我需要验证google id_token，其中一步是检查令牌签名。
首先，我从https://www.googleapis.com/oauth2/v2/certs获取证书并从证书中提取模数（n）和指数（e）部分并生成公钥，然后我拆开令牌（标题，有效负载和摘要）之后，我将已解码的header.payload与Google pKey +摘要一起发送到rsa函数rsa.VerifyPKCS1v15。
我遇到了这个验证错误：crypto/rsa: verification error
这里是代码（我评论了部分代码失败了// validation here fails）：
func ValidateIDToken(auth_token string) (err error){
res, err := http.Get("https://www.googleapis.com/oauth2/v2/certs")
if err != nil {
log.Fatal(err)
return err
}
certs, err := ioutil.ReadAll(res.Body)
res.Body.Close()
if err != nil {
log.Fatal(err)
return err
}
//get modulus and exponent from the cert
var goCertificate interface{}
err = json.Unmarshal(certs, &goCertificate)
k := goCertificate.(map[string]interface{})["keys"]
j := k.([]interface{})
x := j[1]
h := x.(map[string]interface{})["n"]
g := x.(map[string]interface{})["e"]
e64 := base64.StdEncoding
//build the google pub key
nStr := h.(string)
decN, err := base64.StdEncoding.DecodeString(nStr)
if err != nil {
log.Println(err)
return
}
n := big.NewInt(0)
n.SetBytes(decN)
eStr := g.(string)
decE, err := base64.StdEncoding.DecodeString(eStr)
if err != nil {
log.Println(err)
return
}
var eBytes []byte
if len(decE) < 8 {
eBytes = make([]byte, 8-len(decE), 8)
eBytes = append(eBytes, decE...)
} else {
eBytes = decE
}
eReader := bytes.NewReader(eBytes)
var e uint64
err = binary.Read(eReader, binary.BigEndian, &e)
if err != nil {
log.Println(err)
return
}
pKey := rsa.PublicKey{N: n, E: int(e)}
w := strings.SplitAfter(auth_token, ".")
for i, val := range w {
w[i] = strings.Trim(val, ".")
}
y := w[0:2]
//Join just the first two parts, the header and the payload without the signature
o := strings.Join(y, ".")
headerOauth := DecodeB64(nil,[]byte(w[0]),e64)
inblockOauth := DecodeB64(nil,[]byte(w[1]),e64)
toHash := string(headerOauth) + "}." + string(inblockOauth)
digestOauth := DecodeB64(nil, []byte(w[2]),e64)
hasherOauth := sha256.New()
hasherOauth.Write([]byte(toHash))
// validation here fails
err = rsa.VerifyPKCS1v15(&pKey,crypto.SHA256,hasherOauth.Sum(nil),digestOauth)
if err != nil {
log.Printf("Error verifying key %s",err.Error())
return err
}
return err
}
更新1： 这是包含头和有效负载的哈希var：
{"alg":"RS256","kid":"d91c503452d0f8849200a321ffbf7dea76f9371d"}.{"iss":"accounts.google.com","sub":"104869993929250743503","azp":"client_email_till_@.apps.googleusercontent.com","email":"test@test.hr","at_hash":"KAm1M0g-ssMkdjds7jkbVQ","email_verified":true,"aud":client_email_till_@.apps.googleusercontent.com","hd":"test.hr","iat":1412246551,"exp":1412250451}
更新2： 感谢@Florent Morselli的回复，我再次尝试了它失败了，我这次B64解码只有第三部分（签名）但是错误仍然存在，有人可以测试它们 auth_token，只需将ID令牌放在代码中的auth_token变量中，如果有效，请告诉我，谢谢。
package main
import(
"strings"
"encoding/binary"
"errors"
"fmt"
"log"
"encoding/base64"
"io/ioutil"
"crypto"
"crypto/sha256"
"crypto/rsa"
"bytes"
"encoding/json"
"net/http"
"math/big"
)
func main() {
auth_token := ""
w := strings.SplitAfter(auth_token, ".")
for i, val := range w {
w[i] = strings.Trim(val, ".")
