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03/04: gnu: libexif: Fix CVE-2018-20030.
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From: |
guix-commits |
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Subject: |
03/04: gnu: libexif: Fix CVE-2018-20030. |
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Date: |
Wed, 10 Jul 2019 14:34:26 -0400 (EDT) |
efraim pushed a commit to branch master
in repository guix.
commit 5a4e5c26cc3fb24e0e7f6a2d95f03396f3d0b014
Author: Efraim Flashner <address@hidden>
Date: Wed Jul 10 14:27:51 2019 +0300
gnu: libexif: Fix CVE-2018-20030.
* gnu/packages/photo.scm (libexif)[source]: Add patch.
* gnu/packages/patches/libexif-CVE-2018-20030.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register it.
---
gnu/local.mk | 1 +
gnu/packages/patches/libexif-CVE-2018-20030.patch | 120 ++++++++++++++++++++++
gnu/packages/photo.scm | 5 +-
3 files changed, 124 insertions(+), 2 deletions(-)
diff --git a/gnu/local.mk b/gnu/local.mk
index 2821cdc..66f9042 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1006,6 +1006,7 @@ dist_patch_DATA =
\
%D%/packages/patches/libdrm-symbol-check.patch \
%D%/packages/patches/libexif-CVE-2016-6328.patch \
%D%/packages/patches/libexif-CVE-2017-7544.patch \
+ %D%/packages/patches/libexif-CVE-2018-20030.patch \
%D%/packages/patches/libgcrypt-make-yat2m-reproducible.patch \
%D%/packages/patches/libgit2-avoid-python.patch \
%D%/packages/patches/libgit2-mtime-0.patch \
diff --git a/gnu/packages/patches/libexif-CVE-2018-20030.patch
b/gnu/packages/patches/libexif-CVE-2018-20030.patch
new file mode 100644
index 0000000..57e4746
--- /dev/null
+++ b/gnu/packages/patches/libexif-CVE-2018-20030.patch
@@ -0,0 +1,120 @@
+https://github.com/libexif/libexif/commit/6aa11df549114ebda520dde4cdaea2f9357b2c89.patch
+
+NEWS section was removed
+'12' -> '30' on line 79
+
+From 6aa11df549114ebda520dde4cdaea2f9357b2c89 Mon Sep 17 00:00:00 2001
+From: Dan Fandrich <address@hidden>
+Date: Fri, 12 Oct 2018 16:01:45 +0200
+Subject: [PATCH] Improve deep recursion detection in
+ exif_data_load_data_content.
+
+The existing detection was still vulnerable to pathological cases
+causing DoS by wasting CPU. The new algorithm takes the number of tags
+into account to make it harder to abuse by cases using shallow recursion
+but with a very large number of tags. This improves on commit 5d28011c
+which wasn't sufficient to counter this kind of case.
+
+The limitation in the previous fix was discovered by Laurent Delosieres,
+Secunia Research at Flexera (Secunia Advisory SA84652) and is assigned
+the identifier CVE-2018-20030.
+---
+ NEWS | 1 +
+ libexif/exif-data.c | 45 +++++++++++++++++++++++++++++++++++++--------
+ 2 files changed, 38 insertions(+), 8 deletions(-)
+
+diff --git a/libexif/exif-data.c b/libexif/exif-data.c
+index e35403d..a6f9c94 100644
+--- a/libexif/exif-data.c
++++ b/libexif/exif-data.c
+@@ -35,6 +35,7 @@
+ #include <libexif/olympus/exif-mnote-data-olympus.h>
+ #include <libexif/pentax/exif-mnote-data-pentax.h>
+
++#include <math.h>
+ #include <stdlib.h>
+ #include <stdio.h>
+ #include <string.h>
+@@ -350,6 +351,20 @@ if (data->ifd[(i)]->count) {
\
+ break; \
+ }
+
++/*! Calculate the recursion cost added by one level of IFD loading.
++ *
++ * The work performed is related to the cost in the exponential relation
++ * work=1.1**cost
++ */
++static unsigned int
++level_cost(unsigned int n)
++{
++ static const double log_1_1 = 0.09531017980432493;
++
++ /* Adding 0.1 protects against the case where n==1 */
++ return ceil(log(n + 0.1)/log_1_1);
++}
++
+ /*! Load data for an IFD.
