forked from containerd/containerd
/
template.go
193 lines (166 loc) · 4.17 KB
/
template.go
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// +build linux
package apparmor
import (
"bufio"
"fmt"
"io"
"os"
"os/exec"
"path"
"strconv"
"strings"
"text/template"
"github.com/pkg/errors"
)
const dir = "/etc/apparmor.d"
const defaultTemplate = `
{{range $value := .Imports}}
{{$value}}
{{end}}
profile {{.Name}} flags=(attach_disconnected,mediate_deleted) {
{{range $value := .InnerImports}}
{{$value}}
{{end}}
network,
capability,
file,
umount,
deny @{PROC}/* w, # deny write for all files directly in /proc (not in a subdir)
# deny write to files not in /proc/<number>/** or /proc/sys/**
deny @{PROC}/{[^1-9],[^1-9][^0-9],[^1-9s][^0-9y][^0-9s],[^1-9][^0-9][^0-9][^0-9]*}/** w,
deny @{PROC}/sys/[^k]** w, # deny /proc/sys except /proc/sys/k* (effectively /proc/sys/kernel)
deny @{PROC}/sys/kernel/{?,??,[^s][^h][^m]**} w, # deny everything except shm* in /proc/sys/kernel/
deny @{PROC}/sysrq-trigger rwklx,
deny @{PROC}/mem rwklx,
deny @{PROC}/kmem rwklx,
deny @{PROC}/kcore rwklx,
deny mount,
deny /sys/[^f]*/** wklx,
deny /sys/f[^s]*/** wklx,
deny /sys/fs/[^c]*/** wklx,
deny /sys/fs/c[^g]*/** wklx,
deny /sys/fs/cg[^r]*/** wklx,
deny /sys/firmware/** rwklx,
deny /sys/kernel/security/** rwklx,
{{if ge .Version 208095}}
ptrace (trace,read) peer={{.Name}},
{{end}}
}
`
type data struct {
Name string
Imports []string
InnerImports []string
Version int
}
func loadData(name string) (*data, error) {
p := data{
Name: name,
}
if macroExists("tunables/global") {
p.Imports = append(p.Imports, "#include <tunables/global>")
} else {
p.Imports = append(p.Imports, "@{PROC}=/proc/")
}
if macroExists("abstractions/base") {
p.InnerImports = append(p.InnerImports, "#include <abstractions/base>")
}
ver, err := getVersion()
if err != nil {
return nil, errors.Wrap(err, "get apparmor_parser version")
}
p.Version = ver
return &p, nil
}
func generate(p *data, o io.Writer) error {
t, err := template.New("apparmor_profile").Parse(defaultTemplate)
if err != nil {
return err
}
return t.Execute(o, p)
}
func load(path string) error {
out, err := aaParser("-Kr", path)
if err != nil {
return errors.Errorf("%s: %s", err, out)
}
return nil
}
// macrosExists checks if the passed macro exists.
func macroExists(m string) bool {
_, err := os.Stat(path.Join(dir, m))
return err == nil
}
func aaParser(args ...string) (string, error) {
out, err := exec.Command("apparmor_parser", args...).CombinedOutput()
if err != nil {
return "", err
}
return string(out), nil
}
func getVersion() (int, error) {
out, err := aaParser("--version")
if err != nil {
return -1, err
}
return parseVersion(out)
}
// parseVersion takes the output from `apparmor_parser --version` and returns
// a representation of the {major, minor, patch} version as a single number of
// the form MMmmPPP {major, minor, patch}.
func parseVersion(output string) (int, error) {
// output is in the form of the following:
// AppArmor parser version 2.9.1
// Copyright (C) 1999-2008 Novell Inc.
// Copyright 2009-2012 Canonical Ltd.
lines := strings.SplitN(output, "\n", 2)
words := strings.Split(lines[0], " ")
version := words[len(words)-1]
// split by major minor version
v := strings.Split(version, ".")
if len(v) == 0 || len(v) > 3 {
return -1, fmt.Errorf("parsing version failed for output: `%s`", output)
}
// Default the versions to 0.
var majorVersion, minorVersion, patchLevel int
majorVersion, err := strconv.Atoi(v[0])
if err != nil {
return -1, err
}
if len(v) > 1 {
minorVersion, err = strconv.Atoi(v[1])
if err != nil {
return -1, err
}
}
if len(v) > 2 {
patchLevel, err = strconv.Atoi(v[2])
if err != nil {
return -1, err
}
}
// major*10^5 + minor*10^3 + patch*10^0
numericVersion := majorVersion*1e5 + minorVersion*1e3 + patchLevel
return numericVersion, nil
}
func isLoaded(name string) (bool, error) {
f, err := os.Open("/sys/kernel/security/apparmor/profiles")
if err != nil {
return false, err
}
defer f.Close()
r := bufio.NewReader(f)
for {
p, err := r.ReadString('\n')
if err == io.EOF {
break
}
if err != nil {
return false, err
}
if strings.HasPrefix(p, name+" ") {
return true, nil
}
}
return false, nil
}