}
headerOauth, err := base64.URLEncoding.DecodeString(w[0])
res, err := http.Get("https://www.googleapis.com/oauth2/v2/certs")
if err != nil {
fmt.Println(err)
}
certs, err := ioutil.ReadAll(res.Body)
res.Body.Close()
if err != nil {
fmt.Println(err)
}
//extract kid from token header
var header interface{}
err = json.Unmarshal([]byte(string(headerOauth)+"}"), &header)
token_kid := header.(map[string]interface{})["kid"]
fmt.Println("By 1")
//get modulus and exponent from the cert
var goCertificate interface{}
err = json.Unmarshal(certs, &goCertificate)
//k := goCertificate.(map[string]interface{})[token_kid.(string)]
k := goCertificate.(map[string]interface{})["keys"]
///*mod & exp part
j := k.([]interface{})
x := j[0]
if j[0].(map[string]interface{})["kid"] == token_kid {
x = j[0]
}else{
if j[1].(map[string]interface{})["kid"] == token_kid {
x = j[1]
}else{
errors.New("Token is not valid, kid from token and certificate don't match")
}
}
h := x.(map[string]interface{})["n"]
g := x.(map[string]interface{})["e"]
//build the google pub key
nStr := h.(string)
decN, err := base64.URLEncoding.DecodeString(nStr)
if err != nil {
fmt.Println(err)
return
}
n := big.NewInt(0)
n.SetBytes(decN)
eStr := g.(string)
decE, err := base64.URLEncoding.DecodeString(eStr)
if err != nil {
fmt.Println(err)
return
}
var eBytes []byte
if len(decE) < 8 {
eBytes = make([]byte, 8-len(decE), 8)
eBytes = append(eBytes, decE...)
} else {
eBytes = decE
}
eReader := bytes.NewReader(eBytes)
var e uint64
err = binary.Read(eReader, binary.BigEndian, &e)
if err != nil {
log.Println(err)
return
}
pKey := rsa.PublicKey{N: n, E: int(e)}
//inblockOauth := base64.URLEncoding.DecodeString(w[1])
toHash := w[0] + "." + w[1]
digestOauth, err := base64.URLEncoding.DecodeString(w[2])
hasherOauth := sha256.New()
hasherOauth.Write([]byte(toHash))
// verification here fails
err = rsa.VerifyPKCS1v15(&pKey,crypto.SHA256,hasherOauth.Sum(nil),digestOauth)
if err != nil {
fmt.Printf("Error verifying key %s",err.Error())
}
}
答案 0 :(得分：5)
正如聊天中所解释的那样，问题是Base64解码器无法解码标头和签名（如果它们丢失了）＃34; =＆＃34;。
您只需使用以下代码添加它们：
if m := len(h_) % 4; m != 0 {
h_ += strings.Repeat("=", 4-m)
}
以下是完整的代码：
package main
import(
"strings"
"encoding/binary"
"errors"
"fmt"
"log"
"encoding/base64"
"io/ioutil"
"crypto"
"crypto/sha256"
"crypto/rsa"
"bytes"
"encoding/json"
"net/http"
"math/big"
)
func main() {
auth_token := ""
w := strings.Split(auth_token, ".")
h_, s_ := w[0], w[2]
if m := len(h_) % 4; m != 0 {
h_ += strings.Repeat("=", 4-m)
}
if m := len(s_) % 4; m != 0 {
s_ += strings.Repeat("=", 4-m)
}
headerOauth, err := base64.URLEncoding.DecodeString(h_)
res, err := http.Get("https://www.googleapis.com/oauth2/v2/certs")
if err != nil {
fmt.Println(err)
}
certs, err := ioutil.ReadAll(res.Body)
res.Body.Close()
if err != nil {
fmt.Println(err)
}
//extract kid from token header
var header interface{}
err = json.Unmarshal([]byte(string(headerOauth)), &header)
token_kid := header.(map[string]interface{})["kid"]
fmt.Println("By 1")
//get modulus and exponent from the cert
var goCertificate interface{}
err = json.Unmarshal(certs, &goCertificate)
//k := goCertificate.(map[string]interface{})[token_kid.(string)]
k := goCertificate.(map[string]interface{})["keys"]
///*mod & exp part
j := k.([]interface{})
x := j[0]
if j[0].(map[string]interface{})["kid"] == token_kid {
x = j[0]
}else{
if j[1].(map[string]interface{})["kid"] == token_kid {
x = j[1]
}else{
errors.New("Token is not valid, kid from token and certificate don't match")
}
}
h := x.(map[string]interface{})["n"]
g := x.(map[string]interface{})["e"]
//build the google pub key
nStr := h.(string)
decN, err := base64.URLEncoding.DecodeString(nStr)
if err != nil {
fmt.Println(err)
return
}
n := big.NewInt(0)
n.SetBytes(decN)
eStr := g.(string)
decE, err := base64.URLEncoding.DecodeString(eStr)
if err != nil {
fmt.Println(err)
return
}
var eBytes []byte
if len(decE) < 8 {
eBytes = make([]byte, 8-len(decE), 8)
eBytes = append(eBytes, decE...)
