empty trust_root is no trust root.

work around some thoughtful and considerate RPs that take the pain of sending
the trust_root parameter, but do not go into as much trouble as setting it to
anything but an empty string.

Signed-off-by: Michael Krelin <hacker@klever.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/basic_op.cc b/lib/basic_op.cc
index fa659ac..511b51a 100644
--- a/lib/basic_op.cc
+++ b/lib/basic_op.cc
@@ -107,109 +107,115 @@ namespace opkele {
         oum.set_field("ns",OIURI_OPENID20);
         oum.set_field("assoc_type",a->assoc_type());
         oum.set_field("assoc_handle",a->handle());
         oum.set_field("expires_in",util::long_to_string(a->expires_in()));
         secret_t secret = a->secret();
         if(sts=="DH-SHA1" || sts=="DH-SHA256") {
             if(d_len != secret.size())
                 throw bad_input(OPKELE_CP_ "Association secret and session MAC are not of the same size");
             oum.set_field("session_type",sts);
             oum.set_field("dh_server_public",util::bignum_to_base64(dh->pub_key));
             string b64; secret.enxor_to_base64(key_digest,b64);
             oum.set_field("enc_mac_key",b64);
         }else /* TODO: support cleartext over encrypted connection */
             throw unsupported(OPKELE_CP_ "Unsupported session type");
         return oum;
     } catch(unsupported& u) {
         oum.reset_fields();
         oum.set_field("ns",OIURI_OPENID20);
         oum.set_field("error",u.what());
         oum.set_field("error_code","unsupported-type");
         oum.set_field("session_type","DH-SHA256");
         oum.set_field("assoc_type","HMAC-SHA256");
         return oum;
     }
 
     void basic_OP::checkid_(const basic_openid_message& inm,
             extension_t *ext) {
         reset_vars();
         string modestr = inm.get_field("mode");
         if(modestr=="checkid_setup")
             mode = mode_checkid_setup;
         else if(modestr=="checkid_immediate")
             mode = mode_checkid_immediate;
         else
             throw bad_input(OPKELE_CP_ "Invalid checkid_* mode");
         try {
             assoc = retrieve_assoc(invalidate_handle=inm.get_field("assoc_handle"));
             invalidate_handle.clear();
         }catch(failed_lookup&) { }
         try {
             openid2 = (inm.get_field("ns")==OIURI_OPENID20);
         }catch(failed_lookup&) { openid2 = false; }
         try {
             return_to = inm.get_field("return_to");
         }catch(failed_lookup&) { }
         if(openid2) {
             try {
                 realm = inm.get_field("realm");
+                if(realm.empty())
+                    throw failed_lookup(OPKELE_CP_ "Empty realm doesn't count");
             }catch(failed_lookup&) {
                 try {
                     realm = inm.get_field("trust_root");
+                    if(realm.empty())
+                        throw failed_lookup(OPKELE_CP_ "Empty trust_root doesn't count");
                 }catch(failed_lookup&) {
                     if(return_to.empty())
                         throw bad_input(OPKELE_CP_
                                 "Both realm and return_to are unset");
                     realm = return_to;
                 }
             }
         }else{
             try {
                 realm = inm.get_field("trust_root");
+                if(realm.empty())
+                    throw failed_lookup(OPKELE_CP_ "Empty trust_root doesn't count");
             }catch(failed_lookup&) {
                 if(return_to.empty())
                     throw bad_input(OPKELE_CP_
                             "Both realm and return_to are unset");
                 realm = return_to;
             }
         }
         try {
             identity = inm.get_field("identity");
             try {
                 claimed_id = inm.get_field("claimed_id");
             }catch(failed_lookup&) {
                 if(openid2)
                     throw bad_input(OPKELE_CP_
                             "claimed_id and identity must be either both present or both absent");
                 claimed_id = identity;
             }
         }catch(failed_lookup&) {
             if(openid2 && inm.has_field("claimed_id"))
                 throw bad_input(OPKELE_CP_
                     "claimed_id and identity must be either both present or both absent");
         }
         verify_return_to();
         if(ext) ext->op_checkid_hook(inm);
     }
 
     basic_openid_message& basic_OP::id_res(basic_openid_message& om,
             extension_t *ext) {
         assert(!return_to.empty());
         assert(!is_id_select());
         if(!assoc) {
             assoc = alloc_assoc("HMAC-SHA256",SHA256_DIGEST_LENGTH,true);
         }
         time_t now = time(0);
         struct tm gmt; gmtime_r(&now,&gmt);
         char w3timestr[24];
         if(!strftime(w3timestr,sizeof(w3timestr),"%Y-%m-%dT%H:%M:%SZ",&gmt))
             throw failed_conversion(OPKELE_CP_
                     "Failed to build time string for nonce" );
         om.set_field("ns",OIURI_OPENID20);
         om.set_field("mode","id_res");
         om.set_field("op_endpoint",get_op_endpoint());
         string ats = "ns,mode,op_endpoint,return_to,response_nonce,"
             "assoc_handle,signed";
         if(!identity.empty()) {
             om.set_field("identity",identity);
             om.set_field("claimed_id",claimed_id);
             ats += ",identity,claimed_id";