From 803570cd4f7ffbb3d7a329b0b9450748b3ca335d Mon Sep 17 00:00:00 2001
From: Pritha Srivastava <prsrivas@redhat.com>
Date: Tue, 4 May 2021 22:25:58 +0530
Subject: [PATCH] rgw/sts: code to fetch certs using
 .well-known/openid-configuration url which is oidc standard compliant.

The bug and fix were suggested by Pietari Hyvarinen <pietari.hyvarinen@csc.fi>

Fixes: https://tracker.ceph.com/issues/50721

Signed-off-by: Pritha Srivastava <prsrivas@redhat.com>
---
 src/rgw/rgw_rest_sts.cc | 40 +++++++++++++++++++++++++++++++++++++++-
 src/rgw/rgw_rest_sts.h  |  2 ++
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/src/rgw/rgw_rest_sts.cc b/src/rgw/rgw_rest_sts.cc
index 25dd117450c55..7d51d699b6467 100644
--- a/src/rgw/rgw_rest_sts.cc
+++ b/src/rgw/rgw_rest_sts.cc
@@ -198,12 +198,50 @@ WebTokenEngine::get_from_jwt(const DoutPrefixProvider* dpp, const std::string& t
   return t;
 }
 
+std::string
+WebTokenEngine::get_cert_url(const string& iss, const DoutPrefixProvider *dpp, optional_yield y) const
+{
+  string cert_url;
+  string openidc_wellknown_url = iss + "/.well-known/openid-configuration";
+  bufferlist openidc_resp;
+  RGWHTTPTransceiver openidc_req(cct, "GET", openidc_wellknown_url, &openidc_resp);
+
+  //Headers
+  openidc_req.append_header("Content-Type", "application/x-www-form-urlencoded");
+
+  int res = openidc_req.process(y);
+  if (res < 0) {
+    ldpp_dout(dpp, 10) << "HTTP request res: " << res << dendl;
+    throw -EINVAL;
+  }
+
+  //Debug only
+  ldpp_dout(dpp, 20) << "HTTP status: " << openidc_req.get_http_status() << dendl;
+  ldpp_dout(dpp, 20) << "JSON Response is: " << openidc_resp.c_str() << dendl;
+
+  JSONParser parser;
+  if (parser.parse(openidc_resp.c_str(), openidc_resp.length())) {
+    JSONObj::data_val val;
+    if (parser.get_data("jwks_uri", &val)) {
+      cert_url = val.str.c_str();
+      ldpp_dout(dpp, 20) << "Cert URL is: " << cert_url.c_str() << dendl;
+    } else {
+      ldpp_dout(dpp, 0) << "Malformed json returned while fetching openidc url" << dendl;
+    }
+  }
+  return cert_url;
+}
+
 void
 WebTokenEngine::validate_signature(const DoutPrefixProvider* dpp, const jwt::decoded_jwt& decoded, const string& algorithm, const string& iss, const vector<string>& thumbprints, optional_yield y) const
 {
   if (algorithm != "HS256" && algorithm != "HS384" && algorithm != "HS512") {
+    string cert_url = get_cert_url(iss, dpp, y);
+    if (cert_url.empty()) {
+      throw -EINVAL;
+    }
+
     // Get certificate
-    string cert_url = iss + "/protocol/openid-connect/certs";
     bufferlist cert_resp;
     RGWHTTPTransceiver cert_req(cct, "GET", cert_url, &cert_resp);
     //Headers
diff --git a/src/rgw/rgw_rest_sts.h b/src/rgw/rgw_rest_sts.h
index 59c7fa59cb642..396b3cbe52b94 100644
--- a/src/rgw/rgw_rest_sts.h
+++ b/src/rgw/rgw_rest_sts.h
@@ -33,6 +33,8 @@ class WebTokenEngine : public rgw::auth::Engine {
 
   std::string get_role_tenant(const string& role_arn) const;
 
+  std::string get_cert_url(const string& iss, const DoutPrefixProvider *dpp,optional_yield y) const;
+
   boost::optional<WebTokenEngine::token_t>
   get_from_jwt(const DoutPrefixProvider* dpp, const std::string& token, const req_state* const s, optional_yield y) const;
 
-- 
2.39.5