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wp-s3-action/vendor/github.com/aws/aws-sdk-go/private/signer/v4/v4.go
2016-08-16 23:22:31 +02:00

439 lines
13 KiB
Go

// Package v4 implements signing for AWS V4 signer
package v4
import (
"crypto/hmac"
"crypto/sha256"
"encoding/hex"
"fmt"
"io"
"net/http"
"net/url"
"sort"
"strconv"
"strings"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/credentials"
"github.com/aws/aws-sdk-go/aws/request"
"github.com/aws/aws-sdk-go/private/protocol/rest"
)
const (
authHeaderPrefix = "AWS4-HMAC-SHA256"
timeFormat = "20060102T150405Z"
shortTimeFormat = "20060102"
)
var ignoredHeaders = rules{
blacklist{
mapRule{
"Content-Length": struct{}{},
"User-Agent": struct{}{},
},
},
}
// requiredSignedHeaders is a whitelist for build canonical headers.
var requiredSignedHeaders = rules{
whitelist{
mapRule{
"Cache-Control": struct{}{},
"Content-Disposition": struct{}{},
"Content-Encoding": struct{}{},
"Content-Language": struct{}{},
"Content-Md5": struct{}{},
"Content-Type": struct{}{},
"Expires": struct{}{},
"If-Match": struct{}{},
"If-Modified-Since": struct{}{},
"If-None-Match": struct{}{},
"If-Unmodified-Since": struct{}{},
"Range": struct{}{},
"X-Amz-Acl": struct{}{},
"X-Amz-Copy-Source": struct{}{},
"X-Amz-Copy-Source-If-Match": struct{}{},
"X-Amz-Copy-Source-If-Modified-Since": struct{}{},
"X-Amz-Copy-Source-If-None-Match": struct{}{},
"X-Amz-Copy-Source-If-Unmodified-Since": struct{}{},
"X-Amz-Copy-Source-Range": struct{}{},
"X-Amz-Copy-Source-Server-Side-Encryption-Customer-Algorithm": struct{}{},
"X-Amz-Copy-Source-Server-Side-Encryption-Customer-Key": struct{}{},
"X-Amz-Copy-Source-Server-Side-Encryption-Customer-Key-Md5": struct{}{},
"X-Amz-Grant-Full-control": struct{}{},
"X-Amz-Grant-Read": struct{}{},
"X-Amz-Grant-Read-Acp": struct{}{},
"X-Amz-Grant-Write": struct{}{},
"X-Amz-Grant-Write-Acp": struct{}{},
"X-Amz-Metadata-Directive": struct{}{},
"X-Amz-Mfa": struct{}{},
"X-Amz-Request-Payer": struct{}{},
"X-Amz-Server-Side-Encryption": struct{}{},
"X-Amz-Server-Side-Encryption-Aws-Kms-Key-Id": struct{}{},
"X-Amz-Server-Side-Encryption-Customer-Algorithm": struct{}{},
"X-Amz-Server-Side-Encryption-Customer-Key": struct{}{},
"X-Amz-Server-Side-Encryption-Customer-Key-Md5": struct{}{},
"X-Amz-Storage-Class": struct{}{},
"X-Amz-Website-Redirect-Location": struct{}{},
},
},
patterns{"X-Amz-Meta-"},
}
// allowedHoisting is a whitelist for build query headers. The boolean value
// represents whether or not it is a pattern.
var allowedQueryHoisting = inclusiveRules{
blacklist{requiredSignedHeaders},
patterns{"X-Amz-"},
}
type signer struct {
Request *http.Request
Time time.Time
ExpireTime time.Duration
ServiceName string
Region string
CredValues credentials.Value
Credentials *credentials.Credentials
Query url.Values
Body io.ReadSeeker
Debug aws.LogLevelType
Logger aws.Logger
isPresign bool
formattedTime string
formattedShortTime string
signedHeaders string
canonicalHeaders string
canonicalString string
credentialString string
stringToSign string
signature string
authorization string
notHoist bool
signedHeaderVals http.Header
}
// Sign requests with signature version 4.
