diff options
Diffstat (limited to 'gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch')
| -rw-r--r-- | gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch b/gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch new file mode 100644 index 0000000000..edc43f84f1 --- /dev/null +++ b/gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch @@ -0,0 +1,142 @@ +Fix CVE-2012-6702 and CVE-2016-5300. + +https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-6702 +https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5300 + +Patch copied from: +https://sources.debian.net/src/expat/2.1.0-6%2Bdeb8u3/debian/patches/cve-2012-6702-plus-cve-2016-5300-v1.patch/ + +From cb31522769d11a375078a073cba94e7176cb48a4 Mon Sep 17 00:00:00 2001 +From: Sebastian Pipping <sebastian@pipping.org> +Date: Wed, 16 Mar 2016 15:30:12 +0100 +Subject: [PATCH] Resolve call to srand, use more entropy (patch version 1.0) + +Squashed backport against vanilla Expat 2.1.1, addressing: +* CVE-2012-6702 -- unanticipated internal calls to srand +* CVE-2016-5300 -- use of too little entropy + +Since commit e3e81a6d9f0885ea02d3979151c358f314bf3d6d +(released with Expat 2.1.0) Expat called srand by itself +from inside generate_hash_secret_salt for an instance +of XML_Parser if XML_SetHashSalt was either (a) not called +for that instance or if (b) salt 0 was passed to XML_SetHashSalt +prior to parsing. That call to srand passed (rather litle) +entropy extracted from the current time as a seed for srand. + +That call to srand (1) broke repeatability for code calling +srand with a non-random seed prior to parsing with Expat, +and (2) resulted in a rather small set of hashing salts in +Expat in total. + +For a short- to mid-term fix, the new approach avoids calling +srand altogether, extracts more entropy out of the clock and +other sources, too. + +For a long term fix, we may want to read sizeof(long) bytes +from a source like getrandom(..) on Linux, and from similar +sources on other supported architectures. + +https://bugzilla.redhat.com/show_bug.cgi?id=1197087 +--- + CMakeLists.txt | 3 +++ + lib/xmlparse.c | 48 +++++++++++++++++++++++++++++++++++++++++------- + 2 files changed, 44 insertions(+), 7 deletions(-) + +diff --git a/CMakeLists.txt b/CMakeLists.txt +index 353627e..524d514 100755 +--- a/CMakeLists.txt ++++ b/CMakeLists.txt +@@ -41,6 +41,9 @@ include_directories(${CMAKE_BINARY_DIR} ${CMAKE_SOURCE_DIR}/lib) + if(MSVC) + add_definitions(-D_CRT_SECURE_NO_WARNINGS -wd4996) + endif(MSVC) ++if(WIN32) ++ add_definitions(-DCOMPILED_FROM_DSP) ++endif(WIN32) + + set(expat_SRCS + lib/xmlparse.c +diff --git a/lib/xmlparse.c b/lib/xmlparse.c +index e308c79..c5f942f 100644 +--- a/lib/xmlparse.c ++++ b/lib/xmlparse.c +@@ -6,7 +6,14 @@ + #include <string.h> /* memset(), memcpy() */ + #include <assert.h> + #include <limits.h> /* UINT_MAX */ +-#include <time.h> /* time() */ ++ ++#ifdef COMPILED_FROM_DSP ++#define getpid GetCurrentProcessId ++#else ++#include <sys/time.h> /* gettimeofday() */ ++#include <sys/types.h> /* getpid() */ ++#include <unistd.h> /* getpid() */ ++#endif + + #define XML_BUILDING_EXPAT 1 + +@@ -432,7 +439,7 @@ static ELEMENT_TYPE * + getElementType(XML_Parser parser, const ENCODING *enc, + const char *ptr, const char *end); + +-static unsigned long generate_hash_secret_salt(void); ++static unsigned long generate_hash_secret_salt(XML_Parser parser); + static XML_Bool startParsing(XML_Parser parser); + + static XML_Parser +@@ -691,11 +698,38 @@ static const XML_Char implicitContext[] = { + }; + + static unsigned long +-generate_hash_secret_salt(void) ++gather_time_entropy(void) + { +- unsigned int seed = time(NULL) % UINT_MAX; +- srand(seed); +- return rand(); ++#ifdef COMPILED_FROM_DSP ++ FILETIME ft; ++ GetSystemTimeAsFileTime(&ft); /* never fails */ ++ return ft.dwHighDateTime ^ ft.dwLowDateTime; ++#else ++ struct timeval tv; ++ int gettimeofday_res; ++ ++ gettimeofday_res = gettimeofday(&tv, NULL); ++ assert (gettimeofday_res == 0); ++ ++ /* Microseconds time is <20 bits entropy */ ++ return tv.tv_usec; ++#endif ++} ++ ++static unsigned long ++generate_hash_secret_salt(XML_Parser parser) ++{ ++ /* Process ID is 0 bits entropy if attacker has local access ++ * XML_Parser address is few bits of entropy if attacker has local access */ ++ const unsigned long entropy = ++ gather_time_entropy() ^ getpid() ^ (unsigned long)parser; ++ ++ /* Factors are 2^31-1 and 2^61-1 (Mersenne primes M31 and M61) */ ++ if (sizeof(unsigned long) == 4) { ++ return entropy * 2147483647; ++ } else { ++ return entropy * 2305843009213693951; ++ } + } + + static XML_Bool /* only valid for root parser */ +@@ -703,7 +737,7 @@ startParsing(XML_Parser parser) + { + /* hash functions must be initialized before setContext() is called */ + if (hash_secret_salt == 0) +- hash_secret_salt = generate_hash_secret_salt(); ++ hash_secret_salt = generate_hash_secret_salt(parser); + if (ns) { + /* implicit context only set for root parser, since child + parsers (i.e. external entity parsers) will inherit it +-- +2.8.2 + |