Bug #16451878: GEOMETRY QUERY CRASHES SERVER

The GIS WKB reader was checking for the presence of
enough data by first multiplying the number read (where
it could overflow) and only then comparing it to the
number of bytes available.
This can overflow and effectively turn off the check.
Fixed by:
1. Introducing a new function that does division only so
no overflow is possible.
2. Using the proper macros and parenthesizing them.
3. Doing an in-line division check in the only place where
the boundary check is done over a data structure other
than a dense points array.

2 files changed, 59 insertions, 23 deletions

diff --git a/sql/spatial.cc b/sql/spatial.cc
index b1cfd0e5d87..74fc863a18b 100644
--- a/sql/spatial.cc
+++ b/sql/spatial.cc
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -395,13 +395,19 @@ const char *Geometry::get_mbr_for_points(MBR *mbr, const char *data,
 					 uint offset) const
 {
   uint32 points;
+  size_t points_available;
   /* read number of points */
   if (no_data(data, 4))
     return 0;
   points= uint4korr(data);
   data+= 4;
 
-  if (no_data(data, (SIZEOF_STORED_DOUBLE * 2 + offset) * points))
+  /* can't use any of the helper functions due to the offset */
+  points_available=
+    data <= m_data_end ? 
+    (m_data_end - data) / (POINT_DATA_SIZE + offset) : 0;
+
+  if (points_available < points)
     return 0;
 
   /* Calculate MBR for points */
@@ -557,7 +563,7 @@ bool Gis_line_string::get_data_as_wkt(String *txt, const char **end) const
   data += 4;
 
   if (n_points < 1 ||
-      no_data(data, SIZEOF_STORED_DOUBLE * 2 * n_points) ||
+      not_enough_points(data, n_points) ||
       txt->reserve(((MAX_DIGITS_IN_DOUBLE + 1)*2 + 1) * n_points))
     return 1;
 
@@ -594,7 +600,7 @@ int Gis_line_string::geom_length(double *len) const
     return 1;
   n_points= uint4korr(data);
   data+= 4;
-  if (n_points < 1 || no_data(data, SIZEOF_STORED_DOUBLE * 2 * n_points))
+  if (n_points < 1 || not_enough_points(data, n_points))
     return 1;
 
   get_point(&prev_x, &prev_y, data);
@@ -628,8 +634,7 @@ int Gis_line_string::is_closed(int *closed) const
     return 0;
   }
   data+= 4;
-  if (n_points == 0 ||
-      no_data(data, SIZEOF_STORED_DOUBLE * 2 * n_points))
+  if (n_points == 0 || not_enough_points(data, n_points))
     return 1;
 
   /* Get first point */
@@ -798,7 +803,8 @@ bool Gis_polygon::get_data_as_wkt(String *txt, const char **end) const
       return 1;
     n_points= uint4korr(data);
     data+= 4;
-    if (no_data(data, (SIZEOF_STORED_DOUBLE*2) * n_points) ||
+
+    if (not_enough_points(data, n_points) ||
 	txt->reserve(2 + ((MAX_DIGITS_IN_DOUBLE + 1) * 2 + 1) * n_points))
       return 1;
     txt->qs_append('(');
@@ -852,7 +858,7 @@ int Gis_polygon::area(double *ar, const char **end_of_data) const
     if (no_data(data, 4))
       return 1;
     n_points= uint4korr(data);
-    if (no_data(data, (SIZEOF_STORED_DOUBLE*2) * n_points))
+    if (not_enough_points(data, n_points))
       return 1;
     get_point(&prev_x, &prev_y, data+4);
     data+= (4+SIZEOF_STORED_DOUBLE*2);
@@ -888,7 +894,7 @@ int Gis_polygon::exterior_ring(String *result) const
   n_points= uint4korr(data);
   data+= 4;
   length= n_points * POINT_DATA_SIZE;
-  if (no_data(data, length) || result->reserve(1+4+4+ length))
+  if (not_enough_points(data, n_points) || result->reserve(1+4+4+ length))
     return 1;
 
   result->q_append((char) wkb_ndr);
@@ -934,7 +940,7 @@ int Gis_polygon::interior_ring_n(uint32 num, String *result) const
   n_points= uint4korr(data);
   points_size= n_points * POINT_DATA_SIZE;
   data+= 4;
-  if (no_data(data, points_size) || result->reserve(1+4+4+ points_size))
+  if (not_enough_points(data, n_points) || result->reserve(1+4+4+ points_size))
     return 1;
 
   result->q_append((char) wkb_ndr);
@@ -973,7 +979,7 @@ int Gis_polygon::centroid_xy(double *x, double *y) const
       return 1;
     org_n_points= n_points= uint4korr(data);
     data+= 4;
-    if (no_data(data, (SIZEOF_STORED_DOUBLE*2) * n_points))
+    if (not_enough_points(data, n_points))
       return 1;
     get_point(&prev_x, &prev_y, data);
     data+= (SIZEOF_STORED_DOUBLE*2);
@@ -1098,15 +1104,22 @@ uint Gis_multi_point::init_from_wkb(const char *wkb, uint len, wkbByteOrder bo,
 bool Gis_multi_point::get_data_as_wkt(String *txt, const char **end) const
 {
   uint32 n_points;
-  if (no_data(m_data, 4))
+  size_t points_available;
+  const char *data= m_data;
+
+  if (no_data(data, 4))
     return 1;
 
