4 files changed, 350 insertions, 1 deletions

diff --git a/include/Makefile.am b/include/Makefile.am
index 50fcb62..37fb961 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -19,6 +19,7 @@ nobase_include_HEADERS = \
         opkele/basic_rp.h \
         opkele/prequeue_rp.h \
         opkele/iterator.h \
+        opkele/basic_op.h \
         ${NODIST_HEADERS_}
 
 noinst_HEADERS = \
diff --git a/include/opkele/exception.h b/include/opkele/exception.h
index ccb39d9..5c8418e 100644
--- a/include/opkele/exception.h
+++ b/include/opkele/exception.h
@@ -330,6 +330,33 @@ namespace opkele {
                 : exception(OPKELE_E_CONS) { }
     };
 
+    /**
+     * thrown while processing OpenID request in OP. Signifies invalid realm
+     */
+    class bad_realm : public exception {
+        public:
+            bad_realm(OPKELE_E_PARS)
+                : exception(OPKELE_E_CONS) { }
+    };
+
+    /**
+     * thrown when attempting to retrieve return_to of one-way request
+     */
+    class no_return_to : public exception {
+        public:
+            no_return_to(OPKELE_E_PARS)
+                : exception(OPKELE_E_CONS) { }
+    };
+
+    /**
+     * thrown when querying identity of non-identity related request
+     */
+    class non_identity : public exception {
+        public:
+            non_identity(OPKELE_E_PARS)
+                : exception(OPKELE_E_CONS) { }
+    };
+
 }
 
