minio/cmd/signature-v2.go
Anis Elleuch e1f64141a2 presign-v2: Compute signature on encoded URL path (#3612)
Encode the path of the passed presigned url before calculating the signature. This fixes
presigning objects whose names contain characters that are found encoded in urls.
2017-01-23 08:54:32 -08:00

362 lines
10 KiB
Go

/*
* Minio Cloud Storage, (C) 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 cmd
import (
"crypto/hmac"
"crypto/sha1"
"encoding/base64"
"fmt"
"net/http"
"net/url"
"sort"
"strconv"
"strings"
"time"
)
// Signature and API related constants.
const (
signV2Algorithm = "AWS"
)
// 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",
}
func doesPolicySignatureV2Match(formValues map[string]string) APIErrorCode {
cred := serverConfig.GetCredential()
accessKey := formValues["Awsaccesskeyid"]
if accessKey != cred.AccessKey {
return ErrInvalidAccessKeyID
}
signature := formValues["Signature"]
policy := formValues["Policy"]
if signature != calculateSignatureV2(policy, cred.SecretKey) {
return ErrSignatureDoesNotMatch
}
return ErrNone
}
// doesPresignV2SignatureMatch - Verify query headers with presigned signature
// - http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#RESTAuthenticationQueryStringAuth
// returns ErrNone if matches. S3 errors otherwise.
func doesPresignV2SignatureMatch(r *http.Request) APIErrorCode {
// Access credentials.
cred := serverConfig.GetCredential()
// url.RawPath will be valid if path has any encoded characters, if not it will
// be empty - in which case we need to consider url.Path (bug in net/http?)
encodedResource := r.URL.RawPath
encodedQuery := r.URL.RawQuery
if encodedResource == "" {
splits := strings.Split(r.URL.Path, "?")
if len(splits) > 0 {
encodedResource = getURLEncodedName(splits[0])
}
}
queries := strings.Split(encodedQuery, "&")
var filteredQueries []string
var gotSignature string
var expires string
var accessKey string
var err error
for _, query := range queries {
keyval := strings.Split(query, "=")
switch keyval[0] {
case "AWSAccessKeyId":
accessKey, err = url.QueryUnescape(keyval[1])
case "Signature":
gotSignature, err = url.QueryUnescape(keyval[1])
case "Expires":
expires, err = url.QueryUnescape(keyval[1])
default:
unescapedQuery, qerr := url.QueryUnescape(query)
if qerr == nil {
filteredQueries = append(filteredQueries, unescapedQuery)
} else {
err = qerr
}
}
// Check if the query unescaped properly.
if err != nil {
errorIf(err, "Unable to unescape query values", queries)
return ErrInvalidQueryParams
}
}
// Invalid access key.
if accessKey == "" {
return ErrInvalidQueryParams
}
// Validate if access key id same.
if accessKey != cred.AccessKey {
return ErrInvalidAccessKeyID
}
// Make sure the request has not expired.
expiresInt, err := strconv.ParseInt(expires, 10, 64)
if err != nil {
return ErrMalformedExpires
}
// Check if the presigned URL has expired.
if expiresInt < time.Now().UTC().Unix() {
return ErrExpiredPresignRequest
}
expectedSignature := preSignatureV2(r.Method, encodedResource, strings.Join(filteredQueries, "&"), r.Header, expires)
if gotSignature != expectedSignature {
return ErrSignatureDoesNotMatch
}
return ErrNone
}
// Authorization = "AWS" + " " + AWSAccessKeyId + ":" + Signature;
// Signature = Base64( HMAC-SHA1( YourSecretKey, 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>
// doesSignV2Match - Verify authorization header with calculated header in accordance with
// - http://docs.aws.amazon.com/AmazonS3/latest/dev/auth-request-sig-v2.html
// returns true if matches, false otherwise. if error is not nil then it is always false
func validateV2AuthHeader(v2Auth string) APIErrorCode {
if v2Auth == "" {
return ErrAuthHeaderEmpty
}
// Verify if the header algorithm is supported or not.
if !strings.HasPrefix(v2Auth, signV2Algorithm) {
return ErrSignatureVersionNotSupported
}
// below is V2 Signed Auth header format, splitting on `space` (after the `AWS` string).
