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
@@ -359,2 +359,11 @@ namespace opkele {
 
+    /**
+     * 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) { }
+    };
+
 }
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
@@ -2,2 +2,3 @@
 #include <cassert>
+#include <algorithm>
 #include <openssl/sha.h>
@@ -11,2 +12,4 @@
 namespace opkele {
+    using std::pair;
+    using std::mismatch;
 
@@ -319,2 +322,35 @@ namespace opkele {
 
+    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");
+    }
+
 }