rclone/backend/s3/v2sign.go

117 lines
3.0 KiB
Go

// v2 signing
package s3
import (
"crypto/hmac"
"crypto/sha1"
"encoding/base64"
"net/http"
"sort"
"strings"
"time"
)
// URL parameters that need to be added to the signature
var s3ParamsToSign = map[string]struct{}{
"acl": {},
"location": {},
"logging": {},
"notification": {},
"partNumber": {},
"policy": {},
"requestPayment": {},
"torrent": {},
"uploadId": {},
"uploads": {},
"versionId": {},
"versioning": {},
"versions": {},
"response-content-type": {},
"response-content-language": {},
"response-expires": {},
"response-cache-control": {},
"response-content-disposition": {},
"response-content-encoding": {},
}
// sign signs requests using v2 auth
//
// Cobbled together from goamz and aws-sdk-go
func sign(AccessKey, SecretKey string, req *http.Request) {
// Set date
date := time.Now().UTC().Format(time.RFC1123)
req.Header.Set("Date", date)
// Sort out URI
uri := req.URL.EscapedPath()
if uri == "" {
uri = "/"
}
// Look through headers of interest
var md5 string
var contentType string
var headersToSign []string
tmpHeadersToSign := make(map[string][]string)
for k, v := range req.Header {
k = strings.ToLower(k)
switch k {
case "content-md5":
md5 = v[0]
case "content-type":
contentType = v[0]
default:
if strings.HasPrefix(k, "x-amz-") {
tmpHeadersToSign[k] = v
}
}
}
var keys []string
for k := range tmpHeadersToSign {
keys = append(keys, k)
}
// https://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html
sort.Strings(keys)
for _, key := range keys {
vall := strings.Join(tmpHeadersToSign[key], ",")
headersToSign = append(headersToSign, key+":"+vall)
}
// Make headers of interest into canonical string
var joinedHeadersToSign string
if len(headersToSign) > 0 {
joinedHeadersToSign = strings.Join(headersToSign, "\n") + "\n"
}
// Look for query parameters which need to be added to the signature
params := req.URL.Query()
var queriesToSign []string
for k, vs := range params {
if _, ok := s3ParamsToSign[k]; ok {
for _, v := range vs {
if v == "" {
queriesToSign = append(queriesToSign, k)
} else {
queriesToSign = append(queriesToSign, k+"="+v)
}
}
}
}
// Add query parameters to URI
if len(queriesToSign) > 0 {
sort.StringSlice(queriesToSign).Sort()
uri += "?" + strings.Join(queriesToSign, "&")
}
// Make signature
payload := req.Method + "\n" + md5 + "\n" + contentType + "\n" + date + "\n" + joinedHeadersToSign + uri
hash := hmac.New(sha1.New, []byte(SecretKey))
_, _ = hash.Write([]byte(payload))
signature := make([]byte, base64.StdEncoding.EncodedLen(hash.Size()))
base64.StdEncoding.Encode(signature, hash.Sum(nil))
// Set signature in request
req.Header.Set("Authorization", "AWS "+AccessKey+":"+string(signature))
}