157 lines
4 KiB
Go
157 lines
4 KiB
Go
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/*
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* Minio Cloud Storage, (C) 2018 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package policy
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import (
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"encoding/json"
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"fmt"
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"strings"
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"github.com/minio/minio/pkg/policy/condition"
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)
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// Statement - policy statement.
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type Statement struct {
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SID ID `json:"Sid,omitempty"`
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Effect Effect `json:"Effect"`
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Principal Principal `json:"Principal"`
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Actions ActionSet `json:"Action"`
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Resources ResourceSet `json:"Resource"`
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Conditions condition.Functions `json:"Condition,omitempty"`
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}
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// IsAllowed - checks given policy args is allowed to continue the Rest API.
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func (statement Statement) IsAllowed(args Args) bool {
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check := func() bool {
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if !statement.Principal.Match(args.AccountName) {
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return false
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}
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if !statement.Actions.Contains(args.Action) {
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return false
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}
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resource := args.BucketName
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if args.ObjectName != "" {
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if !strings.HasPrefix(args.ObjectName, "/") {
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resource += "/"
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}
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resource += args.ObjectName
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}
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if !statement.Resources.Match(resource) {
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return false
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}
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return statement.Conditions.Evaluate(args.ConditionValues)
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}
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return statement.Effect.IsAllowed(check())
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}
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// isValid - checks whether statement is valid or not.
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func (statement Statement) isValid() error {
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if !statement.Effect.IsValid() {
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return fmt.Errorf("invalid Effect %v", statement.Effect)
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}
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if !statement.Principal.IsValid() {
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return fmt.Errorf("invalid Principal %v", statement.Principal)
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}
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if len(statement.Actions) == 0 {
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return fmt.Errorf("Action must not be empty")
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}
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if len(statement.Resources) == 0 {
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return fmt.Errorf("Resource must not be empty")
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}
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for action := range statement.Actions {
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if action.isObjectAction() {
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if !statement.Resources.objectResourceExists() {
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return fmt.Errorf("unsupported Resource found %v for action %v", statement.Resources, action)
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}
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} else {
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if !statement.Resources.bucketResourceExists() {
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return fmt.Errorf("unsupported Resource found %v for action %v", statement.Resources, action)
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}
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}
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keys := statement.Conditions.Keys()
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keyDiff := keys.Difference(actionConditionKeyMap[action])
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if !keyDiff.IsEmpty() {
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return fmt.Errorf("unsupported condition keys '%v' used for action '%v'", keyDiff, action)
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}
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}
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return nil
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}
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// MarshalJSON - encodes JSON data to Statement.
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func (statement Statement) MarshalJSON() ([]byte, error) {
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if err := statement.isValid(); err != nil {
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return nil, err
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}
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// subtype to avoid recursive call to MarshalJSON()
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type subStatement Statement
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ss := subStatement(statement)
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return json.Marshal(ss)
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}
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// UnmarshalJSON - decodes JSON data to Statement.
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func (statement *Statement) UnmarshalJSON(data []byte) error {
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// subtype to avoid recursive call to UnmarshalJSON()
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type subStatement Statement
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var ss subStatement
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if err := json.Unmarshal(data, &ss); err != nil {
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return err
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}
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s := Statement(ss)
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if err := s.isValid(); err != nil {
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return err
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}
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*statement = s
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return nil
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}
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// Validate - validates Statement is for given bucket or not.
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func (statement Statement) Validate(bucketName string) error {
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if err := statement.isValid(); err != nil {
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return err
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}
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return statement.Resources.Validate(bucketName)
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}
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// NewStatement - creates new statement.
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func NewStatement(effect Effect, principal Principal, actionSet ActionSet, resourceSet ResourceSet, conditions condition.Functions) Statement {
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return Statement{
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Effect: effect,
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Principal: principal,
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Actions: actionSet,
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Resources: resourceSet,
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Conditions: conditions,
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}
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}
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