mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-27 04:47:05 +00:00
d17aff807f
This patch includes the following revert (one conflicting BPF FS patch and three token patch sets, represented by merge commits): - revert0f5d5454c7
"Merge branch 'bpf-fs-mount-options-parsing-follow-ups'"; - revert750e785796
"bpf: Support uid and gid when mounting bpffs"; - revert733763285a
"Merge branch 'bpf-token-support-in-libbpf-s-bpf-object'"; - revertc35919dcce
"Merge branch 'bpf-token-and-bpf-fs-based-delegation'". Link: https://lore.kernel.org/bpf/CAHk-=wg7JuFYwGy=GOMbRCtOL+jwSQsdUaBsRWkDVYbxipbM5A@mail.gmail.com Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
323 lines
7.6 KiB
C
323 lines
7.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/bpf.h>
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#include <linux/filter.h>
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#include <linux/kmod.h>
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#include <linux/module.h>
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#include <linux/netfilter.h>
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#include <net/netfilter/nf_bpf_link.h>
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#include <uapi/linux/netfilter_ipv4.h>
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static unsigned int nf_hook_run_bpf(void *bpf_prog, struct sk_buff *skb,
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const struct nf_hook_state *s)
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{
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const struct bpf_prog *prog = bpf_prog;
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struct bpf_nf_ctx ctx = {
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.state = s,
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.skb = skb,
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};
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return bpf_prog_run(prog, &ctx);
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}
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struct bpf_nf_link {
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struct bpf_link link;
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struct nf_hook_ops hook_ops;
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struct net *net;
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u32 dead;
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const struct nf_defrag_hook *defrag_hook;
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};
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#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4) || IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
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static const struct nf_defrag_hook *
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get_proto_defrag_hook(struct bpf_nf_link *link,
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const struct nf_defrag_hook __rcu **ptr_global_hook,
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const char *mod)
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{
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const struct nf_defrag_hook *hook;
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int err;
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/* RCU protects us from races against module unloading */
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rcu_read_lock();
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hook = rcu_dereference(*ptr_global_hook);
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if (!hook) {
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rcu_read_unlock();
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err = request_module(mod);
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if (err)
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return ERR_PTR(err < 0 ? err : -EINVAL);
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rcu_read_lock();
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hook = rcu_dereference(*ptr_global_hook);
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}
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if (hook && try_module_get(hook->owner)) {
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/* Once we have a refcnt on the module, we no longer need RCU */
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hook = rcu_pointer_handoff(hook);
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} else {
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WARN_ONCE(!hook, "%s has bad registration", mod);
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hook = ERR_PTR(-ENOENT);
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}
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rcu_read_unlock();
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if (!IS_ERR(hook)) {
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err = hook->enable(link->net);
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if (err) {
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module_put(hook->owner);
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hook = ERR_PTR(err);
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}
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}
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return hook;
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}
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#endif
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static int bpf_nf_enable_defrag(struct bpf_nf_link *link)
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{
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const struct nf_defrag_hook __maybe_unused *hook;
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switch (link->hook_ops.pf) {
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#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
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case NFPROTO_IPV4:
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hook = get_proto_defrag_hook(link, &nf_defrag_v4_hook, "nf_defrag_ipv4");
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if (IS_ERR(hook))
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return PTR_ERR(hook);
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link->defrag_hook = hook;
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return 0;
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#endif
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#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
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case NFPROTO_IPV6:
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hook = get_proto_defrag_hook(link, &nf_defrag_v6_hook, "nf_defrag_ipv6");
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if (IS_ERR(hook))
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return PTR_ERR(hook);
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link->defrag_hook = hook;
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return 0;
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#endif
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default:
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return -EAFNOSUPPORT;
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}
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}
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static void bpf_nf_disable_defrag(struct bpf_nf_link *link)
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{
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const struct nf_defrag_hook *hook = link->defrag_hook;
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if (!hook)
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return;
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hook->disable(link->net);
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module_put(hook->owner);
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}
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static void bpf_nf_link_release(struct bpf_link *link)
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{
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struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link);
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if (nf_link->dead)
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return;
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/* do not double release in case .detach was already called */
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if (!cmpxchg(&nf_link->dead, 0, 1)) {
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nf_unregister_net_hook(nf_link->net, &nf_link->hook_ops);
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bpf_nf_disable_defrag(nf_link);
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}
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}
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static void bpf_nf_link_dealloc(struct bpf_link *link)
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{
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struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link);
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kfree(nf_link);
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}
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static int bpf_nf_link_detach(struct bpf_link *link)
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{
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bpf_nf_link_release(link);
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return 0;
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}
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static void bpf_nf_link_show_info(const struct bpf_link *link,
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struct seq_file *seq)
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{
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struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link);
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seq_printf(seq, "pf:\t%u\thooknum:\t%u\tprio:\t%d\n",
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nf_link->hook_ops.pf, nf_link->hook_ops.hooknum,
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nf_link->hook_ops.priority);
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}
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static int bpf_nf_link_fill_link_info(const struct bpf_link *link,
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struct bpf_link_info *info)
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{
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struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link);
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info->netfilter.pf = nf_link->hook_ops.pf;
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info->netfilter.hooknum = nf_link->hook_ops.hooknum;
