initial commit of libopkele - OpenID support library

1 files changed, 316 insertions, 0 deletions

diff --git a/lib/consumer.cc b/lib/consumer.cc
new file mode 100644
index 0000000..bd76b61
--- a/dev/null
+++ b/lib/consumer.cc
@@ -0,0 +1,316 @@
+#include <algorithm>
+#include <opkele/util.h>
+#include <opkele/exception.h>
+#include <opkele/data.h>
+#include <opkele/consumer.h>
+#include <openssl/sha.h>
+#include <openssl/hmac.h>
+#include <mimetic/mimetic.h>
+#include <curl/curl.h>
+#include <pcre++.h>
+
+#include <iostream>
+
+/* silly mimetic */
+#undef PACKAGE
+#undef PACKAGE_BUGREPORT
+#undef PACKAGE_NAME
+#undef PACKAGE_STRING
+#undef PACKAGE_TARNAME
+#undef PACKAGE_VERSION
+#undef VERSION
+
+#include "config.h"
+
+namespace opkele {
+    using namespace std;
+
+    class curl_t {
+	public:
+	    CURL *_c;
+
+	    curl_t() : _c(0) { }
+	    curl_t(CURL *c) : _c(c) { }
+	    ~curl_t() throw() { if(_c) curl_easy_cleanup(_c); }
+
+	    curl_t& operator=(CURL *c) { if(_c) curl_easy_cleanup(_c); _c=c; return *this; }
+
+	    operator const CURL*(void) const { return _c; }
+	    operator CURL*(void) { return _c; }
+    };
+
+    static CURLcode curl_misc_sets(CURL* c) {
+	CURLcode r;
+	(r=curl_easy_setopt(c,CURLOPT_FOLLOWLOCATION,1))
+	|| (r=curl_easy_setopt(c,CURLOPT_MAXREDIRS,5))
+	|| (r=curl_easy_setopt(c,CURLOPT_DNS_CACHE_TIMEOUT,120))
+	|| (r=curl_easy_setopt(c,CURLOPT_DNS_USE_GLOBAL_CACHE,1))
+	|| (r=curl_easy_setopt(c,CURLOPT_USERAGENT,PACKAGE_NAME"/"PACKAGE_VERSION))
+	|| (r=curl_easy_setopt(c,CURLOPT_TIMEOUT,20))
+	;
+	return r;
+    }
+
+    static size_t _curl_tostring(void *ptr,size_t size,size_t nmemb,void *stream) {
+	string *str = (string*)stream;
+	size_t bytes = size*nmemb;
+	size_t get = min(16384-str->length(),bytes);
+	str->append((const char*)ptr,get);
+	return get;
+    }
+
+    assoc_t consumer_t::associate(const string& server) {
+	util::dh_t dh = DH_new();
+	if(!dh)
+	    throw exception_openssl(OPKELE_CP_ "failed to DH_new()");
+	dh->p = util::dec_to_bignum(data::_default_p);
+	dh->g = util::dec_to_bignum(data::_default_g);
+	if(!DH_generate_key(dh))
+	    throw exception_openssl(OPKELE_CP_ "failed to DH_generate_key()");
+	string request = 
+	    "openid.mode=associate"
+	    "&openid.assoc_type=HMAC-SHA1"
+	    "&openid.session_type=DH-SHA1"
+	    "&openid.dh_consumer_public=";
+	request += util::url_encode(util::bignum_to_base64(dh->pub_key));
+	curl_t curl = curl_easy_init();
+	if(!curl)
+	    throw exception_curl(OPKELE_CP_ "failed to curl_easy_init()");
+	string response;
+	CURLcode r;
+	(r=curl_misc_sets(curl))
+	|| (r=curl_easy_setopt(curl,CURLOPT_URL,server.c_str()))
+	|| (r=curl_easy_setopt(curl,CURLOPT_POST,1))
+	|| (r=curl_easy_setopt(curl,CURLOPT_POSTFIELDS,request.data()))
+	|| (r=curl_easy_setopt(curl,CURLOPT_POSTFIELDSIZE,request.length()))
+	|| (r=curl_easy_setopt(curl,CURLOPT_WRITEFUNCTION,_curl_tostring))
+	|| (r=curl_easy_setopt(curl,CURLOPT_WRITEDATA,&response))
+	;
+	if(r)
+	    throw exception_curl(OPKELE_CP_ "failed to curl_easy_setopt()",r);
+	if(r=curl_easy_perform(curl))
+	    throw exception_curl(OPKELE_CP_ "failed to curl_easy_perform()",r);
+	params_t p; p.parse_keyvalues(response);
+	if(p.has_param("assoc_type") && p.get_param("assoc_type")!="HMAC-SHA1")
+	    throw bad_input(OPKELE_CP_ "unsupported assoc_type");
+	string st;
