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#include <cassert>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <opkele/basic_rp.h>
#include <opkele/exception.h>
#include <opkele/uris.h>
#include <opkele/data.h>
#include <opkele/util.h>
#include <opkele/util-internal.h>
#include <opkele/curl.h>
#include <opkele/debug.h>
namespace opkele {
void basic_RP::reset_vars() {
claimed_id.clear(); identity.clear();
}
const string& basic_RP::get_claimed_id() const {
if(claimed_id.empty())
throw non_identity(OPKELE_CP_ "attempting to retreive claimed_id of non-identity assertion");
assert(!identity.empty());
return claimed_id;
}
const string& basic_RP::get_identity() const {
if(identity.empty())
throw non_identity(OPKELE_CP_ "attempting to retrieve identity of non-identity related assertion");
assert(!claimed_id.empty());
return identity;
}
static void dh_get_secret(
secret_t& secret, const basic_openid_message& om,
const char *exp_assoc, const char *exp_sess,
util::dh_t& dh,
size_t d_len, unsigned char *(*d_fun)(const unsigned char*,size_t,unsigned char*),
size_t exp_s_len) try {
if(om.get_field("assoc_type")!=exp_assoc || om.get_field("session_type")!=exp_sess)
throw bad_input(OPKELE_CP_ "Unexpected associate response");
util::bignum_t s_pub = util::base64_to_bignum(om.get_field("dh_server_public"));
vector<unsigned char> ck(DH_size(dh)+1);
unsigned char *ckptr = &(ck.front())+1;
int cklen = DH_compute_key(ckptr,s_pub,dh);
if(cklen<0)
throw exception_openssl(OPKELE_CP_ "failed to DH_compute_key()");
if(cklen && (*ckptr)&0x80) {
(*(--ckptr))=0; ++cklen; }
assert(d_len<=SHA256_DIGEST_LENGTH);
unsigned char key_digest[SHA256_DIGEST_LENGTH];
secret.enxor_from_base64((*d_fun)(ckptr,cklen,key_digest),om.get_field("enc_mac_key"));
if(secret.size()!=exp_s_len)
throw bad_input(OPKELE_CP_ "Secret length isn't consistent with association type");
}catch(opkele::failed_lookup& ofl) {
throw bad_input(OPKELE_CP_ "Incoherent response from OP");
} OPKELE_RETHROW
static void direct_request(basic_openid_message& oum,const basic_openid_message& inm,const string& OP) {
util::curl_pick_t curl = util::curl_pick_t::easy_init();
if(!curl)
throw exception_curl(OPKELE_CP_ "failed to initialize curl");
string request = inm.query_string();
CURLcode r;
(r=curl.misc_sets())
|| (r=curl.easy_setopt(CURLOPT_URL,OP.c_str()))
|| (r=curl.easy_setopt(CURLOPT_POST,1))
|| (r=curl.easy_setopt(CURLOPT_POSTFIELDS,request.data()))
|| (r=curl.easy_setopt(CURLOPT_POSTFIELDSIZE,request.length()))
|| (r=curl.set_write());
if(r)
throw exception_curl(OPKELE_CP_ "failed to set curly options",r);
if( (r=curl.easy_perform()) )
throw exception_curl(OPKELE_CP_ "failed to perform curly request",r);
oum.from_keyvalues(curl.response);
}
assoc_t basic_RP::associate(const string& OP) {
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()");
openid_message_t req;
req.set_field("ns",OIURI_OPENID20);
req.set_field("mode","associate");
req.set_field("dh_modulus",util::bignum_to_base64(dh->p));
req.set_field("dh_gen",util::bignum_to_base64(dh->g));
req.set_field("dh_consumer_public",util::bignum_to_base64(dh->pub_key));
openid_message_t res;
req.set_field("assoc_type","HMAC-SHA256");
req.set_field("session_type","DH-SHA256");
secret_t secret;
int expires_in;
try {
direct_request(res,req,OP);
dh_get_secret( secret, res,
