netdev - Re: [PATCH v4 bpf-next 1/2] bpf: add cg_skb_is_valid_access for BPF_PROG_TYPE_CGROUP

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: <13f972be-ab41-8519-24cc-4e891579dc08@fb.com>
Date:   Fri, 19 Oct 2018 01:33:19 +0000
From:   Alexei Starovoitov <ast@...com>
To:     Daniel Borkmann <daniel@...earbox.net>,
        Song Liu <songliubraving@...com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     "ast@...nel.org" <ast@...nel.org>, Kernel Team <Kernel-team@...com>
Subject: Re: [PATCH v4 bpf-next 1/2] bpf: add cg_skb_is_valid_access for
 BPF_PROG_TYPE_CGROUP_SKB

On 10/18/18 5:14 PM, Daniel Borkmann wrote:
>> +	case bpf_ctx_range(struct __sk_buff, data_meta):
>> +	case bpf_ctx_range(struct __sk_buff, flow_keys):
>> +		return false;
> ... if it's disallowed anyway (disallowing it is the right thing to do,
> but no need to save/restore then..)?
>

that's a good point.
why shouldn't we allow cg_skb to access data_meta?
xdp can set it and cgroup_skb_ingress will consume it here.