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minio/cmd/bucket-policy.go

208 lines
6.3 KiB

/*
* Minio Cloud Storage, (C) 2015, 2016, 2017, 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"
"io"
"reflect"
"sync"
"github.com/minio/minio-go/pkg/policy"
"github.com/minio/minio/pkg/errors"
"github.com/minio/minio/pkg/hash"
)
const (
// Static prefix to be used while constructing bucket ARN.
// refer to S3 docs for more info.
bucketARNPrefix = "arn:aws:s3:::"
// Bucket policy config name.
bucketPolicyConfig = "policy.json"
)
// Global bucket policies list, policies are enforced on each bucket looking
// through the policies here.
type bucketPolicies struct {
rwMutex *sync.RWMutex
// Collection of 'bucket' policies.
bucketPolicyConfigs map[string]policy.BucketAccessPolicy
}
// Fetch bucket policy for a given bucket.
func (bp bucketPolicies) GetBucketPolicy(bucket string) policy.BucketAccessPolicy {
bp.rwMutex.RLock()
defer bp.rwMutex.RUnlock()
return bp.bucketPolicyConfigs[bucket]
}
// Set a new bucket policy for a bucket, this operation will overwrite
// any previous bucket policies for the bucket.
func (bp *bucketPolicies) SetBucketPolicy(bucket string, newpolicy policy.BucketAccessPolicy) error {
bp.rwMutex.Lock()
defer bp.rwMutex.Unlock()
if reflect.DeepEqual(newpolicy, emptyBucketPolicy) {
return errInvalidArgument
}
bp.bucketPolicyConfigs[bucket] = newpolicy
return nil
}
// Delete bucket policy from struct for a given bucket.
func (bp *bucketPolicies) DeleteBucketPolicy(bucket string) error {
bp.rwMutex.Lock()
defer bp.rwMutex.Unlock()
delete(bp.bucketPolicyConfigs, bucket)
return nil
}
// Intialize all bucket policies.
func initBucketPolicies(objAPI ObjectLayer) (*bucketPolicies, error) {
if objAPI == nil {
return nil, errInvalidArgument
}
// List buckets to proceed loading all notification configuration.
buckets, err := objAPI.ListBuckets(context.Background())
if err != nil {
return nil, errors.Cause(err)
}
policies := make(map[string]policy.BucketAccessPolicy)
// Loads bucket policy.
for _, bucket := range buckets {
bp, pErr := ReadBucketPolicy(bucket.Name, objAPI)
if pErr != nil {
// net.Dial fails for rpc client or any
// other unexpected errors during net.Dial.
if !errors.IsErrIgnored(pErr, errDiskNotFound) {
if !isErrBucketPolicyNotFound(pErr) {
return nil, errors.Cause(pErr)
}
}
// Continue to load other bucket policies if possible.
continue
}
policies[bucket.Name] = bp
}
// Return all bucket policies.
return &bucketPolicies{
rwMutex: &sync.RWMutex{},
bucketPolicyConfigs: policies,
}, nil
}
// readBucketPolicyJSON - reads bucket policy for an input bucket, returns BucketPolicyNotFound
// if bucket policy is not found.
func readBucketPolicyJSON(bucket string, objAPI ObjectLayer) (bucketPolicyReader io.Reader, err error) {
policyPath := pathJoin(bucketConfigPrefix, bucket, bucketPolicyConfig)
var buffer bytes.Buffer
err = objAPI.GetObject(context.Background(), minioMetaBucket, policyPath, 0, -1, &buffer, "")
if err != nil {
if isErrObjectNotFound(err) || isErrIncompleteBody(err) {
return nil, PolicyNotFound{Bucket: bucket}
}
errorIf(err, "Unable to load policy for the bucket %s.", bucket)
return nil, errors.Cause(err)
}
return &buffer, nil
}
// ReadBucketPolicy - reads bucket policy for an input bucket, returns BucketPolicyNotFound
// if bucket policy is not found. This function also parses the bucket policy into an object.
func ReadBucketPolicy(bucket string, objAPI ObjectLayer) (policy.BucketAccessPolicy, error) {
// Read bucket policy JSON.
bucketPolicyReader, err := readBucketPolicyJSON(bucket, objAPI)
if err != nil {
return emptyBucketPolicy, err
}
// Parse the saved policy.
var bp policy.BucketAccessPolicy
if err = parseBucketPolicy(bucketPolicyReader, &bp); err != nil {
return emptyBucketPolicy, err
}
return bp, nil
}
// removeBucketPolicy - removes any previously written bucket policy. Returns BucketPolicyNotFound
// if no policies are found.
func removeBucketPolicy(bucket string, objAPI ObjectLayer) error {
policyPath := pathJoin(bucketConfigPrefix, bucket, bucketPolicyConfig)
err := objAPI.DeleteObject(context.Background(), minioMetaBucket, policyPath)
if err != nil {
err = errors.Cause(err)
if _, ok := err.(ObjectNotFound); ok {
return BucketPolicyNotFound{Bucket: bucket}
}
return err
}
return nil
}
// writeBucketPolicy - save a bucket policy that is assumed to be validated.
func writeBucketPolicy(bucket string, objAPI ObjectLayer, bpy policy.BucketAccessPolicy) error {
buf, err := json.Marshal(bpy)
if err != nil {
errorIf(err, "Unable to marshal bucket policy '%#v' to JSON", bpy)
return err
}
policyPath := pathJoin(bucketConfigPrefix, bucket, bucketPolicyConfig)
hashReader, err := hash.NewReader(bytes.NewReader(buf), int64(len(buf)), "", getSHA256Hash(buf))
if err != nil {
errorIf(err, "Unable to set policy for the bucket %s", bucket)
return errors.Cause(err)
}
if _, err = objAPI.PutObject(context.Background(), minioMetaBucket, policyPath, hashReader, nil); err != nil {
errorIf(err, "Unable to set policy for the bucket %s", bucket)
return errors.Cause(err)
}
return nil
}
// persistAndNotifyBucketPolicyChange - takes a policyChange argument,
// persists it to storage, and notify nodes in the cluster about the
// change. In-memory state is updated in response to the notification.
func persistAndNotifyBucketPolicyChange(bucket string, isRemove bool, bktPolicy policy.BucketAccessPolicy, objAPI ObjectLayer) error {
if isRemove {
err := removeBucketPolicy(bucket, objAPI)
if err != nil {
return err
}
} else {
if reflect.DeepEqual(bktPolicy, emptyBucketPolicy) {
return errInvalidArgument
}
if err := writeBucketPolicy(bucket, objAPI, bktPolicy); err != nil {
return err
}
}
return nil
}