From patchwork Thu Apr 20 12:44:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13218729 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 07CAEC77B72 for ; Thu, 20 Apr 2023 12:45:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231945AbjDTMpN (ORCPT ); Thu, 20 Apr 2023 08:45:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232114AbjDTMpL (ORCPT ); Thu, 20 Apr 2023 08:45:11 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D100C7; Thu, 20 Apr 2023 05:45:10 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ppTeu-0002Z1-IB; Thu, 20 Apr 2023 14:45:08 +0200 From: Florian Westphal To: Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, dxu@dxuuu.xyz, qde@naccy.de, Florian Westphal Subject: [PATCH bpf-next v4 1/7] bpf: add bpf_link support for BPF_NETFILTER programs Date: Thu, 20 Apr 2023 14:44:49 +0200 Message-Id: <20230420124455.31099-2-fw@strlen.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230420124455.31099-1-fw@strlen.de> References: <20230420124455.31099-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add bpf_link support skeleton. To keep this reviewable, no bpf program can be invoked yet, if a program is attached only a c-stub is called and not the actual bpf program. Defaults to 'y' if both netfilter and bpf syscall are enabled in kconfig. Uapi example usage: union bpf_attr attr = { }; attr.link_create.prog_fd = progfd; attr.link_create.attach_type = 0; /* unused */ attr.link_create.netfilter.pf = PF_INET; attr.link_create.netfilter.hooknum = NF_INET_LOCAL_IN; attr.link_create.netfilter.priority = -128; err = bpf(BPF_LINK_CREATE, &attr, sizeof(attr)); ... this would attach progfd to ipv4:input hook. Such hook gets removed automatically if the calling program exits. BPF_NETFILTER program invocation is added in followup change. NF_HOOK_OP_BPF enum will eventually be read from nfnetlink_hook, it allows to tell userspace which program is attached at the given hook when user runs 'nft hook list' command rather than just the priority and not-very-helpful 'this hook runs a bpf prog but I can't tell which one'. Will also be used to disallow registration of two bpf programs with same priority in a followup patch. v4: arm32 cmpxchg only supports 32bit operand s/prio/priority/ v3: restrict prog attachment to ip/ip6 for now, lets lift restrictions if more use cases pop up (arptables, ebtables, netdev ingress/egress etc). Signed-off-by: Florian Westphal --- include/linux/netfilter.h | 1 + include/net/netfilter/nf_bpf_link.h | 10 ++ include/uapi/linux/bpf.h | 14 +++ kernel/bpf/syscall.c | 6 ++ net/netfilter/Kconfig | 3 + net/netfilter/Makefile | 1 + net/netfilter/nf_bpf_link.c | 159 ++++++++++++++++++++++++++++ 7 files changed, 194 insertions(+) create mode 100644 include/net/netfilter/nf_bpf_link.h create mode 100644 net/netfilter/nf_bpf_link.c diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index c8e03bcaecaa..0762444e3767 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -80,6 +80,7 @@ typedef unsigned int nf_hookfn(void *priv, enum nf_hook_ops_type { NF_HOOK_OP_UNDEFINED, NF_HOOK_OP_NF_TABLES, + NF_HOOK_OP_BPF, }; struct nf_hook_ops { diff --git a/include/net/netfilter/nf_bpf_link.h b/include/net/netfilter/nf_bpf_link.h new file mode 100644 index 000000000000..eeaeaf3d15de --- /dev/null +++ b/include/net/netfilter/nf_bpf_link.h @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#if IS_ENABLED(CONFIG_NETFILTER_BPF_LINK) +int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog); +#else +static inline int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + return -EOPNOTSUPP; +} +#endif diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 4b20a7269bee..1bb11a6ee667 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -986,6 +986,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_LSM, BPF_PROG_TYPE_SK_LOOKUP, BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */ + BPF_PROG_TYPE_NETFILTER, }; enum bpf_attach_type { @@ -1050,6 +1051,7 @@ enum bpf_link_type { BPF_LINK_TYPE_PERF_EVENT = 7, BPF_LINK_TYPE_KPROBE_MULTI = 8, BPF_LINK_TYPE_STRUCT_OPS = 9, + BPF_LINK_TYPE_NETFILTER = 10, MAX_BPF_LINK_TYPE, }; @@ -1560,6 +1562,12 @@ union bpf_attr { */ __u64 cookie; } tracing; + struct { + __u32 pf; + __u32 hooknum; + __s32 priority; + __u32 flags; + } netfilter; }; } link_create; @@ -6410,6 +6418,12 @@ struct bpf_link_info { struct { __u32 map_id; } struct_ops; + struct { + __u32 pf; + __u32 hooknum; + __s32 priority; + __u32 flags; + } netfilter; }; } __attribute__((aligned(8))); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index bcf1a1920ddd..14f39c1e573e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -35,6 +35,7 @@ #include #include #include +#include #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \ (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \ @@ -2462,6 +2463,7 @@ static bool is_net_admin_prog_type(enum bpf_prog_type prog_type) case BPF_PROG_TYPE_CGROUP_SYSCTL: case BPF_PROG_TYPE_SOCK_OPS: case BPF_PROG_TYPE_EXT: /* extends any prog */ + case BPF_PROG_TYPE_NETFILTER: return true; case BPF_PROG_TYPE_CGROUP_SKB: /* always unpriv */ @@ -4588,6 +4590,7 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) switch (prog->type) { case BPF_PROG_TYPE_EXT: + case BPF_PROG_TYPE_NETFILTER: break; case BPF_PROG_TYPE_PERF_EVENT: case BPF_PROG_TYPE_TRACEPOINT: @@ -4654,6 +4657,9 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) case BPF_PROG_TYPE_XDP: ret = bpf_xdp_link_attach(attr, prog); break; + case BPF_PROG_TYPE_NETFILTER: + ret = bpf_nf_link_attach(attr, prog); + break; #endif case BPF_PROG_TYPE_PERF_EVENT: case BPF_PROG_TYPE_TRACEPOINT: diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index d0bf630482c1..441d1f134110 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -30,6 +30,9 @@ config NETFILTER_FAMILY_BRIDGE config NETFILTER_FAMILY_ARP bool +config NETFILTER_BPF_LINK + def_bool BPF_SYSCALL + config NETFILTER_NETLINK_HOOK tristate "Netfilter base hook dump support" depends on NETFILTER_ADVANCED diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 5ffef1cd6143..d4958e7e7631 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -22,6 +22,7 @@ nf_conntrack-$(CONFIG_DEBUG_INFO_BTF) += nf_conntrack_bpf.o endif obj-$(CONFIG_NETFILTER) = netfilter.o +obj-$(CONFIG_NETFILTER_BPF_LINK) += nf_bpf_link.o obj-$(CONFIG_NETFILTER_NETLINK) += nfnetlink.o obj-$(CONFIG_NETFILTER_NETLINK_ACCT) += nfnetlink_acct.o diff --git a/net/netfilter/nf_bpf_link.c b/net/netfilter/nf_bpf_link.c new file mode 100644 index 000000000000..efa4f3390742 --- /dev/null +++ b/net/netfilter/nf_bpf_link.c @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +#include +#include + +static unsigned int nf_hook_run_bpf(void *bpf_prog, struct sk_buff *skb, + const struct nf_hook_state *s) +{ + return NF_ACCEPT; +} + +struct bpf_nf_link { + struct bpf_link link; + struct nf_hook_ops hook_ops; + struct net *net; + u32 dead; +}; + +static void bpf_nf_link_release(struct bpf_link *link) +{ + struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link); + + if (nf_link->dead) + return; + + /* prevent hook-not-found warning splat from netfilter core when + * .detach was already called + */ + if (!cmpxchg(&nf_link->dead, 0, 1)) + nf_unregister_net_hook(nf_link->net, &nf_link->hook_ops); +} + +static void bpf_nf_link_dealloc(struct bpf_link *link) +{ + struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link); + + kfree(nf_link); +} + +static int bpf_nf_link_detach(struct bpf_link *link) +{ + bpf_nf_link_release(link); + return 0; +} + +static void bpf_nf_link_show_info(const struct bpf_link *link, + struct seq_file *seq) +{ + struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link); + + seq_printf(seq, "pf:\t%u\thooknum:\t%u\tprio:\t%d\n", + nf_link->hook_ops.pf, nf_link->hook_ops.hooknum, + nf_link->hook_ops.priority); +} + +static int bpf_nf_link_fill_link_info(const struct bpf_link *link, + struct bpf_link_info *info) +{ + struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link); + + info->netfilter.pf = nf_link->hook_ops.pf; + info->netfilter.hooknum = nf_link->hook_ops.hooknum; + info->netfilter.priority = nf_link->hook_ops.priority; + info->netfilter.flags = 0; + + return 0; +} + +static int bpf_nf_link_update(struct bpf_link *link, struct bpf_prog *new_prog, + struct bpf_prog *old_prog) +{ + return -EOPNOTSUPP; +} + +static const struct bpf_link_ops bpf_nf_link_lops = { + .release = bpf_nf_link_release, + .dealloc = bpf_nf_link_dealloc, + .detach = bpf_nf_link_detach, + .show_fdinfo = bpf_nf_link_show_info, + .fill_link_info = bpf_nf_link_fill_link_info, + .update_prog = bpf_nf_link_update, +}; + +static int bpf_nf_check_pf_and_hooks(const union bpf_attr *attr) +{ + switch (attr->link_create.netfilter.pf) { + case NFPROTO_IPV4: + case NFPROTO_IPV6: + if (attr->link_create.netfilter.hooknum >= NF_INET_NUMHOOKS) + return -EPROTO; + break; + default: + return -EAFNOSUPPORT; + } + + if (attr->link_create.netfilter.flags) + return -EOPNOTSUPP; + + /* make sure conntrack confirm is always last. + * + * In the future, if userspace can e.g. request defrag, then + * "defrag_requested && prio before NF_IP_PRI_CONNTRACK_DEFRAG" + * should fail. + */ + switch (attr->link_create.netfilter.priority) { + case NF_IP_PRI_FIRST: return -ERANGE; /* sabotage_in and other warts */ + case NF_IP_PRI_LAST: return -ERANGE; /* e.g. conntrack confirm */ + } + + return 0; +} + +int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + struct net *net = current->nsproxy->net_ns; + struct bpf_link_primer link_primer; + struct bpf_nf_link *link; + int err; + + if (attr->link_create.flags) + return -EINVAL; + + err = bpf_nf_check_pf_and_hooks(attr); + if (err) + return err; + + link = kzalloc(sizeof(*link), GFP_USER); + if (!link) + return -ENOMEM; + + bpf_link_init(&link->link, BPF_LINK_TYPE_NETFILTER, &bpf_nf_link_lops, prog); + + link->hook_ops.hook = nf_hook_run_bpf; + link->hook_ops.hook_ops_type = NF_HOOK_OP_BPF; + link->hook_ops.priv = prog; + + link->hook_ops.pf = attr->link_create.netfilter.pf; + link->hook_ops.priority = attr->link_create.netfilter.priority; + link->hook_ops.hooknum = attr->link_create.netfilter.hooknum; + + link->net = net; + link->dead = false; + + err = bpf_link_prime(&link->link, &link_primer); + if (err) { + kfree(link); + return err; + } + + err = nf_register_net_hook(net, &link->hook_ops); + if (err) { + bpf_link_cleanup(&link_primer); + return err; + } + + return bpf_link_settle(&link_primer); +} From patchwork Thu Apr 20 12:44:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13218730 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 8E273C77B76 for ; Thu, 20 Apr 2023 12:45:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233789AbjDTMpR (ORCPT ); Thu, 20 Apr 2023 08:45:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232970AbjDTMpQ (ORCPT ); Thu, 20 Apr 2023 08:45:16 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1572065B6; Thu, 20 Apr 2023 05:45:14 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ppTey-0002ZF-Mh; Thu, 20 Apr 2023 14:45:12 +0200 From: Florian Westphal To: Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, dxu@dxuuu.xyz, qde@naccy.de, Florian Westphal Subject: [PATCH bpf-next v4 2/7] bpf: minimal support for programs hooked into netfilter framework Date: Thu, 20 Apr 2023 14:44:50 +0200 Message-Id: <20230420124455.31099-3-fw@strlen.