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From: "Toke Høiland-Jørgensen" <toke@kernel.org>
To: Byeonguk Jeong <jungbu2855@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Yonghong Song <yonghong.song@linux.dev>
Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] bpf: Fix out-of-bounds write in trie_get_next_key()
Date: Tue, 22 Oct 2024 11:43:41 +0200	[thread overview]
Message-ID: <87a5ewiib6.fsf@toke.dk> (raw)
In-Reply-To: <ZxcDzT/iv/f0Gyz0@localhost.localdomain>

Byeonguk Jeong <jungbu2855@gmail.com> writes:

> 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.
>
> Fixes: b471f2f1de8b ("bpf: implement MAP_GET_NEXT_KEY command for LPM_TRIE map")
> Signed-off-by: Byeonguk Jeong <jungbu2855@gmail.com>

Makes sense!

Reviewed-by: Toke Høiland-Jørgensen <toke@kernel.org>

  reply	other threads:[~2024-10-22  9:43 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-22  1:45 [PATCH] bpf: Fix out-of-bounds write in trie_get_next_key() Byeonguk Jeong
2024-10-22  9:43 ` Toke Høiland-Jørgensen [this message]
2024-10-22 19:51 ` Alexei Starovoitov
2024-10-23  1:29   ` Byeonguk Jeong
2024-10-23  8:44   ` Byeonguk Jeong
2024-10-23  2:03 ` Hou Tao
2024-10-23  7:30   ` Byeonguk Jeong
2024-10-23  9:59     ` Hou Tao
2024-10-24  1:48       ` Byeonguk Jeong
2024-10-24  3:19         ` Hou Tao
2024-10-24  9:08 ` [PATCH] selftests/bpf: Add test for trie_get_next_key() Byeonguk Jeong
2024-10-24  9:41   ` Daniel Borkmann
2024-10-24 22:26     ` Byeonguk Jeong
2024-10-25 11:54       ` Hou Tao
2024-10-25 12:03         ` Daniel Borkmann
2024-10-25 11:53   ` Hou Tao

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