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logger.go
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logger.go
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package main
import (
_ "embed"
"encoding/json"
"fmt"
"log"
"net/url"
"reflect"
"regexp"
"sort"
"strconv"
"strings"
"time"
"github.com/buger/goterm"
"github.com/kenshaw/baseconv"
)
//go:embed map.json
var bIAMMap []byte
//go:embed iam_definition.json
var bIAMSAR []byte
var callLog []Entry
// JSON maps
var iamMap iamMapBase
var iamDef []iamDefService
// Entry is a single CSM entry
type Entry struct {
Region string `json:"Region"`
Type string `json:"Type"`
Service string `json:"Service"`
Method string `json:"Api"`
Parameters map[string][]string
URIParameters map[string]string
FinalHTTPStatusCode int `json:"FinalHttpStatusCode"`
AccessKey string `json:"AccessKey"`
}
// Statement is a single statement within an IAM policy
type Statement struct {
Effect string `json:"Effect"`
Action []string `json:"Action"`
Resource interface{} `json:"Resource"`
}
// IAMPolicy is a full IAM policy
type IAMPolicy struct {
Version string `json:"Version"`
Statement []Statement `json:"Statement"`
}
func loadMaps() {
err := json.Unmarshal(bIAMMap, &iamMap)
if err != nil {
log.Fatal(err)
}
err = json.Unmarshal(bIAMSAR, &iamDef)
if err != nil {
panic(err)
}
}
func getPolicyDocument() []byte {
policy := IAMPolicy{
Version: "2012-10-17",
Statement: []Statement{},
}
if *modeFlag == "csm" {
var actions []string
for _, entry := range callLog {
if *failsonlyFlag && (entry.FinalHTTPStatusCode >= 200 && entry.FinalHTTPStatusCode <= 299) {
continue
}
newActions := getDependantActions(getActions(entry.Service, entry.Method))
for _, newAction := range newActions {
foundAction := false
for _, action := range actions {
if action == newAction {
foundAction = true
break
}
}
if !foundAction {
actions = append(actions, newAction)
}
}
}
if *sortAlphabeticalFlag {
sort.Strings(actions)
}
policy.Statement = append(policy.Statement, Statement{
Effect: "Allow",
Resource: "*",
Action: actions,
})
} else if *modeFlag == "proxy" {
for _, entry := range callLog {
if *failsonlyFlag && (entry.FinalHTTPStatusCode >= 200 && entry.FinalHTTPStatusCode <= 299) {
continue
}
policy.Statement = append(policy.Statement, getStatementsForProxyCall(entry)...)
}
if *forceWildcardResourceFlag {
for i, _ := range policy.Statement {
policy.Statement[i].Resource = []string{"*"}
}
}
policy = aggregatePolicy(policy)
for i := 0; i < len(policy.Statement); i++ { // make any single wildcard resource a non-array
resource := policy.Statement[i].Resource.([]string)
if len(resource) == 1 {
policy.Statement[i].Resource = resource[0]
}
}
}
doc, err := json.MarshalIndent(policy, "", " ")
if err != nil {
panic(err)
}
return doc
}
func removeStatementItem(slice []Statement, i int) []Statement {
copy(slice[i:], slice[i+1:])
return slice[:len(slice)-1]
}
func aggregatePolicy(policy IAMPolicy) IAMPolicy {
for i := 0; i < len(policy.Statement); i++ {
sort.Strings(policy.Statement[i].Resource.([]string))
for j := i + 1; j < len(policy.Statement); j++ {
sort.Strings(policy.Statement[j].Resource.([]string))
if reflect.DeepEqual(policy.Statement[i].Resource.([]string), policy.Statement[j].Resource.([]string)) {
policy.Statement[i].Action = append(policy.Statement[i].Action, policy.Statement[j].Action...) // combine
policy.Statement = removeStatementItem(policy.Statement, j) // remove dupe
j--
}
}
policy.Statement[i].Action = uniqueSlice(policy.Statement[i].Action)
policy.Statement[i].Resource = uniqueSlice(policy.Statement[i].Resource.([]string))
}
return policy
}
func handleLoggedCall() {
