bug#47418: [PATCH] gnu: imagemagick: Fix CVE-2020-27829.

["Léo Le Bouter via Bug reports for GNU Guix" <bug-guix@gnu.org>]

* gnu/packages/patches/imagemagick-CVE-2020-27829.patch: New patch.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/imagemagick.scm (imagemagick/fixed): Apply patch to existing
graft.
---
 gnu/local.mk                                  |  1 +
 gnu/packages/imagemagick.scm                  |  3 ++-
 .../patches/imagemagick-CVE-2020-27829.patch  | 23 +++++++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 gnu/packages/patches/imagemagick-CVE-2020-27829.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 40956598db..fe70238345 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1220,6 +1220,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/id3lib-UTF16-writing-bug.patch			\
   %D%/packages/patches/idris-disable-test.patch			\
   %D%/packages/patches/ilmbase-fix-tests.patch			\
+  %D%/packages/patches/imagemagick-CVE-2020-27829.patch	\
   %D%/packages/patches/inetutils-hurd.patch			\
   %D%/packages/patches/inkscape-poppler-0.76.patch		\
   %D%/packages/patches/intel-xed-fix-nondeterminism.patch	\
diff --git a/gnu/packages/imagemagick.scm b/gnu/packages/imagemagick.scm
index a3562f2e13..1618a28596 100644
--- a/gnu/packages/imagemagick.scm
+++ b/gnu/packages/imagemagick.scm
@@ -143,7 +143,8 @@ text, lines, polygons, ellipses and Bézier curves.")
                                   "6.9.12-2.tar.xz"))
               (sha256
                (base32
-                "17da5zihz58qm41y61sbvw626m5xfwr2nzszlikrvxyq1j1q7asa"))))
+                "17da5zihz58qm41y61sbvw626m5xfwr2nzszlikrvxyq1j1q7asa"))
+              (patches (search-patches "imagemagick-CVE-2020-27829.patch"))))
     (arguments
      (substitute-keyword-arguments (package-arguments imagemagick)
        ((#:phases phases)
diff --git a/gnu/packages/patches/imagemagick-CVE-2020-27829.patch b/gnu/packages/patches/imagemagick-CVE-2020-27829.patch
new file mode 100644
index 0000000000..74debdc98e
--- /dev/null
+++ b/gnu/packages/patches/imagemagick-CVE-2020-27829.patch
@@ -0,0 +1,23 @@
+From 6ee5059cd3ac8d82714a1ab1321399b88539abf0 Mon Sep 17 00:00:00 2001
+From: Cristy <urban-warrior@imagemagick.org>
+Date: Mon, 30 Nov 2020 16:27:26 +0000
+Subject: [PATCH] possible TIFF related-heap buffer overflow (alert & POC by
+ Hardik Shah)
+
+---
+ coders/tiff.c | 2 +-
+ 1 files changed, 1 insertions(+), 1 deletion(-)
+
+diff --git a/coders/tiff.c b/coders/tiff.c
+index e98f927abd..1eecf17aea 100644
+--- a/coders/tiff.c
++++ b/coders/tiff.c
+@@ -1975,7 +1975,7 @@ static Image *ReadTIFFImage(const ImageInfo *image_info,
+         extent+=image->columns*sizeof(uint32);
+ #endif
+         strip_pixels=(unsigned char *) AcquireQuantumMemory(extent,
+-          sizeof(*strip_pixels));
++          2*sizeof(*strip_pixels));
+         if (strip_pixels == (unsigned char *) NULL)
+           ThrowTIFFException(ResourceLimitError,"MemoryAllocationFailed");
+         (void) memset(strip_pixels,0,extent*sizeof(*strip_pixels));
-- 
2.31.0