Do not bomb out on unusual xml

In particular, properly handle directy Type child of XRD element.

As usually, thanks to Joseph Smarr of Plaxo for spotting it ;-)

Signed-off-by: Michael Krelin <hacker@klever.net>

1 files changed, 26 insertions, 15 deletions

diff --git a/lib/discovery.cc b/lib/discovery.cc
index cbdceb3..f8a3988 100644
--- a/lib/discovery.cc
+++ b/lib/discovery.cc
@@ -201,395 +201,406 @@ namespace opkele {
 			throw exception_curl(OPKELE_CP_ "failed to get CURLINFO_EFFECTIVE_URL",r);
 		    string cid = util::strip_uri_fragment_part( idis.canonicalized_id = util::rfc_3986_normalize_uri(eu) );
 		    if(xrds_location.empty()) {
 			if(idis.xrd.empty())
 			    html2xrd(oi,idis);
 			else{
 			    for(const service_type_t *st=op_service_types;
 				    st<&op_service_types[sizeof(op_service_types)/sizeof(*op_service_types)];++st)
 				queue_endpoints(oi,idis,st);
 			}
 		    }else{
 			idis.clear();
 			idis.canonicalized_id = cid;
 			discover_at(idis,xrds_location,xmode_xrd);
 			if(idis.xrd.empty())
 			    html2xrd(oi,idis);
 			else{
 			    for(const service_type_t *st=op_service_types;
 				    st<&op_service_types[sizeof(op_service_types)/sizeof(*op_service_types)];++st)
 				queue_endpoints(oi,idis,st);
 			}
 		    }
 		}
 		return rv;
 	    }
 
 	    void discover_at(idiscovery_t& idis,const string& url,int xm) {
 		CURLcode r = easy_setopt(CURLOPT_MAXREDIRS, (xm&xmode_noredirs)?0:5);
 		if(r)
 		    throw exception_curl(OPKELE_CP_ "failed to set curly maxredirs option");
 		if( (r=easy_setopt(CURLOPT_URL,url.c_str())) )
 		    throw exception_curl(OPKELE_CP_ "failed to set curly urlie",r);
 
 		http_content_type.clear();
 		xmode = xm;
 		prepare_to_parse();
 		if(xmode&xmode_html) {
 		    xrds_location.clear();
 		    save_html.clear();
 		    save_html.reserve(max_html);
 		}
 		xrd = &idis.xrd;
 
 		r = easy_perform();
 		if(r && r!=CURLE_WRITE_ERROR)
 		    throw exception_curl(OPKELE_CP_ "failed to perform curly request",r);
 
 		if(!parser_choked) {
 		    parse(0,0,true);
 		}else if(xmode&xmode_html){
 		    /* TODO: do not bother if we've seen xml */
 		    try {
 			util::tidy_doc_t td = util::tidy_doc_t::create();
 			if(!td)
 			    throw exception_tidy(OPKELE_CP_ "failed to create htmltidy document");
 #ifdef NDEBUG
 			td.opt_set(TidyQuiet,true);
 			td.opt_set(TidyShowWarnings,false);
 #else /* NDEBUG */
 			td.opt_set(TidyQuiet,false);
 			td.opt_set(TidyShowWarnings,true);
 #endif /* NDEBUG */
 			td.opt_set(TidyForceOutput,true);
 			td.opt_set(TidyXhtmlOut,true);
 			td.opt_set(TidyDoctypeMode,TidyDoctypeOmit);
 			td.opt_set(TidyMark,false);
 			td.opt_set(TidyNumEntities,true);
 			if(td.parse_string(save_html)<=0)
 			    throw exception_tidy(OPKELE_CP_ "tidy failed to parse document");
 			if(td.clean_and_repair()<=0)
 			    throw exception_tidy(OPKELE_CP_ "tidy failed to clean and repair");
 			util::tidy_buf_t tide;
 			if(td.save_buffer(tide)<=0)
 			    throw exception_tidy(OPKELE_CP_ "tidy failed to save buffer");
 			prepare_to_parse();
 			parse(tide.c_str(),tide.size(),true);
 		    }catch(exception_tidy& et) { }
 		}
 		save_html.clear();
 	    }
 
 	    void prepare_to_parse() {
 		(*(expat_t*)this) = parser_create_ns();
 		set_user_data(); set_element_handler();
 		set_character_data_handler();
 		set_unknown_encoding_handler();
 
 		if(xmode&xmode_html) {
 		    html_openid1.clear(); html_openid2.clear();
 		    parser_choked = false;
 		}
 
