Add container suplimentary groups support

Author: parrobe

cmd/runmqserver/main.go

@@ -64,6 +64,13 @@ func doMain() error {
 		logTermination(err)
 		return err
 	}
+
+	err = verifyCurrentUser()
+	if err != nil {
+		logTermination(err)
+		return err
+	}
+
 	err = createVolume("/mnt/mqm")
 	if err != nil {
 		logTermination(err)

cmd/runmqserver/mqconfig.go

@@ -18,7 +18,6 @@ package main
 import (
 	"fmt"
 	"io/ioutil"
-	"os/user"
 	"runtime"
 	"strings"
 
@@ -52,25 +51,6 @@ func logBaseImage() error {
 	return nil
 }
 
-func logUser() {
-	u, err := user.Current()
-	if err == nil {
-		g, err := u.GroupIds()
-		if err != nil {
-			log.Printf("Running as user ID %v (%v) with primary group %v", u.Uid, u.Name, u.Gid)
-		} else {
-			// Look for the primary group in the list of group IDs
-			for i, v := range g {
-				if v == u.Gid {
-					// Remove the element from the slice
-					g = append(g[:i], g[i+1:]...)
-				}
-			}
-			log.Printf("Running as user ID %v (%v) with primary group %v, and supplemental groups %v", u.Uid, u.Name, u.Gid, strings.Join(g, ","))
-		}
-	}
-}
-
 // logCapabilities logs the Linux capabilities (e.g. setuid, setgid).  See https://docs.docker.com/engine/reference/run/#runtime-privilege-and-linux-capabilities
 func logCapabilities() error {
 	caps, err := container.Capabilities()

cmd/runmqserver/user.go

@@ -0,0 +1,101 @@
+/*
+© Copyright IBM Corporation 2018
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package main
+
+import (
+	"fmt"
+	"os/user"
+	"strings"
+
+	"github.com/ibm-messaging/mq-container/internal/command"
+)
+
+const groupName string = "suplgroup"
+
+func verifyCurrentUser() error {
+	log.Debug("Verifying current user information")
+	curUser, err := user.Current()
+	if err != nil {
+		return err
+	}
+	log.Debugf("Detected current user as: %v+", curUser)
+	if curUser.Username == "mqm" {
+		// Not supported yet
+		return fmt.Errorf("Container is running as mqm user which is not supported. Please run this container as root")
+	} else if curUser.Username == "root" {
+		// We're running as root so need to check for suplimentary groups.
+		// We can't use the golang User.GroupIDs as it doesn't seem to detect container supplimentary groups..
+		groups, err := getCurrentGroups()
+		for _, e := range groups {
+			_, _, testGroup := command.Run("getent", "group", e)
+			if testGroup != nil {
+				log.Printf("Group %s does not exist on the system... Adding to system and MQM user", e)
+				_, _, err = command.Run("groupadd", "-g", e, groupName)
+				if err != nil {
+					log.Errorf("Failed to create group %s as %s", e, groupName)
+					return err
+				}
+				_, _, err = command.Run("usermod", "-aG", groupName, "mqm")
+				if err != nil {
+					log.Errorf("Failed to add group %s(%s) to the mqm user.", groupName, e)
+					return err
+				}
+			}
+		}
+	} else {
+		// We're running as an unknown user...
+		return fmt.Errorf("Container is running as %s user which is not supported. Please run this container as root", curUser.Username)
+	}
+
+	return nil
+}
+
+func logUser() {
+	u, err := user.Current()
+	if err == nil {
+		g, err := getCurrentGroups()
+		if err != nil && len(g) == 0 {
+			log.Printf("Running as user ID %v (%v) with primary group %v", u.Uid, u.Name, u.Gid)
+		} else {
+			// Look for the primary group in the list of group IDs
+			for i, v := range g {
+				if v == u.Gid {
+					// Remove the element from the slice
+					g = append(g[:i], g[i+1:]...)
+				}
+			}
+			log.Printf("Running as user ID %v (%v) with primary group %v, and supplemental groups %v", u.Uid, u.Name, u.Gid, strings.Join(g, ","))
+		}
+	}
+}
+
+func getCurrentGroups() ([]string, error) {
+	var nilArray []string
+	out, _, err := command.Run("id", "--groups")
+	if err != nil {
+		log.Debug("Unable to get current user groups")
+		return nilArray, err
+	}
+
+	out = strings.TrimSpace(out)
+	if out == "" {
+		// we don't have any groups?
+		return nilArray, fmt.Errorf("Unable to determine groups for current user")
+	}
+
+	groups := strings.Split(out, " ")
+	return groups, nil
+}