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restic/vendor/github.com/minio/minio-go/pkg/s3signer/request-signature-v2.go
2018-03-30 12:33:40 +02:00

317 lines
9.0 KiB
Go

/*
* Minio Go Library for Amazon S3 Compatible Cloud Storage
* Copyright 2015-2017 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 s3signer
import (
"bytes"
"crypto/hmac"
"crypto/sha1"
"encoding/base64"
"fmt"
"net/http"
"net/url"
"sort"
"strconv"
"strings"
"time"
"github.com/minio/minio-go/pkg/s3utils"
)
// Signature and API related constants.
const (
signV2Algorithm = "AWS"
)
// Encode input URL path to URL encoded path.
func encodeURL2Path(req *http.Request, virtualHost bool) (path string) {
if virtualHost {
reqHost := getHostAddr(req)
dotPos := strings.Index(reqHost, ".")
if dotPos > -1 {
bucketName := reqHost[:dotPos]
path = "/" + bucketName
path += req.URL.Path
path = s3utils.EncodePath(path)
return
}
}
path = s3utils.EncodePath(req.URL.Path)
return
}
// PreSignV2 - presign the request in following style.
// https://${S3_BUCKET}.s3.amazonaws.com/${S3_OBJECT}?AWSAccessKeyId=${S3_ACCESS_KEY}&Expires=${TIMESTAMP}&Signature=${SIGNATURE}.
func PreSignV2(req http.Request, accessKeyID, secretAccessKey string, expires int64, virtualHost bool) *http.Request {
// Presign is not needed for anonymous credentials.
if accessKeyID == "" || secretAccessKey == "" {
return &req
}
d := time.Now().UTC()
// Find epoch expires when the request will expire.
epochExpires := d.Unix() + expires
// Add expires header if not present.
if expiresStr := req.Header.Get("Expires"); expiresStr == "" {
req.Header.Set("Expires", strconv.FormatInt(epochExpires, 10))
}
// Get presigned string to sign.
stringToSign := preStringToSignV2(req, virtualHost)
hm := hmac.New(sha1.New, []byte(secretAccessKey))
hm.Write([]byte(stringToSign))
// Calculate signature.
signature := base64.StdEncoding.EncodeToString(hm.Sum(nil))
query := req.URL.Query()
// Handle specially for Google Cloud Storage.
if strings.Contains(getHostAddr(&req), ".storage.googleapis.com") {
query.Set("GoogleAccessId", accessKeyID)
} else {
query.Set("AWSAccessKeyId", accessKeyID)
}
// Fill in Expires for presigned query.
query.Set("Expires", strconv.FormatInt(epochExpires, 10))
// Encode query and save.
req.URL.RawQuery = s3utils.QueryEncode(query)
// Save signature finally.
req.URL.RawQuery += "&Signature=" + s3utils.EncodePath(signature)
// Return.
return &req
}
// PostPresignSignatureV2 - presigned signature for PostPolicy
// request.
func PostPresignSignatureV2(policyBase64, secretAccessKey string) string {
hm := hmac.New(sha1.New, []byte(secretAccessKey))
hm.Write([]byte(policyBase64))
signature := base64.StdEncoding.EncodeToString(hm.Sum(nil))
return signature
}
// Authorization = "AWS" + " " + AWSAccessKeyId + ":" + Signature;
// Signature = Base64( HMAC-SHA1( YourSecretAccessKeyID, UTF-8-Encoding-Of( StringToSign ) ) );
//
// StringToSign = HTTP-Verb + "\n" +
// Content-Md5 + "\n" +
// Content-Type + "\n" +
// Date + "\n" +
// CanonicalizedProtocolHeaders +
// CanonicalizedResource;
//
// CanonicalizedResource = [ "/" + Bucket ] +
// <HTTP-Request-URI, from the protocol name up to the query string> +
// [ subresource, if present. For example "?acl", "?location", "?logging", or "?torrent"];
//
// CanonicalizedProtocolHeaders = <described below>
// SignV2 sign the request before Do() (AWS Signature Version 2).
func SignV2(req http.Request, accessKeyID, secretAccessKey string, virtualHost bool) *http.Request {
// Signature calculation is not needed for anonymous credentials.
if accessKeyID == "" || secretAccessKey == "" {
return &req
}
// Initial time.
d := time.Now().UTC()
// Add date if not present.
if date := req.Header.Get("Date"); date == "" {
req.Header.Set("Date", d.Format(http.TimeFormat))
}
// Calculate HMAC for secretAccessKey.
stringToSign := stringToSignV2(req, virtualHost)
hm := hmac.New(sha1.New, []byte(secretAccessKey))
hm.Write([]byte(stringToSign))
// Prepare auth header.
authHeader := new(bytes.Buffer)
authHeader.WriteString(fmt.Sprintf("%s %s:", signV2Algorithm, accessKeyID))
encoder := base64.NewEncoder(base64.StdEncoding, authHeader)
encoder.Write(hm.Sum(nil))
encoder.Close()
// Set Authorization header.
