libexif: fix CVE-2018-20030.
This commit is contained in:
travankor
Helmut Pozimski
parent
bf28959df2
commit
4f7dddad21
|
|
@ -1,6 +1,21 @@
|
|||
--- libexif/exif-data.c 12 Jul 2012 17:28:26 -0000 1.131
|
||||
+++ libexif/exif-data.c 25 Jul 2017 21:34:06 -0000
|
||||
@@ -255,6 +255,12 @@
|
||||
From c39acd1692023b26290778a02a9232c873f9d71a Mon Sep 17 00:00:00 2001
|
||||
From: Marcus Meissner <marcus@jet.franken.de>
|
||||
Date: Tue, 25 Jul 2017 23:38:56 +0200
|
||||
Subject: [PATCH] On saving makernotes, make sure the makernote container tags
|
||||
has a type with 1 byte components.
|
||||
|
||||
Fixes (at least):
|
||||
https://sourceforge.net/p/libexif/bugs/130
|
||||
https://sourceforge.net/p/libexif/bugs/129
|
||||
---
|
||||
libexif/exif-data.c | 6 ++++++
|
||||
1 file changed, 6 insertions(+)
|
||||
|
||||
diff --git a/libexif/exif-data.c b/libexif/exif-data.c
|
||||
index 67df4db..91f4c33 100644
|
||||
--- a/libexif/exif-data.c
|
||||
+++ b/libexif/exif-data.c
|
||||
@@ -255,6 +255,12 @@ exif_data_save_data_entry (ExifData *data, ExifEntry *e,
|
||||
exif_mnote_data_set_offset (data->priv->md, *ds - 6);
|
||||
exif_mnote_data_save (data->priv->md, &e->data, &e->size);
|
||||
e->components = e->size;
|
||||
|
|
@ -12,4 +27,3 @@
|
|||
+ }
|
||||
}
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,115 @@
|
|||
From 6aa11df549114ebda520dde4cdaea2f9357b2c89 Mon Sep 17 00:00:00 2001
|
||||
From: Dan Fandrich <dan@coneharvesters.com>
|
||||
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;
|
||||
|
|
@ -1,7 +1,7 @@
|
|||
# Template file for 'libexif'
|
||||
pkgname=libexif
|
||||
version=0.6.21
|
||||
revision=5
|
||||
revision=6
|
||||
build_style=gnu-configure
|
||||
configure_args="ac_cv_path_DOXYGEN=false"
|
||||
short_desc="EXIF file library"
|
||||
|
|
@ -10,6 +10,7 @@ license="LGPL-2.1-or-later"
|
|||
homepage="http://sourceforge.net/projects/libexif"
|
||||
distfiles="${SOURCEFORGE_SITE}/${pkgname}/${pkgname}-${version}.tar.bz2"
|
||||
checksum=16cdaeb62eb3e6dfab2435f7d7bccd2f37438d21c5218ec4e58efa9157d4d41a
|
||||
patch_args="-Np1"
|
||||
|
||||
libexif-devel_package() {
|
||||
depends="${sourcepkg}>=${version}_${revision}"
|
||||
|
|
|
|||
Loading…
Reference in New Issue