minio/pkg/iam/policy/resource.go
Harshavardhana 6695fd6a61
Add more context aware error for policy parsing errors (#8726)
In existing functionality we simply return a generic
error such as "MalformedPolicy" which indicates just
a generic string "invalid resource" which is not very
meaningful when there might be multiple types of errors
during policy parsing. This PR ensures that we send
these errors back to client to indicate the actual
error, brings in two concrete types such as

 - iampolicy.Error
 - policy.Error

Refer #8202
2020-01-03 11:28:52 -08:00

138 lines
3.3 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 iampolicy
import (
"encoding/json"
"path"
"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 path.Clean(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, 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 Errorf("invalid resource")
}
return nil
}
// parseResource - parses string to Resource.
func parseResource(s string) (Resource, error) {
if !strings.HasPrefix(s, ResourceARNPrefix) {
return Resource{}, Errorf("invalid resource '%v'", s)
}
pattern := strings.TrimPrefix(s, ResourceARNPrefix)
tokens := strings.SplitN(pattern, "/", 2)
bucketName := tokens[0]
if bucketName == "" {
return Resource{}, 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,
}
}