Log Linux capabilities

Dockerfile-server

@@ -18,14 +18,15 @@ WORKDIR /go/src/github.com/ibm-messaging/mq-container/
 COPY cmd/ ./cmd
 COPY pkg/ ./pkg
 COPY vendor/ ./vendor
-RUN GOOS=linux go build ./cmd/runmqserver/
+RUN go build ./cmd/runmqserver/
-RUN GOOS=linux go build ./cmd/chkmqready/
+RUN go build ./cmd/chkmqready/
-RUN GOOS=linux go build ./cmd/chkmqhealthy/
+RUN go build ./cmd/chkmqhealthy/
 
 # Build stage to run Go unit tests
 FROM golang:1.9 as tester
 COPY pkg/ ./pkg
-RUN cd pkg/name && GOOS=linux go test
+RUN cd pkg/name && go test
+RUN cd pkg/linux/capabilities && go test
 
 # Main build stage, to build MQ image
 FROM ubuntu:16.04

cmd/runmqserver/mqconfig.go

@@ -22,6 +22,7 @@ import (
 	"runtime"
 	"strings"
 
+	"github.com/ibm-messaging/mq-container/pkg/linux/capabilities"
 	"golang.org/x/sys/unix"
 )
 
@@ -62,6 +63,18 @@ func logUser() {
 	}
 }
 
+func logCapabilities() {
+	status, err := readProc("/proc/1/status")
+	if err != nil {
+		// Ignore
+		return
+	}
+	caps, err := capabilities.DetectCapabilities(status)
+	if err == nil {
+		log.Printf("Detected capabilities: %v", strings.Join(caps, ","))
+	}
+}
+
 func readProc(filename string) (value string, err error) {
 	buf, err := ioutil.ReadFile(filename)
 	if err != nil {
@@ -130,6 +143,7 @@ func logConfig() {
 			log.Printf("Maximum file handles: %v", fileMax)
 		}
 		logUser()
+		logCapabilities()
 		readMounts()
 	} else {
 		log.Fatalf("Unsupported platform: %v", runtime.GOOS)