// when making many calls in parallel, the terminal can be glitchy
// if we flush too often, optional flush on timer
if *refreshRateFlag == 0 {
writePolicyToTerminal()
}
}
func countRune(s string, r rune) int {
count := 0
for _, c := range s {
if c == r {
count++
}
}
return count
}
func writePolicyToTerminal() {
if len(callLog) == 0 || *backgroundFlag {
return
}
policyDoc := string(getPolicyDocument())
policyHeight := countRune(policyDoc, '\n') + 1
goterm.Clear()
goterm.MoveCursor(1, 1)
if goterm.Height() < policyHeight {
fmt.Println("\n\n" + policyDoc)
} else {
goterm.Println(policyDoc)
goterm.Flush()
}
}
type iamMapMethod struct {
Action string `json:"action"`
ResourceMappings map[string]iamMapResMapItem `json:"resource_mappings"`
ResourceARNMappings map[string]string `json:"resourcearn_mappings"`
ArnOverride iamMapArnOverride `json:"arn_override"`
}
type iamMapArnOverride struct {
Template string `json:"template"`
}
type iamMapResMapItem struct {
Template string `json:"template"`
}
type iamMapBase struct {
SDKMethodIAMMappings map[string][]iamMapMethod `json:"sdk_method_iam_mappings"`
SDKServiceMappings map[string]string `json:"sdk_service_mappings"`
SDKPermissionlessActions []string `json:"sdk_permissionless_actions"`
}
type mappingInfoItem struct {
Action string `json:"action"`
}
type iamDefService struct {
Prefix string `json:"prefix"`
Privileges []iamDefPrivilege `json:"privileges"`
Resources []iamDefResource `json:"resources"`
}
type iamDefPrivilege struct {
Privilege string `json:"privilege"`
ResourceTypes []iamDefResourceType `json:"resource_types"`
Description string `json:"description"`
}
type iamDefResource struct {
Resource string `json:"resource"`
Arn string `json:"arn"`
}
type iamDefResourceType struct {
DependentActions []string `json:"dependent_actions"`
ResourceType string `json:"resource_type"`
}
func uniqueSlice(slice []string) []string {
keys := make(map[string]bool)
list := []string{}
for _, entry := range slice {
if _, value := keys[entry]; !value {
keys[entry] = true
list = append(list, entry)
}
}
return list
}
func getDependantActions(actions []string) []string {
for _, baseaction := range actions {
splitbase := strings.Split(baseaction, ":")
if len(splitbase) != 2 {
continue
}
baseservice := splitbase[0]
basemethod := splitbase[1]
for _, service := range iamDef {
if strings.ToLower(service.Prefix) == strings.ToLower(baseservice) {
for _, priv := range service.Privileges {
if strings.ToLower(priv.Privilege) == strings.ToLower(basemethod) {
for _, resourceType := range priv.ResourceTypes {
for _, dependentAction := range resourceType.DependentActions {
actions = append(actions, dependentAction)
}
}
}
}
}
}
}
return uniqueSlice(actions)
}
func getActions(service, method string) []string {
var actions []string
// checked if permissionless
for _, permissionlessAction := range iamMap.SDKPermissionlessActions {
if strings.ToLower(permissionlessAction) == fmt.Sprintf("%s.%s", strings.ToLower(service), strings.ToLower(method)) {
return []string{}
}
}
// check IAM mappings
for sdkCall, mappingInfo := range iamMap.SDKMethodIAMMappings {
if fmt.Sprintf("%s.%s", strings.ToLower(service), strings.ToLower(method)) == strings.ToLower(sdkCall) {
for _, item := range mappingInfo {
actions = append(actions, item.Action)
}
}
}
if len(actions) > 0 {
return actions
}
// substitute service name
for sdkService, iamService := range iamMap.SDKServiceMappings {
if service == sdkService {
service = iamService
break
}
}
return []string{
fmt.Sprintf("%s:%s", strings.ToLower(service), method),
}
}
func setTerminalRefresh() {
if *refreshRateFlag <= 0 {
*refreshRateFlag = 1
}