//
// Will sign the requests with the service config's Credentials object
// Signing is skipped if the credentials is the credentials.AnonymousCredentials
// object.
func Sign(req *request.Request) {
// If the request does not need to be signed ignore the signing of the
// request if the AnonymousCredentials object is used.
if req.Config.Credentials == credentials.AnonymousCredentials {
return
}
region := req.ClientInfo.SigningRegion
if region == "" {
region = aws.StringValue(req.Config.Region)
}
name := req.ClientInfo.SigningName
if name == "" {
name = req.ClientInfo.ServiceName
}
s := signer{
Request: req.HTTPRequest,
Time: req.Time,
ExpireTime: req.ExpireTime,
Query: req.HTTPRequest.URL.Query(),
Body: req.Body,
ServiceName: name,
Region: region,
Credentials: req.Config.Credentials,
Debug: req.Config.LogLevel.Value(),
Logger: req.Config.Logger,
notHoist: req.NotHoist,
}
req.Error = s.sign()
req.SignedHeaderVals = s.signedHeaderVals
}
func (v4 *signer) sign() error {
if v4.ExpireTime != 0 {
v4.isPresign = true
}
if v4.isRequestSigned() {
if !v4.Credentials.IsExpired() {
// If the request is already signed, and the credentials have not
// expired yet ignore the signing request.
return nil
}
// The credentials have expired for this request. The current signing
// is invalid, and needs to be request because the request will fail.
if v4.isPresign {
v4.removePresign()
// Update the request's query string to ensure the values stays in
// sync in the case retrieving the new credentials fails.
v4.Request.URL.RawQuery = v4.Query.Encode()
}
}
var err error
v4.CredValues, err = v4.Credentials.Get()
if err != nil {
return err
}
if v4.isPresign {
v4.Query.Set("X-Amz-Algorithm", authHeaderPrefix)
if v4.CredValues.SessionToken != "" {
v4.Query.Set("X-Amz-Security-Token", v4.CredValues.SessionToken)
} else {
v4.Query.Del("X-Amz-Security-Token")
}
} else if v4.CredValues.SessionToken != "" {
v4.Request.Header.Set("X-Amz-Security-Token", v4.CredValues.SessionToken)
}
v4.build()
if v4.Debug.Matches(aws.LogDebugWithSigning) {
v4.logSigningInfo()
}
return nil
}
const logSignInfoMsg = `DEBUG: Request Signiture:
---[ CANONICAL STRING ]-----------------------------
%s
---[ STRING TO SIGN ]--------------------------------
%s%s
-----------------------------------------------------`
const logSignedURLMsg = `
---[ SIGNED URL ]------------------------------------
%s`
func (v4 *signer) logSigningInfo() {
signedURLMsg := ""
if v4.isPresign {
signedURLMsg = fmt.Sprintf(logSignedURLMsg, v4.Request.URL.String())
}
msg := fmt.Sprintf(logSignInfoMsg, v4.canonicalString, v4.stringToSign, signedURLMsg)
v4.Logger.Log(msg)
}
func (v4 *signer) build() {
v4.buildTime() // no depends
v4.buildCredentialString() // no depends
unsignedHeaders := v4.Request.Header
if v4.isPresign {
if !v4.notHoist {
urlValues := url.Values{}
urlValues, unsignedHeaders = buildQuery(allowedQueryHoisting, unsignedHeaders) // no depends
for k := range urlValues {
v4.Query[k] = urlValues[k]
}
}
}
v4.buildCanonicalHeaders(ignoredHeaders, unsignedHeaders)
v4.buildCanonicalString() // depends on canon headers / signed headers
v4.buildStringToSign() // depends on canon string
v4.buildSignature() // depends on string to sign
if v4.isPresign {
v4.Request.URL.RawQuery += "&X-Amz-Signature=" + v4.signature
} else {
parts := []string{
authHeaderPrefix + " Credential=" + v4.CredValues.AccessKeyID + "/" + v4.credentialString,
"SignedHeaders=" + v4.signedHeaders,
"Signature=" + v4.signature,
}
v4.Request.Header.Set("Authorization", strings.Join(parts, ", "))
}
}
func (v4 *signer) buildTime() {
v4.formattedTime = v4.Time.UTC().Format(timeFormat)
v4.formattedShortTime = v4.Time.UTC().Format(shortTimeFormat)
if v4.isPresign {
duration := int64(v4.ExpireTime / time.Second)
v4.Query.Set("X-Amz-Date", v4.formattedTime)
v4.Query.Set("X-Amz-Expires", strconv.FormatInt(duration, 10))
} else {
v4.Request.Header.Set("X-Amz-Date", v4.formattedTime)
}
}
