diff options
Diffstat (limited to 'meta/recipes-support/libexif/libexif/CVE-2018-20030.patch')
| -rw-r--r-- | meta/recipes-support/libexif/libexif/CVE-2018-20030.patch | 115 |
1 files changed, 0 insertions, 115 deletions
diff --git a/meta/recipes-support/libexif/libexif/CVE-2018-20030.patch b/meta/recipes-support/libexif/libexif/CVE-2018-20030.patch deleted file mode 100644 index 76233e6dc9..0000000000 --- a/meta/recipes-support/libexif/libexif/CVE-2018-20030.patch +++ /dev/null @@ -1,115 +0,0 @@ -CVE: CVE-2018-20030 -Upstream-Status: Backport -Signed-off-by: Ross Burton <ross.burton@intel.com> - -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. - -diff --git a/libexif/exif-data.c b/libexif/exif-data.c -index 67df4db..8d9897e 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> -@@ -344,6 +345,20 @@ 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 -@@ -351,13 +366,13 @@ 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; -@@ -372,9 +387,20 @@ 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; - } - -@@ -416,15 +442,18 @@ 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; |