From 73b3f582caa08a976d647537346790b182bbcc10 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Sun, 5 Feb 2023 15:53:16 +0000
Subject: [PATCH] (CVE-2023-0800 CVE-2023-0801 CVE-2023-0802 CVE-2023-0803
 CVE-2023-0804) tiffcrop: added check for assumption on composite images
 (fixes #496)

Closes #501, #500, #498, #497 et #496

See merge request libtiff/libtiff!466

(cherry picked from commit 33aee1275d9d1384791d2206776eb8152d397f00)
---
 tools/tiffcrop.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 66 insertions(+), 2 deletions(-)

diff --git a/tools/tiffcrop.c b/tools/tiffcrop.c
index 7f738d91..77923cf3 100644
--- a/tools/tiffcrop.c
+++ b/tools/tiffcrop.c
@@ -5235,18 +5235,40 @@ computeInputPixelOffsets(struct crop_mask *crop, struct image_data *image,
 
       crop->regionlist[i].buffsize = buffsize;
       crop->bufftotal += buffsize;
+
+      /* For composite images with more than one region, the
+       * combined_length or combined_width always needs to be equal,
+       * respectively.
+       * Otherwise, even the first section/region copy
+       * action might cause buffer overrun. */
       if (crop->img_mode == COMPOSITE_IMAGES)
         {
         switch (crop->edge_ref)
           {
           case EDGE_LEFT:
           case EDGE_RIGHT:
+               if (i > 0 && zlength != crop->combined_length)
+               {
+                   TIFFError(
+                       "computeInputPixelOffsets",
+                       "Only equal length regions can be combined for "
+                       "-E left or right");
+                   return (-1);
+               }
                crop->combined_length = zlength;
                crop->combined_width += zwidth;
                break;
           case EDGE_BOTTOM:
           case EDGE_TOP:  /* width from left, length from top */
           default:
+               if (i > 0 && zwidth != crop->combined_width)
+               {
+                   TIFFError("computeInputPixelOffsets",
+                             "Only equal width regions can be "
+                             "combined for -E "
+                             "top or bottom");
+                   return (-1);
+               }
                crop->combined_width = zwidth;
                crop->combined_length += zlength;
 	       break;
@@ -6390,6 +6412,46 @@ extractCompositeRegions(struct image_data *image,  struct crop_mask *crop,
   crop->combined_width = 0;
   crop->combined_length = 0;
 
+  /* If there is more than one region, check beforehand whether all the width
+   * and length values of the regions are the same, respectively. */
+  switch (crop->edge_ref)
+  {
+      default:
+      case EDGE_TOP:
+      case EDGE_BOTTOM:
+          for (i = 1; i < crop->selections; i++)
+          {
+              uint32_t crop_width0 =
+                  crop->regionlist[i - 1].x2 - crop->regionlist[i - 1].x1 + 1;
+              uint32_t crop_width1 =
+                  crop->regionlist[i].x2 - crop->regionlist[i].x1 + 1;
+              if (crop_width0 != crop_width1)
+              {
+                  TIFFError("extractCompositeRegions",
+                            "Only equal width regions can be combined for -E "
+                            "top or bottom");
+                  return (1);
+              }
+          }
+          break;
+      case EDGE_LEFT:
+      case EDGE_RIGHT:
+          for (i = 1; i < crop->selections; i++)
+          {
+              uint32_t crop_length0 =
+                  crop->regionlist[i - 1].y2 - crop->regionlist[i - 1].y1 + 1;
+              uint32_t crop_length1 =
+                  crop->regionlist[i].y2 - crop->regionlist[i].y1 + 1;
+              if (crop_length0 != crop_length1)
+              {
+                  TIFFError("extractCompositeRegions",
+                            "Only equal length regions can be combined for "
+                            "-E left or right");
+                  return (1);
+              }
+          }
+  }
+
   for (i = 0; i < crop->selections; i++)
     {
     /* rows, columns, width, length are expressed in pixels */
@@ -6414,7 +6476,8 @@ extractCompositeRegions(struct image_data *image,  struct crop_mask *crop,
       default:
       case EDGE_TOP:
       case EDGE_BOTTOM:
-	   if ((i > 0) && (crop_width != crop->regionlist[i - 1].width))
+	   if ((crop->selections > i + 1) &&
+                 (crop_width != crop->regionlist[i + 1].width))
              {
 	     TIFFError ("extractCompositeRegions", 
                           "Only equal width regions can be combined for -E top or bottom");
@@ -6495,7 +6558,8 @@ extractCompositeRegions(struct image_data *image,  struct crop_mask *crop,
 	   break;
       case EDGE_LEFT:  /* splice the pieces of each row together, side by side */
       case EDGE_RIGHT:
-	   if ((i > 0) && (crop_length != crop->regionlist[i - 1].length))
+	   if ((crop->selections > i + 1) &&
+                 (crop_length != crop->regionlist[i + 1].length))
              {
 	     TIFFError ("extractCompositeRegions", 
                           "Only equal length regions can be combined for -E left or right");