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230420124455.31099-1-fw@strlen.de> References: <20230420124455.31099-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This adds minimal support for BPF_PROG_TYPE_NETFILTER bpf programs that will be invoked via the NF_HOOK() points in the ip stack. Invocation incurs an indirect call. This is not a necessity: Its possible to add 'DEFINE_BPF_DISPATCHER(nf_progs)' and handle the program invocation with the same method already done for xdp progs. This isn't done here to keep the size of this chunk down. Verifier restricts verdicts to either DROP or ACCEPT. Signed-off-by: Florian Westphal --- include/linux/bpf_types.h | 4 ++ include/net/netfilter/nf_bpf_link.h | 5 +++ kernel/bpf/btf.c | 6 +++ kernel/bpf/verifier.c | 3 ++ net/core/filter.c | 1 + net/netfilter/nf_bpf_link.c | 70 ++++++++++++++++++++++++++++- 6 files changed, 88 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index d4ee3ccd3753..39a999abb0ce 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -79,6 +79,10 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_LSM, lsm, #endif BPF_PROG_TYPE(BPF_PROG_TYPE_SYSCALL, bpf_syscall, void *, void *) +#ifdef CONFIG_NETFILTER +BPF_PROG_TYPE(BPF_PROG_TYPE_NETFILTER, netfilter, + struct bpf_nf_ctx, struct bpf_nf_ctx) +#endif BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops) diff --git a/include/net/netfilter/nf_bpf_link.h b/include/net/netfilter/nf_bpf_link.h index eeaeaf3d15de..6c984b0ea838 100644 --- a/include/net/netfilter/nf_bpf_link.h +++ b/include/net/netfilter/nf_bpf_link.h @@ -1,5 +1,10 @@ /* SPDX-License-Identifier: GPL-2.0 */ +struct bpf_nf_ctx { + const struct nf_hook_state *state; + struct sk_buff *skb; +}; + #if IS_ENABLED(CONFIG_NETFILTER_BPF_LINK) int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog); #else diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index a0887ee44e89..0054bcecf2cc 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -25,6 +25,9 @@ #include #include #include + +#include + #include #include "../tools/lib/bpf/relo_core.h" @@ -212,6 +215,7 @@ enum btf_kfunc_hook { BTF_KFUNC_HOOK_SK_SKB, BTF_KFUNC_HOOK_SOCKET_FILTER, BTF_KFUNC_HOOK_LWT, + BTF_KFUNC_HOOK_NETFILTER, BTF_KFUNC_HOOK_MAX, }; @@ -7802,6 +7806,8 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) case BPF_PROG_TYPE_LWT_XMIT: case BPF_PROG_TYPE_LWT_SEG6LOCAL: return BTF_KFUNC_HOOK_LWT; + case BPF_PROG_TYPE_NETFILTER: + return BTF_KFUNC_HOOK_NETFILTER; default: return BTF_KFUNC_HOOK_MAX; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1e05355facdc..fc7281d39e46 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -13816,6 +13816,9 @@ static int check_return_code(struct bpf_verifier_env *env) } break; + case BPF_PROG_TYPE_NETFILTER: + range = tnum_range(NF_DROP, NF_ACCEPT); + break; case BPF_PROG_TYPE_EXT: /* freplace program can return anything as its return value * depends on the to-be-replaced kernel func or bpf program. diff --git a/net/core/filter.c b/net/core/filter.c index 44fb997434ad..d9ce04ca22ce 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -11717,6 +11717,7 @@ static int __init bpf_kfunc_init(void) ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_IN, &bpf_kfunc_set_skb); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_XMIT, &bpf_kfunc_set_skb); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_SEG6LOCAL, &bpf_kfunc_set_skb); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_NETFILTER, &bpf_kfunc_set_skb); return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp); } late_initcall(bpf_kfunc_init); diff --git a/net/netfilter/nf_bpf_link.c b/net/netfilter/nf_bpf_link.c index efa4f3390742..49cfc5215386 100644 --- a/net/netfilter/nf_bpf_link.c +++ b/net/netfilter/nf_bpf_link.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include +#include #include #include @@ -8,7 +9,13 @@ static unsigned int nf_hook_run_bpf(void *bpf_prog, struct sk_buff *skb, const struct nf_hook_state *s) { - return NF_ACCEPT; + const struct bpf_prog *prog = bpf_prog; + struct bpf_nf_ctx ctx = { + .state = s, + .skb = skb, + }; + + return bpf_prog_run(prog, &ctx); } struct bpf_nf_link { @@ -157,3 +164,64 @@ int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) return bpf_link_settle(&link_primer); } + +const struct bpf_prog_ops netfilter_prog_ops = { +}; + +static bool nf_ptr_to_btf_id(struct bpf_insn_access_aux *info, const char *name) +{ + struct btf *btf; + s32 type_id; + + btf = bpf_get_btf_vmlinux(); + if (IS_ERR_OR_NULL(btf)) + return false; + + type_id = btf_find_by_name_kind(btf, name, BTF_KIND_STRUCT); + if (WARN_ON_ONCE(type_id < 0)) + return false; + + info->btf = btf; + info->btf_id = type_id; + info->reg_type = PTR_TO_BTF_ID | PTR_TRUSTED; + return true; +} + +static bool nf_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + if (off < 0 || off >= sizeof(struct bpf_nf_ctx)) + return false; + + if (type == BPF_WRITE) + return false; + + switch (off) { + case bpf_ctx_range(struct bpf_nf_ctx, skb): + if (size != sizeof_field(struct bpf_nf_ctx, skb)) + return false; + + return nf_ptr_to_btf_id(info, "sk_buff"); + case bpf_ctx_range(struct bpf_nf_ctx, state): + if (size != sizeof_field(struct bpf_nf_ctx, state)) + return false; + + return nf_ptr_to_btf_id(info, "nf_hook_state"); + default: + return false; + } + + return false; +} + +static const struct bpf_func_proto * +bpf_nf_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + return bpf_base_func_proto(func_id); +} + +const struct bpf_verifier_ops netfilter_verifier_ops = { + .is_valid_access = nf_is_valid_access, + .get_func_proto = bpf_nf_func_proto, +}; From patchwork Thu Apr 20 12:44:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13218731 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 B61D7C77B73 for ; Thu, 20 Apr 2023 12:45:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234391AbjDTMpZ (ORCPT ); Thu, 20 Apr 2023 08:45:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232970AbjDTMpV (ORCPT ); Thu, 20 Apr 2023 08:45:21 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E0A96A5E; Thu, 20 Apr 2023 05:45:18 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ppTf2-0002Zn-Pz; Thu, 20 Apr 2023 14:45:16 +0200 From: Florian Westphal To: Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, dxu@dxuuu.xyz, qde@naccy.de, Florian Westphal Subject: [PATCH bpf-next v4 3/7] netfilter: nfnetlink hook: dump bpf prog id Date: Thu, 20 Apr 2023 14:44:51 +0200 Message-Id: <20230420124455.31099-4-fw@strlen.