+ *
+ * \param[in,out] data #ExifData
+@@ -357,13 +372,13 @@ if (data->ifd[(i)]->count) {
\
+ * \param[in] d pointer to buffer containing raw IFD data
+ * \param[in] ds size of raw data in buffer at \c d
+ * \param[in] offset offset into buffer at \c d at which IFD starts
+- * \param[in] recursion_depth number of times this function has been
+- * recursively called without returning
++ * \param[in] recursion_cost factor indicating how expensive this recursive
++ * call could be
+ */
+ static void
+ exif_data_load_data_content (ExifData *data, ExifIfd ifd,
+ const unsigned char *d,
+- unsigned int ds, unsigned int offset, unsigned int
recursion_depth)
++ unsigned int ds, unsigned int offset, unsigned int
recursion_cost)
+ {
+ ExifLong o, thumbnail_offset = 0, thumbnail_length = 0;
+ ExifShort n;
+@@ -378,9 +393,20 @@ exif_data_load_data_content (ExifData *data, ExifIfd ifd,
+ if ((((int)ifd) < 0) || ( ((int)ifd) >= EXIF_IFD_COUNT))
+ return;
+
+- if (recursion_depth > 30) {
++ if (recursion_cost > 170) {
++ /*
++ * recursion_cost is a logarithmic-scale indicator of how
expensive this
++ * recursive call might end up being. It is an indicator of the
depth of
++ * recursion as well as the potential for worst-case future
recursive
++ * calls. Since it's difficult to tell ahead of time how often
recursion
++ * will occur, this assumes the worst by assuming every tag
could end up
++ * causing recursion.
++ * The value of 170 was chosen to limit typical EXIF structures
to a
++ * recursive depth of about 6, but pathological ones (those
with very
++ * many tags) to only 2.
++ */
+ exif_log (data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA,
"ExifData",
+- "Deep recursion detected!");
++ "Deep/expensive recursion detected!");
+ return;
+ }
+
+@@ -422,15 +448,18 @@ exif_data_load_data_content (ExifData *data, ExifIfd ifd,
+ switch (tag) {
+ case EXIF_TAG_EXIF_IFD_POINTER:
+ CHECK_REC (EXIF_IFD_EXIF);
+- exif_data_load_data_content (data,
EXIF_IFD_EXIF, d, ds, o, recursion_depth + 1);
++ exif_data_load_data_content (data,
EXIF_IFD_EXIF, d, ds, o,
++ recursion_cost + level_cost(n));
+ break;
+ case EXIF_TAG_GPS_INFO_IFD_POINTER:
+ CHECK_REC (EXIF_IFD_GPS);
+- exif_data_load_data_content (data,
EXIF_IFD_GPS, d, ds, o, recursion_depth + 1);
++ exif_data_load_data_content (data,
EXIF_IFD_GPS, d, ds, o,
++ recursion_cost + level_cost(n));
+ break;
+ case EXIF_TAG_INTEROPERABILITY_IFD_POINTER:
+ CHECK_REC (EXIF_IFD_INTEROPERABILITY);
+- exif_data_load_data_content (data,
EXIF_IFD_INTEROPERABILITY, d, ds, o, recursion_depth + 1);
++ exif_data_load_data_content (data,
EXIF_IFD_INTEROPERABILITY, d, ds, o,
++ recursion_cost + level_cost(n));
+ break;
+ case EXIF_TAG_JPEG_INTERCHANGE_FORMAT:
+ thumbnail_offset = o;
diff --git a/gnu/packages/photo.scm b/gnu/packages/photo.scm
index cf7da80..cbfc2de 100644
--- a/gnu/packages/photo.scm
+++ b/gnu/packages/photo.scm
@@ -2,7 +2,7 @@
;;; Copyright © 2014, 2015, 2017, 2019 Ludovic Courtès <address@hidden>
;;; Copyright © 2015 Ricardo Wurmus <address@hidden>
;;; Copyright © 2015, 2017 Andreas Enge <address@hidden>
-;;; Copyright © 2016, 2017, 2018 Efraim Flashner <address@hidden>
+;;; Copyright © 2016, 2017, 2018, 2019 Efraim Flashner <address@hidden>
;;; Copyright © 2017 Roel Janssen <address@hidden>
;;; Copyright © 2018, 2019 Tobias Geerinckx-Rice <address@hidden>
;;; Copyright © 2018 Leo Famulari <address@hidden>
@@ -117,7 +117,8 @@ cameras (CRW/CR2, NEF, RAF, DNG, and others).")
(uri (string-append "mirror://sourceforge/libexif/libexif/"
version "/libexif-" version ".tar.bz2"))
(patches (search-patches "libexif-CVE-2016-6328.patch"
- "libexif-CVE-2017-7544.patch"))
+ "libexif-CVE-2017-7544.patch"
+ "libexif-CVE-2018-20030.patch"))
(sha256
(base32
"06nlsibr3ylfwp28w8f5466l6drgrnydgxrm4jmxzrmk5svaxk8n"))))