"HMAC-SHA256", "DH-SHA256",
dh, SHA256_DIGEST_LENGTH, SHA256, SHA256_DIGEST_LENGTH );
expires_in = util::string_to_long(res.get_field("expires_in"));
}catch(exception&) {
try {
req.set_field("assoc_type","HMAC-SHA1");
req.set_field("session_type","DH-SHA1");
direct_request(res,req,OP);
dh_get_secret( secret, res,
"HMAC-SHA1", "DH-SHA1",
dh, SHA_DIGEST_LENGTH, SHA1, SHA_DIGEST_LENGTH );
expires_in = util::string_to_long(res.get_field("expires_in"));
}catch(bad_input&) {
throw dumb_RP(OPKELE_CP_ "OP failed to supply an association");
}
}
return store_assoc(
OP, res.get_field("assoc_handle"),
res.get_field("assoc_type"), secret,
expires_in );
}
basic_openid_message& basic_RP::checkid_(
basic_openid_message& rv,
mode_t mode,
const string& return_to,const string& realm,
extension_t *ext) {
rv.reset_fields();
rv.set_field("ns",OIURI_OPENID20);
if(mode==mode_checkid_immediate)
rv.set_field("mode","checkid_immediate");
else if(mode==mode_checkid_setup)
rv.set_field("mode","checkid_setup");
else
throw bad_input(OPKELE_CP_ "unknown checkid_* mode");
if(realm.empty() && return_to.empty())
throw bad_input(OPKELE_CP_ "At least one of realm and return_to must be non-empty");
if(!realm.empty()) {
rv.set_field("realm",realm);
rv.set_field("trust_root",realm);
}
if(!return_to.empty())
rv.set_field("return_to",return_to);
const openid_endpoint_t& ep = get_endpoint();
rv.set_field("claimed_id",ep.claimed_id);
rv.set_field("identity",ep.local_id);
try {
rv.set_field("assoc_handle",find_assoc(ep.uri)->handle());
}catch(dumb_RP& drp) {
}catch(failed_lookup& fl) {
try {
rv.set_field("assoc_handle",associate(ep.uri)->handle());
}catch(dumb_RP& drp) { }
} OPKELE_RETHROW
if(ext) ext->rp_checkid_hook(rv);
return rv;
}
class signed_part_message_proxy : public basic_openid_message {
public:
const basic_openid_message& x;
set<string> signeds;
signed_part_message_proxy(const basic_openid_message& xx) : x(xx) {
const string& slist = x.get_field("signed");
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);
signeds.insert(f);
if(co==string::npos) break;
p = co+1;
}
}
bool has_field(const string& n) const {
return signeds.find(n)!=signeds.end() && x.has_field(n); }
const string& get_field(const string& n) const {
if(signeds.find(n)==signeds.end())
throw failed_lookup(OPKELE_CP_ "The field isn't known to be signed");
return x.get_field(n); }
fields_iterator fields_begin() const {
return signeds.begin(); }
fields_iterator fields_end() const {
return signeds.end(); }
};
static void parse_query(const string& u,string::size_type q,
map<string,string>& p) {
if(q==string::npos)
return;
assert(u[q]=='?');
++q;
string::size_type l = u.size();
while(q<l) {
string::size_type eq = u.find('=',q);
string::size_type am = u.find('&',q);
if(am==string::npos) {
if(eq==string::npos) {
p[""] = u.substr(q);
}else{
p[u.substr(q,eq-q)] = u.substr(eq+1);
}
break;
}else{
if(eq==string::npos || eq>am) {
p[""] = u.substr(q,eq-q);
}else{
p[u.substr(q,eq-q)] = u.substr(eq+1,am-eq-1);
}
q = ++am;
}
}
}
void basic_RP::id_res(const basic_openid_message& om,extension_t *ext) {
reset_vars();
bool o2 = om.has_field("ns")
&& om.get_field("ns")==OIURI_OPENID20;
if( (!o2) && om.has_field("user_setup_url"))
throw id_res_setup(OPKELE_CP_ "assertion failed, setup url provided",
om.get_field("user_setup_url"));
string m = om.get_field("mode");