 		cdata = 0; xrd_service = 0; skipping = 0;
 		pt_stack.clear();
 		status_code = 100; status_string.clear();
 	    }
 
 	    void html2xrd(endpoint_discovery_iterator& oi,idiscovery_t& id) {
 		XRD_t& x = id.xrd;
 		if(!html_openid2.uris.empty()) {
 		    html_openid2.types.insert(STURI_OPENID20);
 		    x.services.add(-1,html_openid2);
 		    queue_endpoints(oi,id,&op_service_types[st_index_2]);
 		}
 		if(!html_openid1.uris.empty()) {
 		    html_openid1.types.insert(STURI_OPENID11);
 		    x.services.add(-1,html_openid1);
 		    queue_endpoints(oi,id,&op_service_types[st_index_1]);
 		}
 	    }
 
 	    size_t write(void *p,size_t s,size_t nm) {
 		/* TODO: limit total size */
 		size_t bytes = s*nm;
 		const char *inbuf = (const char*)p;
 		if(xmode&xmode_html) {
 		    size_t mbts = save_html.capacity()-save_html.size();
 		    size_t bts = 0;
 		    if(mbts>0) {
 			bts = (bytes>mbts)?mbts:bytes;
 			save_html.append(inbuf,bts);
 		    }
 		    if(skipping<0) return bts;
 		}
 		if(skipping<0) return 0;
 		bool rp = parse(inbuf,bytes,false);
 		if(!rp) {
 		    parser_choked = true;
 		    skipping = -1;
 		    if(!(xmode&xmode_html))
 			bytes = 0;
 		}
 		return bytes;
 	    }
 	    size_t header(void *p,size_t s,size_t nm) {
 		size_t bytes = s*nm;
 		const char *h = (const char*)p;
 		const char *colon = (const char*)memchr(p,':',bytes);
 		const char *space = (const char*)memchr(p,' ',bytes);
 		if(space && ( (!colon) || space<colon ) ) {
 		    xrds_location.clear(); http_content_type.clear();
 		}else if(colon) {
 		    const char *hv = ++colon;
 		    size_t hnl = colon-h;
 		    int rb;
 		    for(rb = bytes-hnl-1;rb>0 && isspace(*hv);++hv,--rb) ;
 		    while(rb>0 && isspace(hv[rb-1])) --rb;
 		    if(rb) {
 			if( (hnl>=sizeof(XRDS_HEADER))
 				&& !strncasecmp(h,XRDS_HEADER":",
 				    sizeof(XRDS_HEADER)) ) {
 			    xrds_location.assign(hv,rb);
 			}else if( (hnl>=sizeof(CT_HEADER))
 				&& !strncasecmp(h,CT_HEADER":",
 				    sizeof(CT_HEADER)) ) {
 			    const char *sc = (const char*)memchr(
 				    hv,';',rb);
 			    http_content_type.assign(hv,sc?(sc-hv):rb);
 			}
 		    }
 		}
 		return curl_t::header(p,s,nm);
 	    }
 
