Bug 699658: Fix handling of pre-SAFER opened files.

Temp files opened for writing before SAFER is engaged are not subject to the
SAFER restrictions - that is handled by recording in a dictionary, and
checking that as part of the permissions checks.

By adding a custom error handler for invalidaccess, that allowed the filename
to be added to the dictionary (despite the attempted open throwing the error)
thus meaning subsequent accesses were erroneously permitted.

1 files changed, 16 insertions, 1 deletions

diff --git a/Resource/Init/gs_init.ps b/Resource/Init/gs_init.ps
index a6e49f08c..5a5a42857 100644
--- a/Resource/Init/gs_init.ps
+++ b/Resource/Init/gs_init.ps
@@ -2036,6 +2036,19 @@ readonly def
             concatstrings concatstrings .generate_dir_list_templates
         } if
       ]
+      /PermitFileWriting [
+          currentuserparams /PermitFileWriting get aload pop
+          (TMPDIR) getenv not
+          {
+            (TEMP) getenv not
+            {
+              (TMP) getenv not
+              {
+                (/temp) (/tmp)
+              } if
+            } if
+          } if
+      ]
       /LockFilePermissions //true
     >> setuserparams
   }
@@ -2122,7 +2135,9 @@ readonly def
 % the file can be deleted later, even if SAFER is set.
 /.tempfile {
   .tempfile     % filename file
-  //SAFETY /tempfiles get 2 .argindex //true .forceput
+    //SAFETY /safe get not { % only add the filename if we're not yet safe
+    //SAFETY /tempfiles get 2 .argindex //true .forceput
+  } if
 } .bind executeonly odef
 
 % If we are running in SAFER mode, lock things down