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gitea/vendor/github.com/yohcop/openid-go/verify.go
2017-03-17 15:16:08 +01:00

251 lines
7.9 KiB
Go
Vendored

package openid
import (
"errors"
"fmt"
"io/ioutil"
"net/url"
"strings"
)
func Verify(uri string, cache DiscoveryCache, nonceStore NonceStore) (id string, err error) {
return defaultInstance.Verify(uri, cache, nonceStore)
}
func (oid *OpenID) Verify(uri string, cache DiscoveryCache, nonceStore NonceStore) (id string, err error) {
parsedURL, err := url.Parse(uri)
if err != nil {
return "", err
}
values, err := url.ParseQuery(parsedURL.RawQuery)
if err != nil {
return "", err
}
// 11. Verifying Assertions
// When the Relying Party receives a positive assertion, it MUST
// verify the following before accepting the assertion:
// - The value of "openid.signed" contains all the required fields.
// (Section 10.1)
if err = verifySignedFields(values); err != nil {
return "", err
}
// - The signature on the assertion is valid (Section 11.4)
if err = verifySignature(uri, values, oid.urlGetter); err != nil {
return "", err
}
// - The value of "openid.return_to" matches the URL of the current
// request (Section 11.1)
if err = verifyReturnTo(parsedURL, values); err != nil {
return "", err
}
// - Discovered information matches the information in the assertion
// (Section 11.2)
if err = oid.verifyDiscovered(parsedURL, values, cache); err != nil {
return "", err
}
// - An assertion has not yet been accepted from this OP with the
// same value for "openid.response_nonce" (Section 11.3)
if err = verifyNonce(values, nonceStore); err != nil {
return "", err
}
// If all four of these conditions are met, assertion is now
// verified. If the assertion contained a Claimed Identifier, the
// user is now authenticated with that identifier.
return values.Get("openid.claimed_id"), nil
}
// 10.1. Positive Assertions
// openid.signed - Comma-separated list of signed fields.
// This entry consists of the fields without the "openid." prefix that the signature covers.
// This list MUST contain at least "op_endpoint", "return_to" "response_nonce" and "assoc_handle",
// and if present in the response, "claimed_id" and "identity".
func verifySignedFields(vals url.Values) error {
ok := map[string]bool{
"op_endpoint": false,
"return_to": false,
"response_nonce": false,
"assoc_handle": false,
"claimed_id": vals.Get("openid.claimed_id") == "",
"identity": vals.Get("openid.identity") == "",
}
signed := strings.Split(vals.Get("openid.signed"), ",")
for _, sf := range signed {
ok[sf] = true
}
for k, v := range ok {
if !v {
return fmt.Errorf("%v must be signed but isn't", k)
}
}
return nil
}
// 11.1. Verifying the Return URL
// To verify that the "openid.return_to" URL matches the URL that is processing this assertion:
// - The URL scheme, authority, and path MUST be the same between the two
// URLs.
// - Any query parameters that are present in the "openid.return_to" URL
// MUST also be present with the same values in the URL of the HTTP
// request the RP received.
func verifyReturnTo(uri *url.URL, vals url.Values) error {
returnTo := vals.Get("openid.return_to")
rp, err := url.Parse(returnTo)
if err != nil {
return err
}
if uri.Scheme != rp.Scheme ||
uri.Host != rp.Host ||
uri.Path != rp.Path {
return errors.New(
"Scheme, host or path don't match in return_to URL")
}
qp, err := url.ParseQuery(rp.RawQuery)
if err != nil {
return err
}
return compareQueryParams(qp, vals)
}
// Any parameter in q1 must also be present in q2, and values must match.