+	if(p.has_param("session_type")) st = p.get_param("session_type");
+	if((!st.empty()) && st!="DH-SHA1")
+	    throw bad_input(OPKELE_CP_ "unsupported session_type");
+	secret_t secret;
+	if(st.empty()) {
+	    secret.from_base64(p.get_param("mac_key"));
+	}else{
+	    util::bignum_t s_pub = util::base64_to_bignum(p.get_param("dh_server_public"));
+	    vector<unsigned char> ck(DH_size(dh));
+	    int cklen = DH_compute_key(&(ck.front()),s_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);
+	    unsigned char key_sha1[SHA_DIGEST_LENGTH];
+	    SHA1(&(ck.front()),ck.size(),key_sha1);
+	    secret.enxor_from_base64(key_sha1,p.get_param("enc_mac_key"));
+	}
+	int expires_in = 0;
+	if(p.has_param("expires_in")) {
+	    expires_in = util::string_to_long(p.get_param("expires_in"));
+	}else if(p.has_param("issued") && p.has_param("expiry")) {
+	    expires_in = util::w3c_to_time(p.get_param("expiry"))-util::w3c_to_time(p.get_param("issued"));
+	}else
+	    throw bad_input(OPKELE_CP_ "no expiration information");
+	return store_assoc(server,p.get_param("assoc_handle"),secret,expires_in);
+    }
+
+    string consumer_t::checkid_immediate(const string& identity,const string& return_to,const string& trust_root) {
+	return checkid_(mode_checkid_immediate,identity,return_to,trust_root);
+    }
+    string consumer_t::checkid_setup(const string& identity,const string& return_to,const string& trust_root) {
+	return checkid_(mode_checkid_setup,identity,return_to,trust_root);
+    }
+    string consumer_t::checkid_(mode_t mode,const string& identity,const string& return_to,const string& trust_root) {
+	params_t p;
+	if(mode==mode_checkid_immediate)
+	    p["mode"]="checkid_immediate";
+	else if(mode==mode_checkid_setup)
+	    p["mode"]="checkid_setup";
+	else
+	    throw bad_input(OPKELE_CP_ "unknown checkid_* mode");
+	string iurl = util::canonicalize_url(identity);
+	string server, delegate;
+	retrieve_links(iurl,server,delegate);
+	p["identity"] = delegate.empty()?iurl:delegate;
+	if(!trust_root.empty())
+	    p["trust_root"] = trust_root;
+	p["return_to"] = return_to;
+	try {
+	    try {
+		string ah = find_assoc(server)->handle();
+		p["assoc_handle"] = ah;
+	    }catch(failed_lookup& fl) {
+		string ah = associate(server)->handle();
+		p["assoc_handle"] = ah;
+	    }
+	}catch(exception& e) { }
+	return p.append_query(server);
+    }
+
+    void consumer_t::id_res(const params_t& pin,const string& identity) {
+	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"):util::canonicalize_url(identity),server,delegate);
+	try {
+	    assoc_t assoc = retrieve_assoc(server,pin.get_param("openid.assoc_handle"));
+	    const string& sigenc = pin.get_param("openid.sig");
+	    mimetic::Base64::Decoder b;
+	    vector<unsigned char> sig;
+	    mimetic::decode(
+		    sigenc.begin(),sigenc.end(), b,
+		    back_insert_iterator<vector<unsigned char> >(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(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? */
+	    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 {
+		string ih = pin.get_param("openid.invalidate_handle");
+		p["openid.invalidate_handle"] = ih;
+	    }catch(failed_lookup& fl) { }
+	    try {
+		check_authentication(server,p);
+	    }catch(failed_check_authentication& fca) {
+		throw id_res_failed(OPKELE_CP_ "failed to check_authentication()");
+	    }
