This patch is adapted from commit a11f47475e6443b7f32d21f2271f28f417e2ac04 and
fixes CVE-2018-5711.

From a11f47475e6443b7f32d21f2271f28f417e2ac04 Mon Sep 17 00:00:00 2001
From: "Christoph M. Becker" <cmbecker69@gmx.de>
Date: Wed, 29 Nov 2017 19:37:38 +0100
Subject: [PATCH] Fix #420: Potential infinite loop in gdImageCreateFromGifCtx

Due to a signedness confusion in `GetCode_` a corrupt GIF file can
trigger an infinite loop.  Furthermore we make sure that a GIF without
any palette entries is treated as invalid *after* open palette entries
have been removed.

CVE-2018-5711

See also https://bugs.php.net/bug.php?id=75571.
---
 src/gd_gif_in.c             |  12 ++++++------
 1 file changed, 38 insertions(+), 6 deletions(-)

diff --git a/src/gd_gif_in.c b/src/gd_gif_in.c
index daf26e7..0a8bd71 100644
--- a/src/gd_gif_in.c
+++ b/src/gd_gif_in.c
@@ -335,11 +335,6 @@ terminated:
 		return 0;
 	}
 
-	if(!im->colorsTotal) {
-		gdImageDestroy(im);
-		return 0;
-	}
-
 	/* Check for open colors at the end, so
 	 * we can reduce colorsTotal and ultimately
 	 * BitsPerPixel */
@@ -351,6 +346,11 @@ terminated:
 		}
 	}
 
+	if(!im->colorsTotal) {
+		gdImageDestroy(im);
+		return 0;
+	}
+
 	return im;
 }
 
@@ -447,7 +447,7 @@ static int
 GetCode_(gdIOCtx *fd, CODE_STATIC_DATA *scd, int code_size, int flag, int *ZeroDataBlockP)
 {
 	int i, j, ret;
-	unsigned char count;
+	int count;
 
 	if(flag) {
 		scd->curbit = 0;

-- 
2.13.6

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<div class='path'>path: <a href='/guix/log/?id=948793cb4f83d84f32a871779d057856de87bdb5'>root</a>/<a href='/guix/log/tests?id=948793cb4f83d84f32a871779d057856de87bdb5'>tests</a>/<a href='/guix/log/tests/import-github.scm?id=948793cb4f83d84f32a871779d057856de87bdb5'>import-github.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/import-github.scm?id=948793cb4f83d84f32a871779d057856de87bdb5&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-12-26 17:15:06 +0100'>2022-12-26</span></td><td><a href='/guix/commit/tests/import-github.scm?id=a274a6a1acb99738f02de7b226e6a0d3883ec353'>upstream-updater: Rename record field.</a><span class='msg-avail'>...<span class='msg-tooltip'>The next commits will make the functions, which are currently importing the
latest version of a package, change into importing the latest or a given
version of the package (for those updaters supporting specifying a version).
Thus the name ‘latest‘ is no longer appropriate.

* guix/upstream.scm (upstream-updater) Rename field [latest] to
  [import]. (lookup-updater, package-latest-release) Adjust fieldname
  accordingly.
* guix/gnu-maintenance.scm (%gnu-updater, %gnu-ftp-updater,
  %savannah-updater, %sourceforge-updater, %xorg-updater,
  %kernel.org-updater, %generic-html-updater),
  guix/import/cpan.scm (%cpan-updater),
  guix/import/cran.scm (%cran-updater, %bioconductor-updater),
  guix/import/crate.scm (%crate-updater),
  guix/import/egg.scm (%egg-updater),
  guix/import/elpa.scm (%elpa-updater),
  guix/import/gem.scm (%gem-updater),
  guix/import/git.scm (%generic-git-updater),
  guix/import/github.scm (%github-updater),
  guix/import/gnome.scm (%gnome-updater),
  guix/import/hackage.scm (%hackage-updater),
  guix/import/hexpm.scm (%hexpm-updater),
  guix/import/kde.scm (%kde-updater),
  guix/import/launchpad.scm (%launchpad-updater),
  guix/import/minetest.scm (%minetest-updater),
  guix/import/opam.scm (%opam-updater),
  guix/import/pypi.scm (%pypi-updater),
  guix/import/stackage.scm (%stackage-updater),
  tests/import-github.scm (found-sexp)
  tests/transformations.scm ("options-&gt;transformation, with-latest"):
  Adjust fieldname accordingly.
</span></span></td><td>Hartmut Goebel</td></tr>