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");
+    }
+
+}