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author | David S. Miller <davem@davemloft.net> | 2020-02-29 15:53:35 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2020-02-29 15:53:35 -0800 |
commit | 9f0ca0c1a50a7de5c71970aa452941199ed210d9 (patch) | |
tree | b7e19ab2e5bbc951141fb90489923b50b8f263f3 /net/core/bpf_sk_storage.c | |
parent | 9a834f9b04bc5ed2db27eb45b0cc6415ce7c314c (diff) | |
parent | 812285fa5ab129e3a55682314bf235f701564310 (diff) | |
download | linux-9f0ca0c1a50a7de5c71970aa452941199ed210d9.tar.bz2 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:
====================
pull-request: bpf-next 2020-02-28
The following pull-request contains BPF updates for your *net-next* tree.
We've added 41 non-merge commits during the last 7 day(s) which contain
a total of 49 files changed, 1383 insertions(+), 499 deletions(-).
The main changes are:
1) BPF and Real-Time nicely co-exist.
2) bpftool feature improvements.
3) retrieve bpf_sk_storage via INET_DIAG.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/bpf_sk_storage.c')
-rw-r--r-- | net/core/bpf_sk_storage.c | 283 |
1 files changed, 277 insertions, 6 deletions
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 427cfbc0d50d..756b63b6f7b3 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -8,6 +8,7 @@ #include <linux/bpf.h> #include <net/bpf_sk_storage.h> #include <net/sock.h> +#include <uapi/linux/sock_diag.h> #include <uapi/linux/btf.h> static atomic_t cache_idx; @@ -606,6 +607,14 @@ static void bpf_sk_storage_map_free(struct bpf_map *map) kfree(map); } +/* U16_MAX is much more than enough for sk local storage + * considering a tcp_sock is ~2k. + */ +#define MAX_VALUE_SIZE \ + min_t(u32, \ + (KMALLOC_MAX_SIZE - MAX_BPF_STACK - sizeof(struct bpf_sk_storage_elem)), \ + (U16_MAX - sizeof(struct bpf_sk_storage_elem))) + static int bpf_sk_storage_map_alloc_check(union bpf_attr *attr) { if (attr->map_flags & ~SK_STORAGE_CREATE_FLAG_MASK || @@ -619,12 +628,7 @@ static int bpf_sk_storage_map_alloc_check(union bpf_attr *attr) if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (attr->value_size >= KMALLOC_MAX_SIZE - - MAX_BPF_STACK - sizeof(struct bpf_sk_storage_elem) || - /* U16_MAX is much more than enough for sk local storage - * considering a tcp_sock is ~2k. - */ - attr->value_size > U16_MAX - sizeof(struct bpf_sk_storage_elem)) + if (attr->value_size > MAX_VALUE_SIZE) return -E2BIG; return 0; @@ -910,3 +914,270 @@ const struct bpf_func_proto bpf_sk_storage_delete_proto = { .arg1_type = ARG_CONST_MAP_PTR, .arg2_type = ARG_PTR_TO_SOCKET, }; + +struct bpf_sk_storage_diag { + u32 nr_maps; + struct bpf_map *maps[]; +}; + +/* The reply will be like: + * INET_DIAG_BPF_SK_STORAGES (nla_nest) + * SK_DIAG_BPF_STORAGE (nla_nest) + * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32) + * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit) + * SK_DIAG_BPF_STORAGE (nla_nest) + * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32) + * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit) + * .... + */ +static int nla_value_size(u32 value_size) +{ + /* SK_DIAG_BPF_STORAGE (nla_nest) + * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32) + * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit) + */ + return nla_total_size(0) + nla_total_size(sizeof(u32)) + + nla_total_size_64bit(value_size); +} + +void bpf_sk_storage_diag_free(struct bpf_sk_storage_diag *diag) +{ + u32 i; + + if (!diag) + return; + + for (i = 0; i < diag->nr_maps; i++) + bpf_map_put(diag->maps[i]); + + kfree(diag); +} +EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_free); + +static bool diag_check_dup(const struct bpf_sk_storage_diag *diag, + const struct bpf_map *map) +{ + u32 i; + + for (i = 0; i < diag->nr_maps; i++) { + if (diag->maps[i] == map) + return true; + } + + return false; +} + +struct bpf_sk_storage_diag * +bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs) +{ + struct bpf_sk_storage_diag *diag; + struct nlattr *nla; + u32 nr_maps = 0; + int rem, err; + + /* bpf_sk_storage_map is currently limited to CAP_SYS_ADMIN as + * the map_alloc_check() side also does. + */ + if (!capable(CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + + nla_for_each_nested(nla, nla_stgs, rem) { + if (nla_type(nla) == SK_DIAG_BPF_STORAGE_REQ_MAP_FD) + nr_maps++; + } + + diag = kzalloc(sizeof(*diag) + sizeof(diag->maps[0]) * nr_maps, + GFP_KERNEL); + if (!diag) + return