3 files changed, 18 insertions, 3 deletions

diff --git a/include/opkele/consumer.h b/include/opkele/consumer.h
index 50ff692..c463787 100644
--- a/include/opkele/consumer.h
+++ b/include/opkele/consumer.h
@@ -54,32 +54,37 @@ namespace opkele {
              * invalidate stored association. The function should be overridden
              * in the real implementation of the consumer.
              * @param server the OpenID server
              * @param handle association handle
              */
             virtual void invalidate_assoc(const string& server,const string& handle) = 0;
             /**
              * retrieve any unexpired association for the server. If the
              * function is not overridden in the real implementation, the new
              * association will be established for each request.
              *
              * @note
              * The user is responsible for handling associations and this
              * function should never return an expired or invalidated
              * association.
              *
+             * @note
+             * It may be a good idea to pre-expire associations shortly before
+             * their time is really up to avoid association expiry in the
+             * middle of negotiations.
+             *
              * @param server the OpenID server
              * @return the auto_ptr<> for the newly allocated association_t object
              * @throw failed_lookup in case of absence of the handle
              */
             virtual assoc_t find_assoc(const string& server);
 
             /**
              * retrieve the metainformation contained in link tags from the
              * page pointed by url. the function may implement caching of the
              * information.
              * @param url url to harvest for link tags
              * @param server reference to the string object where to put
              * openid.server value
              * @param delegate reference to the string object where to put the
              * openid.delegate value (if any)
              */
@@ -124,32 +129,33 @@ namespace opkele {
              * @param trust_root the trust root to advertise with the request
              * @param ext pointer to an extension(s) hooks object
              * @return the location string
              * @throw exception in case of error
              */
             virtual string checkid_(mode_t mode,const string& identity,const string& return_to,const string& trust_root="",extension_t *ext=0);
             /**
              * verify the id_res response
              * @param pin the response parameters
              * @param identity the identity being checked (if not specified,
              * @param ext pointer to an extension(s) hooks object
              * extracted from the openid.identity parameter
              * @throw id_res_mismatch in case of signature mismatch
              * @throw id_res_setup in case of openid.user_setup_url failure
              * (supposedly checkid_immediate only)
              * @throw id_res_failed in case of failure
+             * @throw id_res_expired_on_delivery if the association expired before it could've been verified
              * @throw exception in case of other failures
              */
             virtual void id_res(const params_t& pin,const string& identity="",extension_t *ext=0);
             /**
              * perform a check_authentication request.
              * @param server the OpenID server
              * @param p request parameters
              */
             void check_authentication(const string& server,const params_t& p);
 
             /**
              * normalize URL by adding http:// and trailing slash if needed.
              * @param url
              * @return normalized url
              */
             static string normalize(const string& url);
diff --git a/include/opkele/exception.h b/include/opkele/exception.h
index 753a818..2ff44b7 100644
--- a/include/opkele/exception.h
+++ b/include/opkele/exception.h
@@ -157,32 +157,41 @@ namespace opkele {
         public:
             string setup_url;
             id_res_setup(OPKELE_E_PARS,const string& su)
                 : id_res_failed(OPKELE_E_CONS), setup_url(su) { }
             ~id_res_setup() throw() { }
     };
     /**
      * thrown in case of signature mismatch
      */
     class id_res_mismatch : public id_res_failed {
         public:
             id_res_mismatch(OPKELE_E_PARS)
                 : id_res_failed(OPKELE_E_CONS) { }
     };
 
     /**
+     * thrown if the association has expired before it could've been verified.
+     */
+    class id_res_expired_on_delivery : public id_res_failed {
+        public:
+            id_res_expired_on_delivery(OPKELE_E_PARS)
+                : id_res_failed(OPKELE_E_CONS) { }
+    };
+
+    /**
      * openssl malfunction occured
      */
     class exception_openssl : public exception {
         public:
             unsigned long _error;
             string _ssl_string;
             exception_openssl(OPKELE_E_PARS);
             ~exception_openssl() throw() { }
     };
 
     /**
      * network operation related error occured
      */
     class exception_network : public exception {
         public:
             exception_network(OPKELE_E_PARS)
diff --git a/lib/consumer.cc b/lib/consumer.cc
index 66db7dd..9f7530f 100644
--- a/lib/consumer.cc
+++ b/lib/consumer.cc
@@ -171,63 +171,63 @@ namespace opkele {
         }catch(failed_lookup& fl) {
             string ah = associate(server)->handle();
             p["assoc_handle"] = ah;
         }
         if(ext) ext->checkid_hook(p,identity);
         return p.append_query(server);
     }
 
     void consumer_t::id_res(const params_t& pin,const string& identity,extension_t *ext) {
         if(pin.has_param("openid.user_setup_url"))
             throw id_res_setup(OPKELE_CP_ "assertion failed, setup url provided",pin.get_param("openid.user_setup_url"));
         string server,delegate;
         retrieve_links(identity.empty()?pin.get_param("openid.identity"):canonicalize(identity),server,delegate);
         params_t ps;
         try {
             assoc_t assoc = retrieve_assoc(server,pin.get_param("openid.assoc_handle"));
-            if(assoc->is_expired()) /* TODO: or should I throw some other exception to force programmer fix his implementation? */
-                throw failed_lookup(OPKELE_CP_ "retrieve_assoc() has returned expired handle");
+            if(assoc->is_expired())
+                throw id_res_expired_on_delivery(OPKELE_CP_ "retrieve_assoc() has returned expired handle");
             const string& sigenc = pin.get_param("openid.sig");
             vector<unsigned char> sig;
             util::decode_base64(sigenc,sig);
             const string& slist = pin.get_param("openid.signed");
             string kv;
             string::size_type p = 0;
             while(true) {
                 string::size_type co = slist.find(',',p);
                 string f = (co==string::npos)?slist.substr(p):slist.substr(p,co-p);
                 kv += f;
                 kv += ':';
                 f.insert(0,"openid.");
                 kv += pin.get_param(f);
                 kv += '\n';
                 if(ext) ps[f.substr(sizeof("openid.")-1)] = pin.get_param(f);
                 if(co==string::npos)
                     break;
                 p = co+1;
             }
             secret_t secret = assoc->secret();
             unsigned int md_len = 0;
             unsigned char *md = HMAC(
                     EVP_sha1(),
                     &(secret.front()),secret.size(),
                     (const unsigned char *)kv.data(),kv.length(),
                     0,&md_len);
             if(sig.size()!=md_len || memcmp(&(sig.front()),md,md_len))
                 throw id_res_mismatch(OPKELE_CP_ "signature mismatch");
-        }catch(failed_lookup& e) { /* XXX: more specific? */
+        }catch(failed_lookup& e) {
             const string& slist = pin.get_param("openid.signed");
             string::size_type pp = 0;
             params_t p;
             while(true) {
                 string::size_type co = slist.find(',',pp);
                 string f = "openid.";
                 f += (co==string::npos)?slist.substr(pp):slist.substr(pp,co-pp);
                 p[f] = pin.get_param(f);
                 if(co==string::npos)
                     break;
                 pp = co+1;
             }
             p["openid.assoc_handle"] = pin.get_param("openid.assoc_handle");
             p["openid.sig"] = pin.get_param("openid.sig");
             p["openid.signed"] = pin.get_param("openid.signed");
             try {