func compareQueryParams(q1, q2 url.Values) error {
for k := range q1 {
v1 := q1.Get(k)
v2 := q2.Get(k)
if v1 != v2 {
return fmt.Errorf(
"URLs query params don't match: Param %s different: %s vs %s",
k, v1, v2)
}
}
return nil
}
func (oid *OpenID) verifyDiscovered(uri *url.URL, vals url.Values, cache DiscoveryCache) error {
version := vals.Get("openid.ns")
if version != "http://specs.openid.net/auth/2.0" {
return errors.New("Bad protocol version")
}
endpoint := vals.Get("openid.op_endpoint")
if len(endpoint) == 0 {
return errors.New("missing openid.op_endpoint url param")
}
localID := vals.Get("openid.identity")
if len(localID) == 0 {
return errors.New("no localId to verify")
}
claimedID := vals.Get("openid.claimed_id")
if len(claimedID) == 0 {
// If no Claimed Identifier is present in the response, the
// assertion is not about an identifier and the RP MUST NOT use the
// User-supplied Identifier associated with the current OpenID
// authentication transaction to identify the user. Extension
// information in the assertion MAY still be used.
// --- This library does not support this case. So claimed
// identifier must be present.
return errors.New("no claimed_id to verify")
}
// 11.2. Verifying Discovered Information
// If the Claimed Identifier in the assertion is a URL and contains a
// fragment, the fragment part and the fragment delimiter character "#"
// MUST NOT be used for the purposes of verifying the discovered
// information.
claimedIDVerify := claimedID
if fragmentIndex := strings.Index(claimedID, "#"); fragmentIndex != -1 {
claimedIDVerify = claimedID[0:fragmentIndex]
}
// If the Claimed Identifier is included in the assertion, it
// MUST have been discovered by the Relying Party and the
// information in the assertion MUST be present in the
// discovered information. The Claimed Identifier MUST NOT be an
// OP Identifier.
if discovered := cache.Get(claimedIDVerify); discovered != nil &&
discovered.OpEndpoint() == endpoint &&
discovered.OpLocalID() == localID &&
discovered.ClaimedID() == claimedIDVerify {
return nil
}
// If the Claimed Identifier was not previously discovered by the
// Relying Party (the "openid.identity" in the request was
// "http://specs.openid.net/auth/2.0/identifier_select" or a different
// Identifier, or if the OP is sending an unsolicited positive
// assertion), the Relying Party MUST perform discovery on the Claimed
// Identifier in the response to make sure that the OP is authorized to
// make assertions about the Claimed Identifier.
if ep, _, _, err := oid.Discover(claimedID); err == nil {
if ep == endpoint {
// This claimed ID points to the same endpoint, therefore this
// endpoint is authorized to make assertions about that claimed ID.
// TODO: There may be multiple endpoints found during discovery.
// They should all be checked.
cache.Put(claimedIDVerify, &SimpleDiscoveredInfo{opEndpoint: endpoint, opLocalID: localID, claimedID: claimedIDVerify})
return nil
}
}
return errors.New("Could not verify the claimed ID")
}
func verifyNonce(vals url.Values, store NonceStore) error {
nonce := vals.Get("openid.response_nonce")
endpoint := vals.Get("openid.op_endpoint")
return store.Accept(endpoint, nonce)
}
func verifySignature(uri string, vals url.Values, getter httpGetter) error {
// To have the signature verification performed by the OP, the
// Relying Party sends a direct request to the OP. To verify the
// signature, the OP uses a private association that was generated
// when it issued the positive assertion.
// 11.4.2.1. Request Parameters
params := make(url.Values)
// openid.mode: Value: "check_authentication"
params.Add("openid.mode", "check_authentication")
// Exact copies of all fields from the authentication response,
// except for "openid.mode".
for k, vs := range vals {
if k == "openid.mode" {
continue
}
for _, v := range vs {
params.Add(k, v)
}
}
resp, err := getter.Post(vals.Get("openid.op_endpoint"), params)
if err != nil {
return err
}
defer resp.Body.Close()
content, err := ioutil.ReadAll(resp.Body)
response := string(content)
lines := strings.Split(response, "\n")
isValid := false
nsValid := false
for _, l := range lines {
if l == "is_valid:true" {
isValid = true
} else if l == "ns:http://specs.openid.net/auth/2.0" {
nsValid = true
}
}
if isValid && nsValid {
// Yay !
return nil
}
return errors.New("Could not verify assertion with provider")
}