minio/bucket-policy-handlers.go

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/*
* Minio Cloud Storage, (C) 2015, 2016 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 main
import (
"bytes"
"io"
"io/ioutil"
"net/http"
"regexp"
"strings"
mux "github.com/gorilla/mux"
"github.com/minio/minio/pkg/fs"
"github.com/minio/minio/pkg/probe"
)
// maximum supported access policy size.
const maxAccessPolicySize = 20 * 1024 * 1024 // 20KiB.
// Verify if a given action is valid for the url path based on the
// existing bucket access policy.
func bucketPolicyEvalStatements(action string, resource string, conditions map[string]string, statements []policyStatement) bool {
for _, statement := range statements {
if bucketPolicyMatchStatement(action, resource, conditions, statement) {
if statement.Effect == "Allow" {
return true
}
// Do not uncomment kept here for readability.
// else statement.Effect == "Deny"
return false
}
}
// None match so deny.
return false
}
// Verify if action, resource and conditions match input policy statement.
func bucketPolicyMatchStatement(action string, resource string, conditions map[string]string, statement policyStatement) bool {
// Verify if action matches.
if bucketPolicyActionMatch(action, statement) {
// Verify if resource matches.
if bucketPolicyResourceMatch(resource, statement) {
// Verify if condition matches.
if bucketPolicyConditionMatch(conditions, statement) {
return true
}
}
}
return false
}
// Verify if given action matches with policy statement.
func bucketPolicyActionMatch(action string, statement policyStatement) bool {
for _, policyAction := range statement.Actions {
// Policy action can be a regex, validate the action with matching string.
matched, e := regexp.MatchString(policyAction, action)
fatalIf(probe.NewError(e), "Invalid pattern, please verify the pattern string.", nil)
if matched {
return true
}
}
return false
}
// Verify if given resource matches with policy statement.
func bucketPolicyResourceMatch(resource string, statement policyStatement) bool {
for _, presource := range statement.Resources {
matched, e := regexp.MatchString(presource, strings.TrimPrefix(resource, "/"))
fatalIf(probe.NewError(e), "Invalid pattern, please verify the pattern string.", nil)
// For any path matches, we return quickly and the let the caller continue.
if matched {
return true
}
}
return false
}
// Verify if given condition matches with policy statement.
func bucketPolicyConditionMatch(conditions map[string]string, statement policyStatement) bool {
// Supports following conditions.
// - StringEquals
// - StringNotEquals
//
// Supported applicable condition keys for each conditions.
// - s3:prefix
// - s3:max-keys
var conditionMatches = true
for condition, conditionKeys := range statement.Conditions {
if condition == "StringEquals" {
if conditionKeys["s3:prefix"] != conditions["prefix"] {
conditionMatches = false
break
}
if conditionKeys["s3:max-keys"] != conditions["max-keys"] {
conditionMatches = false
break
}
} else if condition == "StringNotEquals" {
if conditionKeys["s3:prefix"] == conditions["prefix"] {
conditionMatches = false
break
}
if conditionKeys["s3:max-keys"] == conditions["max-keys"] {
conditionMatches = false
break
}
}
}
return conditionMatches
}
// PutBucketPolicyHandler - PUT Bucket policy
// -----------------
// This implementation of the PUT operation uses the policy
// subresource to add to or replace a policy on a bucket
func (api storageAPI) PutBucketPolicyHandler(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
bucket := vars["bucket"]
switch getRequestAuthType(r) {
default:
// For all unknown auth types return error.
writeErrorResponse(w, r, ErrAccessDenied, r.URL.Path)
return
case authTypePresigned, authTypeSigned:
if s3Error := isReqAuthenticated(r); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
}
// If Content-Length is unknown or zero, deny the
// request. PutBucketPolicy always needs a Content-Length if
// incoming request is not chunked.
if !contains(r.TransferEncoding, "chunked") {
if r.ContentLength == -1 || r.ContentLength == 0 {
writeErrorResponse(w, r, ErrMissingContentLength, r.URL.Path)
return
}
// If Content-Length is greater than maximum allowed policy size.
if r.ContentLength > maxAccessPolicySize {
writeErrorResponse(w, r, ErrEntityTooLarge, r.URL.Path)
return
}
}
// Read access policy up to maxAccessPolicySize.
