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@@ -1,115 +0,0 @@
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-CVE: CVE-2018-20030
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-Upstream-Status: Backport
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-Signed-off-by: Ross Burton <ross.burton@intel.com>
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-
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-From 6aa11df549114ebda520dde4cdaea2f9357b2c89 Mon Sep 17 00:00:00 2001
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-From: Dan Fandrich <dan@coneharvesters.com>
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-Date: Fri, 12 Oct 2018 16:01:45 +0200
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-Subject: [PATCH] Improve deep recursion detection in
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- exif_data_load_data_content.
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-
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-The existing detection was still vulnerable to pathological cases
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-causing DoS by wasting CPU. The new algorithm takes the number of tags
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-into account to make it harder to abuse by cases using shallow recursion
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-but with a very large number of tags. This improves on commit 5d28011c
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-which wasn't sufficient to counter this kind of case.
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-
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-The limitation in the previous fix was discovered by Laurent Delosieres,
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-Secunia Research at Flexera (Secunia Advisory SA84652) and is assigned
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-the identifier CVE-2018-20030.
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-
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-diff --git a/libexif/exif-data.c b/libexif/exif-data.c
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-index 67df4db..8d9897e 100644
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---- a/libexif/exif-data.c
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-+++ b/libexif/exif-data.c
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-@@ -35,6 +35,7 @@
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- #include <libexif/olympus/exif-mnote-data-olympus.h>
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- #include <libexif/pentax/exif-mnote-data-pentax.h>
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-
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-+#include <math.h>
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- #include <stdlib.h>
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- #include <stdio.h>
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- #include <string.h>
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-@@ -344,6 +345,20 @@ if (data->ifd[(i)]->count) { \
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- break; \
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- }
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-
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-+/*! Calculate the recursion cost added by one level of IFD loading.
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-+ *
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-+ * The work performed is related to the cost in the exponential relation
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-+ * work=1.1**cost
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-+ */
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-+static unsigned int
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-+level_cost(unsigned int n)
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-+{
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-+ static const double log_1_1 = 0.09531017980432493;
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-+
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-+ /* Adding 0.1 protects against the case where n==1 */
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-+ return ceil(log(n + 0.1)/log_1_1);
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-+}
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-+
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- /*! Load data for an IFD.
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- *
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- * \param[in,out] data #ExifData
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-@@ -351,13 +366,13 @@ if (data->ifd[(i)]->count) { \
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- * \param[in] d pointer to buffer containing raw IFD data
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- * \param[in] ds size of raw data in buffer at \c d
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- * \param[in] offset offset into buffer at \c d at which IFD starts
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-- * \param[in] recursion_depth number of times this function has been
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-- * recursively called without returning
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-+ * \param[in] recursion_cost factor indicating how expensive this recursive
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-+ * call could be
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- */
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- static void
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- exif_data_load_data_content (ExifData *data, ExifIfd ifd,
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- const unsigned char *d,
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-- unsigned int ds, unsigned int offset, unsigned int recursion_depth)
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-+ unsigned int ds, unsigned int offset, unsigned int recursion_cost)
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- {
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- ExifLong o, thumbnail_offset = 0, thumbnail_length = 0;
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- ExifShort n;
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-@@ -372,9 +387,20 @@ exif_data_load_data_content (ExifData *data, ExifIfd ifd,
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- if ((((int)ifd) < 0) || ( ((int)ifd) >= EXIF_IFD_COUNT))
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- return;
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-
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-- if (recursion_depth > 30) {
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-+ if (recursion_cost > 170) {
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-+ /*
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-+ * recursion_cost is a logarithmic-scale indicator of how expensive this
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-+ * recursive call might end up being. It is an indicator of the depth of
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-+ * recursion as well as the potential for worst-case future recursive
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-+ * calls. Since it's difficult to tell ahead of time how often recursion
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-+ * will occur, this assumes the worst by assuming every tag could end up
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-+ * causing recursion.
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-+ * The value of 170 was chosen to limit typical EXIF structures to a
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-+ * recursive depth of about 6, but pathological ones (those with very
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-+ * many tags) to only 2.
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-+ */
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- exif_log (data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifData",
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-- "Deep recursion detected!");
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-+ "Deep/expensive recursion detected!");
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- return;
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- }
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-
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-@@ -416,15 +442,18 @@ exif_data_load_data_content (ExifData *data, ExifIfd ifd,
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- switch (tag) {
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- case EXIF_TAG_EXIF_IFD_POINTER:
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- CHECK_REC (EXIF_IFD_EXIF);
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-- exif_data_load_data_content (data, EXIF_IFD_EXIF, d, ds, o, recursion_depth + 1);
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-+ exif_data_load_data_content (data, EXIF_IFD_EXIF, d, ds, o,
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-+ recursion_cost + level_cost(n));
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- break;
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- case EXIF_TAG_GPS_INFO_IFD_POINTER:
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- CHECK_REC (EXIF_IFD_GPS);
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-- exif_data_load_data_content (data, EXIF_IFD_GPS, d, ds, o, recursion_depth + 1);
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-+ exif_data_load_data_content (data, EXIF_IFD_GPS, d, ds, o,
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-+ recursion_cost + level_cost(n));
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- break;
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- case EXIF_TAG_INTEROPERABILITY_IFD_POINTER:
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- CHECK_REC (EXIF_IFD_INTEROPERABILITY);
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-- exif_data_load_data_content (data, EXIF_IFD_INTEROPERABILITY, d, ds, o, recursion_depth + 1);
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-+ exif_data_load_data_content (data, EXIF_IFD_INTEROPERABILITY, d, ds, o,
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-+ recursion_cost + level_cost(n));
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- break;
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- case EXIF_TAG_JPEG_INTERCHANGE_FORMAT:
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- thumbnail_offset = o;
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