 	    void start_element(const XML_Char *n,const XML_Char **a) {
 		if(skipping<0) return;
 		if(skipping) {
 		    if(xmode&xmode_html)
 			html_start_element(n,a);
 		    ++skipping; return;
 		}
 		if(pt_stack.empty()) {
 		    if(is_qelement(n,NSURI_XRDS "\tXRDS"))
 			return;
 		    if(is_qelement(n,NSURI_XRD "\tXRD")) {
 			assert(xrd);
 			xrd->clear();
 			pt_stack.push_back(n);
 		    }else if(xmode&xmode_html) {
 			html_start_element(n,a);
 		    }else{
 			skipping = -1;
 		    }
 		}else{
 		    int pt_s = pt_stack.size();
 		    if(pt_s==1) {
 			if(is_qelement(n,NSURI_XRD "\tCanonicalID")) {
 			    assert(xrd);
 			    cdata = &(xrd->canonical_ids.add(element_priority(a),string()));
 			}else if(is_qelement(n,NSURI_XRD "\tLocalID")) {
 			    assert(xrd);
 			    cdata = &(xrd->local_ids.add(element_priority(a),string()));
 			}else if(is_qelement(n,NSURI_XRD "\tProviderID")) {
 			    assert(xrd);
 			    cdata = &(xrd->provider_id);
 			}else if(is_qelement(n,NSURI_XRD "\tService")) {
 			    assert(xrd);
 			    xrd_service = &(xrd->services.add(element_priority(a),
 					service_t()));
 			    pt_stack.push_back(n);
 			}else if(is_qelement(n,NSURI_XRD "\tStatus")) {
 			    for(;*a;) {
 				if(!strcasecmp(*(a++),"code")) {
 				    if(sscanf(*(a++),"%ld",&status_code)==1 && status_code!=100) {
 					cdata = &status_string;
 					pt_stack.push_back(n);
 					break;
 				    }
 				}else
 				    ++a;
 			    }
 			}else if(is_qelement(n,NSURI_XRD "\tExpires")) {
 			    assert(xrd);
 			    cdata_buf.clear();
 			    cdata = &cdata_buf;
 			}else if(xmode&xmode_html) {
 			    html_start_element(n,a);
 			}else{
 			    skipping = 1;
 			}
 		    }else if(pt_s==2) {
 			if(is_qelement(pt_stack.back().c_str(), NSURI_XRD "\tService")) {
 			    if(is_qelement(n,NSURI_XRD "\tType")) {
 				assert(xrd); assert(xrd_service);
 				cdata_buf.clear();
 				cdata = &cdata_buf;
 			    }else if(is_qelement(n,NSURI_XRD "\tURI")) {
 				assert(xrd); assert(xrd_service);
 				const char *append = element_attr(a,"append");
 				xrd::uri_t& uri = xrd_service->uris.add(element_priority(a),xrd::uri_t("",append?append:""));
 				cdata = &uri.uri;
 			    }else if(is_qelement(n,NSURI_XRD "\tLocalID")
 				    || is_qelement(n,NSURI_OPENID10 "\tDelegate") ) {
 				assert(xrd); assert(xrd_service);
 				cdata = &(xrd_service->local_ids.add(element_priority(a),string()));
 			    }else if(is_qelement(n,NSURI_XRD "\tProviderID")) {
 				    assert(xrd); assert(xrd_service);
 				    cdata = &(xrd_service->provider_id);
 			    }else{
 				skipping = 1;
 			    }
 			}else
 			    skipping = 1;
 		    }else if(xmode&xmode_html) {
 			html_start_element(n,a);
 		    }else{
 			skipping = 1;
 		    }
 		}
 	    }
 	    void end_element(const XML_Char *n) {
 		if(skipping<0) return;
 		if(skipping) {
 		    --skipping; return;
 		}
 		if(is_qelement(n,NSURI_XRD "\tType")) {
-		    assert(xrd); assert(xrd_service); assert(cdata==&cdata_buf);
-		    xrd_service->types.insert(cdata_buf);
+		    if(xrd && xrd_service) {
+			assert(cdata==&cdata_buf);
+			xrd_service->types.insert(cdata_buf);
+		    }
 		}else if(is_qelement(n,NSURI_XRD "\tService")) {
-		    assert(xrd); assert(xrd_service);
-		    assert(!pt_stack.empty());
-		    assert(pt_stack.back()==(NSURI_XRD "\tService"));
-		    pt_stack.pop_back();
-		    xrd_service = 0;
-		}else if(is_qelement(n,NSURI_XRD "\tStatus")) {
-		    assert(xrd);
-		    if(is_qelement(pt_stack.back().c_str(),n)) {
-			assert(cdata==&status_string);
+		    if(!(xrd && xrd_service)) {
+			skipping = -1;
+		    }else{
+			assert(!pt_stack.empty());
+			assert(pt_stack.back()==(NSURI_XRD "\tService"));
 			pt_stack.pop_back();
-			if(status_code!=100)
-			    skipping = -1;
+			xrd_service = 0;
+		    }
+		}else if(is_qelement(n,NSURI_XRD "\tStatus")) {
+		    if(!xrd) {
+			skipping=-1;
+		    }else{
+			if(is_qelement(pt_stack.back().c_str(),n)) {
+			    assert(cdata==&status_string);
+			    pt_stack.pop_back();
+			    if(status_code!=100)
+				skipping = -1;
+			}
 		    }
 		}else if(is_qelement(n,NSURI_XRD "\tExpires")) {
-		    assert(xrd);
-		    xrd->expires = util::w3c_to_time(cdata_buf);
+		    if(!xrd) {
+			skipping=-1;
+		    }else{
+			xrd->expires = util::w3c_to_time(cdata_buf);
+		    }
 		}else if((xmode&xmode_html) && is_element(n,"head")) {
 		    skipping = -1;
 		}
 		cdata = 0;
 	    }
 	    void character_data(const XML_Char *s,int l) {
 		if(skipping) return;
 		if(cdata) cdata->append(s,l);
 	    }
 
