Re: [PATCH v2] bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing
From: Jakub Kicinski <kuba@kernel.org>
Date: 2023-07-26 03:11:50
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On Tue, 25 Jul 2023 10:33:30 +0800 Lin Ma wrote:
The nla_for_each_nested parsing in function bpf_sk_storage_diag_alloc
does not check the length of the nested attribute. This can lead to an
out-of-attribute read and allow a malformed nlattr (e.g., length 0) to
be viewed as a 4 byte integer.
This patch adds an additional check when the nlattr is getting counted.
This makes sure the latter nla_get_u32 can access the attributes with
the correct length.
Fixes: 1ed4d92458a9 ("bpf: INET_DIAG support in bpf_sk_storage")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Lin Ma <redacted>Reviewed-by: Jakub Kicinski <kuba@kernel.org> Those who parse manually must do checks manually. It is what it is.