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authorYonghong Song <yhs@fb.com>2020-08-05 08:50:56 +0300
committerAlexei Starovoitov <ast@kernel.org>2020-08-07 02:39:14 +0300
commit5e7b30205cef80f6bb922e61834437ca7bff5837 (patch)
tree801934cf852ef6e5574ad7e489d299ead055b939 /net/core
parent6bcaf41f9613278cd5897fc80ab93033bda8efaa (diff)
downloadlinux-5e7b30205cef80f6bb922e61834437ca7bff5837.tar.xz
bpf: Change uapi for bpf iterator map elements
Commit a5cbe05a6673 ("bpf: Implement bpf iterator for map elements") added bpf iterator support for map elements. The map element bpf iterator requires info to identify a particular map. In the above commit, the attr->link_create.target_fd is used to carry map_fd and an enum bpf_iter_link_info is added to uapi to specify the target_fd actually representing a map_fd: enum bpf_iter_link_info { BPF_ITER_LINK_UNSPEC = 0, BPF_ITER_LINK_MAP_FD = 1, MAX_BPF_ITER_LINK_INFO, }; This is an extensible approach as we can grow enumerator for pid, cgroup_id, etc. and we can unionize target_fd for pid, cgroup_id, etc. But in the future, there are chances that more complex customization may happen, e.g., for tasks, it could be filtered based on both cgroup_id and user_id. This patch changed the uapi to have fields __aligned_u64 iter_info; __u32 iter_info_len; for additional iter_info for link_create. The iter_info is defined as union bpf_iter_link_info { struct { __u32 map_fd; } map; }; So future extension for additional customization will be easier. The bpf_iter_link_info will be passed to target callback to validate and generic bpf_iter framework does not need to deal it any more. Note that map_fd = 0 will be considered invalid and -EBADF will be returned to user space. Fixes: a5cbe05a6673 ("bpf: Implement bpf iterator for map elements") Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200805055056.1457463-1-yhs@fb.com
Diffstat (limited to 'net/core')
-rw-r--r--net/core/bpf_sk_storage.c37
1 files changed, 29 insertions, 8 deletions
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index d3377c90a291..b988f48153a4 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -1384,18 +1384,39 @@ static int bpf_iter_init_sk_storage_map(void *priv_data,
return 0;
}
-static int bpf_iter_check_map(struct bpf_prog *prog,
- struct bpf_iter_aux_info *aux)
+static int bpf_iter_attach_map(struct bpf_prog *prog,
+ union bpf_iter_link_info *linfo,
+ struct bpf_iter_aux_info *aux)
{
- struct bpf_map *map = aux->map;
+ struct bpf_map *map;
+ int err = -EINVAL;
+
+ if (!linfo->map.map_fd)
+ return -EBADF;
+
+ map = bpf_map_get_with_uref(linfo->map.map_fd);
+ if (IS_ERR(map))
+ return PTR_ERR(map);
if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
- return -EINVAL;
+ goto put_map;
- if (prog->aux->max_rdonly_access > map->value_size)
- return -EACCES;
+ if (prog->aux->max_rdonly_access > map->value_size) {
+ err = -EACCES;
+ goto put_map;
+ }
+ aux->map = map;
return 0;
+
+put_map:
+ bpf_map_put_with_uref(map);
+ return err;
+}
+
+static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
+{
+ bpf_map_put_with_uref(aux->map);
}
static const struct seq_operations bpf_sk_storage_map_seq_ops = {
@@ -1414,8 +1435,8 @@ static const struct bpf_iter_seq_info iter_seq_info = {
static struct bpf_iter_reg bpf_sk_storage_map_reg_info = {
.target = "bpf_sk_storage_map",
- .check_target = bpf_iter_check_map,
- .req_linfo = BPF_ITER_LINK_MAP_FD,
+ .attach_target = bpf_iter_attach_map,
+ .detach_target = bpf_iter_detach_map,
.ctx_arg_info_size = 2,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__bpf_sk_storage_map, sk),