From b39be1019b4acc1aa50c6026463c543332e95a31 Mon Sep 17 00:00:00 2001
From: Catalin Enache <catalin.enache@windriver.com>
Date: Mon, 8 May 2017 16:18:14 +0300

Subject: [PATCH] Bug 697693: Prevent SEGV due to integer overflow.

While building a Huffman table, the start and end points were susceptible
to integer overflow.

Thank you to Jiaqi for finding this issue and suggesting a patch.

Upstream-Status: Backport
CVE: CVE-2017-7975

Signed-off-by: Catalin Enache <catalin.enache@windriver.com>

Contents of this patch were extracted from a larger patch which addressed
two CVE's.  The context (location of {) was also modified to apply to
ghostscript 9.21.

Signed-off-by: Joe Slater <joe.slater@windriver.com>


--- a/jbig2dec/jbig2_huffman.c
+++ b/jbig2dec/jbig2_huffman.c
@@ -421,8 +421,8 @@ jbig2_build_huffman_table(Jbig2Ctx *ctx,
 
             if (PREFLEN == CURLEN) {
                 int RANGELEN = lines[CURTEMP].RANGELEN;
-                int start_j = CURCODE << shift;
-                int end_j = (CURCODE + 1) << shift;
+                uint32_t start_j = CURCODE << shift;
+                uint32_t end_j = (CURCODE + 1) << shift;
                 byte eflags = 0;
 
                 if (end_j > max_j) {