From 233f36303bf205e23d1419165c107b1c9c0a0512 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Vladim=C3=ADr=20=C4=8Cun=C3=A1t?= Date: Sat, 16 Nov 2019 18:22:59 +0100 Subject: [PATCH] libexif: convert to fetchpatch --- .../libraries/libexif/CVE-2018-20030-2.patch | 115 ------------------ .../development/libraries/libexif/default.nix | 10 +- 2 files changed, 6 insertions(+), 119 deletions(-) delete mode 100644 pkgs/development/libraries/libexif/CVE-2018-20030-2.patch diff --git a/pkgs/development/libraries/libexif/CVE-2018-20030-2.patch b/pkgs/development/libraries/libexif/CVE-2018-20030-2.patch deleted file mode 100644 index d59b071e61c7..000000000000 --- a/pkgs/development/libraries/libexif/CVE-2018-20030-2.patch +++ /dev/null @@ -1,115 +0,0 @@ -From 6aa11df549114ebda520dde4cdaea2f9357b2c89 Mon Sep 17 00:00:00 2001 -From: Dan Fandrich -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 - #include - -+#include - #include - #include - #include -@@ -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 > 12) { -+ 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/pkgs/development/libraries/libexif/default.nix b/pkgs/development/libraries/libexif/default.nix index 98556c474ef8..833ccf5dca5d 100644 --- a/pkgs/development/libraries/libexif/default.nix +++ b/pkgs/development/libraries/libexif/default.nix @@ -19,10 +19,12 @@ stdenv.mkDerivation rec { url = "https://github.com/libexif/libexif/commit/5d28011c40ec86cf52cffad541093d37c263898a.patch"; sha256 = "1wv8s962wmbn2m2xypgirf12g6msrbplpsmd5bh86irfwhkcppj3"; }) - # This is basically - # https://github.com/libexif/libexif/commit/6aa11df549114ebda520dde4cdaea2f9357b2c89.patch, - # but without the addition to ./NEWS - ./CVE-2018-20030-2.patch + (fetchpatch { + name = "CVE-2018-20030-2.patch"; + url = "https://github.com/libexif/libexif/commit/6aa11df549114ebda520dde4cdaea2f9357b2c89.patch"; + sha256 = "01aqvz63glwq6wg0wr7ykqqghb4abgq77ghvhizbzadg1k4h7drx"; + excludes = [ "NEWS" ]; + }) ]; buildInputs = [ gettext ];