minio/pkg/iam/policy/resource.go

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/*
* 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 iampolicy
import (
"encoding/json"
"fmt"
"strings"
"github.com/minio/minio/pkg/policy/condition"
"github.com/minio/minio/pkg/wildcard"
)
// ResourceARNPrefix - resource ARN prefix as per AWS S3 specification.
const ResourceARNPrefix = "arn:aws:s3:::"
// Resource - resource in policy statement.
type Resource struct {
BucketName string
Pattern string
}
func (r Resource) isBucketPattern() bool {
return !strings.Contains(r.Pattern, "/") || r.Pattern == "*"
}
func (r Resource) isObjectPattern() bool {
return strings.Contains(r.Pattern, "/") || strings.Contains(r.BucketName, "*") || r.Pattern == "*/*"
}
// IsValid - checks whether Resource is valid or not.
func (r Resource) IsValid() bool {
return r.Pattern != ""
}
// Match - matches object name with resource pattern.
func (r Resource) Match(resource string, conditionValues map[string][]string) bool {
pattern := r.Pattern
for _, key := range condition.CommonKeys {
// Empty values are not supported for policy variables.
if rvalues, ok := conditionValues[key.Name()]; ok && rvalues[0] != "" {
pattern = strings.Replace(pattern, key.VarName(), rvalues[0], -1)
}
}
if strings.HasPrefix(resource, pattern) {
return true
}
return wildcard.Match(pattern, resource)
}
// MarshalJSON - encodes Resource to JSON data.
func (r Resource) MarshalJSON() ([]byte, error) {
if !r.IsValid() {
return nil, fmt.Errorf("invalid resource %v", r)
}
return json.Marshal(r.String())
}
func (r Resource) String() string {
return ResourceARNPrefix + r.Pattern
}
// UnmarshalJSON - decodes JSON data to Resource.
func (r *Resource) UnmarshalJSON(data []byte) error {
var s string
if err := json.Unmarshal(data, &s); err != nil {
return err
}
parsedResource, err := parseResource(s)
if err != nil {
return err
}
*r = parsedResource
return nil
}
// Validate - validates Resource is for given bucket or not.
func (r Resource) Validate() error {
if !r.IsValid() {
return fmt.Errorf("invalid resource")
}
return nil
}
// parseResource - parses string to Resource.
func parseResource(s string) (Resource, error) {
if !strings.HasPrefix(s, ResourceARNPrefix) {
return Resource{}, fmt.Errorf("invalid resource '%v'", s)
}
pattern := strings.TrimPrefix(s, ResourceARNPrefix)
tokens := strings.SplitN(pattern, "/", 2)
bucketName := tokens[0]
if bucketName == "" {
return Resource{}, fmt.Errorf("invalid resource format '%v'", s)
}
return Resource{
BucketName: bucketName,
Pattern: pattern,
}, nil
}
// NewResource - creates new resource.
func NewResource(bucketName, keyName string) Resource {
pattern := bucketName
if keyName != "" {
if !strings.HasPrefix(keyName, "/") {
pattern += "/"
}
pattern += keyName
}
return Resource{
BucketName: bucketName,
Pattern: pattern,
}
}