mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-26 08:51:13 +00:00
84 lines
2.5 KiB
Diff
84 lines
2.5 KiB
Diff
|
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] 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 <limits.h>
|
||
|
#include <stdio.h>
|
||
|
#include <stdlib.h>
|
||
|
#include <string.h>
|
||
|
@@ -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)
|
||
|
{
|