From 6310531fe2f75e535a8abc6e62adbd65bca5c904 Mon Sep 17 00:00:00 2001 From: Justin Humm Date: Thu, 7 Nov 2019 01:46:24 +0100 Subject: [PATCH 1/2] libexif: fix CVE-2018-20030 Also: - Use GitHub as source for CVE-2017-7544.patch [0]. The resulting patch is identical, but comes in a different format. - Update the website, as http://libexif.sourceforge.net/ shows only a move notice. - Add erictapen as maintainer. [0] https://github.com/libexif/libexif/commit/c39acd1692023b26290778a02a9232c873f9d71a --- .../libraries/libexif/CVE-2018-20030-2.patch | 115 ++++++++++++++++++ .../development/libraries/libexif/default.nix | 23 ++-- 2 files changed, 131 insertions(+), 7 deletions(-) create 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 new file mode 100644 index 000000000000..d59b071e61c7 --- /dev/null +++ b/pkgs/development/libraries/libexif/CVE-2018-20030-2.patch @@ -0,0 +1,115 @@ +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 5a8f5126680e..98556c474ef8 100644 --- a/pkgs/development/libraries/libexif/default.nix +++ b/pkgs/development/libraries/libexif/default.nix @@ -9,21 +9,30 @@ stdenv.mkDerivation rec { }; patches = [ - (fetchpatch { - name = "CVE-2017-7544.patch"; - url = https://sourceforge.net/p/libexif/bugs/_discuss/thread/fc394c4b/489a/attachment/xx.pat; - sha256 = "1qgk8hgnxr8d63jsc4vljxz9yg33mbml280dq4a6050rmk9wq4la"; - }) + (fetchpatch { + name = "CVE-2017-7544.patch"; + url = "https://github.com/libexif/libexif/commit/c39acd1692023b26290778a02a9232c873f9d71a.patch"; + sha256 = "0xgx6ly2i4q05shb61mfx6njwf1yp347jkznm0ka4m85i41xm6sd"; + }) + (fetchpatch { + name = "CVE-2018-20030-1.patch"; + 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 ]; - patchFlags = "-p0"; buildInputs = [ gettext ]; meta = { - homepage = http://libexif.sourceforge.net/; + homepage = https://libexif.github.io/; description = "A library to read and manipulate EXIF data in digital photographs"; license = stdenv.lib.licenses.lgpl21; platforms = stdenv.lib.platforms.unix; + maintainers = [ stdenv.lib.maintainers.erictapen ]; }; } 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 2/2] 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 ];