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230420124455.31099-1-fw@strlen.de> References: <20230420124455.31099-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This allows userspace ("nft list hooks") to show which bpf program is attached to which hook. Without this, user only knows bpf prog is attached at prio x, y, z at INPUT and FORWARD, but can't tell which program is where. v4: kdoc fixups (Simon Horman) Link: https://lore.kernel.org/bpf/ZEELzpNCnYJuZyod@corigine.com/ Signed-off-by: Florian Westphal --- include/uapi/linux/netfilter/nfnetlink_hook.h | 24 +++++- net/netfilter/nfnetlink_hook.c | 81 ++++++++++++++++--- 2 files changed, 89 insertions(+), 16 deletions(-) diff --git a/include/uapi/linux/netfilter/nfnetlink_hook.h b/include/uapi/linux/netfilter/nfnetlink_hook.h index bbcd285b22e1..84a561a74b98 100644 --- a/include/uapi/linux/netfilter/nfnetlink_hook.h +++ b/include/uapi/linux/netfilter/nfnetlink_hook.h @@ -32,8 +32,12 @@ enum nfnl_hook_attributes { /** * enum nfnl_hook_chain_info_attributes - chain description * - * NFNLA_HOOK_INFO_DESC: nft chain and table name (enum nft_table_attributes) (NLA_NESTED) - * NFNLA_HOOK_INFO_TYPE: chain type (enum nfnl_hook_chaintype) (NLA_U32) + * @NFNLA_HOOK_INFO_DESC: nft chain and table name (NLA_NESTED) + * @NFNLA_HOOK_INFO_TYPE: chain type (enum nfnl_hook_chaintype) (NLA_U32) + * + * NFNLA_HOOK_INFO_DESC depends on NFNLA_HOOK_INFO_TYPE value: + * NFNL_HOOK_TYPE_NFTABLES: enum nft_table_attributes + * NFNL_HOOK_TYPE_BPF: enum nfnl_hook_bpf_attributes */ enum nfnl_hook_chain_info_attributes { NFNLA_HOOK_INFO_UNSPEC, @@ -55,10 +59,24 @@ enum nfnl_hook_chain_desc_attributes { /** * enum nfnl_hook_chaintype - chain type * - * @NFNL_HOOK_TYPE_NFTABLES nf_tables base chain + * @NFNL_HOOK_TYPE_NFTABLES: nf_tables base chain + * @NFNL_HOOK_TYPE_BPF: bpf program */ enum nfnl_hook_chaintype { NFNL_HOOK_TYPE_NFTABLES = 0x1, + NFNL_HOOK_TYPE_BPF, +}; + +/** + * enum nfnl_hook_bpf_attributes - bpf prog description + * + * @NFNLA_HOOK_BPF_ID: bpf program id (NLA_U32) + */ +enum nfnl_hook_bpf_attributes { + NFNLA_HOOK_BPF_UNSPEC, + NFNLA_HOOK_BPF_ID, + __NFNLA_HOOK_BPF_MAX, }; +#define NFNLA_HOOK_BPF_MAX (__NFNLA_HOOK_BPF_MAX - 1) #endif /* _NFNL_HOOK_H */ diff --git a/net/netfilter/nfnetlink_hook.c b/net/netfilter/nfnetlink_hook.c index 8120aadf6a0f..ade8ee1988b1 100644 --- a/net/netfilter/nfnetlink_hook.c +++ b/net/netfilter/nfnetlink_hook.c @@ -5,6 +5,7 @@ * Author: Florian Westphal */ +#include #include #include #include @@ -57,35 +58,76 @@ struct nfnl_dump_hook_data { u8 hook; }; +static struct nlattr *nfnl_start_info_type(struct sk_buff *nlskb, enum nfnl_hook_chaintype t) +{ + struct nlattr *nest = nla_nest_start(nlskb, NFNLA_HOOK_CHAIN_INFO); + int ret; + + if (!nest) + return NULL; + + ret = nla_put_be32(nlskb, NFNLA_HOOK_INFO_TYPE, htonl(t)); + if (ret == 0) + return nest; + + nla_nest_cancel(nlskb, nest); + return NULL; +} + +static int nfnl_hook_put_bpf_prog_info(struct sk_buff *nlskb, + const struct nfnl_dump_hook_data *ctx, + unsigned int seq, + const struct bpf_prog *prog) +{ + struct nlattr *nest, *nest2; + int ret; + + if (!IS_ENABLED(CONFIG_NETFILTER_BPF_LINK)) + return 0; + + if (WARN_ON_ONCE(!prog)) + return 0; + + nest = nfnl_start_info_type(nlskb, NFNL_HOOK_TYPE_BPF); + if (!nest) + return -EMSGSIZE; + + nest2 = nla_nest_start(nlskb, NFNLA_HOOK_INFO_DESC); + if (!nest2) + goto cancel_nest; + + ret = nla_put_be32(nlskb, NFNLA_HOOK_BPF_ID, htonl(prog->aux->id)); + if (ret) + goto cancel_nest; + + nla_nest_end(nlskb, nest2); + nla_nest_end(nlskb, nest); + return 0; + +cancel_nest: + nla_nest_cancel(nlskb, nest); + return -EMSGSIZE; +} + static int nfnl_hook_put_nft_chain_info(struct sk_buff *nlskb, const struct nfnl_dump_hook_data *ctx, unsigned int seq, - const struct nf_hook_ops *ops) + struct nft_chain *chain) { struct net *net = sock_net(nlskb->sk); struct nlattr *nest, *nest2; - struct nft_chain *chain; int ret = 0; - if (ops->hook_ops_type != NF_HOOK_OP_NF_TABLES) - return 0; - - chain = ops->priv; if (WARN_ON_ONCE(!chain)) return 0; if (!nft_is_active(net, chain)) return 0; - nest = nla_nest_start(nlskb, NFNLA_HOOK_CHAIN_INFO); + nest = nfnl_start_info_type(nlskb, NFNL_HOOK_TYPE_NFTABLES); if (!nest) return -EMSGSIZE; - ret = nla_put_be32(nlskb, NFNLA_HOOK_INFO_TYPE, - htonl(NFNL_HOOK_TYPE_NFTABLES)); - if (ret) - goto cancel_nest; - nest2 = nla_nest_start(nlskb, NFNLA_HOOK_INFO_DESC); if (!nest2) goto cancel_nest; @@ -171,7 +213,20 @@ static int nfnl_hook_dump_one(struct sk_buff *nlskb, if (ret) goto nla_put_failure; - ret = nfnl_hook_put_nft_chain_info(nlskb, ctx, seq, ops); + switch (ops->hook_ops_type) { + case NF_HOOK_OP_NF_TABLES: + ret = nfnl_hook_put_nft_chain_info(nlskb, ctx, seq, ops->priv); + break; + case NF_HOOK_OP_BPF: + ret = nfnl_hook_put_bpf_prog_info(nlskb, ctx, seq, ops->priv); + break; + case NF_HOOK_OP_UNDEFINED: + break; + default: + WARN_ON_ONCE(1); + break; + } + if (ret) goto nla_put_failure; From patchwork Thu Apr 20 12:44:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13218732 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 71E3FC77B76 for ; Thu, 20 Apr 2023 12:45:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234242AbjDTMpc (ORCPT ); Thu, 20 Apr 2023 08:45:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233374AbjDTMp3 (ORCPT ); Thu, 20 Apr 2023 08:45:29 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D3216E9F; Thu, 20 Apr 2023 05:45:22 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ppTf6-0002a4-TD; Thu, 20 Apr 2023 14:45:20 +0200 From: Florian Westphal To: Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, dxu@dxuuu.xyz, qde@naccy.de, Florian Westphal Subject: [PATCH bpf-next v4 4/7] netfilter: disallow bpf hook attachment at same priority Date: Thu, 20 Apr 2023 14:44:52 +0200 Message-Id: <20230420124455.31099-5-fw@strlen.