This is a portion of the patch we were carrying for CVE-2009-2347 in 3.8.2.
Unfortunately the upstream fix in 3.9.2 is incomplete, so we still need this
part.  Reported upstream at
http://bugzilla.maptools.org/show_bug.cgi?id=2079


diff -Naur tiff-3.9.2.orig/tools/tiff2rgba.c tiff-3.9.2/tools/tiff2rgba.c
--- tiff-3.9.2.orig/tools/tiff2rgba.c	2009-08-20 16:23:53.000000000 -0400
+++ tiff-3.9.2/tools/tiff2rgba.c	2009-12-03 12:19:07.000000000 -0500
@@ -125,6 +125,17 @@
     return (0);
 }
 
+static tsize_t
+multiply(tsize_t m1, tsize_t m2)
+{
+    tsize_t prod = m1 * m2;
+
+    if (m1 && prod / m1 != m2)
+        prod = 0;		/* overflow */
+
+    return prod;
+}
+
 static int
 cvt_by_tile( TIFF *in, TIFF *out )
 
@@ -134,6 +145,7 @@
     uint32  tile_width, tile_height;
     uint32  row, col;
     uint32  *wrk_line;
+    tsize_t raster_size;
     int	    ok = 1;
 
     TIFFGetField(in, TIFFTAG_IMAGEWIDTH, &width);
@@ -151,7 +163,14 @@
     /*
      * Allocate tile buffer
      */
-    raster = (uint32*)_TIFFmalloc(tile_width * tile_height * sizeof (uint32));
+    raster_size = multiply(multiply(tile_width, tile_height), sizeof (uint32));
+    if (!raster_size) {
+	TIFFError(TIFFFileName(in),
+		  "Can't allocate buffer for raster of size %lux%lu",
+		  (unsigned long) tile_width, (unsigned long) tile_height);
+	return (0);
+    }
+    raster = (uint32*)_TIFFmalloc(raster_size);
     if (raster == 0) {
         TIFFError(TIFFFileName(in), "No space for raster buffer");
         return (0);
@@ -159,7 +178,7 @@
 
     /*
      * Allocate a scanline buffer for swapping during the vertical
-     * mirroring pass.
+     * mirroring pass.  (Request can't overflow given prior checks.)
      */
     wrk_line = (uint32*)_TIFFmalloc(tile_width * sizeof (uint32));
     if (!wrk_line) {
@@ -236,6 +255,7 @@
     uint32  width, height;		/* image width & height */
     uint32  row;
     uint32  *wrk_line;
+    tsize_t raster_size;
     int	    ok = 1;
 
     TIFFGetField(in, TIFFTAG_IMAGEWIDTH, &width);
@@ -251,7 +271,14 @@
     /*
      * Allocate strip buffer
      */
-    raster = (uint32*)_TIFFmalloc(width * rowsperstrip * sizeof (uint32));
+    raster_size = multiply(multiply(width, rowsperstrip), sizeof (uint32));
+    if (!raster_size) {
+	TIFFError(TIFFFileName(in),
+		  "Can't allocate buffer for raster of size %lux%lu",
+		  (unsigned long) width, (unsigned long) rowsperstrip);
+	return (0);
+    }
+    raster = (uint32*)_TIFFmalloc(raster_size);
     if (raster == 0) {
         TIFFError(TIFFFileName(in), "No space for raster buffer");
         return (0);
@@ -259,7 +286,7 @@
 
     /*
      * Allocate a scanline buffer for swapping during the vertical
-     * mirroring pass.
+     * mirroring pass.  (Request can't overflow given prior checks.)
      */
     wrk_line = (uint32*)_TIFFmalloc(width * sizeof (uint32));
     if (!wrk_line) {