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Run audit as shell script instead of as single line command (#610)

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* Run audit as shell script instead of as single line command

* Rename runExecCommands to runAudit

* Fix tests

Co-authored-by: Liz Rice <liz@lizrice.com>
This commit is contained in:
Huang Huang 2020-06-22 15:45:31 +08:00 committed by GitHub
parent 122bc4b351
commit c7b518e76b
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 92 additions and 166 deletions
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172
check/check.go
View File

@ -17,10 +17,7 @@ package check
import (
"bytes"
"fmt"
"io"
"os"
"os/exec"
"regexp"
"strings"
"github.com/golang/glog"
@ -65,22 +62,20 @@ const (
// Check contains information about a recommendation in the
// CIS Kubernetes document.
type Check struct {
ID string `yaml:"id" json:"test_number"`
Text string `json:"test_desc"`
Audit string `json:"audit"`
AuditConfig string `yaml:"audit_config"`
Type string `json:"type"`
Commands []*exec.Cmd `json:"omit"`
ConfigCommands []*exec.Cmd `json:"omit"`
Tests *tests `json:"omit"`
Set bool `json:"omit"`
Remediation string `json:"remediation"`
TestInfo []string `json:"test_info"`
ID string `yaml:"id" json:"test_number"`
Text string `json:"test_desc"`
Audit string `json:"audit"`
AuditConfig string `yaml:"audit_config"`
Type string `json:"type"`
Tests *tests `json:"omit"`
Set bool `json:"omit"`
Remediation string `json:"remediation"`
TestInfo []string `json:"test_info"`
State `json:"status"`
ActualValue string `json:"actual_value"`
Scored bool `json:"scored"`
ExpectedResult string `json:"expected_result"`
Reason string `json:"reason,omitempty"`
Reason string `json:"reason,omitempty"`
}
// Runner wraps the basic Run method.
@ -128,9 +123,9 @@ func (c *Check) run() State {
}
lastCommand := c.Audit
hasAuditConfig := c.ConfigCommands != nil
hasAuditConfig := c.AuditConfig != ""
state, finalOutput, retErrmsgs := performTest(c.Audit, c.Commands, c.Tests)
state, finalOutput, retErrmsgs := performTest(c.Audit, c.Tests)
if len(state) > 0 {
c.Reason = retErrmsgs
c.State = state
@ -166,7 +161,7 @@ func (c *Check) run() State {
currentTests.TestItems[i] = nti
}
state, finalOutput, retErrmsgs = performTest(c.AuditConfig, c.ConfigCommands, currentTests)
state, finalOutput, retErrmsgs = performTest(c.AuditConfig, currentTests)
if len(state) > 0 {
c.Reason = retErrmsgs
c.State = state
@ -200,78 +195,13 @@ func (c *Check) run() State {
return c.State
}
// textToCommand transforms an input text representation of commands to be
// run into a slice of commands.
// TODO: Make this more robust.
func textToCommand(s string) []*exec.Cmd {
glog.V(3).Infof("textToCommand: %q\n", s)
cmds := []*exec.Cmd{}
cp := strings.Split(s, "|")
for _, v := range cp {
v = strings.Trim(v, " ")
// TODO:
// GOAL: To split input text into arguments for exec.Cmd.
//
// CHALLENGE: The input text may contain quoted strings that
// must be passed as a unit to exec.Cmd.
// eg. bash -c 'foo bar'
// 'foo bar' must be passed as unit to exec.Cmd if not the command
// will fail when it is executed.
// eg. exec.Cmd("bash", "-c", "foo bar")
//
// PROBLEM: Current solution assumes the grouped string will always
// be at the end of the input text.
re := regexp.MustCompile(`^(.*)(['"].*['"])$`)
grps := re.FindStringSubmatch(v)
var cs []string
if len(grps) > 0 {
s := strings.Trim(grps[1], " ")
cs = strings.Split(s, " ")
s1 := grps[len(grps)-1]
s1 = strings.Trim(s1, "'\"")
cs = append(cs, s1)
} else {
cs = strings.Split(v, " ")
}
cmd := exec.Command(cs[0], cs[1:]...)
cmds = append(cmds, cmd)
}
return cmds
}
func isShellCommand(s string) bool {
cmd := exec.Command("/bin/sh", "-c", "command -v "+s)
out, err := cmd.Output()
if err != nil {
exitWithError(fmt.Errorf("failed to check if command: %q is valid %v", s, err))
}
if strings.Contains(string(out), s) {
return true
}
return false
}
func performTest(audit string, commands []*exec.Cmd, tests *tests) (State, *testOutput, string) {
func performTest(audit string, tests *tests) (State, *testOutput, string) {
if len(strings.TrimSpace(audit)) == 0 {
return "", failTestItem("missing command"), "missing audit command"
}
var out bytes.Buffer
state, retErrmsgs := runExecCommands(audit, commands, &out)
if len(state) > 0 {
return state, nil, retErrmsgs
}
errmsgs := retErrmsgs
errmsgs := runAudit(audit, &out)
finalOutput := tests.execute(out.String())
if finalOutput == nil {
@ -281,73 +211,17 @@ func performTest(audit string, commands []*exec.Cmd, tests *tests) (State, *test
return "", finalOutput, errmsgs
}
func runExecCommands(audit string, commands []*exec.Cmd, out *bytes.Buffer) (State, string) {
var err error
func runAudit(audit string, out *bytes.Buffer) string {
errmsgs := ""
// Check if command exists or exit with WARN.
for _, cmd := range commands {
if !isShellCommand(cmd.Path) {
errmsgs += fmt.Sprintf("Command '%s' not found\n", cmd.Path)
return WARN, errmsgs
}
}
// Run commands.
n := len(commands)
if n == 0 {
// Likely a warning message.
return WARN, errmsgs
}
// Each command runs,
// cmd0 out -> cmd1 in, cmd1 out -> cmd2 in ... cmdn out -> os.stdout
// cmd0 err should terminate chain
cs := commands
// Initialize command pipeline
cs[n-1].Stdout = out
i := 1
for i < n {
cs[i-1].Stdout, err = cs[i].StdinPipe()
if err != nil {
errmsgs += fmt.Sprintf("failed to run: %s, command: %s, error: %s\n", audit, cs[i].Args, err)
}
i++
}
// Start command pipeline
i = 0
for i < n {
err := cs[i].Start()
if err != nil {
errmsgs += fmt.Sprintf("failed to run: %s, command: %s, error: %s\n", audit, cs[i].Args, err)
}
i++
}
// Complete command pipeline
i = 0
for i < n {
err := cs[i].Wait()
if err != nil {
errmsgs += fmt.Sprintf("failed to run: %s, command: %s, error: %s\n", audit, cs[i].Args, err)
}
if i < n-1 {
cs[i].Stdout.(io.Closer).Close()
}
i++
cmd := exec.Command("/bin/sh")
cmd.Stdin = strings.NewReader(audit)
cmd.Stdout = out
cmd.Stderr = out
if err := cmd.Run(); err != nil {
errmsgs += fmt.Sprintf("failed to run: %q, output: %q, error: %s\n", audit, out.String(), err)
}
glog.V(3).Infof("Command %q - Output:\n\n %q\n - Error Messages:%q \n", audit, out.String(), errmsgs)
return "", errmsgs
}
func exitWithError(err error) {
fmt.Fprintf(os.Stderr, "\n%v\n", err)
// flush before exit non-zero
glog.Flush()
os.Exit(1)
return errmsgs
}

