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
@@ -59,205 +59,211 @@ namespace opkele {
 	claimed_id = c;
     }
 
     basic_openid_message& basic_OP::associate(
 	    basic_openid_message& oum,
 	    const basic_openid_message& inm) try {
 	assert(inm.get_field("mode")=="associate");
 	util::dh_t dh;
 	util::bignum_t c_pub;
 	unsigned char key_digest[SHA256_DIGEST_LENGTH];
 	size_t d_len = 0;
 	string sts = inm.get_field("session_type");
 	string ats = inm.get_field("assoc_type");
 	if(sts=="DH-SHA1" || sts=="DH-SHA256") {
 	    if(!(dh = DH_new()))
 		throw exception_openssl(OPKELE_CP_ "failed to DH_new()");
 	    c_pub = util::base64_to_bignum(inm.get_field("dh_consumer_public"));
 	    try { dh->p = util::base64_to_bignum(inm.get_field("dh_modulus"));
 	    }catch(failed_lookup&) {
 		dh->p = util::dec_to_bignum(data::_default_p); }
 	    try { dh->g = util::base64_to_bignum(inm.get_field("dh_gen"));
 	    }catch(failed_lookup&) {
 		dh->g = util::dec_to_bignum(data::_default_g); }
 	    if(!DH_generate_key(dh))
 		throw exception_openssl(OPKELE_CP_ "failed to DH_generate_key()");
 	    vector<unsigned char> ck(DH_size(dh)+1);
 	    unsigned char *ckptr = &(ck.front())+1;
 	    int cklen = DH_compute_key(ckptr,c_pub,dh);
 	    if(cklen<0)
 		throw exception_openssl(OPKELE_CP_ "failed to DH_compute_key()");
 	    if(cklen && (*ckptr)&0x80) {
 		(*(--ckptr)) = 0; ++cklen; }
 	    if(sts=="DH-SHA1") {
 		SHA1(ckptr,cklen,key_digest); d_len = SHA_DIGEST_LENGTH;
 	    }else if(sts=="DH-SHA256") {
 		SHA256(ckptr,cklen,key_digest); d_len = SHA256_DIGEST_LENGTH;
 	    }else
 		throw internal_error(OPKELE_CP_ "I thought I knew the session type");
 	}else
 	    throw unsupported(OPKELE_CP_ "Unsupported session_type");
 	assoc_t a;
 	if(ats=="HMAC-SHA1")
 	    a = alloc_assoc(ats,SHA_DIGEST_LENGTH,false);
 	else if(ats=="HMAC-SHA256")
 	    a = alloc_assoc(ats,SHA256_DIGEST_LENGTH,false);
 	else
 	    throw unsupported(OPKELE_CP_ "Unsupported assoc_type");
 	oum.reset_fields();
 	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";
 	}
 	om.set_field("return_to",return_to);
 	string nonce = w3timestr;
 	om.set_field("response_nonce",alloc_nonce(nonce));
 	if(!invalidate_handle.empty()) {
 	    om.set_field("invalidate_handle",invalidate_handle);
 	    ats += ",invalidate_handle";
 	}
 	om.set_field("assoc_handle",assoc->handle());
 	om.add_to_signed(ats);
 	if(ext) ext->op_id_res_hook(om);
 	om.set_field("sig",util::base64_signature(assoc,om));
 	return om;
     }
 
     basic_openid_message& basic_OP::cancel(basic_openid_message& om) {
 	assert(!return_to.empty());
 	om.set_field("ns",OIURI_OPENID20);
 	om.set_field("mode","cancel");
 	return om;
     }
 
     basic_openid_message& basic_OP::error(basic_openid_message& om,
 	    const string& err,const string& contact,
 	    const string& reference ) {
 	assert(!return_to.empty());
 	om.set_field("ns",OIURI_OPENID20);
 	om.set_field("mode","error");
 	om.set_field("error",err);
 	if(!contact.empty()) om.set_field("contact",contact);
 	if(!reference.empty()) om.set_field("reference",reference);
 	return om;
     }
 
     basic_openid_message& basic_OP::setup_needed(
 	    basic_openid_message& oum,const basic_openid_message& inm) {
 	assert(mode==mode_checkid_immediate);
 	assert(!return_to.empty());
 	if(openid2) {
 	    oum.set_field("ns",OIURI_OPENID20);
 	    oum.set_field("mode","setup_needed");
 	}else{
 	    oum.set_field("mode","id_res");
 	    static const string setupmode = "checkid_setup";
 	    oum.set_field("user_setup_url",
 		    util::change_mode_message_proxy(inm,setupmode)
 		    .append_query(get_op_endpoint()));
 	}