From patchwork Fri Oct 19 16:27:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 986862 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="lUng4gdc"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 42cBDs0RHVz9sj4 for ; Sat, 20 Oct 2018 03:28:45 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727699AbeJTAfc (ORCPT ); Fri, 19 Oct 2018 20:35:32 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:60394 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727038AbeJTAfc (ORCPT ); Fri, 19 Oct 2018 20:35:32 -0400 Received: from pps.filterd (m0001255.ppops.net [127.0.0.1]) by mx0b-00082601.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w9JGMb1D013918 for ; Fri, 19 Oct 2018 09:28:41 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=yrens1zq7jyWQHUqH/daV4ORaEBuDQJedaxVzpPCKLY=; b=lUng4gdcgujfbhv1lXCuDmqjrSsxLDGOwtHvJBJekJ3RnPlTuC1fqMwhUVSGokg2RdWi M+8pwZ0P4n3xT6EEv4arpkV+93IWJ+ZWInZslkGDy5flX2kobSu/EoL1D3bfGuWILLaQ dl02Ogs65I1BnuJuRD+b5NBLcir+xxaJqBw= Received: from mail.thefacebook.com ([199.201.64.23]) by mx0b-00082601.pphosted.com with ESMTP id 2n7gj5rkfy-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Fri, 19 Oct 2018 09:28:41 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::129) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1531.3; Fri, 19 Oct 2018 09:27:53 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 093E062E0E28; Fri, 19 Oct 2018 09:27:50 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig006.ftw2.facebook.com To: CC: , , , , Song Liu Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v7 bpf-next 1/2] bpf: add cg_skb_is_valid_access for BPF_PROG_TYPE_CGROUP_SKB Date: Fri, 19 Oct 2018 09:27:47 -0700 Message-ID: <20181019162748.1285423-2-songliubraving@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181019162748.1285423-1-songliubraving@fb.com> References: <20181019162748.1285423-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-10-19_07:, , signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org BPF programs of BPF_PROG_TYPE_CGROUP_SKB need to access headers in the skb. This patch enables direct access of skb for these programs. Two helper functions bpf_compute_and_save_data_end() and bpf_restore_data_end() are introduced. There are used in __cgroup_bpf_run_filter_skb(), to compute proper data_end for the BPF program, and restore original data afterwards. Signed-off-by: Song Liu --- include/linux/filter.h | 21 +++++++++++++++++++++ kernel/bpf/cgroup.c | 6 ++++++ net/core/filter.c | 36 +++++++++++++++++++++++++++++++++++- 3 files changed, 62 insertions(+), 1 deletion(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 5771874bc01e..91b4c934f02e 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -548,6 +548,27 @@ static inline void bpf_compute_data_pointers(struct sk_buff *skb) cb->data_end = skb->data + skb_headlen(skb); } +/* Similar to bpf_compute_data_pointers(), except that save orginal + * data in cb->data and cb->meta_data for restore. + */ +static inline void bpf_compute_and_save_data_end( + struct sk_buff *skb, void **saved_data_end) +{ + struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb; + + *saved_data_end = cb->data_end; + cb->data_end = skb->data + skb_headlen(skb); +} + +/* Restore data saved by bpf_compute_data_pointers(). */ +static inline void bpf_restore_data_end( + struct sk_buff *skb, void *saved_data_end) +{ + struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb; + + cb->data_end = saved_data_end; +} + static inline u8 *bpf_skb_cb(struct sk_buff *skb) { /* eBPF programs may read/write skb->cb[] area to transfer meta diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 00f6ed2e4f9a..9425c2fb872f 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -553,6 +553,7 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk, { unsigned int offset = skb->data - skb_network_header(skb); struct sock *save_sk; + void *saved_data_end; struct cgroup *cgrp; int ret; @@ -566,8 +567,13 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk, save_sk = skb->sk; skb->sk = sk; __skb_push(skb, offset); + + /* compute pointers for the bpf prog */ + bpf_compute_and_save_data_end(skb, &saved_data_end); + ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], skb, bpf_prog_run_save_cb); + bpf_restore_data_end(skb, saved_data_end); __skb_pull(skb, offset); skb->sk = save_sk; return ret == 1 ? 0 : -EPERM; diff --git a/net/core/filter.c b/net/core/filter.c index 1a3ac6c46873..e3ca30bd6840 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5346,6 +5346,40 @@ static bool sk_filter_is_valid_access(int off, int size, return bpf_skb_is_valid_access(off, size, type, prog, info); } +static bool cg_skb_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + switch (off) { + case bpf_ctx_range(struct __sk_buff, tc_classid): + case bpf_ctx_range(struct __sk_buff, data_meta): + case bpf_ctx_range(struct __sk_buff, flow_keys): + return false; + } + if (type == BPF_WRITE) { + switch (off) { + case bpf_ctx_range(struct __sk_buff, mark): + case bpf_ctx_range(struct __sk_buff, priority): + case bpf_ctx_range_till(struct __sk_buff, cb[0], cb[4]): + break; + default: + return false; + } + } + + switch (off) { + case bpf_ctx_range(struct __sk_buff, data): + info->reg_type = PTR_TO_PACKET; + break; + case bpf_ctx_range(struct __sk_buff, data_end): + info->reg_type = PTR_TO_PACKET_END; + break; + } + + return bpf_skb_is_valid_access(off, size, type, prog, info); +} + static bool lwt_is_valid_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, @@ -7038,7 +7072,7 @@ const struct bpf_prog_ops xdp_prog_ops = { const struct bpf_verifier_ops cg_skb_verifier_ops = { .get_func_proto = cg_skb_func_proto, - .is_valid_access = sk_filter_is_valid_access, + .is_valid_access = cg_skb_is_valid_access, .convert_ctx_access = bpf_convert_ctx_access, };