initial commit of libopkele - OpenID support library

1 files changed, 169 insertions, 0 deletions

diff --git a/lib/server.cc b/lib/server.cc
new file mode 100644
index 0000000..51d4554
--- a/dev/null
+++ b/lib/server.cc
@@ -0,0 +1,169 @@
+#include <vector>
+#include <openssl/sha.h>
+#include <openssl/hmac.h>
+#include <mimetic/mimetic.h>
+#include <opkele/util.h>
+#include <opkele/exception.h>
+#include <opkele/server.h>
+#include <opkele/data.h>
+
+namespace opkele {
+    using namespace std;
+
+    void server_t::associate(const params_t& pin,params_t& pout) {
+	util::dh_t dh;
+	util::bignum_t c_pub;
+	unsigned char key_sha1[SHA_DIGEST_LENGTH];
+	enum {
+	    sess_cleartext,
+	    sess_dh_sha1
+	} st = sess_cleartext;
+	if(
+		pin.has_param("openid.session_type")
+		&& pin.get_param("openid.session_type")=="DH-SHA1" ) {
+	    /* TODO: fallback to cleartext in case of exceptions here? */
+	    if(!(dh = DH_new()))
+		throw exception_openssl(OPKELE_CP_ "failed to DH_new()");
+	    c_pub = util::base64_to_bignum(pin.get_param("openid.dh_consumer_public"));
+	    if(pin.has_param("openid.dh_modulus"))
+		dh->p = util::base64_to_bignum(pin.get_param("openid.dh_modulus"));
+	    else
+		dh->p = util::dec_to_bignum(data::_default_p);
+	    if(pin.has_param("openid.dh_gen"))
+		dh->g = util::base64_to_bignum(pin.get_param("openid.dh_gen"));
+	    else
+		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));
+	    int cklen = DH_compute_key(&(ck.front()),c_pub,dh);
+	    if(cklen<0)
+		throw exception_openssl(OPKELE_CP_ "failed to DH_compute_key()");
+	    ck.resize(cklen);
+	    // OpenID algorithm requires extra zero in case of set bit here
+	    if(ck[0]&0x80) ck.insert(ck.begin(),1,0);
+	    SHA1(&(ck.front()),ck.size(),key_sha1);
+	    st = sess_dh_sha1;
+	}
+	assoc_t assoc = alloc_assoc(mode_associate);
+	time_t now = time(0);
+	pout.clear();
+	pout["assoc_type"] = assoc->assoc_type();
+	pout["assoc_handle"] = assoc->handle();
+	/* TODO: eventually remove deprecated stuff */
+	pout["issued"] = util::time_to_w3c(now);
+	pout["expiry"] = util::time_to_w3c(now+assoc->expires_in());
+	pout["expires_in"] = util::long_to_string(assoc->expires_in());
+	secret_t secret = assoc->secret();
+	switch(st) {
+	    case sess_dh_sha1:
+		pout["session_type"] = "DH-SHA1";
+		pout["dh_server_public"] = util::bignum_to_base64(dh->pub_key);
+		secret.enxor_to_base64(key_sha1,pout["enc_mac_key"]);
+		break;
+	    default:
+		secret.to_base64(pout["mac_key"]);
+		break;
+	}
+    }
+
+    void server_t::checkid_immediate(const params_t& pin,string& return_to,params_t& pout) {
+	checkid_(mode_checkid_immediate,pin,return_to,pout);
+    }
+
+    void server_t::checkid_setup(const params_t& pin,string& return_to,params_t& pout) {
+	checkid_(mode_checkid_setup,pin,return_to,pout);
+    }
+
+    void server_t::checkid_(mode_t mode,const params_t& pin,string& return_to,params_t& pout) {
+	if(mode!=mode_checkid_immediate && mode!=mode_checkid_setup)
+	    throw bad_input(OPKELE_CP_ "invalid checkid_* mode");
+	assoc_t assoc;
+	try {
+	    assoc = retrieve_assoc(pin.get_param("openid.assoc_handle"));
+	}catch(failed_lookup& fl) {
+	    // no handle specified or no valid handle found, going dumb
+	    assoc = alloc_assoc(mode_checkid_setup);
+	}
+	string trust_root;
+	try {
+	    trust_root = pin.get_param("openid.trust_root");
+	}catch(failed_lookup& fl) { }
+	string identity = pin.get_param("openid.identity");
+	return_to = pin.get_param("openid.return_to");
+	validate(*assoc,pin,identity,trust_root);
+	pout.clear();
+	pout["mode"] = "id_res";
+	pout["assoc_handle"] = assoc->handle();
+	if(pin.has_param("openid.assoc_handle") && assoc->stateless())
+	    pout["invalidate_handle"] = pin.get_param("openid.assoc_handle");
+	pout["identity"] = identity;
+	pout["return_to"] = return_to;
+	/* TODO: eventually remove deprecated stuff */
+	time_t now = time(0);
+	pout["issued"] = util::time_to_w3c(now);
+	pout["valid_to"] = util::time_to_w3c(now+120);
+	pout["exipres_in"] = "120";
+	pout.sign(assoc->secret(),pout["sig"],pout["signed"]="mode,identity,return_to");
+    }
+
+    void server_t::check_authentication(const params_t& pin,params_t& pout) {
+	vector<unsigned char>  sig;
+	mimetic::Base64::Decoder b;
+	const string& sigenc = pin.get_param("openid.sig");
+	mimetic::decode(
+		sigenc.begin(),sigenc.end(), b,
+		back_insert_iterator<vector<unsigned char> >(sig));
+	assoc_t assoc;
+	try {
+	    assoc = retrieve_assoc(pin.get_param("openid.assoc_handle"));
+	}catch(failed_lookup& fl) {
+	    throw failed_assertion(OPKELE_CP_ "invalid handle or handle not specified");
+	}
+	if(!assoc->stateless())
+	    throw stateful_handle(OPKELE_CP_ "will not do check_authentication on a stateful handle");
+	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 += ':';
+	    if(f=="mode")
+		kv += "id_res";
+	    else {
+		f.insert(0,"openid.");
+		kv += pin.get_param(f);
+	    }
+	    kv += '\n';
+	    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);
+	pout.clear();
+	if(sig.size()==md_len && !memcmp(&(sig.front()),md,md_len)) {
+	    pout["is_valid"]="true";
+	    pout["lifetime"]="60"; /* TODO: eventually remove deprecated stuff */
+	}else{
+	    pout["is_valid"]="false";
+	    pout["lifetime"]="0"; /* TODO: eventually remove deprecated stuff */
+	}
+	if(pin.has_param("openid.invalidate_handle")) {
+	    string h = pin.get_param("openid.invalidate_handle");
+	    try {
+		assoc_t assoc = retrieve_assoc(h);
+	    }catch(invalid_handle& ih) {
+		pout["invalidate_handle"] = h;
+	    }catch(failed_lookup& fl) { }
+	}
+    }
+
+}