linux-kernel - Re: [syzbot] [net?] KASAN: use-after-free Read in __skb_flow

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240118023348.1310-1-hdanton@sina.com>
Date: Thu, 18 Jan 2024 10:33:48 +0800
From: Hillf Danton <hdanton@...a.com>
To: syzbot <syzbot+bfde3bef047a81b8fde6@...kaller.appspotmail.com>
Cc: linux-kernel@...r.kernel.org,
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [net?] KASAN: use-after-free Read in __skb_flow_dissect (3)

On Mon, 01 Jan 2024 09:18:16 -0800
> syzbot found the following issue on:
> 
> HEAD commit:    f5837722ffec Merge tag 'mm-hotfixes-stable-2023-12-27-15-0..
> git tree:       upstream
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=122dfc65e80000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git  master

--- x/net/core/filter.c
+++ y/net/core/filter.c
@@ -2147,6 +2147,10 @@ static int __bpf_redirect_no_mac(struct
 		kfree_skb(skb);
 		return -ERANGE;
 	}
+	if (skb_headlen(skb) <= mlen + sizeof(struct iphdr)) {
+		kfree_skb(skb);
+		return -ERANGE;
+	}
 
 	if (mlen) {
 		__skb_pull(skb, mlen);
--