From patchwork Wed Apr 5 16:11:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13202162 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7E8DFC76188 for ; Wed, 5 Apr 2023 16:12:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233862AbjDEQMW (ORCPT ); Wed, 5 Apr 2023 12:12:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233855AbjDEQMA (ORCPT ); Wed, 5 Apr 2023 12:12:00 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E0A26E90; Wed, 5 Apr 2023 09:11:54 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1pk5jl-0007mc-31; Wed, 05 Apr 2023 18:11:53 +0200 From: Florian Westphal To: Cc: netfilter-devel@vger.kernel.org, bpf@vger.kernel.org, dxu@dxuuu.xyz, qde@naccy.de, Florian Westphal Subject: [PATCH bpf-next 6/6] bpf: add test_run support for netfilter program type Date: Wed, 5 Apr 2023 18:11:16 +0200 Message-Id: <20230405161116.13565-7-fw@strlen.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230405161116.13565-1-fw@strlen.de> References: <20230405161116.13565-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net also add two simple retval tests: as-is, a return value other than accept or drop will cause issues. NF_QUEUE could be implemented later IFF we can guarantee that attachment of such programs can be rejected if they get attached to a pf/hook that doesn't support async reinjection. NF_STOLEN could be implemented via trusted helpers that will eventually free the skb, else this would leak the skb reference. Signed-off-by: Florian Westphal --- include/linux/bpf.h | 3 + net/bpf/test_run.c | 143 ++++++++++++++++++ net/netfilter/nf_bpf_link.c | 1 + .../selftests/bpf/verifier/netfilter.c | 23 +++ 4 files changed, 170 insertions(+) create mode 100644 tools/testing/selftests/bpf/verifier/netfilter.c diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 2d8f3f639e68..453cee1efdd3 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2235,6 +2235,9 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog, int bpf_prog_test_run_sk_lookup(struct bpf_prog *prog, const union bpf_attr *kattr, union bpf_attr __user *uattr); +int bpf_prog_test_run_nf(struct bpf_prog *prog, + const union bpf_attr *kattr, + union bpf_attr __user *uattr); bool btf_ctx_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, struct bpf_insn_access_aux *info); diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index f1652f5fbd2e..c14f577fd987 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -19,7 +19,9 @@ #include #include #include +#include #include +#include #define CREATE_TRACE_POINTS #include @@ -1690,6 +1692,147 @@ int bpf_prog_test_run_syscall(struct bpf_prog *prog, return err; } +static int verify_and_copy_hook_state(struct nf_hook_state *state, + const struct nf_hook_state *user, + struct net_device *dev) +{ + if (user->in || user->out) + return -EINVAL; + + if (user->net || user->sk || user->okfn) + return -EINVAL; + + switch (user->pf) { + case NFPROTO_IPV4: + case NFPROTO_IPV6: + switch (state->hook) { + case NF_INET_PRE_ROUTING: + state->in = dev; + break; + case NF_INET_LOCAL_IN: + state->in = dev; + break; + case NF_INET_FORWARD: + state->in = dev; + state->out = dev; + break; + case NF_INET_LOCAL_OUT: + state->out = dev; + break; + case NF_INET_POST_ROUTING: + state->out = dev; + break; + } + + break; + default: + return -EINVAL; + } + + state->pf = user->pf; + state->hook = user->hook; + + return 0; +} + +int bpf_prog_test_run_nf(struct bpf_prog *prog, + const union bpf_attr *kattr, + union bpf_attr __user *uattr) +{ + struct net *net = current->nsproxy->net_ns; + struct net_device *dev = net->loopback_dev; + struct nf_hook_state *user_ctx, hook_state = { + .pf = NFPROTO_IPV4, + .hook = NF_INET_PRE_ROUTING, + }; + u32 size = kattr->test.data_size_in; + u32 repeat = kattr->test.repeat; + const struct ethhdr *eth; + struct bpf_nf_ctx ctx = { + .state = &hook_state, + }; + struct sk_buff *skb = NULL; + u32 retval, duration; + void *data; + int ret; + + if (kattr->test.flags || kattr->test.cpu || kattr->test.batch_size) + return -EINVAL; + + if (size < ETH_HLEN + sizeof(struct iphdr)) + return -EINVAL; + + data = bpf_test_init(kattr, kattr->test.data_size_in, size, + NET_SKB_PAD + NET_IP_ALIGN, + SKB_DATA_ALIGN(sizeof(struct skb_shared_info))); + if (IS_ERR(data)) + return PTR_ERR(data); + + eth = (struct ethhdr *)data; + + if (!repeat) + repeat = 1; + + user_ctx = bpf_ctx_init(kattr, sizeof(struct nf_hook_state)); + if (IS_ERR(user_ctx)) { + kfree(data); + return PTR_ERR(user_ctx); + } + + if (user_ctx) { + ret = verify_and_copy_hook_state(&hook_state, user_ctx, dev); + if (ret) + goto out; + } + + skb = slab_build_skb(data); + if (!skb) { + ret = -ENOMEM; + goto out; + } + + data = NULL; /* data released via kfree_skb */ + + skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); + __skb_put(skb, size); + + skb->protocol = eth_type_trans(skb, dev); + + skb_reset_network_header(skb); + + ret = -EINVAL; + + switch (skb->protocol) { + case htons(ETH_P_IP): + if (hook_state.pf == NFPROTO_IPV4) + break; + goto out; + case htons(ETH_P_IPV6): + if (size < ETH_HLEN + sizeof(struct ipv6hdr)) + goto out; + if (hook_state.pf == NFPROTO_IPV6) + break; + goto out; + default: + ret = -EPROTO; + goto out; + } + + ctx.skb = skb; + + ret = bpf_test_run(prog, &ctx, repeat, &retval, &duration, false); + if (ret) + goto out; + + ret = bpf_test_finish(kattr, uattr, NULL, NULL, 0, retval, duration); + +out: + kfree(user_ctx); + kfree_skb(skb); + kfree(data); + return ret; +} + static const struct btf_kfunc_id_set bpf_prog_test_kfunc_set = { .owner = THIS_MODULE, .set = &test_sk_check_kfunc_ids, diff --git a/net/netfilter/nf_bpf_link.c b/net/netfilter/nf_bpf_link.c index 4b22a31d6df5..c27fd569adf1 100644 --- a/net/netfilter/nf_bpf_link.c +++ b/net/netfilter/nf_bpf_link.c @@ -128,6 +128,7 @@ int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) } const struct bpf_prog_ops netfilter_prog_ops = { + .test_run = bpf_prog_test_run_nf, }; static bool nf_ptr_to_btf_id(struct bpf_insn_access_aux *info, const char *name) diff --git a/tools/testing/selftests/bpf/verifier/netfilter.c b/tools/testing/selftests/bpf/verifier/netfilter.c new file mode 100644 index 000000000000..deeb87afdf50 --- /dev/null +++ b/tools/testing/selftests/bpf/verifier/netfilter.c @@ -0,0 +1,23 @@ +{ + "netfilter, accept all", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_NETFILTER, + .retval = 1, + .data = { + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x08, 0x00, + }, +}, +{ + "netfilter, stolen verdict", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "At program exit the register R0 has value (0x2; 0x0) should have been in (0x0; 0x1)", + .prog_type = BPF_PROG_TYPE_NETFILTER, +},