check if return_to matches realm

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

2 files changed, 45 insertions, 0 deletions

diff --git a/include/opkele/exception.h b/include/opkele/exception.h
index 5c8418e..33f89cc 100644
--- a/include/opkele/exception.h
+++ b/include/opkele/exception.h
@@ -352,11 +352,20 @@ namespace opkele {
      * thrown when querying identity of non-identity related request
      */
     class non_identity : public exception {
 	public:
 	    non_identity(OPKELE_E_PARS)
 		: exception(OPKELE_E_CONS) { }
     };
 
+    /**
+     * thrown if return_to URL doesn't match realm
+     */
+    class bad_return_to : public exception {
+	public:
+	    bad_return_to(OPKELE_E_PARS)
+		: exception(OPKELE_E_CONS) { }
+    };
+
 }
 
 #endif /* __OPKELE_EXCEPTION_H */
diff --git a/lib/basic_op.cc b/lib/basic_op.cc
index 22012bc..f7573aa 100644
--- a/lib/basic_op.cc
+++ b/lib/basic_op.cc
@@ -1,19 +1,22 @@
 #include <time.h>
 #include <cassert>
+#include <algorithm>
 #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 {
+    using std::pair;
+    using std::mismatch;
 
     void basic_op::reset_vars() {
 	assoc.reset();
 	return_to.clear(); realm.clear();
 	claimed_id.clear(); identity.clear();
 	invalidate_handle.clear();
     }
 
@@ -312,9 +315,42 @@ namespace opkele {
 	    invalidate_nonce(nonce);
 	}
 	return oum;
     }catch(failed_check_authentication& ) {
 	oum.set_field("is_valid","false");
 	return oum;
     }
 
+    void basic_op::verify_return_to() {
+	string nrealm = opkele::util::rfc_3986_normalize_uri(realm);
+	if(nrealm.find('#')!=string::npos)
+	    throw opkele::bad_realm(OPKELE_CP_ "authentication realm contains URI fragment");
+	string nrt = opkele::util::rfc_3986_normalize_uri(return_to);
+	string::size_type pr = nrealm.find("://");
+	string::size_type prt = nrt.find("://");
+	assert(!(pr==string::npos || prt==string::npos));
+	pr += sizeof("://")-1;
+	prt += sizeof("://")-1;
+	if(!strncmp(nrealm.c_str()+pr,"*.",2)) {
+	    pr = nrealm.find('.',pr);
+	    prt = nrt.find('.',prt);
+	    assert(pr!=string::npos);
+	    if(prt==string::npos)
+		throw bad_return_to(
+			OPKELE_CP_ "return_to URL doesn't match realm");
+	    // TODO: check for overgeneralized realm
+	}
+	string::size_type lr = nrealm.length();
+	string::size_type lrt = nrt.length();
+	if( (lrt-prt) < (lr-pr) )
+	    throw bad_return_to(
+		    OPKELE_CP_ "return_to URL doesn't match realm");
+	pair<const char*,const char*> mp = mismatch(
+		nrealm.c_str()+pr,nrealm.c_str()+lr,
+		nrt.c_str()+prt);
+	if( (*(mp.first-1))!='/'
+		&& !strchr("/?#",*mp.second) )
+	    throw bad_return_to(
+		    OPKELE_CP_ "return_to URL doesn't match realm");
+    }
+
 }