ticker := time.NewTicker(time.Duration(*refreshRateFlag) * time.Second)
quit := make(chan struct{})
go func() {
for {
select {
case <-ticker.C:
writePolicyToTerminal()
case <-quit:
ticker.Stop()
return
}
}
}()
}
type resourceType struct {
ResourceType string `json:"resourceType"`
}
func resolveSpecials(arn string, call Entry, mandatory bool, resourceArnTemplate *string) []string {
startIndex := strings.Index(arn, "%%")
endIndex := strings.LastIndex(arn, "%%")
if startIndex > -1 && endIndex != startIndex {
parts := strings.Split(arn[startIndex+2:endIndex], "%")
if len(parts) < 2 {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
switch parts[0] {
case "iftruthy":
if len(parts) == 3 { // weird bug for empty string false values
parts = append(parts, "")
}
if len(parts) != 4 {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
fullyResolved, arns := subARNParameters(parts[1], call, true)
if len(arns) < 1 || arns[0] == "" || !fullyResolved {
if parts[3] == "" {
if mandatory {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + parts[3] + arn[endIndex+2:]}
}
if parts[2] == "" && mandatory {
if mandatory {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + parts[2] + arn[endIndex+2:]}
case "urlencode":
if len(parts) != 2 {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
fullyResolved, arns := subARNParameters(parts[1], call, true)
if len(arns) < 1 || arns[0] == "" || !fullyResolved {
if mandatory {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + url.QueryEscape(arns[0]) + arn[endIndex+2:]}
case "iftemplatematch":
if len(parts) != 2 || resourceArnTemplate == nil {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
fullyResolved, arns := subARNParameters(parts[1], call, true)
if len(arns) < 1 || arns[0] == "" || !fullyResolved {
return []string{arn[0:startIndex] + arn[endIndex+2:]}
}
template := regexp.MustCompile(`\\\$\\\{.+?\\\}`).ReplaceAllString(regexp.QuoteMeta(*resourceArnTemplate), ".*?")
if regexp.MustCompile(template).MatchString(arns[0]) {
return []string{arn[0:startIndex] + arns[0] + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + arn[endIndex+2:]}
case "many":
manyParts := []string{}
for _, part := range parts[1:] {
fullyResolved, arns := subARNParameters(part, call, true)
if len(arns) < 1 || arns[0] == "" || !fullyResolved {
if mandatory {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + arn[endIndex+2:]}
}
manyParts = append(manyParts, arns[0])
}
return manyParts
case "regex":
if len(parts) != 3 {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
fullyResolved, arns := subARNParameters(parts[1], call, true)
if len(arns) < 1 || arns[0] == "" || !fullyResolved {
if mandatory {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + arn[endIndex+2:]}
}
if parts[2][0] == '/' {
parts[2] = parts[2][1 : len(parts[2])-2]
}
r := regexp.MustCompile(parts[2])
groups := r.FindStringSubmatch(strings.ReplaceAll(arns[0], `$`, `$$`))
if len(groups) < 2 || groups[1] == "" {
if mandatory {
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + arn[endIndex+2:]}
}
return []string{arn[0:startIndex] + groups[1] + arn[endIndex+2:]}
default: // unknown function
return []string{arn[0:startIndex] + "*" + arn[endIndex+2:]}
}
}
return []string{arn}
}
func getStatementsForProxyCall(call Entry) (statements []Statement) {
lowerPriv := strings.ToLower(fmt.Sprintf("%s.%s", call.Service, call.Method))
for iamMapMethodName, iamMapMethods := range iamMap.SDKMethodIAMMappings {
if strings.ToLower(iamMapMethodName) == lowerPriv {
for mappedPrivIndex, mappedPriv := range iamMapMethods {
resources := []string{}
// arn_override
if mappedPriv.ArnOverride.Template != "" {