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230420124455.31099-1-fw@strlen.de> References: <20230420124455.31099-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This is just to avoid ordering issues between multiple bpf programs, this could be removed later in case it turns out to be too cautious. bpf prog could still be shared with non-bpf hook, otherwise we'd have to make conntrack hook registration fail just because a bpf program has same priority. Signed-off-by: Florian Westphal --- net/netfilter/core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 358220b58521..f0783e42108b 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -119,6 +119,18 @@ nf_hook_entries_grow(const struct nf_hook_entries *old, for (i = 0; i < old_entries; i++) { if (orig_ops[i] != &dummy_ops) alloc_entries++; + + /* Restrict BPF hook type to force a unique priority, not + * shared at attach time. + * + * This is mainly to avoid ordering issues between two + * different bpf programs, this doesn't prevent a normal + * hook at same priority as a bpf one (we don't want to + * prevent defrag, conntrack, iptables etc from attaching). + */ + if (reg->priority == orig_ops[i]->priority && + reg->hook_ops_type == NF_HOOK_OP_BPF) + return ERR_PTR(-EBUSY); } } From patchwork Thu Apr 20 12:44:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13218733 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 47B27C77B76 for ; Thu, 20 Apr 2023 12:45:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234006AbjDTMpk (ORCPT ); Thu, 20 Apr 2023 08:45:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234455AbjDTMph (ORCPT ); Thu, 20 Apr 2023 08:45:37 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D9CA5B85; Thu, 20 Apr 2023 05:45:26 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ppTfB-0002aJ-0u; Thu, 20 Apr 2023 14:45:25 +0200 From: Florian Westphal To: Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, dxu@dxuuu.xyz, qde@naccy.de, Florian Westphal , Quentin Monnet Subject: [PATCH bpf-next v4 5/7] tools: bpftool: print netfilter link info Date: Thu, 20 Apr 2023 14:44:53 +0200 Message-Id: <20230420124455.31099-6-fw@strlen.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230420124455.31099-1-fw@strlen.de> References: <20230420124455.31099-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Dump protocol family, hook and priority value: $ bpftool link 2: netfilter prog 14 ip input prio -128 pids install(3264) 5: netfilter prog 14 ip6 forward prio 21 pids a.out(3387) 9: netfilter prog 14 ip prerouting prio 123 pids a.out(5700) 10: netfilter prog 14 ip input prio 21 pids test2(5701) v2: Quentin Monnet suggested to also add 'bpftool net' support: $ bpftool net xdp: tc: flow_dissector: netfilter: ip prerouting prio 21 prog_id 14 ip input prio -128 prog_id 14 ip input prio 21 prog_id 14 ip forward prio 21 prog_id 14 ip output prio 21 prog_id 14 ip postrouting prio 21 prog_id 14 'bpftool net' only dumps netfilter link type, links are sorted by protocol family, hook and priority. v4: fix bpf.h copy, 'reserved' member was removed (Alexei) use p_err, not fprintf (Quentin) Suggested-by: Quentin Monnet Link: https://lore.kernel.org/bpf/eeeaac99-9053-90c2-aa33-cc1ecb1ae9ca@isovalent.com/ Reviewed-by: Quentin Monnet Signed-off-by: Florian Westphal --- tools/bpf/bpftool/link.c | 83 ++++++++++++++++++++++++++ tools/bpf/bpftool/main.h | 3 + tools/bpf/bpftool/net.c | 106 +++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 14 +++++ tools/lib/bpf/libbpf.c | 2 + 5 files changed, 208 insertions(+) diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c index f985b79cca27..d98dbc50cf4c 100644 --- a/tools/bpf/bpftool/link.c +++ b/tools/bpf/bpftool/link.c @@ -3,6 +3,8 @@ #include #include +#include +#include #include #include #include @@ -135,6 +137,18 @@ static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr) } } +void netfilter_dump_json(const struct bpf_link_info *info, json_writer_t *wtr) +{ + jsonw_uint_field(json_wtr, "pf", + info->netfilter.pf); + jsonw_uint_field(json_wtr, "hook", + info->netfilter.hooknum); + jsonw_int_field(json_wtr, "prio", + info->netfilter.priority); + jsonw_uint_field(json_wtr, "flags", + info->netfilter.flags); +} + static int get_prog_info(int prog_id, struct bpf_prog_info *info) { __u32 len = sizeof(*info); @@ -195,6 +209,10 @@ static int show_link_close_json(int fd, struct bpf_link_info *info) info->netns.netns_ino); show_link_attach_type_json(info->netns.attach_type, json_wtr); break; + case BPF_LINK_TYPE_NETFILTER: + netfilter_dump_json(info, json_wtr); + break; + default: break; } @@ -263,6 +281,68 @@ static void show_iter_plain(struct bpf_link_info *info) } } +static const char * const pf2name[] = { + [NFPROTO_INET] = "inet", + [NFPROTO_IPV4] = "ip", + [NFPROTO_ARP] = "arp", + [NFPROTO_NETDEV] = "netdev", + [NFPROTO_BRIDGE] = "bridge", + [NFPROTO_IPV6] = "ip6", +}; + +static const char * const inethook2name[] = { + [NF_INET_PRE_ROUTING] = "prerouting", + [NF_INET_LOCAL_IN] = "input", + [NF_INET_FORWARD] = "forward", + [NF_INET_LOCAL_OUT] = "output", + [NF_INET_POST_ROUTING] = "postrouting", +}; + +static