gnu: mupdf: Fix CVE-2016-{6265,6525}.

* gnu/packages/patches/mupdf-CVE-2016-6265.patch,
gnu/packages/patches/mupdf-CVE-2016-6525.patch: New files.
* gnu/local.mk (dist_patch_DATA): Add them.
* gnu/packages/pdf.scm (mupdf): Use them.

3 files changed, 53 insertions, 0 deletions

diff --git a/gnu/packages/patches/mupdf-CVE-2016-6265.patch b/gnu/packages/patches/mupdf-CVE-2016-6265.patch
new file mode 100644
index 0000000000..58f5c3726c
--- /dev/null
+++ b/gnu/packages/patches/mupdf-CVE-2016-6265.patch
@@ -0,0 +1,30 @@
+Fix CVE-2016-6265 (use after free in pdf_load_xref()).
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-6265
+https://security-tracker.debian.org/tracker/CVE-2016-6265
+
+Patch copied from upstream source repository:
+
+http://git.ghostscript.com/?p=mupdf.git;h=fa1936405b6a84e5c9bb440912c23d532772f958
+
+diff --git a/source/pdf/pdf-xref.c b/source/pdf/pdf-xref.c
+index 576c315..3222599 100644
+--- a/source/pdf/pdf-xref.c
++++ b/source/pdf/pdf-xref.c
+@@ -1184,8 +1184,14 @@ pdf_load_xref(fz_context *ctx, pdf_document *doc, pdf_lexbuf *buf)
+ 				fz_throw(ctx, FZ_ERROR_GENERIC, "object offset out of range: %d (%d 0 R)", (int)entry->ofs, i);
+ 		}
+ 		if (entry->type == 'o')
+-			if (entry->ofs <= 0 || entry->ofs >= xref_len || pdf_get_xref_entry(ctx, doc, entry->ofs)->type != 'n')
+-				fz_throw(ctx, FZ_ERROR_GENERIC, "invalid reference to an objstm that does not exist: %d (%d 0 R)", (int)entry->ofs, i);
++		{
++			/* Read this into a local variable here, because pdf_get_xref_entry
++			 * may solidify the xref, hence invalidating "entry", meaning we
++			 * need a stashed value for the throw. */
++			fz_off_t ofs = entry->ofs;
++			if (ofs <= 0 || ofs >= xref_len || pdf_get_xref_entry(ctx, doc, ofs)->type != 'n')
++				fz_throw(ctx, FZ_ERROR_GENERIC, "invalid reference to an objstm that does not exist: %d (%d 0 R)", (int)ofs, i);
++		}
+ 	}
+ }
+ 
diff --git a/gnu/packages/patches/mupdf-CVE-2016-6525.patch b/gnu/packages/patches/mupdf-CVE-2016-6525.patch
new file mode 100644
index 0000000000..370af5ade6
--- /dev/null
+++ b/gnu/packages/patches/mupdf-CVE-2016-6525.patch
@@ -0,0 +1,21 @@
+Fix CVE-2016-6525 (heap overflow in pdf_load_mesh_params()).
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-6525
+https://security-tracker.debian.org/tracker/CVE-2016-6525
+
+Patch copied from upstream source repository:
+http://git.ghostscript.com/?p=mupdf.git;h=39b0f07dd960f34e7e6bf230ffc3d87c41ef0f2e
+
+diff --git a/source/pdf/pdf-shade.c b/source/pdf/pdf-shade.c
+index 7815b3c..6e25efa 100644
+--- a/source/pdf/pdf-shade.c
++++ b/source/pdf/pdf-shade.c
+@@ -206,7 +206,7 @@ pdf_load_mesh_params(fz_context *ctx, pdf_document *doc, fz_shade *shade, pdf_ob
+ 	obj = pdf_dict_get(ctx, dict, PDF_NAME_Decode);
+ 	if (pdf_array_len(ctx, obj) >= 6)
+ 	{
+-		n = (pdf_array_len(ctx, obj) - 4) / 2;
++		n = fz_mini(FZ_MAX_COLORS, (pdf_array_len(ctx, obj) - 4) / 2);
+ 		shade->u.m.x0 = pdf_to_real(ctx, pdf_array_get(ctx, obj, 0));
+ 		shade->u.m.x1 = pdf_to_real(ctx, pdf_array_get(ctx, obj, 1));
+ 		shade->u.m.y0 = pdf_to_real(ctx, pdf_array_get(ctx, obj, 2));
diff --git a/gnu/packages/pdf.scm b/gnu/packages/pdf.scm
index f9523c6fc1..74e89070b8 100644
--- a/gnu/packages/pdf.scm
+++ b/gnu/packages/pdf.scm
@@ -474,6 +474,8 @@ extracting content or merging files.")
                             name "-" version "-source.tar.gz"))
         (sha256
           (base32 "01n26cy41lc2fjri63s4js23ixxb4nd37aafry3hz4i4id6wd8x2"))
+        (patches (search-patches "mupdf-CVE-2016-6265.patch"
+                                 "mupdf-CVE-2016-6525.patch"))
         (modules '((guix build utils)))
         (snippet
             ;; Don't build the bundled-in third party libraries.