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mirror of https://git.openwrt.org/openwrt/openwrt.git synced 2024-10-18 21:48:23 +02:00

zlib: backport null dereference fix

The curl developers found test case that crashed in their testing when
using zlib patched against CVE-2022-37434, same patch we've backported
in commit 7df6795d4c25 ("zlib: backport fix for heap-based buffer
over-read (CVE-2022-37434)"). So we need to backport following patch in
order to fix issue introduced in that previous CVE-2022-37434 fix.

References: https://github.com/curl/curl/issues/9271
Fixes: 7df6795d4c25 ("zlib: backport fix for heap-based buffer over-read (CVE-2022-37434)")
Signed-off-by: Petr Štetiar <ynezz@true.cz>
This commit is contained in:
Petr Štetiar 2022-08-09 07:50:19 +02:00
parent eada892577
commit f443e9de70

@ -0,0 +1,29 @@
From 1eb7682f845ac9e9bf9ae35bbfb3bad5dacbd91d Mon Sep 17 00:00:00 2001
From: Mark Adler <fork@madler.net>
Date: Mon, 8 Aug 2022 10:50:09 -0700
Subject: [PATCH] Fix extra field processing bug that dereferences NULL
state->head.
The recent commit to fix a gzip header extra field processing bug
introduced the new bug fixed here.
---
inflate.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/inflate.c b/inflate.c
index 7a7289749..2a3c4fe98 100644
--- a/inflate.c
+++ b/inflate.c
@@ -763,10 +763,10 @@ int flush;
copy = state->length;
if (copy > have) copy = have;
if (copy) {
- len = state->head->extra_len - state->length;
if (state->head != Z_NULL &&
state->head->extra != Z_NULL &&
- len < state->head->extra_max) {
+ (len = state->head->extra_len - state->length) <
+ state->head->extra_max) {
zmemcpy(state->head->extra + len, next,
len + copy > state->head->extra_max ?
state->head->extra_max - len : copy);