gnu: mupdf: Fix CVE-2017-15587.

* gnu/packages/patches/mupdf-CVE-2017-15587.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/pdf.scm (mupdf)[source](patches): Use it.

gnu/local.mk

@@ -877,6 +877,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/mozjs38-version-detection.patch		\
   %D%/packages/patches/mumps-build-parallelism.patch		\
   %D%/packages/patches/mupdf-build-with-openjpeg-2.1.patch	\
+  %D%/packages/patches/mupdf-CVE-2017-15587.patch		\
   %D%/packages/patches/mupen64plus-ui-console-notice.patch	\
   %D%/packages/patches/musl-CVE-2016-8859.patch			\
   %D%/packages/patches/mutt-store-references.patch		\

gnu/packages/patches/mupdf-CVE-2017-15587.patch

@@ -0,0 +1,21 @@
+Fix CVE-2017-15587.
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-15587
+https://nandynarwhals.org/CVE-2017-15587/
+
+Copied from upstream:
+<https://git.ghostscript.com/?p=mupdf.git;h=82df2631d7d0446b206ea6b434ea609b6c28b0e8>
+
+diff --git a/source/pdf/pdf-xref.c b/source/pdf/pdf-xref.c
+index 66bd0ed..6292793 100644
+--- a/source/pdf/pdf-xref.c
++++ b/source/pdf/pdf-xref.c
+@@ -924,7 +924,7 @@ pdf_read_new_xref_section(fz_context *ctx, pdf_document *doc, fz_stream *stm, fz
+ 	pdf_xref_entry *table;
+ 	int i, n;
+ 
+-	if (i0 < 0 || i1 < 0)
++	if (i0 < 0 || i1 < 0 || (i0+i1) < 0)
+ 		fz_throw(ctx, FZ_ERROR_GENERIC, "negative xref stream entry index");
+ 	//if (i0 + i1 > pdf_xref_len(ctx, doc))
+ 	//	fz_throw(ctx, FZ_ERROR_GENERIC, "xref stream has too many entries");

gnu/packages/pdf.scm

@@ -540,7 +540,8 @@ extracting content or merging files.")
         (sha256
          (base32
           "02phamcchgsmvjnb3ir7r5sssvx9fcrscn297z73b82n1jl79510"))
-        (patches (search-patches "mupdf-build-with-openjpeg-2.1.patch"))
+        (patches (search-patches "mupdf-build-with-openjpeg-2.1.patch"
+                                 "mupdf-CVE-2017-15587.patch"))
         (modules '((guix build utils)))
         (snippet
             ;; Delete all the bundled libraries except for mujs, which is