 #endif /* __OPKELE_EXCEPTION_H */
diff --git a/lib/Makefile.am b/lib/Makefile.am
index c58ec3f..ac312d1 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -29,6 +29,7 @@ libopkele_la_SOURCES = \
                        discovery.cc \
                        basic_rp.cc \
                        prequeue_rp.cc \
-                       openid_message.cc
+                       openid_message.cc \
+                       basic_op.cc
 libopkele_la_LDFLAGS = \
         -version-info 2:0:0
diff --git a/lib/basic_op.cc b/lib/basic_op.cc
new file mode 100644
index 0000000..22012bc
--- a/dev/null
+++ b/lib/basic_op.cc
@@ -0,0 +1,320 @@
+#include <time.h>
+#include <cassert>
+#include <openssl/sha.h>
+#include <openssl/hmac.h>
+#include <opkele/data.h>
+#include <opkele/basic_op.h>
+#include <opkele/exception.h>
+#include <opkele/util.h>
+#include <opkele/uris.h>
+
+namespace opkele {
+
+    void basic_op::reset_vars() {
+        assoc.reset();
+        return_to.clear(); realm.clear();
+        claimed_id.clear(); identity.clear();
+        invalidate_handle.clear();
+    }
+
+    bool basic_op::has_return_to() const {
+        return !return_to.empty();
+    }
+    const string& basic_op::get_return_to() const {
+        if(return_to.empty())
+            throw no_return_to(OPKELE_CP_ "No return_to URL provided with request");
+        return return_to;
+    }
+
+    const string& basic_op::get_realm() const {
+        assert(!realm.empty());
+        return realm;
+    }
+
+    bool basic_op::has_identity() const {
+        return !identity.empty();
+    }
+    const string& basic_op::get_claimed_id() const {
+        if(claimed_id.empty())
+            throw non_identity(OPKELE_CP_ "attempting to retrieve claimed_id of non-identity related request");
+        assert(!identity.empty());
+        return claimed_id;
+    }
+    const string& basic_op::get_identity() const {
+        if(identity.empty())
+            throw non_identity(OPKELE_CP_ "attempting to retrieve identity of non-identity related request");
+        assert(!claimed_id.empty());
+        return identity;
+    }
+
+    bool basic_op::is_id_select() const {
+        return identity==IDURI_SELECT20;
+    }
+
+    void basic_op::select_identity(const string& c,const string& i) {
+        claimed_id = c; identity = i;
+    }
+    void basic_op::set_claimed_id(const string& c) {
+        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;
+        enum {
+            sess_cleartext, sess_dh_sha1, sess_dh_sha256
+        } st = sess_cleartext;
+        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 assoc;
+        if(ats=="HMAC-SHA1")
+            assoc = alloc_assoc(ats,SHA_DIGEST_LENGTH,true);
+        else if(ats=="HMAC-SHA256")
+            assoc = alloc_assoc(ats,SHA256_DIGEST_LENGTH,true);
+        else
+            throw unsupported(OPKELE_CP_ "Unsupported assoc_type");
+        oum.reset_fields();
+        oum.set_field("ns",OIURI_OPENID20);
+        oum.set_field("assoc_type",assoc->assoc_type());
+        oum.set_field("assoc_handle",assoc->handle());
+        oum.set_field("expires_in",util::long_to_string(assoc->expires_in()));
+        secret_t secret = assoc->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 mode = inm.get_field("mode");
+        if(mode=="checkid_setup")
+            mode = mode_checkid_setup;
+        else if(mode=="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&) {
+            // no handle specified or no valid assoc found, go dumb
+            assoc = alloc_assoc("HMAC-SHA256",SHA256_DIGEST_LENGTH,true);
+        }
+        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");
+            }catch(failed_lookup&) {
+                try {
+                    realm = inm.get_field("trust_root");
+                }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");
+            }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");
+            }
+        }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();
+    }
+
+    basic_openid_message& basic_op::id_res(basic_openid_message& om) {
+        assert(assoc);
+        assert(!return_to.empty());
+        assert(!is_id_select());
+        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,assoc->stateless()));
+        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);
+        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& error,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",error);
+        om.set_field("contact",contact);
+        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()));
+        }
+        return oum;
+    }
+
+    basic_openid_message& basic_op::check_authentication(
+            basic_openid_message& oum,
+            const basic_openid_message& inm) try {
+        assert(inm.get_field("mode")=="check_authentication");
+        oum.reset_fields();
+        oum.set_field("ns",OIURI_OPENID20);
+        bool o2;
+        try {
+            o2 = (inm.get_field("ns")==OIURI_OPENID20);
+        }catch(failed_lookup&) { o2 = false; }
+        string nonce;
+        if(o2) {
+            try {
+                if(!check_nonce(nonce = inm.get_field("response_nonce")))
+                    throw failed_check_authentication(OPKELE_CP_ "Invalid nonce");
+            }catch(failed_lookup&) {
+                throw failed_check_authentication(OPKELE_CP_ "No nonce provided with check_authentication request");
+            }
+        }
+        try {
+            assoc = retrieve_assoc(inm.get_field("assoc_handle"));
+            if(!assoc->stateless())
+                throw failed_check_authentication(OPKELE_CP_ "Will not do check_authentication on a stateful handle");
+        }catch(failed_lookup&) {
+            throw failed_check_authentication(OPKELE_CP_ "No assoc_handle or invalid assoc_handle specified with check_authentication request");
+        }
+        static const string idresmode = "id_res";
+        try {
+            if(util::base64_signature(assoc,util::change_mode_message_proxy(inm,idresmode))!=inm.get_field("sig"))
+                throw failed_check_authentication(OPKELE_CP_ "Signature mismatch");
+        }catch(failed_lookup&) {
+            throw failed_check_authentication(OPKELE_CP_ "failed to calculate signature");
+        }
+        oum.set_field("is_valid","true");
+        try {
+            string h = inm.get_field("invalidate_handle");
+            try {
+                assoc_t ih = retrieve_assoc(h);
+            }catch(invalid_handle& ih) {
+                oum.set_field("invalidate_handle",h);
+            }catch(failed_lookup& ih) {
+                oum.set_field("invalidate_handle",h);
+            }
+        }catch(failed_lookup&) { }
+        if(o2) {
+            assert(!nonce.empty());
+            invalidate_nonce(nonce);
+        }
+        return oum;
+    }catch(failed_check_authentication& ) {
+        oum.set_field("is_valid","false");
+        return oum;
+    }
+
+}