Cursor support buffer patch

Here is a small patch for the cursor support which Jan recently added.
The code assumed that there would be a '\0' in buf after storing the
characters in new->refname, but it did nothing to ensure that.

I can't convince myself that this code does not have the possibility
of buffer overflow.  However, I have not tried to fix that.  For that
matter, I see other possibilities for buffer overflow in gram.y, such
as in decl_cursor_arglist.  Buffer overflow of this sort is not good,
as it means that anybody who is permitted to create functions can
completely break security.

Ian

Index: gram.y
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/pl/plpgsql/src/gram.y,v
retrieving revision 1.20
diff -u -p -r1.20 gram.y
--- gram.y    2001/05/31 17:15:40    1.20
+++ gram.y    2001/06/06 06:35:46
@@ -385,7 +385,8 @@ decl_statement    : decl_varname decl_const
                                 *cp2++ = '\\';
                             *cp2++ = *cp1++;
                         }
-                        strcat(buf, "'");
+                        *cp2++ = '\'';
+                        *cp2 = '\0';
                         curname_def->query = strdup(buf);
                         new->default_val = curname_def;