+	}
+    }
+
+    void consumer_t::check_authentication(const string& server,const params_t& p) {
+	string request = "openid.mode=check_authentication";
+	for(params_t::const_iterator i=p.begin();i!=p.end();++i) {
+	    if(i->first!="openid.mode") {
+		request += '&';
+		request += i->first;
+		request += '=';
+		request += util::url_encode(i->second);
+	    }
+	}
+	curl_t curl = curl_easy_init();
+	if(!curl)
+	    throw exception_curl(OPKELE_CP_ "failed to curl_easy_init()");
+	string response;
+	CURLcode r;
+	(r=curl_misc_sets(curl))
+	|| (r=curl_easy_setopt(curl,CURLOPT_URL,server.c_str()))
+	|| (r=curl_easy_setopt(curl,CURLOPT_POST,1))
+	|| (r=curl_easy_setopt(curl,CURLOPT_POSTFIELDS,request.data()))
+	|| (r=curl_easy_setopt(curl,CURLOPT_POSTFIELDSIZE,request.length()))
+	|| (r=curl_easy_setopt(curl,CURLOPT_WRITEFUNCTION,_curl_tostring))
+	|| (r=curl_easy_setopt(curl,CURLOPT_WRITEDATA,&response))
+	;
+	if(r)
+	    throw exception_curl(OPKELE_CP_ "failed to curl_easy_setopt()",r);
+	if(r=curl_easy_perform(curl))
+	    throw exception_curl(OPKELE_CP_ "failed to curl_easy_perform()",r);
+	params_t pp; pp.parse_keyvalues(response);
+	if(pp.has_param("invalidate_handle"))
+	    invalidate_assoc(server,pp.get_param("invalidate_handle"));
+	if(pp.has_param("is_valid")) {
+	    if(pp.get_param("is_valid")=="true")
+		return;
+	}else if(pp.has_param("lifetime")) {
+	    if(util::string_to_long(pp.get_param("lifetime")))
+		return;
+	}
+	throw failed_check_authentication(OPKELE_CP_ "failed to verify response");
+    }
+
+    void consumer_t::retrieve_links(const string& url,string& server,string& delegate) {
+	server.erase();
+	delegate.erase();
+	curl_t curl = curl_easy_init();
+	if(!curl)
+	    throw exception_curl(OPKELE_CP_ "failed to curl_easy_init()");
+	string html;
+	CURLcode r;
+	(r=curl_misc_sets(curl))
+	|| (r=curl_easy_setopt(curl,CURLOPT_URL,url.c_str()))
+	|| (r=curl_easy_setopt(curl,CURLOPT_WRITEFUNCTION,_curl_tostring))
+	|| (r=curl_easy_setopt(curl,CURLOPT_WRITEDATA,&html))
+	;
+	if(r)
+	    throw exception_curl(OPKELE_CP_ "failed to curl_easy_setopt()",r);
+	r = curl_easy_perform(curl);
+	if(r && r!=CURLE_WRITE_ERROR)
+	    throw exception_curl(OPKELE_CP_ "failed to curl_easy_perform()",r);
+	pcrepp::Pcre bre("<body\\b",PCRE_CASELESS);
+	// strip out everything past body
+	if(bre.search(html))
+	    html.erase(bre.get_match_start());
+	pcrepp::Pcre hdre("<head[^>]*>",PCRE_CASELESS);
+	if(!hdre.search(html))
+	    throw bad_input(OPKELE_CP_ "failed to find head");
+	html.erase(0,hdre.get_match_end()+1);
+	pcrepp::Pcre lre("<link\\b([^>]+)>",PCRE_CASELESS),
+	    rre("\\brel=['\"]([^'\"]+)['\"]",PCRE_CASELESS),
+	    hre("\\bhref=['\"]([^'\"]+)['\"]",PCRE_CASELESS);
+	while(lre.search(html)) {
+	    string attrs = lre[0];
+	    html.erase(0,lre.get_match_end()+1);
+	    if(!(rre.search(attrs)&&hre.search(attrs)))
+		continue;
+	    if(rre[0]=="openid.server") {
+		server = hre[0];
+		if(!delegate.empty())
+		    break;
+	    }else if(rre[0]=="openid.delegate") {
+		delegate = hre[0];
+		if(!server.empty())
+		    break;
+	    }
+	}
+	if(server.empty())
+	    throw failed_assertion(OPKELE_CP_ "The location has no openid.server declaration");
+    }
+
+    assoc_t consumer_t::find_assoc(const string& server) {
+	throw failed_lookup(OPKELE_CP_ "no find_assoc() provided");
+    }
+
+}