From 399719595f413158b3510128eb85f944654f960c Mon Sep 17 00:00:00 2001
From: DRC <information@libjpeg-turbo.org>
Date: Tue, 12 Jun 2018 20:27:00 -0500
Subject: [PATCH] tjLoadImage(): Fix FPE triggered by malformed BMP

In rdbmp.c, it is necessary to guard against 32-bit overflow/wraparound
when allocating the row buffer, because since BMP files have 32-bit
width and height fields, the value of biWidth can be up to 4294967295.
Specifically, if biWidth is 1073741824 and cinfo->input_components = 4,
then the samplesperrow argument in alloc_sarray() would wrap around to
0, and a division by zero error would occur at line 458 in jmemmgr.c.

If biWidth is set to a higher value, then samplesperrow would wrap
around to a small number, which would likely cause a buffer overflow
(this has not been tested or verified.)
---
 rdbmp.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/rdbmp.c b/rdbmp.c
index eaa7086..4104b68 100644
--- a/rdbmp.c
+++ b/rdbmp.c
@@ -434,6 +434,12 @@ start_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
     progress->total_extra_passes++; /* count file input as separate pass */
   }
 
+  /* Ensure that biWidth * cinfo->input_components doesn't exceed the maximum
+     value of the JDIMENSION type.  This is only a danger with BMP files, since
+     their width and height fields are 32-bit integers. */
+  if ((unsigned long long)biWidth *
+      (unsigned long long)cinfo->input_components > 0xFFFFFFFFULL)
+    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
   /* Allocate one-row buffer for returned data */
   source->pub.buffer = (*cinfo->mem->alloc_sarray)
     ((j_common_ptr) cinfo, JPOOL_IMAGE,
-- 
2.17.1