pkg/linux/capabilities/capabilities.go

@@ -0,0 +1,158 @@
+/*
+© Copyright IBM Corporation 2017
+
+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.
+*/
+
+// capabilities allows querying of information on Linux capabilities
+package capabilities
+
+import (
+	"errors"
+	"strconv"
+	"strings"
+)
+
+// DetectCapabilities determines Linux capabilities, based on the contents of a Linux "status" file.
+// For example, the contents of file `/proc/1/status`
+func DetectCapabilities(status string) ([]string, error) {
+	lines := strings.Split(status, "\n")
+	for _, line := range lines {
+		if strings.HasPrefix(strings.TrimSpace(line), "CapPrm:") {
+			words := strings.Fields(line)
+			cap, err := strconv.ParseUint(words[1], 16, 64)
+			if err != nil {
+				return nil, err
+			}
+			return getCapabilities(cap), nil
+		}
+	}
+	return nil, errors.New("Unable to detect capabilities")
+}
+
+// getCapabilities converts an encoded uint64 into a slice of string names of Linux capabilities
+func getCapabilities(cap uint64) []string {
+	caps := make([]string, 0, 37)
+	if cap&0x0000000040000000 == 0x0000000040000000 {
+		caps = append(caps, "AUDIT_CONTROL")
+	}
+	if cap&0x0000000020000000 == 0x0000000020000000 {
+		caps = append(caps, "AUDIT_WRITE")
+	}
+	if cap&0x0000001000000000 == 0x0000001000000000 {
+		caps = append(caps, "BLOCK_SUSPEND")
+	}
+	if cap&0x0000000000000001 == 0x0000000000000001 {
+		caps = append(caps, "CHOWN")
+	}
+	if cap&0x0000000000000002 == 0x0000000000000002 {
+		caps = append(caps, "DAC_OVERRIDE")
+	}
+	if cap&0x0000000000000004 == 0x0000000000000004 {
+		caps = append(caps, "DAC_READ_SEARCH")
+	}
+	if cap&0x0000000000000008 == 0x0000000000000008 {
+		caps = append(caps, "FOWNER")
+	}
+	if cap&0x0000000000000010 == 0x0000000000000010 {
+		caps = append(caps, "FSETID")
+	}
+	if cap&0x0000000000004000 == 0x0000000000004000 {
+		caps = append(caps, "IPC_LOCK")
+	}
+	if cap&0x0000000000008000 == 0x0000000000008000 {
+		caps = append(caps, "IPC_OWNER")
+	}
+	if cap&0x0000000000000020 == 0x0000000000000020 {
+		caps = append(caps, "KILL")
+	}
+	if cap&0x0000000010000000 == 0x0000000010000000 {
+		caps = append(caps, "LEASE")
+	}
+	if cap&0x0000000000000200 == 0x0000000000000200 {
+		caps = append(caps, "LINUX_IMMUTABLE")
+	}
+	if cap&0x0000000200000000 == 0x0000000200000000 {
+		caps = append(caps, "MAC_ADMIN")
+	}
+	if cap&0x0000000100000000 == 0x0000000100000000 {
+		caps = append(caps, "MAC_OVERRIDE")
+	}
+	if cap&0x0000000008000000 == 0x0000000008000000 {
+		caps = append(caps, "MKNOD")
+	}
+	if cap&0x0000000000001000 == 0x0000000000001000 {
+		caps = append(caps, "NET_ADMIN")
+	}
+	if cap&0x0000000000000400 == 0x0000000000000400 {
+		caps = append(caps, "NET_BIND_SERVICE")
+	}
+	if cap&0x0000000000000800 == 0x0000000000000800 {
+		caps = append(caps, "NET_BROADCAST")
+	}
+	if cap&0x0000000000002000 == 0x0000000000002000 {
+		caps = append(caps, "NET_RAW")
+	}
+	if cap&0x0000000080000000 == 0x0000000080000000 {
+		caps = append(caps, "SETFCAP")
+	}
+	if cap&0x0000000000000040 == 0x0000000000000040 {
+		caps = append(caps, "SETGID")
+	}
+	if cap&0x0000000000000100 == 0x0000000000000100 {
+		caps = append(caps, "SETPCAP")
+	}
+	if cap&0x0000000000000080 == 0x0000000000000080 {
+		caps = append(caps, "SETUID")
+	}
+	if cap&0x0000000400000000 == 0x0000000400000000 {
+		caps = append(caps, "SYSLOG")
+	}
+	if cap&0x0000000000200000 == 0x0000000000200000 {
+		caps = append(caps, "SYS_ADMIN")
+	}
+	if cap&0x0000000000400000 == 0x0000000000400000 {
+		caps = append(caps, "SYS_BOOT")
+	}
+	if cap&0x0000000000040000 == 0x0000000000040000 {
+		caps = append(caps, "SYS_CHROOT")
+	}
+	if cap&0x0000000000010000 == 0x0000000000010000 {
+		caps = append(caps, "SYS_MODULE")
+	}
+	if cap&0x0000000000800000 == 0x0000000000800000 {
+		caps = append(caps, "SYS_NICE")
+	}
+	if cap&0x0000000000100000 == 0x0000000000100000 {
+		caps = append(caps, "SYS_PACCT")
+	}
+	if cap&0x0000000000080000 == 0x0000000000080000 {
+		caps = append(caps, "SYS_PTRACE")
+	}
+	if cap&0x0000000000020000 == 0x0000000000020000 {
+		caps = append(caps, "SYS_RAWIO")
+	}
+	if cap&0x0000000001000000 == 0x0000000001000000 {
+		caps = append(caps, "SYS_RESOURCE")
+	}
+	if cap&0x0000000002000000 == 0x0000000002000000 {
+		caps = append(caps, "SYS_TIME")
+	}
+	if cap&0x0000000004000000 == 0x0000000004000000 {
+		caps = append(caps, "SYS_TTY_CONFIG")
+	}
+	if cap&0x0000000800000000 == 0x0000000800000000 {
+		caps = append(caps, "WAKE_ALARM")
+	}
+	return caps
+}

pkg/linux/capabilities/capabilities_test.go

@@ -0,0 +1,39 @@
+/*
+© Copyright IBM Corporation 2017
+
+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 capabilities
+
+import (
+	"reflect"
+	"testing"
+)
+
+var capTests = []struct {
+	in  uint64
+	out []string
+}{
+	{0x0000000040000000, []string{"AUDIT_CONTROL"}},
+	// Default values when you run a Docker container without changing capabilities:
+	{0x00000000a80425fb, []string{"AUDIT_WRITE", "CHOWN", "DAC_OVERRIDE", "FOWNER", "FSETID", "KILL", "MKNOD", "NET_BIND_SERVICE", "NET_RAW", "SETFCAP", "SETGID", "SETPCAP", "SETUID", "SYS_CHROOT"}},
+}
+
+func TestGetCapabilities(t *testing.T) {
+	for _, table := range capTests {
+		caps := getCapabilities(table.in)
+		if !reflect.DeepEqual(caps, table.out) {
+			t.Errorf("getCapabilities(%v) - expected %v, got %v", table.in, table.out, caps)
+		}
+	}
+}