mirror of https://github.com/restic/restic.git
321 lines
9.0 KiB
Go
321 lines
9.0 KiB
Go
/*
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* Minio Go Library for Amazon S3 Compatible Cloud Storage
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* Copyright 2015-2017 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 s3signer
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import (
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"bytes"
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"crypto/hmac"
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"crypto/sha1"
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"encoding/base64"
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"fmt"
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"net/http"
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"net/url"
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"path/filepath"
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"sort"
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"strconv"
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"strings"
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"time"
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"github.com/minio/minio-go/pkg/s3utils"
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)
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// Signature and API related constants.
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const (
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signV2Algorithm = "AWS"
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)
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// Encode input URL path to URL encoded path.
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func encodeURL2Path(u *url.URL) (path string) {
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// Encode URL path.
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if isS3, _ := filepath.Match("*.s3*.amazonaws.com", u.Host); isS3 {
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bucketName := u.Host[:strings.LastIndex(u.Host, ".s3")]
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path = "/" + bucketName
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path += u.Path
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path = s3utils.EncodePath(path)
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return
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}
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if strings.HasSuffix(u.Host, ".storage.googleapis.com") {
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path = "/" + strings.TrimSuffix(u.Host, ".storage.googleapis.com")
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path += u.Path
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path = s3utils.EncodePath(path)
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return
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}
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path = s3utils.EncodePath(u.Path)
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return
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}
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// PreSignV2 - presign the request in following style.
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// https://${S3_BUCKET}.s3.amazonaws.com/${S3_OBJECT}?AWSAccessKeyId=${S3_ACCESS_KEY}&Expires=${TIMESTAMP}&Signature=${SIGNATURE}.
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func PreSignV2(req http.Request, accessKeyID, secretAccessKey string, expires int64) *http.Request {
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// Presign is not needed for anonymous credentials.
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if accessKeyID == "" || secretAccessKey == "" {
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return &req
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}
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d := time.Now().UTC()
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// Find epoch expires when the request will expire.
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epochExpires := d.Unix() + expires
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// Add expires header if not present.
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if expiresStr := req.Header.Get("Expires"); expiresStr == "" {
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req.Header.Set("Expires", strconv.FormatInt(epochExpires, 10))
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}
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// Get presigned string to sign.
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stringToSign := preStringToSignV2(req)
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hm := hmac.New(sha1.New, []byte(secretAccessKey))
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hm.Write([]byte(stringToSign))
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// Calculate signature.
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signature := base64.StdEncoding.EncodeToString(hm.Sum(nil))
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query := req.URL.Query()
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// Handle specially for Google Cloud Storage.
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if strings.Contains(req.URL.Host, ".storage.googleapis.com") {
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query.Set("GoogleAccessId", accessKeyID)
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} else {
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query.Set("AWSAccessKeyId", accessKeyID)
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}
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// Fill in Expires for presigned query.
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query.Set("Expires", strconv.FormatInt(epochExpires, 10))
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// Encode query and save.
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req.URL.RawQuery = s3utils.QueryEncode(query)
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// Save signature finally.
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req.URL.RawQuery += "&Signature=" + s3utils.EncodePath(signature)
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// Return.
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return &req
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}
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// PostPresignSignatureV2 - presigned signature for PostPolicy
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// request.
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func PostPresignSignatureV2(policyBase64, secretAccessKey string) string {
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hm := hmac.New(sha1.New, []byte(secretAccessKey))
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hm.Write([]byte(policyBase64))
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signature := base64.StdEncoding.EncodeToString(hm.Sum(nil))
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return signature
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}
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// Authorization = "AWS" + " " + AWSAccessKeyId + ":" + Signature;
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// Signature = Base64( HMAC-SHA1( YourSecretAccessKeyID, UTF-8-Encoding-Of( StringToSign ) ) );
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//
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// StringToSign = HTTP-Verb + "\n" +
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// Content-Md5 + "\n" +
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// Content-Type + "\n" +
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// Date + "\n" +
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// CanonicalizedProtocolHeaders +
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// CanonicalizedResource;
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//
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// CanonicalizedResource = [ "/" + Bucket ] +
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// <HTTP-Request-URI, from the protocol name up to the query string> +
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// [ subresource, if present. For example "?acl", "?location", "?logging", or "?torrent"];
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//
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// CanonicalizedProtocolHeaders = <described below>
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// SignV2 sign the request before Do() (AWS Signature Version 2).
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func SignV2(req http.Request, accessKeyID, secretAccessKey string) *http.Request {
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// Signature calculation is not needed for anonymous credentials.
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if accessKeyID == "" || secretAccessKey == "" {
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return &req
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}
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// Initial time.
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d := time.Now().UTC()
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// Add date if not present.
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if date := req.Header.Get("Date"); date == "" {
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req.Header.Set("Date", d.Format(http.TimeFormat))
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}
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// Calculate HMAC for secretAccessKey.
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stringToSign := stringToSignV2(req)
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hm := hmac.New(sha1.New, []byte(secretAccessKey))
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hm.Write([]byte(stringToSign))
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// Prepare auth header.
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authHeader := new(bytes.Buffer)
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authHeader.WriteString(fmt.Sprintf("%s %s:", signV2Algorithm, accessKeyID))
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encoder := base64.NewEncoder(base64.StdEncoding, authHeader)
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encoder.Write(hm.Sum(nil))
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encoder.Close()
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// Set Authorization header.
