minio/cmd/policy.go
Harshavardhana 5353edcc38
Support policy variable replacement (#7085)
This PR supports iam and bucket policies to have
policy variable replacements in resource and
condition key values.

For example
- ${aws:username}
- ${aws:userid}
2019-01-21 10:27:14 +05:30

312 lines
8.7 KiB
Go

/*
* Minio Cloud Storage, (C) 2018 Minio, Inc.
*
* 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 cmd
import (
"bytes"
"context"
"encoding/json"
"fmt"
"net/http"
"path"
"strings"
"sync"
"time"
miniogopolicy "github.com/minio/minio-go/pkg/policy"
"github.com/minio/minio-go/pkg/set"
"github.com/minio/minio/cmd/logger"
"github.com/minio/minio/pkg/event"
"github.com/minio/minio/pkg/handlers"
"github.com/minio/minio/pkg/policy"
)
// PolicySys - policy subsystem.
type PolicySys struct {
sync.RWMutex
bucketPolicyMap map[string]policy.Policy
}
// removeDeletedBuckets - to handle a corner case where we have cached the policy for a deleted
// bucket. i.e if we miss a delete-bucket notification we should delete the corresponding
// bucket policy during sys.refresh()
func (sys *PolicySys) removeDeletedBuckets(bucketInfos []BucketInfo) {
buckets := set.NewStringSet()
for _, info := range bucketInfos {
buckets.Add(info.Name)
}
sys.Lock()
defer sys.Unlock()
for bucket := range sys.bucketPolicyMap {
if !buckets.Contains(bucket) {
delete(sys.bucketPolicyMap, bucket)
}
}
}
// Set - sets policy to given bucket name. If policy is empty, existing policy is removed.
func (sys *PolicySys) Set(bucketName string, policy policy.Policy) {
sys.Lock()
defer sys.Unlock()
if policy.IsEmpty() {
delete(sys.bucketPolicyMap, bucketName)
} else {
sys.bucketPolicyMap[bucketName] = policy
}
}
// Remove - removes policy for given bucket name.
func (sys *PolicySys) Remove(bucketName string) {
sys.Lock()
defer sys.Unlock()
delete(sys.bucketPolicyMap, bucketName)
}
// IsAllowed - checks given policy args is allowed to continue the Rest API.
func (sys *PolicySys) IsAllowed(args policy.Args) bool {
sys.RLock()
defer sys.RUnlock()
// If policy is available for given bucket, check the policy.
if p, found := sys.bucketPolicyMap[args.BucketName]; found {
return p.IsAllowed(args)
}
// As policy is not available for given bucket name, returns IsOwner i.e.
// operation is allowed only for owner.
return args.IsOwner
}
// Refresh PolicySys.
func (sys *PolicySys) refresh(objAPI ObjectLayer) error {
buckets, err := objAPI.ListBuckets(context.Background())
if err != nil {
logger.LogIf(context.Background(), err)
return err
}
sys.removeDeletedBuckets(buckets)
for _, bucket := range buckets {
config, err := objAPI.GetBucketPolicy(context.Background(), bucket.Name)
if err != nil {
if _, ok := err.(BucketPolicyNotFound); ok {
sys.Remove(bucket.Name)
}
continue
}
// This part is specifically written to handle migration
// when the Version string is empty, this was allowed
// in all previous minio releases but we need to migrate
// those policies by properly setting the Version string
// from now on.
if config.Version == "" {
logger.Info("Found in-consistent bucket policies, Migrating them for Bucket: (%s)", bucket.Name)
config.Version = policy.DefaultVersion
if err = savePolicyConfig(context.Background(), objAPI, bucket.Name, config); err != nil {
logger.LogIf(context.Background(), err)
return err
}
}
sys.Set(bucket.Name, *config)
}
return nil
}
// Init - initializes policy system from policy.json of all buckets.
func (sys *PolicySys) Init(objAPI ObjectLayer) error {
if objAPI == nil {
return errInvalidArgument
}
defer func() {
// Refresh PolicySys in background.
go func() {
ticker := time.NewTicker(globalRefreshBucketPolicyInterval)
defer ticker.Stop()
for {
select {
case <-GlobalServiceDoneCh:
return
case <-ticker.C:
sys.refresh(objAPI)
}
}
}()
}()
doneCh := make(chan struct{})
defer close(doneCh)
// Initializing policy needs a retry mechanism for
// the following reasons:
// - Read quorum is lost just after the initialization
// of the object layer.
retryTimerCh := newRetryTimerSimple(doneCh)
for {
select {
case _ = <-retryTimerCh:
// Load PolicySys once during boot.