func (v4 *signer) buildCredentialString() {
v4.credentialString = strings.Join([]string{
v4.formattedShortTime,
v4.Region,
v4.ServiceName,
"aws4_request",
}, "/")
if v4.isPresign {
v4.Query.Set("X-Amz-Credential", v4.CredValues.AccessKeyID+"/"+v4.credentialString)
}
}
func buildQuery(r rule, header http.Header) (url.Values, http.Header) {
query := url.Values{}
unsignedHeaders := http.Header{}
for k, h := range header {
if r.IsValid(k) {
query[k] = h
} else {
unsignedHeaders[k] = h
}
}
return query, unsignedHeaders
}
func (v4 *signer) buildCanonicalHeaders(r rule, header http.Header) {
var headers []string
headers = append(headers, "host")
for k, v := range header {
canonicalKey := http.CanonicalHeaderKey(k)
if !r.IsValid(canonicalKey) {
continue // ignored header
}
lowerCaseKey := strings.ToLower(k)
headers = append(headers, lowerCaseKey)
if v4.signedHeaderVals == nil {
v4.signedHeaderVals = make(http.Header)
}
v4.signedHeaderVals[lowerCaseKey] = v
}
sort.Strings(headers)
v4.signedHeaders = strings.Join(headers, ";")
if v4.isPresign {
v4.Query.Set("X-Amz-SignedHeaders", v4.signedHeaders)
}
headerValues := make([]string, len(headers))
for i, k := range headers {
if k == "host" {
headerValues[i] = "host:" + v4.Request.URL.Host
} else {
headerValues[i] = k + ":" +
strings.Join(v4.Request.Header[http.CanonicalHeaderKey(k)], ",")
}
}
v4.canonicalHeaders = strings.Join(headerValues, "\n")
}
func (v4 *signer) buildCanonicalString() {
v4.Request.URL.RawQuery = strings.Replace(v4.Query.Encode(), "+", "%20", -1)
uri := v4.Request.URL.Opaque
if uri != "" {
uri = "/" + strings.Join(strings.Split(uri, "/")[3:], "/")
} else {
uri = v4.Request.URL.Path
}
if uri == "" {
uri = "/"
}
if v4.ServiceName != "s3" {
uri = rest.EscapePath(uri, false)
}
v4.canonicalString = strings.Join([]string{
v4.Request.Method,
uri,
v4.Request.URL.RawQuery,
v4.canonicalHeaders + "\n",
v4.signedHeaders,
v4.bodyDigest(),
}, "\n")
}
func (v4 *signer) buildStringToSign() {
v4.stringToSign = strings.Join([]string{
authHeaderPrefix,
v4.formattedTime,
v4.credentialString,
hex.EncodeToString(makeSha256([]byte(v4.canonicalString))),
}, "\n")
}
func (v4 *signer) buildSignature() {
secret := v4.CredValues.SecretAccessKey
date := makeHmac([]byte("AWS4"+secret), []byte(v4.formattedShortTime))
region := makeHmac(date, []byte(v4.Region))
service := makeHmac(region, []byte(v4.ServiceName))
credentials := makeHmac(service, []byte("aws4_request"))
signature := makeHmac(credentials, []byte(v4.stringToSign))
v4.signature = hex.EncodeToString(signature)
}
func (v4 *signer) bodyDigest() string {
hash := v4.Request.Header.Get("X-Amz-Content-Sha256")
if hash == "" {
if v4.isPresign && v4.ServiceName == "s3" {
hash = "UNSIGNED-PAYLOAD"
} else if v4.Body == nil {
hash = hex.EncodeToString(makeSha256([]byte{}))
} else {
hash = hex.EncodeToString(makeSha256Reader(v4.Body))
}
v4.Request.Header.Add("X-Amz-Content-Sha256", hash)
}
return hash
}
// isRequestSigned returns if the request is currently signed or presigned
func (v4 *signer) isRequestSigned() bool {
if v4.isPresign && v4.Query.Get("X-Amz-Signature") != "" {
return true
}
if v4.Request.Header.Get("Authorization") != "" {
return true
}
return false
}
// unsign removes signing flags for both signed and presigned requests.
func (v4 *signer) removePresign() {
v4.Query.Del("X-Amz-Algorithm")
v4.Query.Del("X-Amz-Signature")
v4.Query.Del("X-Amz-Security-Token")
v4.Query.Del("X-Amz-Date")
v4.Query.Del("X-Amz-Expires")
v4.Query.Del("X-Amz-Credential")
v4.Query.Del("X-Amz-SignedHeaders")
}
func makeHmac(key []byte, data []byte) []byte {
hash := hmac.New(sha256.New, key)
hash.Write(data)
return hash.Sum(nil)
}
func makeSha256(data []byte) []byte {
hash := sha256.New()
hash.Write(data)
return hash.Sum(nil)
}
func makeSha256Reader(reader io.ReadSeeker) []byte {
hash := sha256.New()
start, _ := reader.Seek(0, 1)
defer reader.Seek(start, 0)
io.Copy(hash, reader)
return hash.Sum(nil)
}