From 4cd9ae41c5f7fd4de6d9a2970f8243c9555428a7 Mon Sep 17 00:00:00 2001 From: Robert Marko Date: Tue, 12 May 2020 22:18:33 +0200 Subject: [PATCH] libjson-c: backport security fixes This backports upstream fixes for the out of bounds write vulnerability in json-c. It was reported and patches in this upstream PR: https://github.com/json-c/json-c/pull/592 Addresses CVE-2020-12762 Signed-off-by: Robert Marko Signed-off-by: Luka Perkov [bump PKG_RELEASE, rebase patches on top of json-c 0.12] Signed-off-by: Jo-Philipp Wich (backported from commit bc0288b76816578f5aeccb2abd679f82bfc5738e) --- package/libs/libjson-c/Makefile | 2 +- package/libs/libjson-c/patches/000-libm.patch | 2 +- ...Prevent-division-by-zero-in-linkhash.patch | 32 +++++++ .../patches/002-Fix-integer-overflows.patch | 83 +++++++++++++++++++ 4 files changed, 117 insertions(+), 2 deletions(-) create mode 100644 package/libs/libjson-c/patches/001-Prevent-division-by-zero-in-linkhash.patch create mode 100644 package/libs/libjson-c/patches/002-Fix-integer-overflows.patch diff --git a/package/libs/libjson-c/Makefile b/package/libs/libjson-c/Makefile index 23cc7b5de4..522de06984 100644 --- a/package/libs/libjson-c/Makefile +++ b/package/libs/libjson-c/Makefile @@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk PKG_NAME:=json-c PKG_VERSION:=0.12.1 -PKG_RELEASE:=3 +PKG_RELEASE:=3.1 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)-nodoc.tar.gz PKG_SOURCE_URL:=https://s3.amazonaws.com/json-c_releases/releases/ diff --git a/package/libs/libjson-c/patches/000-libm.patch b/package/libs/libjson-c/patches/000-libm.patch index 45adb0597f..e196b422fa 100644 --- a/package/libs/libjson-c/patches/000-libm.patch +++ b/package/libs/libjson-c/patches/000-libm.patch @@ -1,6 +1,6 @@ --- a/configure.ac +++ b/configure.ac -@@ -43,12 +43,6 @@ +@@ -43,12 +43,6 @@ AC_FUNC_MEMCMP AC_FUNC_MALLOC AC_FUNC_REALLOC AC_CHECK_FUNCS(strcasecmp strdup strerror snprintf vsnprintf vasprintf open vsyslog strncasecmp setlocale) diff --git a/package/libs/libjson-c/patches/001-Prevent-division-by-zero-in-linkhash.patch b/package/libs/libjson-c/patches/001-Prevent-division-by-zero-in-linkhash.patch new file mode 100644 index 0000000000..5345328d7c --- /dev/null +++ b/package/libs/libjson-c/patches/001-Prevent-division-by-zero-in-linkhash.patch @@ -0,0 +1,32 @@ +From 77d935b7ae7871a1940cd827e850e6063044ec45 Mon Sep 17 00:00:00 2001 +From: Tobias Stoeckmann +Date: Mon, 4 May 2020 19:46:45 +0200 +Subject: [PATCH 2/2] Prevent division by zero in linkhash. + +If a linkhash with a size of zero is created, then modulo operations +are prone to division by zero operations. + +Purely protective measure against bad usage. +--- + linkhash.c | 3 +++ + 1 file changed, 3 insertions(+) + +--- a/linkhash.c ++++ b/linkhash.c +@@ -10,6 +10,7 @@ + * + */ + ++#include + #include + #include + #include +@@ -431,6 +432,8 @@ struct lh_table* lh_table_new(int size, + int i; + struct lh_table *t; + ++ /* Allocate space for elements to avoid divisions by zero. */ ++ assert(size > 0); + t = (struct lh_table*)calloc(1, sizeof(struct lh_table)); + if(!t) lh_abort("lh_table_new: calloc failed\n"); + t->count = 0; diff --git a/package/libs/libjson-c/patches/002-Fix-integer-overflows.patch b/package/libs/libjson-c/patches/002-Fix-integer-overflows.patch new file mode 100644 index 0000000000..2298785b9c --- /dev/null +++ b/package/libs/libjson-c/patches/002-Fix-integer-overflows.patch @@ -0,0 +1,83 @@ +From d07b91014986900a3a75f306d302e13e005e9d67 Mon Sep 17 00:00:00 2001 +From: Tobias Stoeckmann +Date: Mon, 4 May 2020 19:47:25 +0200 +Subject: [PATCH] Fix integer overflows. + +The data structures linkhash and printbuf are limited to 2 GB in size +due to a signed integer being used to track their current size. + +If too much data is added, then size variable can overflow, which is +an undefined behaviour in C programming language. + +Assuming that a signed int overflow just leads to a negative value, +like it happens on many sytems (Linux i686/amd64 with gcc), then +printbuf is vulnerable to an out of boundary write on 64 bit systems. +--- + linkhash.c | 7 +++++-- + printbuf.c | 19 ++++++++++++++++--- + 2 files changed, 21 insertions(+), 5 deletions(-) + +--- a/linkhash.c ++++ b/linkhash.c +@@ -498,7 +498,12 @@ int lh_table_insert(struct lh_table *t, + unsigned long h, n; + + t->inserts++; +- if(t->count >= t->size * LH_LOAD_FACTOR) lh_table_resize(t, t->size * 2); ++ if(t->count >= t->size * LH_LOAD_FACTOR) { ++ /* Avoid signed integer overflow with large tables. */ ++ int new_size = (t->size > INT_MAX / 2) ? INT_MAX : (t->size * 2); ++ if (t->size != INT_MAX) ++ lh_table_resize(t, new_size); ++ } + + h = t->hash_fn(k); + n = h % t->size; +--- a/printbuf.c ++++ b/printbuf.c +@@ -15,6 +15,7 @@ + + #include "config.h" + ++#include + #include + #include + #include +@@ -63,7 +64,16 @@ static int printbuf_extend(struct printb + if (p->size >= min_size) + return 0; + +- new_size = json_max(p->size * 2, min_size + 8); ++ /* Prevent signed integer overflows with large buffers. */ ++ if (min_size > INT_MAX - 8) ++ return -1; ++ if (p->size > INT_MAX / 2) ++ new_size = min_size + 8; ++ else { ++ new_size = p->size * 2; ++ if (new_size < min_size + 8) ++ new_size = min_size + 8; ++ } + #ifdef PRINTBUF_DEBUG + MC_DEBUG("printbuf_memappend: realloc " + "bpos=%d min_size=%d old_size=%d new_size=%d\n", +@@ -78,6 +88,9 @@ static int printbuf_extend(struct printb + + int printbuf_memappend(struct printbuf *p, const char *buf, int size) + { ++ /* Prevent signed integer overflows with large buffers. */ ++ if (size > INT_MAX - p->bpos - 1) ++ return -1; + if (p->size <= p->bpos + size + 1) { + if (printbuf_extend(p, p->bpos + size + 1) < 0) + return -1; +@@ -94,6 +107,9 @@ int printbuf_memset(struct printbuf *pb, + + if (offset == -1) + offset = pb->bpos; ++ /* Prevent signed integer overflows with large buffers. */ ++ if (len > INT_MAX - offset) ++ return -1; + size_needed = offset + len; + if (pb->size < size_needed) + { -- 2.30.2