diff options
Diffstat (limited to 'kernel/bpf/net_namespace.c')
| -rw-r--r-- | kernel/bpf/net_namespace.c | 139 |
1 files changed, 129 insertions, 10 deletions
diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c index 310241ca7991..542f275bf252 100644 --- a/kernel/bpf/net_namespace.c +++ b/kernel/bpf/net_namespace.c @@ -25,6 +25,32 @@ struct bpf_netns_link { /* Protects updates to netns_bpf */ DEFINE_MUTEX(netns_bpf_mutex); +static void netns_bpf_attach_type_unneed(enum netns_bpf_attach_type type) +{ + switch (type) { +#ifdef CONFIG_INET + case NETNS_BPF_SK_LOOKUP: + static_branch_dec(&bpf_sk_lookup_enabled); + break; +#endif + default: + break; + } +} + +static void netns_bpf_attach_type_need(enum netns_bpf_attach_type type) +{ + switch (type) { +#ifdef CONFIG_INET + case NETNS_BPF_SK_LOOKUP: + static_branch_inc(&bpf_sk_lookup_enabled); + break; +#endif + default: + break; + } +} + /* Must be called with netns_bpf_mutex held. */ static void netns_bpf_run_array_detach(struct net *net, enum netns_bpf_attach_type type) @@ -36,12 +62,50 @@ static void netns_bpf_run_array_detach(struct net *net, bpf_prog_array_free(run_array); } +static int link_index(struct net *net, enum netns_bpf_attach_type type, + struct bpf_netns_link *link) +{ + struct bpf_netns_link *pos; + int i = 0; + + list_for_each_entry(pos, &net->bpf.links[type], node) { + if (pos == link) + return i; + i++; + } + return -ENOENT; +} + +static int link_count(struct net *net, enum netns_bpf_attach_type type) +{ + struct list_head *pos; + int i = 0; + + list_for_each(pos, &net->bpf.links[type]) + i++; + return i; +} + +static void fill_prog_array(struct net *net, enum netns_bpf_attach_type type, + struct bpf_prog_array *prog_array) +{ + struct bpf_netns_link *pos; + unsigned int i = 0; + + list_for_each_entry(pos, &net->bpf.links[type], node) { + prog_array->items[i].prog = pos->link.prog; + i++; + } +} + static void bpf_netns_link_release(struct bpf_link *link) { struct bpf_netns_link *net_link = container_of(link, struct bpf_netns_link, link); enum netns_bpf_attach_type type = net_link->netns_type; + struct bpf_prog_array *old_array, *new_array; struct net *net; + int cnt, idx; mutex_lock(&netns_bpf_mutex); @@ -53,13 +117,41 @@ static void bpf_netns_link_release(struct bpf_link *link) if (!net) goto out_unlock; - netns_bpf_run_array_detach(net, type); + /* Mark attach point as unused */ + netns_bpf_attach_type_unneed(type); + + /* Remember link position in case of safe delete */ + idx = link_index(net, type, net_link); list_del(&net_link->node); + cnt = link_count(net, type); + if (!cnt) { + netns_bpf_run_array_detach(net, type); + goto out_unlock; + } + + old_array = rcu_dereference_protected(net->bpf.run_array[type], + lockdep_is_held(&netns_bpf_mutex)); + new_array = bpf_prog_array_alloc(cnt, GFP_KERNEL); + if (!new_array) { + WARN_ON(bpf_prog_array_delete_safe_at(old_array, idx)); + goto out_unlock; + } + fill_prog_array(net, type, new_array); + rcu_assign_pointer(net->bpf.run_array[type], new_array); + bpf_prog_array_free(old_array); + out_unlock: + net_link->net = NULL; mutex_unlock(&netns_bpf_mutex); } +static int bpf_netns_link_detach(struct bpf_link *link) +{ + bpf_netns_link_release(link); + return 0; +} + static void bpf_netns_link_dealloc(struct bpf_link *link) { struct bpf_netns_link *net_link = @@ -77,7 +169,7 @@ static int