359 lines
11 KiB
Go
359 lines
11 KiB
Go
/*
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* Minio Cloud Storage, (C) 2015, 2016 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 cmd
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import (
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"fmt"
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"io"
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"io/ioutil"
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"net"
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"net/http"
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"runtime"
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"strings"
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humanize "github.com/dustin/go-humanize"
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mux "github.com/gorilla/mux"
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"github.com/minio/minio-go/pkg/set"
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"github.com/minio/minio/pkg/wildcard"
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)
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// maximum supported access policy size.
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const maxAccessPolicySize = 20 * humanize.KiByte
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// Verify if a given action is valid for the url path based on the
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// existing bucket access policy.
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func bucketPolicyEvalStatements(action string, resource string, conditions map[string]set.StringSet, statements []policyStatement) bool {
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for _, statement := range statements {
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if bucketPolicyMatchStatement(action, resource, conditions, statement) {
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if statement.Effect == "Allow" {
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return true
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}
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// Do not uncomment kept here for readability.
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// else statement.Effect == "Deny"
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return false
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}
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}
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// None match so deny.
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return false
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}
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// Verify if action, resource and conditions match input policy statement.
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func bucketPolicyMatchStatement(action string, resource string, conditions map[string]set.StringSet, statement policyStatement) bool {
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// Verify if action, resource and condition match in given statement.
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return (bucketPolicyActionMatch(action, statement) &&
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bucketPolicyResourceMatch(resource, statement) &&
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bucketPolicyConditionMatch(conditions, statement))
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}
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// Verify if given action matches with policy statement.
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func bucketPolicyActionMatch(action string, statement policyStatement) bool {
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return !statement.Actions.FuncMatch(actionMatch, action).IsEmpty()
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}
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// Match function matches wild cards in 'pattern' for resource.
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func resourceMatch(pattern, resource string) bool {
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if runtime.GOOS == "windows" {
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// For windows specifically make sure we are case insensitive.
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return wildcard.Match(strings.ToLower(pattern), strings.ToLower(resource))
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}
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return wildcard.Match(pattern, resource)
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}
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// Match function matches wild cards in 'pattern' for action.
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func actionMatch(pattern, action string) bool {
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return wildcard.MatchSimple(pattern, action)
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}
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func refererMatch(pattern, referer string) bool {
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return wildcard.MatchSimple(pattern, referer)
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}
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// isIPInCIDR - checks if a given a IP address is a member of the given subnet.
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func isIPInCIDR(cidr, ip string) bool {
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// AWS S3 spec says IPs must use standard CIDR notation.
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// http://docs.aws.amazon.com/AmazonS3/latest/dev/example-bucket-policies.html#example-bucket-policies-use-case-3.
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_, cidrNet, err := net.ParseCIDR(cidr)
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if err != nil {
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return false // If provided CIDR can't be parsed no IP will be in the subnet.
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}
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addr := net.ParseIP(ip)
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return cidrNet.Contains(addr)
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}
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// Verify if given resource matches with policy statement.
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func bucketPolicyResourceMatch(resource string, statement policyStatement) bool {
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// the resource rule for object could contain "*" wild card.
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// the requested object can be given access based on the already set bucket policy if
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// the match is successful.
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// More info: http://docs.aws.amazon.com/AmazonS3/latest/dev/s3-arn-format.html.
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return !statement.Resources.FuncMatch(resourceMatch, resource).IsEmpty()
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}
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// Verify if given condition matches with policy statement.
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func bucketPolicyConditionMatch(conditions map[string]set.StringSet, statement policyStatement) bool {
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// Supports following conditions.
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// - StringEquals
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// - StringNotEquals
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// - StringLike
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// - StringNotLike
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// - IpAddress
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// - NotIpAddress
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//
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// Supported applicable condition keys for each conditions.
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// - s3:prefix
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// - s3:max-keys
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// - s3:aws-Referer
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// - s3:aws-SourceIp
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// The following loop evaluates the logical AND of all the
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// conditions in the statement. Note: we can break out of the
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// loop if and only if a condition evaluates to false.
