67 lines
1.9 KiB
Diff
67 lines
1.9 KiB
Diff
From f51fcd59a8bbeb60eaf8ae0e398556be2fa3317a Mon Sep 17 00:00:00 2001
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From: Wang Haitao <wanghaitao.ouyang@foxmail.com>
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Date: Tue, 14 Mar 2023 22:25:54 +0800
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Subject: [PATCH] Fix CVE-2020-12762
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reference: https://github.com/json-c/json-c/pull/592/files
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I reproduce this CVE using the code from https://github.com/json-c/json-c/pull/592
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And it fix it and no more segmentation fault
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---
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printbuf.c | 20 +++++++++++++++++---
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1 file changed, 17 insertions(+), 3 deletions(-)
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diff --git a/printbuf.c b/printbuf.c
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index e9cde11..b02a363 100644
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--- a/printbuf.c
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+++ b/printbuf.c
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@@ -13,6 +13,7 @@
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#include "config.h"
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+#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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@@ -68,9 +69,16 @@ static int printbuf_extend(struct printbuf *p, int min_size)
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if (p->size >= min_size)
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return 0;
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- new_size = p->size * 2;
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- if (new_size < min_size + 8)
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- new_size = min_size + 8;
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+ /* Prevent signed integer overflows with large buffers. */
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+ if (min_size > INT_MAX - 8)
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+ return -1;
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+ if (p->size > INT_MAX / 2)
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+ new_size = min_size + 8;
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+ else {
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+ new_size = p->size * 2;
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+ if (new_size < min_size + 8)
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+ new_size = min_size + 8;
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+ }
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#ifdef PRINTBUF_DEBUG
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MC_DEBUG("printbuf_memappend: realloc "
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"bpos=%d min_size=%d old_size=%d new_size=%d\n",
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@@ -85,6 +93,9 @@ static int printbuf_extend(struct printbuf *p, int min_size)
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int printbuf_memappend(struct printbuf *p, const char *buf, int size)
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{
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+ /* Prevent signed integer overflows with large buffers. */
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+ if (size > INT_MAX - p->bpos - 1)
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+ return -1;
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if (p->size <= p->bpos + size + 1) {
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if (printbuf_extend(p, p->bpos + size + 1) < 0)
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return -1;
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@@ -136,6 +147,9 @@ int printbuf_memset(struct printbuf *pb, int offset, int charvalue, int len)
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if (offset == -1)
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offset = pb->bpos;
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+ /* Prevent signed integer overflows with large buffers. */
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+ if (len > INT_MAX - offset)
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+ return -1;
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size_needed = offset + len;
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if (pb->size < size_needed)
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{
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