bpf_netns_link_update_prog(struct bpf_link *link, enum netns_bpf_attach_type type = net_link->netns_type; struct bpf_prog_array *run_array; struct net *net; - int ret = 0; + int idx, ret; if (old_prog && old_prog != link->prog) return -EPERM; @@ -95,7 +187,10 @@ static int bpf_netns_link_update_prog(struct bpf_link *link, run_array = rcu_dereference_protected(net->bpf.run_array[type], lockdep_is_held(&netns_bpf_mutex)); - WRITE_ONCE(run_array->items[0].prog, new_prog); + idx = link_index(net, type, net_link); + ret = bpf_prog_array_update_at(run_array, idx, new_prog); + if (ret) + goto out_unlock; old_prog = xchg(&link->prog, new_prog); bpf_prog_put(old_prog); @@ -140,6 +235,7 @@ static void bpf_netns_link_show_fdinfo(const struct bpf_link *link, static const struct bpf_link_ops bpf_netns_link_ops = { .release = bpf_netns_link_release, .dealloc = bpf_netns_link_dealloc, + .detach = bpf_netns_link_detach, .update_prog = bpf_netns_link_update_prog, .fill_link_info = bpf_netns_link_fill_info, .show_fdinfo = bpf_netns_link_show_fdinfo, @@ -309,18 +405,30 @@ int netns_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype) return ret; } +static int netns_bpf_max_progs(enum netns_bpf_attach_type type) +{ + switch (type) { + case NETNS_BPF_FLOW_DISSECTOR: + return 1; + case NETNS_BPF_SK_LOOKUP: + return 64; + default: + return 0; + } +} + static int netns_bpf_link_attach(struct net *net, struct bpf_link *link, enum netns_bpf_attach_type type) { struct bpf_netns_link *net_link = container_of(link, struct bpf_netns_link, link); struct bpf_prog_array *run_array; - int err; + int cnt, err; mutex_lock(&netns_bpf_mutex); - /* Allow attaching only one prog or link for now */ - if (!list_empty(&net->bpf.links[type])) { + cnt = link_count(net, type); + if (cnt >= netns_bpf_max_progs(type)) { err = -E2BIG; goto out_unlock; } @@ -334,6 +442,9 @@ static int netns_bpf_link_attach(struct net *net, struct bpf_link *link, case NETNS_BPF_FLOW_DISSECTOR: err = flow_dissector_bpf_prog_attach_check(net, link->prog); break; + case NETNS_BPF_SK_LOOKUP: + err = 0; /* nothing to check */ + break; default: err = -EINVAL; break; @@ -341,16 +452,22 @@ static int netns_bpf_link_attach(struct net *net, struct bpf_link *link, if (err) goto out_unlock; - run_array = bpf_prog_array_alloc(1, GFP_KERNEL); + run_array = bpf_prog_array_alloc(cnt + 1, GFP_KERNEL); if (!run_array) { err = -ENOMEM; goto out_unlock; } - run_array->items[0].prog = link->prog; - rcu_assign_pointer(net->bpf.run_array[type], run_array); list_add_tail(&net_link->node, &net->bpf.links[type]); + fill_prog_array(net, type, run_array); + run_array = rcu_replace_pointer(net->bpf.run_array[type], run_array, + lockdep_is_held(&netns_bpf_mutex)); + bpf_prog_array_free(run_array); + + /* Mark attach point as used */ + netns_bpf_attach_type_need(type); + out_unlock: mutex_unlock(&netns_bpf_mutex); return err; @@ -426,8 +543,10 @@ static void __net_exit netns_bpf_pernet_pre_exit(struct net *net) mutex_lock(&netns_bpf_mutex); for (type = 0; type < MAX_NETNS_BPF_ATTACH_TYPE; type++) { netns_bpf_run_array_detach(net, type); - list_for_each_entry(net_link, &net->bpf.links[type], node) + list_for_each_entry(net_link, &net->bpf.links[type], node) { net_link->net = NULL; /* auto-detach link */ + netns_bpf_attach_type_unneed(type); + } if (net->bpf.progs[type]) bpf_prog_put(net->bpf.progs[type]); } |