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for condition, conditionKeyVal := range statement.Conditions {
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prefixConditon := conditionKeyVal["s3:prefix"]
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maxKeyCondition := conditionKeyVal["s3:max-keys"]
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if condition == "StringEquals" {
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// If there is no condition with "s3:prefix" or "s3:max-keys" condition key
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// then there is nothing to check condition against.
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if !prefixConditon.IsEmpty() && !prefixConditon.Equals(conditions["prefix"]) {
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return false
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}
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if !maxKeyCondition.IsEmpty() && !maxKeyCondition.Equals(conditions["max-keys"]) {
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return false
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}
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} else if condition == "StringNotEquals" {
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// If there is no condition with "s3:prefix" or "s3:max-keys" condition key
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// then there is nothing to check condition against.
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if !prefixConditon.IsEmpty() && prefixConditon.Equals(conditions["prefix"]) {
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return false
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}
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if !maxKeyCondition.IsEmpty() && maxKeyCondition.Equals(conditions["max-keys"]) {
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return false
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}
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} else if condition == "StringLike" {
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awsReferers := conditionKeyVal["aws:Referer"]
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// Skip empty condition, it is trivially satisfied.
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if awsReferers.IsEmpty() {
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continue
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}
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// wildcard match of referer in statement was not empty.
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// StringLike has a match, i.e, condition evaluates to true.
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refererFound := false
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for referer := range conditions["referer"] {
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if !awsReferers.FuncMatch(refererMatch, referer).IsEmpty() {
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refererFound = true
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break
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}
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}
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// No matching referer found, so the condition is false.
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if !refererFound {
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return false
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}
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} else if condition == "StringNotLike" {
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awsReferers := conditionKeyVal["aws:Referer"]
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// Skip empty condition, it is trivially satisfied.
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if awsReferers.IsEmpty() {
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continue
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}
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// wildcard match of referer in statement was not empty.
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// StringNotLike has a match, i.e, condition evaluates to false.
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for referer := range conditions["referer"] {
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if !awsReferers.FuncMatch(refererMatch, referer).IsEmpty() {
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return false
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}
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}
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} else if condition == "IpAddress" {
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awsIps := conditionKeyVal["aws:SourceIp"]
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// Skip empty condition, it is trivially satisfied.
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if awsIps.IsEmpty() {
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continue
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}
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// wildcard match of ip if statement was not empty.
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// Find a valid ip.
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ipFound := false
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for ip := range conditions["ip"] {
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if !awsIps.FuncMatch(isIPInCIDR, ip).IsEmpty() {
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ipFound = true
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break
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}
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}
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if !ipFound {
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return false
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}
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} else if condition == "NotIpAddress" {
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awsIps := conditionKeyVal["aws:SourceIp"]
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// Skip empty condition, it is trivially satisfied.
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if awsIps.IsEmpty() {
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continue
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}
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// wildcard match of ip if statement was not empty.
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// Find if nothing matches.
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for ip := range conditions["ip"] {
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if !awsIps.FuncMatch(isIPInCIDR, ip).IsEmpty() {
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return false
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}
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}
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}
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}
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return true
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}
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// PutBucketPolicyHandler - PUT Bucket policy
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// -----------------
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// This implementation of the PUT operation uses the policy
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// subresource to add to or replace a policy on a bucket
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func (api objectAPIHandlers) PutBucketPolicyHandler(w http.ResponseWriter, r *http.Request) {
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objAPI := api.ObjectAPI()
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if objAPI == nil {
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writeErrorResponse(w, ErrServerNotInitialized, r.URL)
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return
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}
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if s3Error := checkRequestAuthType(r, "", "", serverConfig.GetRegion()); s3Error != ErrNone {
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writeErrorResponse(w, s3Error, r.URL)
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return
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}
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vars := mux.Vars(r)
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bucket := vars["bucket"]
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// Before proceeding validate if bucket exists.
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_, err := objAPI.GetBucketInfo(bucket)
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if err != nil {
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errorIf(err, "Unable to find bucket info.")
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writeErrorResponse(w, toAPIErrorCode(err), r.URL)
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return
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}
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// If Content-Length is unknown or zero, deny the
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// request. PutBucketPolicy always needs a Content-Length.