arns := resolveSpecials(mappedPriv.ArnOverride.Template, call, false, nil)
if len(arns) == 0 || len(arns) > 1 || arns[0] != "" { // skip if empty after resolving specials
for _, arn := range arns {
fullyResolved, subbedArns := subARNParameters(arn, call, false)
for _, subbedArn := range subbedArns {
if mappedPrivIndex == 0 || fullyResolved {
resources = append(resources, subbedArn) // sub full parameters and add to resources
}
}
}
}
if len(resources) == 0 && len(mappedPriv.ResourceMappings) == 0 {
continue
}
}
// resourcearn_mappings
if len(mappedPriv.ResourceARNMappings) > 0 {
for _, service := range iamDef { // in the SAR
if service.Prefix == strings.ToLower(strings.Split(mappedPriv.Action, ":")[0]) { // find the service for the call
for _, servicePrivilege := range service.Privileges {
if strings.ToLower(strings.Split(mappedPriv.Action, ":")[1]) == strings.ToLower(servicePrivilege.Privilege) { // find the method for the call
for _, resourceType := range servicePrivilege.ResourceTypes { // get all resource types for the privilege
resourceArnTemplate := ""
for _, resource := range service.Resources { // go through the service resources
if resource.Resource == strings.Replace(resourceType.ResourceType, "*", "", -1) && resource.Resource != "" { // match the resource type (doesn't matter if mandatory)
resourceArnTemplate = resource.Arn
}
}
for mapResType, mapResTemplate := range mappedPriv.ResourceARNMappings {
if strings.Replace(resourceType.ResourceType, "*", "", -1) == mapResType {
mandatory := strings.HasSuffix(resourceType.ResourceType, "*")
resARNMappingTemplates := resolveSpecials(mapResTemplate, call, false, &resourceArnTemplate)
if len(resARNMappingTemplates) == 1 && resARNMappingTemplates[0] == "" {
continue
}
if len(resARNMappingTemplates) == 0 && mandatory && len(mappedPriv.ResourceMappings) == 0 {
resARNMappingTemplates = []string{"*"}
}
for _, resARNMappingTemplate := range resARNMappingTemplates {
fullyResolved, subbedArns := subARNParameters(resARNMappingTemplate, call, false)
if mandatory || fullyResolved { // check if mandatory or fully resolved
resources = append(resources, subbedArns...) // sub full parameters and add to resources
}
}
}
}
}
}
}
}
}
}
// resource_mappings
if len(resources) == 0 {
for _, service := range iamDef { // in the SAR
if service.Prefix == strings.ToLower(strings.Split(mappedPriv.Action, ":")[0]) { // find the service for the call
for _, servicePrivilege := range service.Privileges {
if strings.ToLower(strings.Split(mappedPriv.Action, ":")[1]) == strings.ToLower(servicePrivilege.Privilege) { // find the method for the call
for _, resourceType := range servicePrivilege.ResourceTypes { // get all resource types for the privilege
for _, resource := range service.Resources { // go through the service resources
if resource.Resource == strings.Replace(resourceType.ResourceType, "*", "", -1) && resource.Resource != "" { // match the resource type (doesn't matter if mandatory)
arns := []string{resource.Arn} // the base ARN template, matrix init
newArns := []string{}
mandatory := strings.HasSuffix(resourceType.ResourceType, "*")
// substitute the resource_mappings
for resMappingVar, resMapping := range mappedPriv.ResourceMappings { // for each mapping
resMappingTemplates := resolveSpecials(resMapping.Template, call, false, &resource.Arn) // get a list of resolved template strings
if len(resMappingTemplates) == 1 && resMappingTemplates[0] == "" {
continue
}
for _, arn := range arns { // for each of the arn list
newArns = []string{}
for _, resMappingTemplate := range resMappingTemplates {