-  n_points= uint4korr(m_data);
-  if (no_data(m_data+4,
-	      n_points * (SIZEOF_STORED_DOUBLE * 2 + WKB_HEADER_SIZE)) ||
+  n_points= uint4korr(data);
+  data+= 4;
+  points_available= data <= m_data_end ?
+    (m_data_end - data) / (POINT_DATA_SIZE + WKB_HEADER_SIZE) : 0;
+
+  /* can't use any of the helper functions due to WKB_HEADER_SIZE */
+  if (n_points > points_available ||
       txt->reserve(((MAX_DIGITS_IN_DOUBLE + 1) * 2 + 1) * n_points))
     return 1;
-  *end= append_points(txt, n_points, m_data+4, WKB_HEADER_SIZE);
+  *end= append_points(txt, n_points, data, WKB_HEADER_SIZE);
   txt->length(txt->length()-1);			// Remove end ','
   return 0;
 }
@@ -1260,7 +1273,7 @@ bool Gis_multi_line_string::get_data_as_wkt(String *txt,
       return 1;
     n_points= uint4korr(data + WKB_HEADER_SIZE);
     data+= WKB_HEADER_SIZE + 4;
-    if (no_data(data, n_points * (SIZEOF_STORED_DOUBLE*2)) ||
+    if (not_enough_points(data, n_points) ||
 	txt->reserve(2 + ((MAX_DIGITS_IN_DOUBLE + 1) * 2 + 1) * n_points))
       return 1;
     txt->qs_append('(');
@@ -1320,8 +1333,8 @@ int Gis_multi_line_string::geometry_n(uint32 num, String *result) const
     if (no_data(data, WKB_HEADER_SIZE + 4))
       return 1;
     n_points= uint4korr(data + WKB_HEADER_SIZE);
-    length= WKB_HEADER_SIZE + 4+ POINT_DATA_SIZE * n_points;
-    if (no_data(data, length))
+    length= WKB_HEADER_SIZE + 4 + POINT_DATA_SIZE * n_points;
+    if (not_enough_points(data + WKB_HEADER_SIZE + 4, n_points))
       return 1;
     if (!--num)
       break;
@@ -1521,7 +1534,7 @@ bool Gis_multi_polygon::get_data_as_wkt(String *txt, const char **end) const
         return 1;
       uint32 n_points= uint4korr(data);
       data+= 4;
-      if (no_data(data, (SIZEOF_STORED_DOUBLE * 2) * n_points) ||
+      if (not_enough_points(data, n_points) ||
 	  txt->reserve(2 + ((MAX_DIGITS_IN_DOUBLE + 1) * 2 + 1) * n_points,
 		       512))
 	return 1;
diff --git a/sql/spatial.h b/sql/spatial.h
index 80972421f83..075ae0ecc89 100644
--- a/sql/spatial.h
+++ b/sql/spatial.h
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -22,7 +22,7 @@
 
 const uint SRID_SIZE= 4;
 const uint SIZEOF_STORED_DOUBLE= 8;
-const uint POINT_DATA_SIZE= SIZEOF_STORED_DOUBLE*2; 
+const uint POINT_DATA_SIZE= (SIZEOF_STORED_DOUBLE * 2); 
 const uint WKB_HEADER_SIZE= 1+4;
 const uint32 GET_SIZE_ERROR= ((uint32) -1);
 
@@ -317,10 +317,33 @@ protected:
   const char *get_mbr_for_points(MBR *mbr, const char *data, uint offset)
     const;
 
-  inline bool no_data(const char *cur_data, uint32 data_amount) const
+  /**
+     Check if there're enough data remaining as requested
+
+     @arg cur_data     pointer to the position in the binary form
+     @arg data_amount  number of points expected
+     @return           true if not enough data
+  */
+  inline bool no_data(const char *cur_data, size_t data_amount) const
   {
     return (cur_data + data_amount > m_data_end);
   }
+
+  /**
+     Check if there're enough points remaining as requested
+
+     Need to perform the calculation in logical units, since multiplication
+     can overflow the size data type.
+
+     @arg data             pointer to the begining of the points array
+     @arg expected_points  number of points expected
+     @return               true if there are not enough points
+  */
+  inline bool not_enough_points(const char *data, uint32 expected_points) const
+  {
+    return (m_data_end < data ||
+            (expected_points > ((m_data_end - data) / POINT_DATA_SIZE)));
+  }
   const char *m_data;
   const char *m_data_end;
 };