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if r.ContentLength == -1 || r.ContentLength == 0 {
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writeErrorResponse(w, ErrMissingContentLength, r.URL)
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return
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}
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// If Content-Length is greater than maximum allowed policy size.
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if r.ContentLength > maxAccessPolicySize {
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writeErrorResponse(w, ErrEntityTooLarge, r.URL)
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return
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}
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// Read access policy up to maxAccessPolicySize.
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// http://docs.aws.amazon.com/AmazonS3/latest/dev/access-policy-language-overview.html
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// bucket policies are limited to 20KB in size, using a limit reader.
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policyBytes, err := ioutil.ReadAll(io.LimitReader(r.Body, maxAccessPolicySize))
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if err != nil {
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errorIf(err, "Unable to read from client.")
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writeErrorResponse(w, toAPIErrorCode(err), r.URL)
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return
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}
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// Parse validate and save bucket policy.
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if s3Error := parseAndPersistBucketPolicy(bucket, policyBytes, objAPI); s3Error != ErrNone {
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writeErrorResponse(w, s3Error, r.URL)
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return
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}
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// Success.
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writeSuccessNoContent(w)
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}
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// DeleteBucketPolicyHandler - DELETE Bucket policy
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// -----------------
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// This implementation of the DELETE operation uses the policy
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// subresource to add to remove a policy on a bucket.
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func (api objectAPIHandlers) DeleteBucketPolicyHandler(w http.ResponseWriter, r *http.Request) {
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objAPI := api.ObjectAPI()
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if objAPI == nil {
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writeErrorResponse(w, ErrServerNotInitialized, r.URL)
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return
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}
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if s3Error := checkRequestAuthType(r, "", "", serverConfig.GetRegion()); s3Error != ErrNone {
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writeErrorResponse(w, s3Error, r.URL)
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return
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}
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vars := mux.Vars(r)
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bucket := vars["bucket"]
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// Before proceeding validate if bucket exists.
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_, err := objAPI.GetBucketInfo(bucket)
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if err != nil {
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errorIf(err, "Unable to find bucket info.")
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writeErrorResponse(w, toAPIErrorCode(err), r.URL)
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return
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}
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// Delete bucket access policy, by passing an empty policy
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// struct.
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if err := persistAndNotifyBucketPolicyChange(bucket, policyChange{true, nil}, objAPI); err != nil {
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switch err.(type) {
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case BucketPolicyNotFound:
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writeErrorResponse(w, ErrNoSuchBucketPolicy, r.URL)
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default:
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writeErrorResponse(w, ErrInternalError, r.URL)
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}
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return
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}
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// Success.
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writeSuccessNoContent(w)
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}
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// GetBucketPolicyHandler - GET Bucket policy
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// -----------------
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// This operation uses the policy
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// subresource to return the policy of a specified bucket.
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func (api objectAPIHandlers) GetBucketPolicyHandler(w http.ResponseWriter, r *http.Request) {
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objAPI := api.ObjectAPI()
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if objAPI == nil {
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writeErrorResponse(w, ErrServerNotInitialized, r.URL)
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return
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}
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if s3Error := checkRequestAuthType(r, "", "", serverConfig.GetRegion()); s3Error != ErrNone {
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writeErrorResponse(w, s3Error, r.URL)
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return
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}
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vars := mux.Vars(r)
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bucket := vars["bucket"]
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// Before proceeding validate if bucket exists.
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_, err := objAPI.GetBucketInfo(bucket)
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if err != nil {
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errorIf(err, "Unable to find bucket info.")
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writeErrorResponse(w, toAPIErrorCode(err), r.URL)
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return
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}
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// Read bucket access policy.
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policy, err := readBucketPolicy(bucket, objAPI)
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if err != nil {
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errorIf(err, "Unable to read bucket policy.")
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switch err.(type) {
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case BucketPolicyNotFound:
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writeErrorResponse(w, ErrNoSuchBucketPolicy, r.URL)
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default:
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writeErrorResponse(w, ErrInternalError, r.URL)
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}
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return
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}
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// Write to client.
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fmt.Fprint(w, policy)
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}
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