/
callback_handler.go
110 lines (91 loc) · 4.12 KB
/
callback_handler.go
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// Copyright 2020-2024 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
// Package callback provides a handler for the OIDC callback endpoint.
package callback
import (
"net/http"
"net/url"
"github.com/ory/fosite"
"go.pinniped.dev/internal/federationdomain/downstreamsession"
"go.pinniped.dev/internal/federationdomain/federationdomainproviders"
"go.pinniped.dev/internal/federationdomain/formposthtml"
"go.pinniped.dev/internal/federationdomain/oidc"
"go.pinniped.dev/internal/httputil/httperr"
"go.pinniped.dev/internal/httputil/securityheader"
"go.pinniped.dev/internal/plog"
)
func NewHandler(
upstreamIDPs federationdomainproviders.FederationDomainIdentityProvidersFinderI,
oauthHelper fosite.OAuth2Provider,
stateDecoder, cookieDecoder oidc.Decoder,
redirectURI string,
) http.Handler {
handler := httperr.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
state, err := validateRequest(r, stateDecoder, cookieDecoder)
if err != nil {
return err
}
idp, err := upstreamIDPs.FindUpstreamIDPByDisplayName(state.UpstreamName)
if err != nil || idp == nil {
plog.Warning("upstream provider not found")
return httperr.New(http.StatusUnprocessableEntity, "upstream provider not found")
}
downstreamAuthParams, err := url.ParseQuery(state.AuthParams)
if err != nil {
plog.Error("error reading state downstream auth params", err)
return httperr.New(http.StatusBadRequest, "error reading state downstream auth params")
}
// Recreate enough of the original authorize request so we can pass it to NewAuthorizeRequest().
reconstitutedAuthRequest := &http.Request{Form: downstreamAuthParams}
authorizeRequester, err := oauthHelper.NewAuthorizeRequest(r.Context(), reconstitutedAuthRequest)
if err != nil {
plog.Error("error using state downstream auth params", err,
"fositeErr", oidc.FositeErrorForLog(err))
return httperr.New(http.StatusBadRequest, "error using state downstream auth params")
}
// Automatically grant certain scopes, but only if they were requested.
// This is instead of asking the user to approve these scopes. Note that `NewAuthorizeRequest` would have returned
// an error if the client requested a scope that they are not allowed to request, so we don't need to worry about that here.
downstreamsession.AutoApproveScopes(authorizeRequester)
identity, loginExtras, err := idp.LoginFromCallback(r.Context(), authcode(r), state.PKCECode, state.Nonce, redirectURI)
if err != nil {
return err
}
session, err := downstreamsession.NewPinnipedSession(r.Context(), idp, &downstreamsession.SessionConfig{
UpstreamIdentity: identity,
UpstreamLoginExtras: loginExtras,
ClientID: authorizeRequester.GetClient().GetID(),
GrantedScopes: authorizeRequester.GetGrantedScopes(),
})
if err != nil {
return httperr.Wrap(http.StatusUnprocessableEntity, err.Error(), err)
}
authorizeResponder, err := oauthHelper.NewAuthorizeResponse(r.Context(), authorizeRequester, session)
if err != nil {
plog.WarningErr("error while generating and saving authcode", err,
"identityProviderDisplayName", idp.GetDisplayName(), "fositeErr", oidc.FositeErrorForLog(err))
return httperr.Wrap(http.StatusInternalServerError, "error while generating and saving authcode", err)
}
oauthHelper.WriteAuthorizeResponse(r.Context(), w, authorizeRequester, authorizeResponder)
return nil
})
return securityheader.WrapWithCustomCSP(handler, formposthtml.ContentSecurityPolicy())
}
func authcode(r *http.Request) string {
return r.FormValue("code")
}
func validateRequest(r *http.Request, stateDecoder, cookieDecoder oidc.Decoder) (*oidc.UpstreamStateParamData, error) {
if r.Method != http.MethodGet {
return nil, httperr.Newf(http.StatusMethodNotAllowed, "%s (try GET)", r.Method)
}
_, decodedState, err := oidc.ReadStateParamAndValidateCSRFCookie(r, cookieDecoder, stateDecoder)
if err != nil {
plog.InfoErr("state or CSRF error", err)
return nil, err
}
if authcode(r) == "" {
plog.Info("code param not found")
return nil, httperr.New(http.StatusBadRequest, "code param not found")
}
return decodedState, nil
}