Make path_recv() and poly_recv() reject paths/polygons containing no points.

The zero-point case is sensible so far as the data structure is concerned,
so maybe we ought to allow it sometime; but right now the textual input
routines for these types don't allow it, and it seems that not all the
functions for the types are prepared to cope.
Report and patch by Merlin Moncure.

diff --git a/src/backend/utils/adt/geo_ops.c b/src/backend/utils/adt/geo_ops.c
index b2e603a46affabfa5e683ad751bc9d4ee5dcb865..ec21c59dff91082d45f4116d07ca32a655abef5d 100644 (file)
--- a/src/backend/utils/adt/geo_ops.c
+++ b/src/backend/utils/adt/geo_ops.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/utils/adt/geo_ops.c,v 1.97 2007/11/15 21:14:39 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/utils/adt/geo_ops.c,v 1.98 2007/12/18 00:04:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1456,7 +1456,7 @@ path_recv(PG_FUNCTION_ARGS)
 
    closed = pq_getmsgbyte(buf);
    npts = pq_getmsgint(buf, sizeof(int32));
-   if (npts < 0 || npts >= (int32) ((INT_MAX - offsetof(PATH, p[0])) / sizeof(Point)))
+   if (npts <= 0 || npts >= (int32) ((INT_MAX - offsetof(PATH, p[0])) / sizeof(Point)))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
             errmsg("invalid number of points in external \"path\" value")));
@@ -3484,7 +3484,7 @@ poly_recv(PG_FUNCTION_ARGS)
    int         size;
 
    npts = pq_getmsgint(buf, sizeof(int32));
-   if (npts < 0 || npts >= (int32) ((INT_MAX - offsetof(POLYGON, p[0])) / sizeof(Point)))
+   if (npts <= 0 || npts >= (int32) ((INT_MAX - offsetof(POLYGON, p[0])) / sizeof(Point)))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
          errmsg("invalid number of points in external \"polygon\" value")));