ERR_PTR(-ENOMEM); + + nla_for_each_nested(nla, nla_stgs, rem) { + struct bpf_map *map; + int map_fd; + + if (nla_type(nla) != SK_DIAG_BPF_STORAGE_REQ_MAP_FD) + continue; + + map_fd = nla_get_u32(nla); + map = bpf_map_get(map_fd); + if (IS_ERR(map)) { + err = PTR_ERR(map); + goto err_free; + } + if (map->map_type != BPF_MAP_TYPE_SK_STORAGE) { + bpf_map_put(map); + err = -EINVAL; + goto err_free; + } + if (diag_check_dup(diag, map)) { + bpf_map_put(map); + err = -EEXIST; + goto err_free; + } + diag->maps[diag->nr_maps++] = map; + } + + return diag; + +err_free: + bpf_sk_storage_diag_free(diag); + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_alloc); + +static int diag_get(struct bpf_sk_storage_data *sdata, struct sk_buff *skb) +{ + struct nlattr *nla_stg, *nla_value; + struct bpf_sk_storage_map *smap; + + /* It cannot exceed max nlattr's payload */ + BUILD_BUG_ON(U16_MAX - NLA_HDRLEN < MAX_VALUE_SIZE); + + nla_stg = nla_nest_start(skb, SK_DIAG_BPF_STORAGE); + if (!nla_stg) + return -EMSGSIZE; + + smap = rcu_dereference(sdata->smap); + if (nla_put_u32(skb, SK_DIAG_BPF_STORAGE_MAP_ID, smap->map.id)) + goto errout; + + nla_value = nla_reserve_64bit(skb, SK_DIAG_BPF_STORAGE_MAP_VALUE, + smap->map.value_size, + SK_DIAG_BPF_STORAGE_PAD); + if (!nla_value) + goto errout; + + if (map_value_has_spin_lock(&smap->map)) + copy_map_value_locked(&smap->map, nla_data(nla_value), + sdata->data, true); + else + copy_map_value(&smap->map, nla_data(nla_value), sdata->data); + + nla_nest_end(skb, nla_stg); + return 0; + +errout: + nla_nest_cancel(skb, nla_stg); + return -EMSGSIZE; +} + +static int bpf_sk_storage_diag_put_all(struct sock *sk, struct sk_buff *skb, + int stg_array_type, + unsigned int *res_diag_size) +{ + /* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */ + unsigned int diag_size = nla_total_size(0); + struct bpf_sk_storage *sk_storage; + struct bpf_sk_storage_elem *selem; + struct bpf_sk_storage_map *smap; + struct nlattr *nla_stgs; + unsigned int saved_len; + int err = 0; + + rcu_read_lock(); + + sk_storage = rcu_dereference(sk->sk_bpf_storage); + if (!sk_storage || hlist_empty(&sk_storage->list)) { + rcu_read_unlock(); + return 0; + } + + nla_stgs = nla_nest_start(skb, stg_array_type); + if (!nla_stgs) + /* Continue to learn diag_size */ + err = -EMSGSIZE; + + saved_len = skb->len; + hlist_for_each_entry_rcu(selem, &sk_storage->list, snode) { + smap = rcu_dereference(SDATA(selem)->smap); + diag_size += nla_value_size(smap->map.value_size); + + if (nla_stgs && diag_get(SDATA(selem), skb)) + /* Continue to learn diag_size */ + err = -EMSGSIZE; + } + + rcu_read_unlock(); + + if (nla_stgs) { + if (saved_len == skb->len) + nla_nest_cancel(skb, nla_stgs); + else + nla_nest_end(skb, nla_stgs); + } + + if (diag_size == nla_total_size(0)) { + *res_diag_size = 0; + return 0; + } + + *res_diag_size = diag_size; + return err; +} + +int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag, + struct sock *sk, struct sk_buff *skb, + int stg_array_type, + unsigned int *res_diag_size) +{ + /* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */ + unsigned int diag_size = nla_total_size(0); + struct bpf_sk_storage *sk_storage; + struct bpf_sk_storage_data *sdata; + struct nlattr *nla_stgs; + unsigned int saved_len; + int err = 0; + u32 i; + + *res_diag_size = 0; + + /* No map has been specified. Dump all. */ + if (!diag->nr_maps) + return bpf_sk_storage_diag_put_all(sk, skb, stg_array_type, + res_diag_size); + + rcu_read_lock(); + sk_storage = rcu_dereference(sk->sk_bpf_storage); + if (!sk_storage || hlist_empty(&sk_storage->list)) { + rcu_read_unlock(); + return 0; + } + + nla_stgs = nla_nest_start(skb, stg_array_type); + if (!nla_stgs) + /* Continue to learn diag_size */ + err = -EMSGSIZE; + + saved_len = skb->len; + for (i = 0; i < diag->nr_maps; i++) { + sdata = __sk_storage_lookup(sk_storage, + (struct bpf_sk_storage_map *)diag->maps[i], + false); + + if (!sdata) + continue; + + diag_size += nla_value_size(diag->maps[i]->value_size); + + if (nla_stgs && diag_get(sdata, skb)) + /* Continue to learn diag_size */ + err = -EMSGSIZE; + } + rcu_read_unlock(); + + if (nla_stgs) { + if (saved_len == skb->len) + nla_nest_cancel(skb, nla_stgs); + else + nla_nest_end(skb, nla_stgs); + } + + if (diag_size == nla_total_size(0)) { + *res_diag_size = 0; + return 0; + } + + *res_diag_size = diag_size; + return err; +} +EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_put); |