if(o2 && m=="setup_needed")
throw id_res_setup(OPKELE_CP_ "setup needed, no setup url provided");
if(m=="cancel")
throw id_res_cancel(OPKELE_CP_ "authentication cancelled");
bool go_dumb=false;
try {
string OP = o2
?om.get_field("op_endpoint")
:get_endpoint().uri;
assoc_t assoc = retrieve_assoc(
OP,om.get_field("assoc_handle"));
if(om.get_field("sig")!=util::base64_signature(assoc,om))
throw id_res_mismatch(OPKELE_CP_ "signature mismatch");
}catch(dumb_RP& drp) {
go_dumb=true;
}catch(failed_lookup& e) {
go_dumb=true;
} OPKELE_RETHROW
if(go_dumb) {
try {
string OP = o2
?om.get_field("op_endpoint")
:get_endpoint().uri;
check_authentication(OP,om);
}catch(failed_check_authentication& fca) {
throw id_res_failed(OPKELE_CP_ "failed to check_authentication()");
} OPKELE_RETHROW
}
signed_part_message_proxy signeds(om);
if(o2) {
check_nonce(om.get_field("op_endpoint"),
om.get_field("response_nonce"));
static const char *mustsign[] = {
"op_endpoint", "return_to", "response_nonce", "assoc_handle",
"claimed_id", "identity" };
for(size_t ms=0;ms<(sizeof(mustsign)/sizeof(*mustsign));++ms) {
if(om.has_field(mustsign[ms]) && !signeds.has_field(mustsign[ms]))
throw bad_input(OPKELE_CP_ string("Field '")+mustsign[ms]+"' is not signed against the specs");
}
if( (
(om.has_field("claimed_id")?1:0)
^
(om.has_field("identity")?1:0)
)&1 )
throw bad_input(OPKELE_CP_ "claimed_id and identity must be either both present or both absent");
string turl = util::rfc_3986_normalize_uri(get_this_url());
util::strip_uri_fragment_part(turl);
string rurl = util::rfc_3986_normalize_uri(om.get_field("return_to"));
util::strip_uri_fragment_part(rurl);
string::size_type
tq = turl.find('?'), rq = rurl.find('?');
if(
((tq==string::npos)?turl:turl.substr(0,tq))
!=
((rq==string::npos)?rurl:rurl.substr(0,rq))
)
throw id_res_bad_return_to(OPKELE_CP_ "return_to url doesn't match request url");
map<string,string> tp; parse_query(turl,tq,tp);
map<string,string> rp; parse_query(rurl,rq,rp);
for(map<string,string>::const_iterator rpi=rp.begin();rpi!=rp.end();++rpi) {
map<string,string>::const_iterator tpi = tp.find(rpi->first);
if(tpi==tp.end())
throw id_res_bad_return_to(OPKELE_CP_ string("Parameter '")+rpi->first+"' from return_to is missing from the request");
if(tpi->second!=rpi->second)
throw id_res_bad_return_to(OPKELE_CP_ string("Parameter '")+rpi->first+"' from return_to doesn't matche the request");
}
if(om.has_field("claimed_id")) {
claimed_id = om.get_field("claimed_id");
identity = om.get_field("identity");
verify_OP(
om.get_field("op_endpoint"),
claimed_id, identity );
}
}else{
claimed_id = get_endpoint().claimed_id;
/* TODO: check if this is the identity we asked for */
identity = om.get_field("identity");
}
if(ext) ext->rp_id_res_hook(om,signeds);
}
void basic_RP::check_authentication(const string& OP,
const basic_openid_message& om){
openid_message_t res;
static const string checkauthmode = "check_authentication";
direct_request(res,util::change_mode_message_proxy(om,checkauthmode),OP);
if(res.has_field("is_valid")) {
if(res.get_field("is_valid")=="true") {
if(res.has_field("invalidate_handle"))
invalidate_assoc(OP,res.get_field("invalidate_handle"));
return;
}
}
throw failed_check_authentication(
OPKELE_CP_ "failed to verify response");
}
}
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