// http://docs.aws.amazon.com/AmazonS3/latest/dev/access-policy-language-overview.html
// bucket policies are limited to 20KB in size, using a limit reader.
bucketPolicyBuf, e := ioutil.ReadAll(io.LimitReader(r.Body, maxAccessPolicySize))
if e != nil {
errorIf(probe.NewError(e).Trace(bucket), "Reading policy failed.", nil)
writeErrorResponse(w, r, ErrInternalError, r.URL.Path)
return
}
// Parse bucket policy.
bucketPolicy, e := parseBucketPolicy(bucketPolicyBuf)
if e != nil {
errorIf(probe.NewError(e), "Unable to parse bucket policy.", nil)
writeErrorResponse(w, r, ErrInvalidPolicyDocument, r.URL.Path)
return
}
// Parse check bucket policy.
if s3Error := checkBucketPolicy(bucket, bucketPolicy); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
// Save bucket policy.
err := writeBucketPolicy(bucket, bucketPolicyBuf)
if err != nil {
errorIf(err.Trace(bucket, string(bucketPolicyBuf)), "SaveBucketPolicy failed.", nil)
switch err.ToGoError().(type) {
case fs.BucketNameInvalid:
writeErrorResponse(w, r, ErrInvalidBucketName, r.URL.Path)
default:
writeErrorResponse(w, r, ErrInternalError, r.URL.Path)
}
return
}
writeSuccessNoContent(w)
}
// DeleteBucketPolicyHandler - DELETE Bucket policy
// -----------------
// This implementation of the DELETE operation uses the policy
// subresource to add to remove a policy on a bucket.
func (api storageAPI) DeleteBucketPolicyHandler(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
bucket := vars["bucket"]
switch getRequestAuthType(r) {
default:
// For all unknown auth types return error.
writeErrorResponse(w, r, ErrAccessDenied, r.URL.Path)
return
case authTypePresigned, authTypeSigned:
if s3Error := isReqAuthenticated(r); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
}
// Delete bucket access policy.
err := removeBucketPolicy(bucket)
if err != nil {
errorIf(err.Trace(bucket), "DeleteBucketPolicy failed.", nil)
switch err.ToGoError().(type) {
case fs.BucketNameInvalid:
writeErrorResponse(w, r, ErrInvalidBucketName, r.URL.Path)
case fs.BucketPolicyNotFound:
writeErrorResponse(w, r, ErrNoSuchBucketPolicy, r.URL.Path)
default:
writeErrorResponse(w, r, ErrInternalError, r.URL.Path)
}
return
}
writeSuccessNoContent(w)
}
// GetBucketPolicyHandler - GET Bucket policy
// -----------------
// This operation uses the policy
// subresource to return the policy of a specified bucket.
func (api storageAPI) GetBucketPolicyHandler(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
bucket := vars["bucket"]
switch getRequestAuthType(r) {
default:
// For all unknown auth types return error.
writeErrorResponse(w, r, ErrAccessDenied, r.URL.Path)
return
case authTypePresigned, authTypeSigned:
if s3Error := isReqAuthenticated(r); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
}
// Read bucket access policy.
p, err := readBucketPolicy(bucket)
if err != nil {
errorIf(err.Trace(bucket), "GetBucketPolicy failed.", nil)
switch err.ToGoError().(type) {
case fs.BucketNameInvalid:
writeErrorResponse(w, r, ErrInvalidBucketName, r.URL.Path)
case fs.BucketPolicyNotFound:
writeErrorResponse(w, r, ErrNoSuchBucketPolicy, r.URL.Path)
default:
writeErrorResponse(w, r, ErrInternalError, r.URL.Path)
}
return
}
io.Copy(w, bytes.NewReader(p))
}