 	    void html_start_element(const XML_Char *n,const XML_Char **a) {
 		if(is_element(n,"meta")) {
 		    bool heq = false;
 		    string l;
 		    for(;*a;a+=2) {
 			if(!( strcasecmp(a[0],"http-equiv")
 				|| strcasecmp(a[1],XRDS_HEADER) ))
 			    heq = true;
 			else if(!strcasecmp(a[0],"content"))
 			    l.assign(a[1]);
 		    }
 		    if(heq)
 			xrds_location = l;
 		}else if(is_element(n,"link")) {
 		    string rels;
 		    string href;
 		    for(;*a;a+=2) {
 			if( !strcasecmp(a[0],"rel") ) {
 			    rels.assign(a[1]);
 			}else if( !strcasecmp(a[0],"href") ) {
 			    const char *ns = a[1];
 			    for(;*ns && isspace(*ns);++ns) ;
 			    href.assign(ns);
 			    string::size_type lns=href.find_last_not_of(data::_whitespace_chars);
 			    href.erase(lns+1);
 			}
 		    }
 		    for(string::size_type ns=rels.find_first_not_of(data::_whitespace_chars);
 			    ns!=string::npos; ns=rels.find_first_not_of(data::_whitespace_chars,ns)) {
 			string::size_type s = rels.find_first_of(data::_whitespace_chars,ns);
 			string rel;
 			if(s==string::npos) {
 			    rel.assign(rels,ns,string::npos);
 			    ns = string::npos;
 			}else{
 			    rel.assign(rels,ns,s-ns);
 			    ns = s;
 			}
 			if(rel=="openid.server")
 			    html_openid1.uris.add(-1,xrd::uri_t(href));
 			else if(rel=="openid.delegate")
 			    html_openid1.local_ids.add(-1,href);
 			else if(rel=="openid2.provider")
 			    html_openid2.uris.add(-1,xrd::uri_t(href));
 			else if(rel=="openid2.local_id")
 			    html_openid2.local_ids.add(-1,href);
 		    }
 		}else if(is_element(n,"body")) {
 		    skipping = -1;
 		}
 	    }
 
 	    void queue_endpoints(endpoint_discovery_iterator& oi,
 		    const idiscovery_t &id,
 		    const service_type_t *st) {
 		openid_endpoint_t ep;
 		ep.claimed_id = id.canonicalized_id;
 		for(xrd::services_t::const_iterator isvc=id.xrd.services.begin();
 			isvc!=id.xrd.services.end(); ++isvc) {
 		    const xrd::service_t svc = isvc->second;
 		    if(svc.types.find(st->uri)==svc.types.end()) continue;
 		    for(xrd::uris_t::const_iterator iu=svc.uris.begin();iu!=svc.uris.end();++iu) {
 			ep.uri = iu->second.uri;
 			if(id.xri_identity) {
 			    if(iu->second.append=="qxri") {
 				ep.uri += id.normalized_id;
 			    } /* TODO: else handle other append attribute values */
 			}
 			if(st->forceid) {
 			    ep.local_id = ep.claimed_id = st->forceid;
 			    *(oi++) = ep;
 			}else{
 			    if(svc.local_ids.empty()) {
 				ep.local_id = ep.claimed_id;
 				*(oi++) = ep;
 			    }else{
 				for(xrd::local_ids_t::const_iterator ilid=svc.local_ids.begin();
 					ilid!=svc.local_ids.end(); ++ilid) {
 				    ep.local_id = ilid->second;
 				    *(oi++) = ep;
 				}
 			    }
 			}
 		    }
 		}
 	    }
 
 	    int unknown_encoding(const XML_Char *n,XML_Encoding *i) {
 		for(int ii=0;ii < sizeof(i->map)/sizeof(i->map[0]);++ii)
 		    i->map[ii] = ii;
 		i->convert = 0; i->release = 0;
 		return XML_STATUS_OK;
 	    }
 
     };
 
     string idiscover(endpoint_discovery_iterator oi,const string& identity) {
 	idigger_t idigger;
 	return idigger.discover(oi,identity);
     }
 
     void yadiscover(endpoint_discovery_iterator oi,const string& yurl,const char **types,bool redirs) try {
 	idigger_t idigger;
 	idigger.yadiscover(oi,yurl,types,redirs);
     }catch(exception_curl& ec) {
 	if(redirs || ec._error!=CURLE_TOO_MANY_REDIRECTS)
 	    throw;
     }
 
 }