From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7F48C43381 for ; Mon, 1 Apr 2019 20:57:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A252F208E4 for ; Mon, 1 Apr 2019 20:57:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="EMQCLgQD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728570AbfDAU5s (ORCPT ); Mon, 1 Apr 2019 16:57:48 -0400 Received: from mail-it1-f201.google.com ([209.85.166.201]:44629 "EHLO mail-it1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728483AbfDAU5r (ORCPT ); Mon, 1 Apr 2019 16:57:47 -0400 Received: by mail-it1-f201.google.com with SMTP id v193so720869itv.9 for ; Mon, 01 Apr 2019 13:57:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=vNIYa8Lob8GaCf02abW7dYTE9zt9QRXGalzndleWpZA=; b=EMQCLgQDuQTAzGxVEy19Fng5ugj3v7m37tmEY6bvRSt9o83AbNiERl4vKuNs3eUh4M mie5mXt4/l/t+mTl9rm0N2271oh+8thQkKlsNtSt//RdRrdTPPOdHqfdOFcYfOmO/Et9 eGBaxMuUZMMj/0RuqHfjstTl4k+riFBaXN5UE/xjpUBwuX38ryL3u6dUFuq7n2DO2+qv 196GPlOc6JvaF5SQOT+wUp9kvZWcUjhg+fSze//9ZPMoB6lb72ZTGIPMyaTiE8kYuk2k cd7JYfczEzYSwtFna/ofOw54FFNEojOXlG8IG16q4DNz8mzJExqMaWm/eJ41q/TC7w4n dICQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=vNIYa8Lob8GaCf02abW7dYTE9zt9QRXGalzndleWpZA=; b=bneXnUstHiyAXmCNufT23t9ZQ+GY11zwvy5OmHgsDJW0g7/YxgQglKaZNr+nuxLpE6 bPH9i76iaA9jKYbe2pTZsC5i0KCc9XqwgXA26HlQ6xbkAkYQkKymJlj4sjKQfUY7YxtP XTYYnyhZpxpi/p5MOa/tiPh1JXTGPxbKoetmy0c6QL1pGxNpb5uuQxLg4mz/arbc87jr UoP/ySZgpMUx9XKoeURS76dXQ6EU3u1I3mm2yG20SJLm5zLc8bPQAX4K3d4u8vPeS8Wp dJmQ2P0ZfJn2oznpALxO2GzcA1BrNHrFQzqbyD5prRzVz4fnOIqmtmCHgPopdKU/Hwqa ikOw== X-Gm-Message-State: APjAAAXxA4LlK90i7lQ98DpBeyyYpMoC04yn+H0NiAY7X5gQirzTE2FI kk6UAhGW3Nfbtg5XC3wd9gogtrHhhzZGfH8ZEbPwmixS3qkC2HKy6NU0HhkzmTgMSDmdO3oFoj3 3c7RNp5rTYqUI11hWRt3lnL11YWyZG1qVqWX/fIaO3e0yFH/GAhYGzg== X-Google-Smtp-Source: APXvYqwFTeO6Cqilra7ujGMHast//X8d5iHsRbhdDVJn+wzOKGpSotypRN7vxhibxq97hoqkFPZsWBg= X-Received: by 2002:a24:764b:: with SMTP id z72mr7401300itb.22.1554152266677; Mon, 01 Apr 2019 13:57:46 -0700 (PDT) Date: Mon, 1 Apr 2019 13:57:33 -0700 In-Reply-To: <20190401205734.4400-1-sdf@google.com> Message-Id: <20190401205734.4400-5-sdf@google.com> Mime-Version: 1.0 References: <20190401205734.4400-1-sdf@google.com> X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH bpf 4/5] flow_dissector: allow access only to a subset of __sk_buff fields From: Stanislav Fomichev To: netdev@vger.kernel.org, bpf@vger.kernel.org Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net, simon.horman@netronome.com, willemb@google.com, peterpenkov96@gmail.com, Stanislav Fomichev Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Use whitelist instead of a blacklist and allow only a small set of fields that might be relevant in the context of flow dissector: * data * data_end * flow_keys This is required for the eth_get_headlen case where we have only a chunk of data to dissect (i.e. trying to read the other skb fields doesn't make sense). Note, that it is a breaking API change! However, we've provided flow_keys->n_proto as a substitute for skb->protocol; and there is no need to manually handle skb->vlan_present. So even if we break somebody, the migration is trivial. Unfortunately, we can't support eth_get_headlen use-case without those breaking changes. Signed-off-by: Stanislav Fomichev --- net/core/filter.c | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index 647c63a7b25b..fc92ebc4e200 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -6613,14 +6613,8 @@ static bool flow_dissector_is_valid_access(int off, int size, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { - if (type == BPF_WRITE) { - switch (off) { - case bpf_ctx_range_till(struct __sk_buff, cb[0], cb[4]): - break; - default: - return false; - } - } + if (type == BPF_WRITE) + return false; switch (off) { case bpf_ctx_range(struct __sk_buff, data): @@ -6632,11 +6626,7 @@ static bool flow_dissector_is_valid_access(int off, int size, case bpf_ctx_range_ptr(struct __sk_buff, flow_keys): info->reg_type = PTR_TO_FLOW_KEYS; break; - case bpf_ctx_range(struct __sk_buff, tc_classid): - case bpf_ctx_range(struct __sk_buff, data_meta): - case bpf_ctx_range_till(struct __sk_buff, family, local_port): - case bpf_ctx_range(struct __sk_buff, tstamp): - case bpf_ctx_range(struct __sk_buff, wire_len): + default: return false; } -- 2.21.0.392.gf8f6787159e-goog