minio/pkg/server/signature-v4_test.go
2015-07-12 13:36:02 -07:00

273 lines
7.4 KiB
Go

/*
* Minimal object storage library (C) 2015 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 server
import (
"bytes"
"crypto/hmac"
"crypto/sha256"
"encoding/hex"
"errors"
"io"
"io/ioutil"
"net/http"
"regexp"
"sort"
"strings"
"time"
"unicode/utf8"
)
const (
authHeader = "AWS4-HMAC-SHA256"
iso8601Format = "20060102T150405Z"
yyyymmdd = "20060102"
)
///
/// Excerpts from @lsegal - https://github.com/aws/aws-sdk-js/issues/659#issuecomment-120477258
///
/// User-Agent:
///
/// This is ignored from signing because signing this causes problems with generating pre-signed URLs
/// (that are executed by other agents) or when customers pass requests through proxies, which may
/// modify the user-agent.
///
/// Content-Length:
///
/// This is ignored from signing because generating a pre-signed URL should not provide a content-length
/// constraint, specifically when vending a S3 pre-signed PUT URL. The corollary to this is that when
/// sending regular requests (non-pre-signed), the signature contains a checksum of the body, which
/// implicitly validates the payload length (since changing the number of bytes would change the checksum)
/// and therefore this header is not valuable in the signature.
///
/// Content-Type:
///
/// Signing this header causes quite a number of problems in browser environments, where browsers
/// like to modify and normalize the content-type header in different ways. There is more information
/// on this in https://github.com/aws/aws-sdk-js/issues/244. Avoiding this field simplifies logic
/// and reduces the possibility of future bugs
///
/// Authorization:
///
/// Is skipped for obvious reasons
///
var ignoredHeaders = map[string]bool{
"Authorization": true,
"Content-Type": true,
"Content-Length": true,
"User-Agent": true,
}
// urlEncodedName encode the strings from UTF-8 byte representations to HTML hex escape sequences
//
// This is necessary since regular url.Parse() and url.Encode() functions do not support UTF-8
// non english characters cannot be parsed due to the nature in which url.Encode() is written
//
// This function on the other hand is a direct replacement for url.Encode() technique to support
// pretty much every UTF-8 character.
func urlEncodeName(name string) (string, error) {
// if object matches reserved string, no need to encode them
reservedNames := regexp.MustCompile("^[a-zA-Z0-9-_.~/]+$")
if reservedNames.MatchString(name) {
return name, nil
}
var encodedName string
for _, s := range name {
if 'A' <= s && s <= 'Z' || 'a' <= s && s <= 'z' || '0' <= s && s <= '9' { // §2.3 Unreserved characters (mark)
encodedName = encodedName + string(s)
continue
}
switch s {
case '-', '_', '.', '~', '/': // §2.3 Unreserved characters (mark)
encodedName = encodedName + string(s)
continue
default:
len := utf8.RuneLen(s)
if len < 0 {
return "", errors.New("invalid utf-8")
}
u := make([]byte, len)
utf8.EncodeRune(u, s)
for _, r := range u {
hex := hex.EncodeToString([]byte{r})
encodedName = encodedName + "%" + strings.ToUpper(hex)
}
}
}
return encodedName, nil
}
// sum256Reader calculate sha256 sum for an input read seeker
func sum256Reader(reader io.ReadSeeker) ([]byte, error) {
h := sha256.New()
var err error
start, _ := reader.Seek(0, 1)
defer reader.Seek(start, 0)
for err == nil {
length := 0
byteBuffer := make([]byte, 1024*1024)
length, err = reader.Read(byteBuffer)
byteBuffer = byteBuffer[0:length]
h.Write(byteBuffer)
}
if err != io.EOF {
return nil, err
}
return h.Sum(nil), nil
}
// sum256 calculate sha256 sum for an input byte array
func sum256(data []byte) []byte {
hash := sha256.New()
hash.Write(data)
return hash.Sum(nil)
}
// sumHMAC calculate hmac between two input byte array
func sumHMAC(key []byte, data []byte) []byte {
hash := hmac.New(sha256.New, key)
hash.Write(data)
return hash.Sum(nil)
}
func (s *MyAPISignatureV4Suite) newRequest(method, urlStr string, contentLength int64, body io.ReadSeeker) (*http.Request, error) {
t := time.Now().UTC()
req, err := http.NewRequest(method, urlStr, nil)
if err != nil {
return nil, err
}
req.Header.Set("x-amz-date", t.Format(iso8601Format))
if method == "" {
method = "POST"
}
// add Content-Length
req.ContentLength = contentLength
// add body
switch {
case body == nil:
req.Body = nil
default:
req.Body = ioutil.NopCloser(body)
}
// save for subsequent use
hash := func() string {
switch {
case body == nil:
return hex.EncodeToString(sum256([]byte{}))
default:
sum256Bytes, _ := sum256Reader(body)
return hex.EncodeToString(sum256Bytes)
}
}
hashedPayload := hash()
req.Header.Set("x-amz-content-sha256", hashedPayload)
var headers []string
vals := make(map[string][]string)
for k, vv := range req.Header {
if _, ok := ignoredHeaders[http.CanonicalHeaderKey(k)]; ok {
continue // ignored header
}
headers = append(headers, strings.ToLower(k))
vals[strings.ToLower(k)] = vv
}
headers = append(headers, "host")
sort.Strings(headers)
var canonicalHeaders bytes.Buffer
for _, k := range headers {
canonicalHeaders.WriteString(k)
canonicalHeaders.WriteByte(':')
switch {
case k == "host":
canonicalHeaders.WriteString(req.URL.Host)
fallthrough
default:
for idx, v := range vals[k] {
if idx > 0 {
canonicalHeaders.WriteByte(',')
}
canonicalHeaders.WriteString(v)
}
canonicalHeaders.WriteByte('\n')
}
}
signedHeaders := strings.Join(headers, ";")
req.URL.RawQuery = strings.Replace(req.URL.Query().Encode(), "+", "%20", -1)
encodedPath, _ := urlEncodeName(req.URL.Path)
// convert any space strings back to "+"
encodedPath = strings.Replace(encodedPath, "+", "%20", -1)
//
// canonicalRequest =
// <HTTPMethod>\n
// <CanonicalURI>\n
// <CanonicalQueryString>\n
// <CanonicalHeaders>\n
// <SignedHeaders>\n
// <HashedPayload>
//
canonicalRequest := strings.Join([]string{
req.Method,
encodedPath,
req.URL.RawQuery,
canonicalHeaders.String(),
signedHeaders,
hashedPayload,
}, "\n")
scope := strings.Join([]string{
t.Format(yyyymmdd),
"milkyway",
"s3",
"aws4_request",
}, "/")
stringToSign := authHeader + "\n" + t.Format(iso8601Format) + "\n"
stringToSign = stringToSign + scope + "\n"
stringToSign = stringToSign + hex.EncodeToString(sum256([]byte(canonicalRequest)))
date := sumHMAC([]byte("AWS4"+s.secretAccessKey), []byte(t.Format(yyyymmdd)))
region := sumHMAC(date, []byte("milkyway"))
service := sumHMAC(region, []byte("s3"))
signingKey := sumHMAC(service, []byte("aws4_request"))
signature := hex.EncodeToString(sumHMAC(signingKey, []byte(stringToSign)))
// final Authorization header
parts := []string{
authHeader + " Credential=" + s.accessKeyID + "/" + scope,
"SignedHeaders=" + signedHeaders,
"Signature=" + signature,
}
auth := strings.Join(parts, ", ")
req.Header.Set("Authorization", auth)
return req, nil
}