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info->netfilter.priority = nf_link->hook_ops.priority;
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info->netfilter.flags = 0;
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return 0;
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}
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static int bpf_nf_link_update(struct bpf_link *link, struct bpf_prog *new_prog,
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struct bpf_prog *old_prog)
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{
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return -EOPNOTSUPP;
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}
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static const struct bpf_link_ops bpf_nf_link_lops = {
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.release = bpf_nf_link_release,
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.dealloc = bpf_nf_link_dealloc,
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.detach = bpf_nf_link_detach,
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.show_fdinfo = bpf_nf_link_show_info,
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.fill_link_info = bpf_nf_link_fill_link_info,
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.update_prog = bpf_nf_link_update,
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};
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static int bpf_nf_check_pf_and_hooks(const union bpf_attr *attr)
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{
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int prio;
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switch (attr->link_create.netfilter.pf) {
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case NFPROTO_IPV4:
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case NFPROTO_IPV6:
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if (attr->link_create.netfilter.hooknum >= NF_INET_NUMHOOKS)
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return -EPROTO;
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break;
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default:
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return -EAFNOSUPPORT;
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}
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if (attr->link_create.netfilter.flags & ~BPF_F_NETFILTER_IP_DEFRAG)
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return -EOPNOTSUPP;
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/* make sure conntrack confirm is always last */
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prio = attr->link_create.netfilter.priority;
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if (prio == NF_IP_PRI_FIRST)
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return -ERANGE; /* sabotage_in and other warts */
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else if (prio == NF_IP_PRI_LAST)
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return -ERANGE; /* e.g. conntrack confirm */
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else if ((attr->link_create.netfilter.flags & BPF_F_NETFILTER_IP_DEFRAG) &&
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prio <= NF_IP_PRI_CONNTRACK_DEFRAG)
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return -ERANGE; /* cannot use defrag if prog runs before nf_defrag */
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return 0;
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}
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int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
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{
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struct net *net = current->nsproxy->net_ns;
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struct bpf_link_primer link_primer;
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struct bpf_nf_link *link;
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int err;
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if (attr->link_create.flags)
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return -EINVAL;
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err = bpf_nf_check_pf_and_hooks(attr);
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if (err)
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return err;
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link = kzalloc(sizeof(*link), GFP_USER);
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if (!link)
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return -ENOMEM;
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bpf_link_init(&link->link, BPF_LINK_TYPE_NETFILTER, &bpf_nf_link_lops, prog);
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link->hook_ops.hook = nf_hook_run_bpf;
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link->hook_ops.hook_ops_type = NF_HOOK_OP_BPF;
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link->hook_ops.priv = prog;
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link->hook_ops.pf = attr->link_create.netfilter.pf;
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link->hook_ops.priority = attr->link_create.netfilter.priority;
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link->hook_ops.hooknum = attr->link_create.netfilter.hooknum;
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link->net = net;
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link->dead = false;
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link->defrag_hook = NULL;
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err = bpf_link_prime(&link->link, &link_primer);
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if (err) {
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kfree(link);
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return err;
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}
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if (attr->link_create.netfilter.flags & BPF_F_NETFILTER_IP_DEFRAG) {
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err = bpf_nf_enable_defrag(link);
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if (err) {
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bpf_link_cleanup(&link_primer);
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return err;
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}
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}
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err = nf_register_net_hook(net, &link->hook_ops);
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if (err) {
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bpf_nf_disable_defrag(link);
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bpf_link_cleanup(&link_primer);
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return err;
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}
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return bpf_link_settle(&link_primer);
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}
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const struct bpf_prog_ops netfilter_prog_ops = {
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.test_run = bpf_prog_test_run_nf,
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};
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static bool nf_ptr_to_btf_id(struct bpf_insn_access_aux *info, const char *name)
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{
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struct btf *btf;
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s32 type_id;
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btf = bpf_get_btf_vmlinux();
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if (IS_ERR_OR_NULL(btf))
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return false;
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type_id = btf_find_by_name_kind(btf, name, BTF_KIND_STRUCT);
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if (WARN_ON_ONCE(type_id < 0))
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return false;
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info->btf = btf;
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info->btf_id = type_id;
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info->reg_type = PTR_TO_BTF_ID | PTR_TRUSTED;
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return true;
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}
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static bool nf_is_valid_access(int off, int size, enum bpf_access_type type,
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const struct bpf_prog *prog,
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struct bpf_insn_access_aux *info)
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{
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if (off < 0 || off >= sizeof(struct bpf_nf_ctx))
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return false;
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if (type == BPF_WRITE)
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return false;
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switch (off) {
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case bpf_ctx_range(struct bpf_nf_ctx, skb):
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if (size != sizeof_field(struct bpf_nf_ctx, skb))
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return false;
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return nf_ptr_to_btf_id(info, "sk_buff");
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case bpf_ctx_range(struct bpf_nf_ctx, state):
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if (size != sizeof_field(struct bpf_nf_ctx, state))
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return false;
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return nf_ptr_to_btf_id(info, "nf_hook_state");
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default:
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return false;
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}
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return false;
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}
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static const struct bpf_func_proto *
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bpf_nf_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
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{
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return bpf_base_func_proto(func_id);
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}
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const struct bpf_verifier_ops netfilter_verifier_ops = {
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.is_valid_access = nf_is_valid_access,
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.get_func_proto = bpf_nf_func_proto,
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};
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