linux-kernel - Re: [PATCH] bpf: Fix out-of-bounds write in trie_get_next

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: <CAADnVQ+Ow2E8qghEZw6x63VS4gM5rDtbM9R-ob00Rha2yBvfgA@mail.gmail.com>
Date: Tue, 22 Oct 2024 12:51:05 -0700
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: Byeonguk Jeong <jungbu2855@...il.com>
Cc: Daniel Borkmann <daniel@...earbox.net>, Yonghong Song <yonghong.song@...ux.dev>, 
	bpf <bpf@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] bpf: Fix out-of-bounds write in trie_get_next_key()

On Mon, Oct 21, 2024 at 6:49 PM Byeonguk Jeong <jungbu2855@...il.com> wrote:
>
> trie_get_next_key() allocates a node stack with size trie->max_prefixlen,
> while it writes (trie->max_prefixlen + 1) nodes to the stack when it has
> full paths from the root to leaves. For example, consider a trie with
> max_prefixlen is 8, and the nodes with key 0x00/0, 0x00/1, 0x00/2, ...
> 0x00/8 inserted. Subsequent calls to trie_get_next_key with _key with
> .prefixlen = 8 make 9 nodes be written on the node stack with size 8.

Hmm. It sounds possible, but pls demonstrate it with a selftest.
With the amount of fuzzing I'm surprised it was not discovered earlier.

pw-bot: cr