74
check/check_test.go
View File

@ -15,7 +15,8 @@
package check
import (
"os/exec"
"bytes"
"strings"
"testing"
)
@ -33,8 +34,8 @@ func TestCheck_Run(t *testing.T) {
{
check: Check{ // Not scored checks with passing tests are marked pass
Scored: false,
Audit: ":", Commands: []*exec.Cmd{exec.Command("")},
Tests: &tests{TestItems: []*testItem{&testItem{}}},
Audit: ":",
Tests: &tests{TestItems: []*testItem{&testItem{}}},
},
Expected: PASS,
},
@ -44,8 +45,8 @@ func TestCheck_Run(t *testing.T) {
{
check: Check{ // Scored checks with passing tests are marked pass
Scored: true,
Audit: ":", Commands: []*exec.Cmd{exec.Command("")},
Tests: &tests{TestItems: []*testItem{&testItem{}}},
Audit: ":",
Tests: &tests{TestItems: []*testItem{&testItem{}}},
},
Expected: PASS,
},
@ -111,3 +112,66 @@ func TestCheckAuditConfig(t *testing.T) {
}
}
}
func Test_runAudit(t *testing.T) {
type args struct {
audit string
out *bytes.Buffer
output string
}
tests := []struct {
name string
args args
errMsg string
output string
}{
{
name: "run success",
args: args{
audit: "echo 'hello world'",
out: &bytes.Buffer{},
},
errMsg: "",
output: "hello world\n",
},
{
name: "run multiple lines script",
args: args{
audit: `
hello() {
echo "hello world"
}
hello
`,
out: &bytes.Buffer{},
},
errMsg: "",
output: "hello world\n",
},
{
name: "run failed",
args: args{
audit: "unknown_command",
out: &bytes.Buffer{},
},
errMsg: "failed to run: \"unknown_command\", output: \"/bin/sh: ",
output: "not found\n",
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
errMsg := runAudit(tt.args.audit, tt.args.out)
if errMsg != "" && !strings.Contains(errMsg, tt.errMsg) {
t.Errorf("runAudit() errMsg = %q, want %q", errMsg, tt.errMsg)
}
output := tt.args.out.String()
if errMsg == "" && output != tt.output {
t.Errorf("runAudit() output = %q, want %q", output, tt.output)
}
if errMsg != "" && !strings.Contains(output, tt.output) {
t.Errorf("runAudit() output = %q, want %q", output, tt.output)
}
})
}
}

12
check/controls.go
View File

@ -70,18 +70,6 @@ func NewControls(t NodeType, in []byte) (*Controls, error) {
return nil, fmt.Errorf("non-%s controls file specified", t)
}
// Prepare audit commands
for _, group := range c.Groups {
for _, check := range group.Checks {
glog.V(3).Infof("Check.ID %s", check.ID)
check.Commands = textToCommand(check.Audit)
if len(check.AuditConfig) > 0 {
glog.V(3).Infof("Check.ID has audit_config %s", check.ID)
check.ConfigCommands = textToCommand(check.AuditConfig)
}
}
}
return c, nil
}