req.Header.Set("Authorization", authHeader.String())
return &req
}
// From the Amazon docs:
//
// StringToSign = HTTP-Verb + "\n" +
// Content-Md5 + "\n" +
// Content-Type + "\n" +
// Expires + "\n" +
// CanonicalizedProtocolHeaders +
// CanonicalizedResource;
func preStringToSignV2(req http.Request, virtualHost bool) string {
buf := new(bytes.Buffer)
// Write standard headers.
writePreSignV2Headers(buf, req)
// Write canonicalized protocol headers if any.
writeCanonicalizedHeaders(buf, req)
// Write canonicalized Query resources if any.
writeCanonicalizedResource(buf, req, virtualHost)
return buf.String()
}
// writePreSignV2Headers - write preSign v2 required headers.
func writePreSignV2Headers(buf *bytes.Buffer, req http.Request) {
buf.WriteString(req.Method + "\n")
buf.WriteString(req.Header.Get("Content-Md5") + "\n")
buf.WriteString(req.Header.Get("Content-Type") + "\n")
buf.WriteString(req.Header.Get("Expires") + "\n")
}
// From the Amazon docs:
//
// StringToSign = HTTP-Verb + "\n" +
// Content-Md5 + "\n" +
// Content-Type + "\n" +
// Date + "\n" +
// CanonicalizedProtocolHeaders +
// CanonicalizedResource;
func stringToSignV2(req http.Request, virtualHost bool) string {
buf := new(bytes.Buffer)
// Write standard headers.
writeSignV2Headers(buf, req)
// Write canonicalized protocol headers if any.
writeCanonicalizedHeaders(buf, req)
// Write canonicalized Query resources if any.
writeCanonicalizedResource(buf, req, virtualHost)
return buf.String()
}
// writeSignV2Headers - write signV2 required headers.
func writeSignV2Headers(buf *bytes.Buffer, req http.Request) {
buf.WriteString(req.Method + "\n")
buf.WriteString(req.Header.Get("Content-Md5") + "\n")
buf.WriteString(req.Header.Get("Content-Type") + "\n")
buf.WriteString(req.Header.Get("Date") + "\n")
}
// writeCanonicalizedHeaders - write canonicalized headers.
func writeCanonicalizedHeaders(buf *bytes.Buffer, req http.Request) {
var protoHeaders []string
vals := make(map[string][]string)
for k, vv := range req.Header {
// All the AMZ headers should be lowercase
lk := strings.ToLower(k)
if strings.HasPrefix(lk, "x-amz") {
protoHeaders = append(protoHeaders, lk)
vals[lk] = vv
}
}
sort.Strings(protoHeaders)
for _, k := range protoHeaders {
buf.WriteString(k)
buf.WriteByte(':')
for idx, v := range vals[k] {
if idx > 0 {
buf.WriteByte(',')
}
if strings.Contains(v, "\n") {
// TODO: "Unfold" long headers that
// span multiple lines (as allowed by
// RFC 2616, section 4.2) by replacing
// the folding white-space (including
// new-line) by a single space.
buf.WriteString(v)
} else {
buf.WriteString(v)
}
}
buf.WriteByte('\n')
}
}
// AWS S3 Signature V2 calculation rule is give here:
// http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#RESTAuthenticationStringToSign
// Whitelist resource list that will be used in query string for signature-V2 calculation.
// The list should be alphabetically sorted
var resourceList = []string{
"acl",
"delete",
"lifecycle",
"location",
"logging",
"notification",
"partNumber",
"policy",
"requestPayment",
"response-cache-control",
"response-content-disposition",
"response-content-encoding",
"response-content-language",
"response-content-type",
"response-expires",
"torrent",
"uploadId",
"uploads",
"versionId",
"versioning",
"versions",
"website",
}
// From the Amazon docs:
//
// CanonicalizedResource = [ "/" + Bucket ] +
// <HTTP-Request-URI, from the protocol name up to the query string> +
// [ sub-resource, if present. For example "?acl", "?location", "?logging", or "?torrent"];
func writeCanonicalizedResource(buf *bytes.Buffer, req http.Request, virtualHost bool) {
// Save request URL.
requestURL := req.URL
// Get encoded URL path.
buf.WriteString(encodeURL2Path(&req, virtualHost))
if requestURL.RawQuery != "" {
var n int
vals, _ := url.ParseQuery(requestURL.RawQuery)
// Verify if any sub resource queries are present, if yes
// canonicallize them.
for _, resource := range resourceList {
if vv, ok := vals[resource]; ok && len(vv) > 0 {
n++
// First element
switch n {
case 1:
buf.WriteByte('?')
// The rest
default:
buf.WriteByte('&')
}
buf.WriteString(resource)
// Request parameters
if len(vv[0]) > 0 {
buf.WriteByte('=')
buf.WriteString(vv[0])
}
}
}
}
}