const char * const arphook2name[] = { + [NF_ARP_IN] = "input", + [NF_ARP_OUT] = "output", +}; + +void netfilter_dump_plain(const struct bpf_link_info *info) +{ + const char *hookname = NULL, *pfname = NULL; + unsigned int hook = info->netfilter.hooknum; + unsigned int pf = info->netfilter.pf; + + if (pf < ARRAY_SIZE(pf2name)) + pfname = pf2name[pf]; + + switch (pf) { + case NFPROTO_BRIDGE: /* bridge shares numbers with enum nf_inet_hooks */ + case NFPROTO_IPV4: + case NFPROTO_IPV6: + case NFPROTO_INET: + if (hook < ARRAY_SIZE(inethook2name)) + hookname = inethook2name[hook]; + break; + case NFPROTO_ARP: + if (hook < ARRAY_SIZE(arphook2name)) + hookname = arphook2name[hook]; + default: + break; + } + + if (pfname) + printf("\n\t%s", pfname); + else + printf("\n\tpf: %d", pf); + + if (hookname) + printf(" %s", hookname); + else + printf(", hook %u,", hook); + + printf(" prio %d", info->netfilter.priority); + + if (info->netfilter.flags) + printf(" flags 0x%x", info->netfilter.flags); +} + static int show_link_close_plain(int fd, struct bpf_link_info *info) { struct bpf_prog_info prog_info; @@ -301,6 +381,9 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info) printf("\n\tnetns_ino %u ", info->netns.netns_ino); show_link_attach_type_plain(info->netns.attach_type); break; + case BPF_LINK_TYPE_NETFILTER: + netfilter_dump_plain(info); + break; default: break; } diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index 00d11ca6d3f2..63d9aa1012a9 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -264,4 +264,7 @@ static inline bool hashmap__empty(struct hashmap *map) return map ? hashmap__size(map) == 0 : true; } +/* print netfilter bpf_link info */ +void netfilter_dump_plain(const struct bpf_link_info *info); +void netfilter_dump_json(const struct bpf_link_info *info, json_writer_t *wtr); #endif diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c index c40e44c938ae..26a49965bf71 100644 --- a/tools/bpf/bpftool/net.c +++ b/tools/bpf/bpftool/net.c @@ -647,6 +647,108 @@ static int do_detach(int argc, char **argv) return 0; } +static int netfilter_link_compar(const void *a, const void *b) +{ + const struct bpf_link_info *nfa = a; + const struct bpf_link_info *nfb = b; + int delta; + + delta = nfa->netfilter.pf - nfb->netfilter.pf; + if (delta) + return delta; + + delta = nfa->netfilter.hooknum - nfb->netfilter.hooknum; + if (delta) + return delta; + + if (nfa->netfilter.priority < nfb->netfilter.priority) + return -1; + if (nfa->netfilter.priority > nfb->netfilter.priority) + return 1; + + return nfa->netfilter.flags - nfb->netfilter.flags; +} + +static void show_link_netfilter(void) +{ + unsigned int nf_link_len = 0, nf_link_count = 0; + struct bpf_link_info *nf_link_info = NULL; + __u32 id = 0; + + while (true) { + struct bpf_link_info info; + int fd, err; + __u32 len; + + err = bpf_link_get_next_id(id, &id); + if (err) { + if (errno == ENOENT) + break; + p_err("can't get next link: %s (id %d)", strerror(errno), id); + break; + } + + fd = bpf_link_get_fd_by_id(id); + if (fd < 0) { + p_err("can't get link by id (%u): %s", id, strerror(errno)); + continue; + } + + memset(&info, 0, sizeof(info)); + len = sizeof(info); + + err = bpf_link_get_info_by_fd(fd, &info, &len); + + close(fd); + + if (err) { + p_err("can't get link info for fd %d: %s", fd, strerror(errno)); + continue; + } + + if (info.type != BPF_LINK_TYPE_NETFILTER) + continue; + + if (nf_link_count >= nf_link_len) { + static const unsigned int max_link_count = INT_MAX / sizeof(info); + struct bpf_link_info *expand; + + if (nf_link_count > max_link_count) { + p_err("cannot handle more than %u links\n", max_link_count); + break; + } + + nf_link_len += 16; + + expand = realloc(nf_link_info, nf_link_len * sizeof(info)); + if (!expand) { + p_err("realloc: %s", strerror(errno)); + break; + } + + nf_link_info = expand; + } + + nf_link_info[nf_link_count] = info; + nf_link_count++; + } + + qsort(nf_link_info, nf_link_count, sizeof(*nf_link_info), netfilter_link_compar); + + for (id = 0; id < nf_link_count; id++) { + NET_START_OBJECT; + if (json_output) + netfilter_dump_json(&nf_link_info[id], json_wtr); + else + netfilter_dump_plain(&nf_link_info[id]); + + NET_DUMP_UINT("id", " prog_id %u", nf_link_info[id].prog_id); + NET_END_OBJECT; + } + + free(nf_link_info); +} + static int do_show(int argc, char **argv) { struct bpf_attach_info attach_info = {}; @@ -701,6 +803,10 @@ static int do_show(int argc, char **argv) NET_DUMP_UINT("id", "id %u", attach_info.flow_dissector_id); NET_END_ARRAY("\n"); + NET_START_ARRAY("netfilter", "%s:\n"); + show_link_netfilter(); + NET_END_ARRAY("\n"); + NET_END_OBJECT; if (json_output) jsonw_end_array(json_wtr); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 4b20a7269bee..1bb11a6ee667 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -986,6 +986,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_LSM, BPF_PROG_TYPE_SK_LOOKUP, BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */ + BPF_PROG_TYPE_NETFILTER, }; enum bpf_attach_type { @@ -1050,6 +1051,7 @@ enum bpf_link_type { BPF_LINK_TYPE_PERF_EVENT = 7, BPF_LINK_TYPE_KPROBE_MULTI = 8, BPF_LINK_TYPE_STRUCT_OPS = 9, + BPF_LINK_TYPE_NETFILTER = 10, MAX_BPF_LINK_TYPE, }; @@ -1560,6 +1562,12 @@ union bpf_attr { */ __u64 cookie; } tracing; + struct { + __u32 pf; + __u32 hooknum; + __s32 priority; + __u32 flags; + } netfilter; }; } link_create; @@ -6410,6 +6418,12 @@ struct bpf_link_info { struct { __u32 map_id; } struct_ops; + struct { + __u32 pf; + __u32 hooknum; + __s32 priority; + __u32 flags; + } netfilter; }; } __attribute__((aligned(8))); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2600d8384252..80127d250f81 