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req.Header.Set("Authorization", authHeader.String())
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return &req
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}
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// From the Amazon docs:
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//
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// StringToSign = HTTP-Verb + "\n" +
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// Content-Md5 + "\n" +
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// Content-Type + "\n" +
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// Expires + "\n" +
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// CanonicalizedProtocolHeaders +
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// CanonicalizedResource;
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func preStringToSignV2(req http.Request) string {
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buf := new(bytes.Buffer)
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// Write standard headers.
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writePreSignV2Headers(buf, req)
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// Write canonicalized protocol headers if any.
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writeCanonicalizedHeaders(buf, req)
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// Write canonicalized Query resources if any.
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writeCanonicalizedResource(buf, req)
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return buf.String()
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}
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// writePreSignV2Headers - write preSign v2 required headers.
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func writePreSignV2Headers(buf *bytes.Buffer, req http.Request) {
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buf.WriteString(req.Method + "\n")
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buf.WriteString(req.Header.Get("Content-Md5") + "\n")
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buf.WriteString(req.Header.Get("Content-Type") + "\n")
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buf.WriteString(req.Header.Get("Expires") + "\n")
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}
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// From the Amazon docs:
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//
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// StringToSign = HTTP-Verb + "\n" +
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// Content-Md5 + "\n" +
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// Content-Type + "\n" +
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// Date + "\n" +
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// CanonicalizedProtocolHeaders +
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// CanonicalizedResource;
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func stringToSignV2(req http.Request) string {
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buf := new(bytes.Buffer)
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// Write standard headers.
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writeSignV2Headers(buf, req)
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// Write canonicalized protocol headers if any.
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writeCanonicalizedHeaders(buf, req)
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// Write canonicalized Query resources if any.
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writeCanonicalizedResource(buf, req)
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return buf.String()
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}
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// writeSignV2Headers - write signV2 required headers.
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func writeSignV2Headers(buf *bytes.Buffer, req http.Request) {
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buf.WriteString(req.Method + "\n")
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buf.WriteString(req.Header.Get("Content-Md5") + "\n")
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buf.WriteString(req.Header.Get("Content-Type") + "\n")
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buf.WriteString(req.Header.Get("Date") + "\n")
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}
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// writeCanonicalizedHeaders - write canonicalized headers.
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func writeCanonicalizedHeaders(buf *bytes.Buffer, req http.Request) {
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var protoHeaders []string
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vals := make(map[string][]string)
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for k, vv := range req.Header {
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// All the AMZ headers should be lowercase
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lk := strings.ToLower(k)
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if strings.HasPrefix(lk, "x-amz") {
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protoHeaders = append(protoHeaders, lk)
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vals[lk] = vv
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}
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}
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sort.Strings(protoHeaders)
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for _, k := range protoHeaders {
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buf.WriteString(k)
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buf.WriteByte(':')
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for idx, v := range vals[k] {
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if idx > 0 {
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buf.WriteByte(',')
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}
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if strings.Contains(v, "\n") {
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// TODO: "Unfold" long headers that
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// span multiple lines (as allowed by
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// RFC 2616, section 4.2) by replacing
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// the folding white-space (including
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// new-line) by a single space.
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buf.WriteString(v)
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} else {
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buf.WriteString(v)
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}
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}
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buf.WriteByte('\n')
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}
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}
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// AWS S3 Signature V2 calculation rule is give here:
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// http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#RESTAuthenticationStringToSign
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// Whitelist resource list that will be used in query string for signature-V2 calculation.
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// The list should be alphabetically sorted
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var resourceList = []string{
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"acl",
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"delete",
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"lifecycle",
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"location",
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"logging",
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"notification",
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"partNumber",
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"policy",
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"requestPayment",
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"response-cache-control",
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"response-content-disposition",
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"response-content-encoding",
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"response-content-language",
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"response-content-type",
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"response-expires",
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"torrent",
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"uploadId",
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"uploads",
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"versionId",
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"versioning",
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"versions",
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"website",
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}
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// From the Amazon docs:
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//
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// CanonicalizedResource = [ "/" + Bucket ] +
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// <HTTP-Request-URI, from the protocol name up to the query string> +
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// [ sub-resource, if present. For example "?acl", "?location", "?logging", or "?torrent"];
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func writeCanonicalizedResource(buf *bytes.Buffer, req http.Request) {
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// Save request URL.
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requestURL := req.URL
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// Get encoded URL path.
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buf.WriteString(encodeURL2Path(requestURL))
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if requestURL.RawQuery != "" {
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var n int
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vals, _ := url.ParseQuery(requestURL.RawQuery)
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// Verify if any sub resource queries are present, if yes
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// canonicallize them.
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for _, resource := range resourceList {
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if vv, ok := vals[resource]; ok && len(vv) > 0 {
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n++
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// First element
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switch n {
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case 1:
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buf.WriteByte('?')
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// The rest
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default:
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buf.WriteByte('&')
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}
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buf.WriteString(resource)
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// Request parameters
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if len(vv[0]) > 0 {
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buf.WriteByte('=')
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buf.WriteString(vv[0])
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}
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}
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}
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}
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}
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