variableReplaced := regexp.MustCompile(`\$\{`+resMappingVar+`\}`).ReplaceAllString(arn, strings.ReplaceAll(resMappingTemplate, `$`, `$$`)) // escape $ for regexp
newArns = append(newArns, variableReplaced)
}
}
arns = newArns
}
if len(arns) == 0 && mandatory {
arns = []string{"*"}
}
for _, arn := range arns {
fullyResolved, subbedArns := subARNParameters(arn, call, false)
if mandatory || fullyResolved { // check if mandatory or fully resolved
resources = append(resources, subbedArns...) // sub full parameters and add to resources
}
}
}
}
}
}
}
}
}
}
// default (last ditch)
if len(resources) == 0 {
resources = []string{"*"}
}
statements = append(statements, Statement{
Effect: "Allow",
Resource: resources,
Action: []string{mappedPriv.Action},
})
}
}
}
return statements
}
func getAccountFromAccessKey(accessKeyId string) (string, error) {
base10 := "0123456789"
base32AwsFlavour := "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"
offsetStr, err := baseconv.Convert("QAAAAAAA", base32AwsFlavour, base10)
if err != nil {
return "", err
}
offset, err := strconv.Atoi(offsetStr)
if err != nil {
return "", err
}
offsetAccountIdStr, err := baseconv.Convert(accessKeyId[4:12], base32AwsFlavour, base10)
if err != nil {
return "", err
}
offsetAccountId, err := strconv.Atoi(offsetAccountIdStr)
if err != nil {
return "", err
}
accountId := 2 * (offsetAccountId - offset)
if strings.Index(base32AwsFlavour, accessKeyId[12:13]) >= strings.Index(base32AwsFlavour, "Q") {
accountId++
}
if accountId < 0 {
return "", fmt.Errorf("negative account ID")
}
return fmt.Sprintf("%012d", accountId), nil
}
func subARNParameters(arn string, call Entry, specialsOnly bool) (bool, []string) {
arns := []string{arn}
// parameter substitution
for paramVarName, params := range call.Parameters {
newArns := []string{}
for _, param := range params {
for _, arn := range arns {
newArns = append(newArns, regexp.MustCompile(`\$\{`+strings.ReplaceAll(strings.ReplaceAll(paramVarName, "[", "\\["), "]", "\\]")+`\}`).ReplaceAllString(arn, param)) // might have dupes but resolved out later
}
}
arns = newArns
}
// URI parameter substitution
for paramVarName, param := range call.URIParameters {
newArns := []string{}
for _, arn := range arns {
newArns = append(newArns, regexp.MustCompile(`\$\{`+strings.ReplaceAll(strings.ReplaceAll(paramVarName, "[", "\\["), "]", "\\]")+`\}`).ReplaceAllString(arn, param)) // might have dupes but resolved out later
}
arns = newArns
}
if specialsOnly {
anyMatched := false
for _, arn := range arns {
matched, _ := regexp.Match(`\$\{.+?\}`, []byte(arn))
if matched {
anyMatched = true
}
}
return !anyMatched, arns
}
account := *accountIDFlag
var err error
if account == "" && call.AccessKey != "" {
account, err = getAccountFromAccessKey(call.AccessKey)
if err != nil || account == "" {
account = "123456789012"
}
}
partition := "aws"
if call.Region[0:3] == "cn-" {
partition = "aws-cn"
}
if call.Region[0:7] == "us-gov-" {
partition = "aws-us-gov"
}
anyUnresolved := false
result := []string{}
for _, arn := range arns {
arn = regexp.MustCompile(`\$\{Partition\}`).ReplaceAllString(arn, partition)
arn = regexp.MustCompile(`\$\{Region\}`).ReplaceAllString(arn, call.Region)
arn = regexp.MustCompile(`\$\{Account\}`).ReplaceAllString(arn, account)
unresolvedArn := arn
arn = regexp.MustCompile(`\$\{.+?\}`).ReplaceAllString(arn, "*") // TODO: preserve ${aws:*} variables
if unresolvedArn != arn {
anyUnresolved = true
}
result = append(result, arn)
}
return !anyUnresolved, result
}
func mapServicePrefix(prefix string, mappings iamMapBase) string {
for sdkprefix, mappedprefix := range mappings.SDKServiceMappings {
if sdkprefix == prefix {
return mappedprefix
}
}
return prefix
}