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -130,6 +130,7 @@ static const char * const link_type_name[] = { [BPF_LINK_TYPE_PERF_EVENT] = "perf_event", [BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi", [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops", + [BPF_LINK_TYPE_NETFILTER] = "netfilter", }; static const char * const map_type_name[] = { @@ -8710,6 +8711,7 @@ static const struct bpf_sec_def section_defs[] = { SEC_DEF("struct_ops+", STRUCT_OPS, 0, SEC_NONE), SEC_DEF("struct_ops.s+", STRUCT_OPS, 0, SEC_SLEEPABLE), SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE), + SEC_DEF("netfilter", NETFILTER, 0, SEC_NONE), }; static size_t custom_sec_def_cnt; From patchwork Thu Apr 20 12:44:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13218734 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 F188AC77B76 for ; Thu, 20 Apr 2023 12:45:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234536AbjDTMps (ORCPT ); Thu, 20 Apr 2023 08:45:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234109AbjDTMpm (ORCPT ); Thu, 20 Apr 2023 08:45:42 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC276C7; Thu, 20 Apr 2023 05:45:30 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ppTfF-0002aW-4j; Thu, 20 Apr 2023 14:45:29 +0200 From: Florian Westphal To: Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, dxu@dxuuu.xyz, qde@naccy.de, Florian Westphal Subject: [PATCH bpf-next v4 6/7] bpf: add test_run support for netfilter program type Date: Thu, 20 Apr 2023 14:44:54 +0200 Message-Id: <20230420124455.31099-7-fw@strlen.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230420124455.31099-1-fw@strlen.de> References: <20230420124455.31099-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net add glue code so a bpf program can be run using userspace-provided netfilter state and packet/skb. Default is to use ipv4:output hook point, but this can be overridden by userspace. Userspace provided netfilter state is restricted, only hook and protocol families can be overridden and only to ipv4/ipv6. Signed-off-by: Florian Westphal --- include/linux/bpf.h | 3 + net/bpf/test_run.c | 158 ++++++++++++++++++++++++++++++++++++ net/netfilter/nf_bpf_link.c | 1 + 3 files changed, 162 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 18b592fde896..e53ceee1df37 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2264,6 +2264,9 @@ 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 f170e8a17974..e79e3a415ca9 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 @@ -1691,6 +1693,162 @@ 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; +} + +static __be16 nfproto_eth(int nfproto) +{ + switch (nfproto) { + case NFPROTO_IPV4: + return htons(ETH_P_IP); + case NFPROTO_IPV6: + break; + } + + return htons(ETH_P_IPV6); +} + +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_LOCAL_OUT, + }; + u32 size = kattr->test.data_size_in; + u32 repeat = kattr->test.repeat; + 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 < 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); + + 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); + + ret = -EINVAL; + + if (hook_state.hook != NF_INET_LOCAL_OUT) { + if (size < ETH_HLEN + sizeof(struct iphdr)) + goto out; + + skb->protocol = eth_type_trans(skb, dev); + 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; + } + + skb_reset_network_header(skb); + } else { + skb->protocol = nfproto_eth(hook_state.pf); + } + + 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 49cfc5215386..c36da56d756f 100644 --- a/net/netfilter/nf_bpf_link.c +++ b/net/netfilter/nf_bpf_link.c @@ -166,6 +166,7 @@ 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) From patchwork Thu Apr 20 12:44:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13218735 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 3A650C77B72 for ; Thu, 20 Apr 2023 12:45:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234109AbjDTMpv (ORCPT ); Thu, 20 Apr 2023 08:45:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234825AbjDTMps (ORCPT ); Thu, 20 Apr 2023 08:45:48 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB6BD7A97; Thu, 20 Apr 2023 05:45:34 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ppTfJ-0002b1-8Y; Thu, 20 Apr 2023 14:45:33 +0200 From: Florian Westphal To: Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, dxu@dxuuu.xyz, qde@naccy.de, Florian Westphal Subject: [PATCH bpf-next v4 7/7] selftests/bpf: add missing netfilter return value and ctx access tests Date: Thu, 20 Apr 2023 14:44:55 +0200 Message-Id: <20230420124455.31099-8-fw@strlen.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230420124455.31099-1-fw@strlen.de> References: <20230420124455.31099-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Extend prog_tests with two test cases: # ./test_progs --allow=verifier_netfilter_retcode #278/1 verifier_netfilter_retcode/bpf_exit with invalid return code. test1:OK #278/2 verifier_netfilter_retcode/bpf_exit with valid return code. test2:OK #278/3 verifier_netfilter_retcode/bpf_exit with valid return code. test3:OK #278/4 verifier_netfilter_retcode/bpf_exit with invalid return code. test4:OK #278 verifier_netfilter_retcode:OK This checks that only accept and drop (0,1) are permitted. NF_QUEUE could be implemented later if 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 can guarantee that the skb will eventually be free'd. v4: test case for bpf_nf_ctx access checks, requested by Alexei Starovoitov. # ./test_progs --allow=verifier_netfilter_ctx #280/1 verifier_netfilter_ctx/netfilter invalid context access, size too short:OK #280/2 verifier_netfilter_ctx/netfilter invalid context access, size too short:OK #280/3 verifier_netfilter_ctx/netfilter invalid context access, past end of ctx:OK #280/4 verifier_netfilter_ctx/netfilter invalid context, write:OK #280/5 verifier_netfilter_ctx/netfilter valid context access:OK #280/6 verifier_netfilter_ctx/netfilter valid context access @unpriv:OK #280 verifier_netfilter_ctx:OK Summary: 1/6 PASSED, 0 SKIPPED, 0 FAILED This checks: 1/2: partial reads of ctx->{skb,state} are rejected 3. read access past sizeof(ctx) is rejected 4. write to ctx content, e.g. 