if err := sys.refresh(objAPI); err != nil {
if err == errDiskNotFound ||
strings.Contains(err.Error(), InsufficientReadQuorum{}.Error()) ||
strings.Contains(err.Error(), InsufficientWriteQuorum{}.Error()) {
logger.Info("Waiting for policy subsystem to be initialized..")
continue
}
return err
}
return nil
}
}
}
// NewPolicySys - creates new policy system.
func NewPolicySys() *PolicySys {
return &PolicySys{
bucketPolicyMap: make(map[string]policy.Policy),
}
}
func getConditionValues(request *http.Request, locationConstraint string, username string) map[string][]string {
currTime := UTCNow()
principalType := func() string {
if username != "" {
return "User"
}
return "Anonymous"
}()
args := map[string][]string{
"CurrenTime": {currTime.Format(event.AMZTimeFormat)},
"EpochTime": {fmt.Sprintf("%d", currTime.Unix())},
"principaltype": {principalType},
"SecureTransport": {fmt.Sprintf("%t", request.TLS != nil)},
"SourceIp": {handlers.GetSourceIP(request)},
"UserAgent": {request.UserAgent()},
"Referer": {request.Referer()},
"userid": {username},
"username": {username},
}
for key, values := range request.Header {
if existingValues, found := args[key]; found {
args[key] = append(existingValues, values...)
} else {
args[key] = values
}
}
for key, values := range request.URL.Query() {
if existingValues, found := args[key]; found {
args[key] = append(existingValues, values...)
} else {
args[key] = values
}
}
if locationConstraint != "" {
args["LocationConstraint"] = []string{locationConstraint}
}
return args
}
// getPolicyConfig - get policy config for given bucket name.
func getPolicyConfig(objAPI ObjectLayer, bucketName string) (*policy.Policy, error) {
// Construct path to policy.json for the given bucket.
configFile := path.Join(bucketConfigPrefix, bucketName, bucketPolicyConfig)
configData, err := readConfig(context.Background(), objAPI, configFile)
if err != nil {
if err == errConfigNotFound {
err = BucketPolicyNotFound{Bucket: bucketName}
}
return nil, err
}
return policy.ParseConfig(bytes.NewReader(configData), bucketName)
}
func savePolicyConfig(ctx context.Context, objAPI ObjectLayer, bucketName string, bucketPolicy *policy.Policy) error {
data, err := json.Marshal(bucketPolicy)
if err != nil {
return err
}
// Construct path to policy.json for the given bucket.
configFile := path.Join(bucketConfigPrefix, bucketName, bucketPolicyConfig)
return saveConfig(ctx, objAPI, configFile, data)
}
func removePolicyConfig(ctx context.Context, objAPI ObjectLayer, bucketName string) error {
// Construct path to policy.json for the given bucket.
configFile := path.Join(bucketConfigPrefix, bucketName, bucketPolicyConfig)
if err := objAPI.DeleteObject(ctx, minioMetaBucket, configFile); err != nil {
if _, ok := err.(ObjectNotFound); ok {
return BucketPolicyNotFound{Bucket: bucketName}
}
return err
}
return nil
}
// PolicyToBucketAccessPolicy - converts policy.Policy to minio-go/policy.BucketAccessPolicy.
func PolicyToBucketAccessPolicy(bucketPolicy *policy.Policy) (*miniogopolicy.BucketAccessPolicy, error) {
// Return empty BucketAccessPolicy for empty bucket policy.
if bucketPolicy == nil {
return &miniogopolicy.BucketAccessPolicy{Version: policy.DefaultVersion}, nil
}
data, err := json.Marshal(bucketPolicy)
if err != nil {
// This should not happen because bucketPolicy is valid to convert to JSON data.
return nil, err
}
var policyInfo miniogopolicy.BucketAccessPolicy
if err = json.Unmarshal(data, &policyInfo); err != nil {
// This should not happen because data is valid to JSON data.
return nil, err
}
return &policyInfo, nil
}
// BucketAccessPolicyToPolicy - converts minio-go/policy.BucketAccessPolicy to policy.Policy.
func BucketAccessPolicyToPolicy(policyInfo *miniogopolicy.BucketAccessPolicy) (*policy.Policy, error) {
data, err := json.Marshal(policyInfo)
if err != nil {
// This should not happen because policyInfo is valid to convert to JSON data.
return nil, err
}
var bucketPolicy policy.Policy
if err = json.Unmarshal(data, &bucketPolicy); err != nil {
// This should not happen because data is valid to JSON data.
return nil, err
}
return &bucketPolicy, nil
}