.IsNil)
+	c.Logf("%s", stderr.String())
+	c.Check(stdout.String(), check.Equals, "")
+	c.Check(stderr.String(), check.Matches, `(?ms).*authentication succeeded.*`)
+}
diff --git a/lib/pam/pam_arvados.go b/lib/pam/pam_arvados.go
index 389033ba96..34b9080536 100644
--- a/lib/pam/pam_arvados.go
+++ b/lib/pam/pam_arvados.go
@@ -24,6 +24,7 @@ package main
 import (
 	"io/ioutil"
 	"log/syslog"
+	"os"
 
 	"context"
 	"errors"
@@ -104,8 +105,16 @@ func authenticate(logger *logrus.Logger, username, token string, argv []string)
 			logger.Warnf("unkown option: %s\n", arg)
 		}
 	}
+	if hostname == "" || hostname == "-" {
+		h, err := os.Hostname()
+		if err != nil {
+			logger.WithError(err).Warnf("cannot get hostname -- try using an explicit hostname in pam config")
+			return fmt.Errorf("cannot get hostname: %w", err)
+		}
+		hostname = h
+	}
 	logger.Debugf("username=%q arvados_api_host=%q hostname=%q insecure=%t", username, apiHost, hostname, insecure)
-	if apiHost == "" || hostname == "" {
+	if apiHost == "" {
 		logger.Warnf("cannot authenticate: config error: arvados_api_host and hostname must be non-empty")
 		return errors.New("config error")
 	}