} else {
eBytes = decE
}
eReader := bytes.NewReader(eBytes)
var e uint64
err = binary.Read(eReader, binary.BigEndian, &e)
if err != nil {
log.Println(err)
return
}
pKey := rsa.PublicKey{N: n, E: int(e)}
//inblockOauth := base64.URLEncoding.DecodeString(w[1])
toHash := w[0] + "." + w[1]
digestOauth, err := base64.URLEncoding.DecodeString(s_)
hasherOauth := sha256.New()
hasherOauth.Write([]byte(toHash))
// verification of the signature
err = rsa.VerifyPKCS1v15(&pKey,crypto.SHA256,hasherOauth.Sum(nil),digestOauth)
if err != nil {
fmt.Printf("Error verifying key %s",err.Error())
}
fmt.Printf("OK!")
}
答案 1 :(得分：2)
不要使用StdEncoding，它不符合规范要求的URL安全。
改为使用 URLEncoding 。有关更多信息，请参阅https://gobyexample.com/base64-encoding。
Base64 Url Safe与Base64相同，但不包含'/'和'+'（替换为'_'和' - '），并删除尾随'='。
答案 2 :(得分：2)
I send the **decoded** header.payload together with the Google pKey + digest to the rsa function rsa.VerifyPKCS1v15.
这部分你错了。您必须向RSA函数rsa.VerifyPKCS1v15发送编码 header.payload
换句话说：您检查了{"alg":"RS256","kid":"d91c503452d0f8849200a321ffbf7dea76f9371d"}.{"iss":"accounts.google.com","sub":"104869993929250743503","azp":"client_email_till_@.apps.googleusercontent.com","email":"test@test.hr","at_hash":"KAm1M0g-ssMkdjds7jkbVQ","email_verified":true,"aud":client_email_till_@.apps.googleusercontent.com","hd":"test.hr","iat":1412246551,"exp":1412250451} 的签名错误。
您必须检查eyJhbGciOiJSUzI1NiIsImtpZCI6ImQ5MWM1MDM0NTJkMGY4ODQ5MjAwYTMyMWZmYmY3ZGVhNzZmOTM3MWQifQ.eyJpc3MiOiJhY2NvdW50cy5nb29nbGUuY29tIiwic3ViIjoiMTA0ODY5OTkzOTI5MjUwNzQzNTAzIiwiYXpwIjoiY2xpZW50X2VtYWlsX3RpbGxfQC5hcHBzLmdvb2dsZXVzZXJjb250ZW50LmNvbSIsImVtYWlsIjoidGVzdEB0ZXN0LmhyIiwiYXRfaGFzaCI6IktBbTFNMGctc3NNa2RqZHM3amtiVlEiLCJlbWFpbF92ZXJpZmllZCI6dHJ1ZSwiYXVkIjpjbGllbnRfZW1haWxfdGlsbF9ALmFwcHMuZ29vZ2xldXNlcmNvbnRlbnQuY29tIiwiaGQiOiJ0ZXN0LmhyIiwiaWF0IjoxNDEyMjQ2NTUxLCJleHAiOjE0MTIyNTA0NTF9的签名。
答案 3 :(得分：1)
要检查的输入应该是$ base64_header。$ base64_claim_set。 来自Google's documentation：
JSON Web签名（JWS）是指导它的规范 为JWT生成签名的机制。的输入 signature是以下内容的字节数组：
{Base64url encoded header}.{Base64url encoded claim set}
我认为你可能刚刚对证书索引进行了硬编码以进行演示。在您的真实代码中，您应该根据＆＃34; kid＆＃34;选择正确的证书。标题中的字段。