reworked zero-padding machinery and added one more instance of zero-padding

3 files changed, 20 insertions, 14 deletions

diff --git a/lib/consumer.cc b/lib/consumer.cc
index 12866f0..282f0cc 100644
--- a/lib/consumer.cc
+++ b/lib/consumer.cc
@@ -70,73 +70,74 @@ namespace opkele {
 	    "&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);
+	    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()");
-	    ck.resize(cklen);
-	    // OpenID algorithm requires extra zero in case of set bit here
-	    if(ck[0]&0x80) ck.insert(ck.begin(),1,0);
+	    if(cklen && (*ckptr)&0x80) {
+		(*(--ckptr)) = 0; ++cklen;
+	    }
 	    unsigned char key_sha1[SHA_DIGEST_LENGTH];
-	    SHA1(&(ck.front()),ck.size(),key_sha1);
+	    SHA1(ckptr,cklen,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,extension_t *ext) {
 	return checkid_(mode_checkid_immediate,identity,return_to,trust_root,ext);
     }
     string consumer_t::checkid_setup(const string& identity,const string& return_to,const string& trust_root,extension_t *ext) {
 	return checkid_(mode_checkid_setup,identity,return_to,trust_root,ext);
     }
     string consumer_t::checkid_(mode_t mode,const string& identity,const string& return_to,const string& trust_root,extension_t *ext) {
 	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 = canonicalize(identity);
 	string server, delegate;
 	retrieve_links(iurl,server,delegate);
 	p["identity"] = delegate.empty()?iurl:delegate;
 	if(!trust_root.empty())
 	    p["trust_root"] = trust_root;
diff --git a/lib/server.cc b/lib/server.cc
index e81d4b6..8db97be 100644
--- a/lib/server.cc
+++ b/lib/server.cc
@@ -5,72 +5,73 @@
 #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));
+	    vector<unsigned char> ck(DH_size(dh)+1);
+	    unsigned char *ckptr = &(ck.front())+1;
 	    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);
+	    if(cklen && (*ckptr)&0x80) {
+		(*(--ckptr)) = 0; ++cklen;
+	    }
+	    SHA1(ckptr,cklen,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,extension_t *ext) {
 	checkid_(mode_checkid_immediate,pin,return_to,pout,ext);
     }
 
     void server_t::checkid_setup(const params_t& pin,string& return_to,params_t& pout,extension_t *ext) {
 	checkid_(mode_checkid_setup,pin,return_to,pout,ext);
     }
 
diff --git a/lib/util.cc b/lib/util.cc
index d9abca7..94f6f53 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -57,67 +57,71 @@ namespace opkele {
 		unsigned char tmp[512];
 		size_t rb = 0;
 		while((rb=BIO_read(b64,tmp,sizeof(tmp)))>0)
 		    rv.insert(rv.end(),tmp,&tmp[rb]);
 		BIO_free_all(b64);
 	    }catch(...) {
 		if(b64) BIO_free_all(b64);
 		throw;
 	    }
 	}
 
 	/*
 	 * big numerics
 	 */
 
 	BIGNUM *base64_to_bignum(const string& b64) {
 	    vector<unsigned char> bin;
 	    decode_base64(b64,bin);
 	    BIGNUM *rv = BN_bin2bn(&(bin.front()),bin.size(),0);
 	    if(!rv)
 		throw failed_conversion(OPKELE_CP_ "failed to BN_bin2bn()");
 	    return rv;
 	}
 
 	BIGNUM *dec_to_bignum(const string& dec) {
 	    BIGNUM *rv = 0;
 	    if(!BN_dec2bn(&rv,dec.c_str()))
 		throw failed_conversion(OPKELE_CP_ "failed to BN_dec2bn()");
 	    return rv;
 	}
 
 	string bignum_to_base64(const BIGNUM *bn) {
-	    vector<unsigned char> bin(BN_num_bytes(bn));
-	    int l = BN_bn2bin(bn,&(bin.front()));
-	    return encode_base64(&(bin.front()),l);
+	    vector<unsigned char> bin(BN_num_bytes(bn)+1);
+	    unsigned char *binptr = &(bin.front())+1;
+	    int l = BN_bn2bin(bn,binptr);
+	    if(l && (*binptr)&0x80){
+		(*(--binptr)) = 0; ++l;
+	    }
+	    return encode_base64(binptr,l);
 	}
 
 	/*
 	 * w3c times
 	 */
 
 	string time_to_w3c(time_t t) {
 	    struct tm tm_t;
 	    if(!gmtime_r(&t,&tm_t))
 		throw failed_conversion(OPKELE_CP_ "failed to BN_dec2bn()");
 	    char rv[25];
 	    if(!strftime(rv,sizeof(rv)-1,"%Y-%m-%dT%H:%M:%SZ",&tm_t))
 		throw failed_conversion(OPKELE_CP_ "failed to strftime()");
 	    return rv;
 	}
 
 	time_t w3c_to_time(const string& w) {
 	    struct tm tm_t;
 	    memset(&tm_t,0,sizeof(tm_t));
 	    if(
 		    sscanf(
 			w.c_str(),
 			"%04d-%02d-%02dT%02d:%02d:%02dZ",
 			&tm_t.tm_year,&tm_t.tm_mon,&tm_t.tm_mday,
 			&tm_t.tm_hour,&tm_t.tm_min,&tm_t.tm_sec
 		    ) != 6 )
 		throw failed_conversion(OPKELE_CP_ "failed to sscanf()");
 	    tm_t.tm_mon--;
 	    tm_t.tm_year-=1900;
 	    time_t rv = mktime(&tm_t);
 	    if(rv==(time_t)-1)
 		throw failed_conversion(OPKELE_CP_ "failed to mktime()");