// Authorization = "AWS" + " " + AWSAccessKeyId + ":" + Signature
authFields := strings.Split(v2Auth, " ")
if len(authFields) != 2 {
return ErrMissingFields
}
// Then will be splitting on ":", this will seprate `AWSAccessKeyId` and `Signature` string.
keySignFields := strings.Split(strings.TrimSpace(authFields[1]), ":")
if len(keySignFields) != 2 {
return ErrMissingFields
}
// Access credentials.
cred := serverConfig.GetCredential()
if keySignFields[0] != cred.AccessKey {
return ErrInvalidAccessKeyID
}
return ErrNone
}
func doesSignV2Match(r *http.Request) APIErrorCode {
v2Auth := r.Header.Get("Authorization")
if apiError := validateV2AuthHeader(v2Auth); apiError != ErrNone {
return apiError
}
// Encode path:
// url.RawPath will be valid if path has any encoded characters, if not it will
// be empty - in which case we need to consider url.Path (bug in net/http?)
encodedResource := r.URL.RawPath
if encodedResource == "" {
splits := strings.Split(r.URL.Path, "?")
if len(splits) > 0 {
encodedResource = getURLEncodedName(splits[0])
}
}
// Encode query strings
encodedQuery := r.URL.Query().Encode()
expectedAuth := signatureV2(r.Method, encodedResource, encodedQuery, r.Header)
if v2Auth != expectedAuth {
return ErrSignatureDoesNotMatch
}
return ErrNone
}
func calculateSignatureV2(stringToSign string, secret string) string {
hm := hmac.New(sha1.New, []byte(secret))
hm.Write([]byte(stringToSign))
return base64.StdEncoding.EncodeToString(hm.Sum(nil))
}
// Return signature-v2 for the presigned request.
func preSignatureV2(method string, encodedResource string, encodedQuery string, headers http.Header, expires string) string {
cred := serverConfig.GetCredential()
stringToSign := presignV2STS(method, encodedResource, encodedQuery, headers, expires)
return calculateSignatureV2(stringToSign, cred.SecretKey)
}
// Return signature-v2 authrization header.
func signatureV2(method string, encodedResource string, encodedQuery string, headers http.Header) string {
cred := serverConfig.GetCredential()
stringToSign := signV2STS(method, encodedResource, encodedQuery, headers)
signature := calculateSignatureV2(stringToSign, cred.SecretKey)
return fmt.Sprintf("%s %s:%s", signV2Algorithm, cred.AccessKey, signature)
}
// Return canonical headers.
func canonicalizedAmzHeadersV2(headers http.Header) string {
var keys []string
keyval := make(map[string]string)
for key := range headers {
lkey := strings.ToLower(key)
if !strings.HasPrefix(lkey, "x-amz-") {
continue
}
keys = append(keys, lkey)
keyval[lkey] = strings.Join(headers[key], ",")
}
sort.Strings(keys)
var canonicalHeaders []string
for _, key := range keys {
canonicalHeaders = append(canonicalHeaders, key+":"+keyval[key])
}
return strings.Join(canonicalHeaders, "\n")
}
// Return canonical resource string.
func canonicalizedResourceV2(encodedPath string, encodedQuery string) string {
queries := strings.Split(encodedQuery, "&")
keyval := make(map[string]string)
for _, query := range queries {
key := query
val := ""
index := strings.Index(query, "=")
if index != -1 {
key = query[:index]
val = query[index+1:]
}
keyval[key] = val
}
var canonicalQueries []string
for _, key := range resourceList {
val, ok := keyval[key]
if !ok {
continue
}
if val == "" {
canonicalQueries = append(canonicalQueries, key)
continue
}
canonicalQueries = append(canonicalQueries, key+"="+val)
}
if len(canonicalQueries) == 0 {
return encodedPath
}
// the queries will be already sorted as resourceList is sorted.
return encodedPath + "?" + strings.Join(canonicalQueries, "&")
}
// Return string to sign for authz header calculation.
func signV2STS(method string, encodedResource string, encodedQuery string, headers http.Header) string {
canonicalHeaders := canonicalizedAmzHeadersV2(headers)
if len(canonicalHeaders) > 0 {
canonicalHeaders += "\n"
}
// From the Amazon docs:
//
// StringToSign = HTTP-Verb + "\n" +
// Content-Md5 + "\n" +
// Content-Type + "\n" +
// Date + "\n" +
// CanonicalizedProtocolHeaders +
// CanonicalizedResource;
stringToSign := strings.Join([]string{
method,
headers.Get("Content-MD5"),
headers.Get("Content-Type"),
headers.Get("Date"),
canonicalHeaders,
}, "\n") + canonicalizedResourceV2(encodedResource, encodedQuery)
return stringToSign
}
// Return string to sign for pre-sign signature calculation.
func presignV2STS(method string, encodedResource string, encodedQuery string, headers http.Header, expires string) string {
canonicalHeaders := canonicalizedAmzHeadersV2(headers)
if len(canonicalHeaders) > 0 {
canonicalHeaders += "\n"
}
// From the Amazon docs:
//
// StringToSign = HTTP-Verb + "\n" +
// Content-Md5 + "\n" +
// Content-Type + "\n" +
// Expires + "\n" +
// CanonicalizedProtocolHeaders +
// CanonicalizedResource;
stringToSign := strings.Join([]string{
method,
headers.Get("Content-MD5"),
headers.Get("Content-Type"),
expires,
canonicalHeaders,
}, "\n") + canonicalizedResourceV2(encodedResource, encodedQuery)
return stringToSign
}