'ctx->skb = NULL;' is rejected 5. ctx->skb and ctx->state can be read (valid case), but ... 6. ... same program fails for unpriv (CAP_NET_ADMIN needed). Link: https://lore.kernel.org/bpf/20230419021152.sjq4gttphzzy6b5f@dhcp-172-26-102-232.dhcp.thefacebook.com/ Signed-off-by: Florian Westphal --- .../selftests/bpf/prog_tests/verifier.c | 4 + .../bpf/progs/verifier_netfilter_ctx.c | 82 +++++++++++++++++++ .../bpf/progs/verifier_netfilter_retcode.c | 49 +++++++++++ 3 files changed, 135 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/verifier_netfilter_ctx.c create mode 100644 tools/testing/selftests/bpf/progs/verifier_netfilter_retcode.c diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index 25bc8958dbfe..2b4ded63ce9f 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c @@ -29,6 +29,8 @@ #include "verifier_map_ret_val.skel.h" #include "verifier_masking.skel.h" #include "verifier_meta_access.skel.h" +#include "verifier_netfilter_ctx.skel.h" +#include "verifier_netfilter_retcode.skel.h" #include "verifier_raw_stack.skel.h" #include "verifier_raw_tp_writable.skel.h" #include "verifier_reg_equal.skel.h" @@ -94,6 +96,8 @@ void test_verifier_map_ptr(void) { RUN(verifier_map_ptr); } void test_verifier_map_ret_val(void) { RUN(verifier_map_ret_val); } void test_verifier_masking(void) { RUN(verifier_masking); } void test_verifier_meta_access(void) { RUN(verifier_meta_access); } +void test_verifier_netfilter_ctx(void) { RUN(verifier_netfilter_ctx); } +void test_verifier_netfilter_retcode(void) { RUN(verifier_netfilter_retcode); } void test_verifier_raw_stack(void) { RUN(verifier_raw_stack); } void test_verifier_raw_tp_writable(void) { RUN(verifier_raw_tp_writable); } void test_verifier_reg_equal(void) { RUN(verifier_reg_equal); } diff --git a/tools/testing/selftests/bpf/progs/verifier_netfilter_ctx.c b/tools/testing/selftests/bpf/progs/verifier_netfilter_ctx.c new file mode 100644 index 000000000000..861b2266179f --- /dev/null +++ b/tools/testing/selftests/bpf/progs/verifier_netfilter_ctx.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "vmlinux.h" + +#include "bpf_misc.h" + +#include +#include + +SEC("netfilter") +__description("netfilter invalid context access, size too short") +__failure __msg("invalid bpf_context access") +__naked void with_invalid_ctx_access_test1(void) +{ + asm volatile (" \ + r2 = *(u8*)(r1 + %[__bpf_nf_ctx_state]); \ + r0 = 0; \ + exit; \ +" : + : __imm_const(__bpf_nf_ctx_state, offsetof(struct bpf_nf_ctx, state)) + : __clobber_all); +} + +SEC("netfilter") +__description("netfilter invalid context access, size too short") +__failure __msg("invalid bpf_context access") +__naked void with_invalid_ctx_access_test2(void) +{ + asm volatile (" \ + r2 = *(u16*)(r1 + %[__bpf_nf_ctx_skb]); \ + r0 = 0; \ + exit; \ +" : + : __imm_const(__bpf_nf_ctx_skb, offsetof(struct bpf_nf_ctx, skb)) + : __clobber_all); +} + +SEC("netfilter") +__description("netfilter invalid context access, past end of ctx") +__failure __msg("invalid bpf_context access") +__naked void with_invalid_ctx_access_test3(void) +{ + asm volatile (" \ + r2 = *(u64*)(r1 + %[__bpf_nf_ctx_size]); \ + r0 = 0; \ + exit; \ +" : + : __imm_const(__bpf_nf_ctx_size, sizeof(struct bpf_nf_ctx)) + : __clobber_all); +} + +SEC("netfilter") +__description("netfilter invalid context, write") +__failure __msg("invalid bpf_context access") +__naked void with_invalid_ctx_access_test4(void) +{ + asm volatile (" \ + r2 = r1; \ + *(u64*)(r2 + 0) = r1; \ + r0 = 1; \ + exit; \ +" : + : __imm_const(__bpf_nf_ctx_skb, offsetof(struct bpf_nf_ctx, skb)) + : __clobber_all); +} + +SEC("netfilter") +__description("netfilter valid context access") +__success __failure_unpriv +__retval(1) +__naked void with_invalid_ctx_access_test5(void) +{ + asm volatile (" \ + r2 = *(u64*)(r1 + %[__bpf_nf_ctx_state]); \ + r1 = *(u64*)(r1 + %[__bpf_nf_ctx_skb]); \ + r0 = 1; \ + exit; \ +" : + : __imm_const(__bpf_nf_ctx_state, offsetof(struct bpf_nf_ctx, state)), + __imm_const(__bpf_nf_ctx_skb, offsetof(struct bpf_nf_ctx, skb)) + : __clobber_all); +} diff --git a/tools/testing/selftests/bpf/progs/verifier_netfilter_retcode.c b/tools/testing/selftests/bpf/progs/verifier_netfilter_retcode.c new file mode 100644 index 000000000000..353ae6da00e1 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/verifier_netfilter_retcode.c @@ -0,0 +1,49 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include "bpf_misc.h" + +SEC("netfilter") +__description("bpf_exit with invalid return code. test1") +__failure __msg("R0 is not a known value") +__naked void with_invalid_return_code_test1(void) +{ + asm volatile (" \ + r0 = *(u64*)(r1 + 0); \ + exit; \ +" ::: __clobber_all); +} + +SEC("netfilter") +__description("bpf_exit with valid return code. test2") +__success +__naked void with_valid_return_code_test2(void) +{ + asm volatile (" \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("netfilter") +__description("bpf_exit with valid return code. test3") +__success +__naked void with_valid_return_code_test3(void) +{ + asm volatile (" \ + r0 = 1; \ + exit; \ +" ::: __clobber_all); +} + +SEC("netfilter") +__description("bpf_exit with invalid return code. test4") +__failure __msg("R0 has value (0x2; 0x0)") +__naked void with_invalid_return_code_test4(void) +{ + asm volatile (" \ + r0 = 2; \ + exit; \ +" ::: __clobber_all); +}