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- From 099016b7e8d70a6d5dd814e788bba08d33d48426 Mon Sep 17 00:00:00 2001
- From: Tobias Stoeckmann <tobias@stoeckmann.org>
- Date: Mon, 4 May 2020 19:41:16 +0200
- Subject: [PATCH 1/3] Protect array_list_del_idx against size_t overflow.
- If the assignment of stop overflows due to idx and count being
- larger than SIZE_T_MAX in sum, out of boundary access could happen.
- It takes invalid usage of this function for this to happen, but
- I decided to add this check so array_list_del_idx is as safe against
- bad usage as the other arraylist functions.
- Upstream-Status: Backport [https://github.com/json-c/json-c/commit/31243e4d1204ef78be34b0fcae73221eee6b83be]
- CVE: CVE-2020-12762
- Signed-off-by: Chee Yang Lee <chee.yang.lee@intel.com>
- ---
- arraylist.c | 3 +++
- 1 file changed, 3 insertions(+)
- diff --git a/arraylist.c b/arraylist.c
- index 12ad8af6d3..e5524aca75 100644
- --- a/arraylist.c
- +++ b/arraylist.c
- @@ -136,6 +136,9 @@ int array_list_del_idx(struct array_list *arr, size_t idx, size_t count)
- {
- size_t i, stop;
-
- + /* Avoid overflow in calculation with large indices. */
- + if (idx > SIZE_T_MAX - count)
- + return -1;
- stop = idx + count;
- if (idx >= arr->length || stop > arr->length)
- return -1;
- From 77d935b7ae7871a1940cd827e850e6063044ec45 Mon Sep 17 00:00:00 2001
- From: Tobias Stoeckmann <tobias@stoeckmann.org>
- Date: Mon, 4 May 2020 19:46:45 +0200
- Subject: [PATCH 2/3] 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(+)
- diff --git a/linkhash.c b/linkhash.c
- index 7ea58c0abf..f05cc38030 100644
- --- a/linkhash.c
- +++ b/linkhash.c
- @@ -12,6 +12,7 @@
-
- #include "config.h"
-
- +#include <assert.h>
- #include <limits.h>
- #include <stdarg.h>
- #include <stddef.h>
- @@ -499,6 +500,8 @@ struct lh_table *lh_table_new(int size, lh_entry_free_fn *free_fn, lh_hash_fn *h
- 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)
- return NULL;
- From d07b91014986900a3a75f306d302e13e005e9d67 Mon Sep 17 00:00:00 2001
- From: Tobias Stoeckmann <tobias@stoeckmann.org>
- Date: Mon, 4 May 2020 19:47:25 +0200
- Subject: [PATCH 3/3] 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(-)
- diff --git a/linkhash.c b/linkhash.c
- index f05cc38030..51e90b13a2 100644
- --- a/linkhash.c
- +++ b/linkhash.c
- @@ -580,9 +580,12 @@ int lh_table_insert_w_hash(struct lh_table *t, const void *k, const void *v, con
- {
- unsigned long n;
-
- - if (t->count >= t->size * LH_LOAD_FACTOR)
- - if (lh_table_resize(t, t->size * 2) != 0)
- + if (t->count >= t->size * LH_LOAD_FACTOR) {
- + /* Avoid signed integer overflow with large tables. */
- + int new_size = INT_MAX / 2 < t->size ? t->size * 2 : INT_MAX;
- + if (t->size == INT_MAX || lh_table_resize(t, new_size) != 0)
- return -1;
- + }
-
- n = h % t->size;
-
- diff --git a/printbuf.c b/printbuf.c
- index 976c12dde5..00822fac4f 100644
- --- a/printbuf.c
- +++ b/printbuf.c
- @@ -15,6 +15,7 @@
-
- #include "config.h"
-
- +#include <limits.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- @@ -65,10 +66,16 @@ static int printbuf_extend(struct printbuf *p, int min_size)
-
- if (p->size >= min_size)
- return 0;
- -
- - new_size = p->size * 2;
- - if (new_size < 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",
- @@ -83,6 +90,9 @@ static int printbuf_extend(struct printbuf *p, int min_size)
-
- 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)
- @@ -100,6 +110,9 @@ int printbuf_memset(struct printbuf *pb, int offset, int charvalue, int len)
-
- 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)
- {
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