diff options
| author | Martin KaFai Lau | 2017-06-05 12:15:48 -0700 |
|---|---|---|
| committer | David S. Miller | 2017-06-06 15:41:23 -0400 |
| commit | 34ad5580f8f9c86cb273ebea25c149613cd1667e (patch) | |
| tree | 47618c705d66fc9f0b977716cd7c1389e1552bdc | |
| parent | f3f1c054c288bb6e503005e6d73611151ed20e91 (diff) | |
bpf: Add BPF_(PROG|MAP)_GET_NEXT_ID command
This patch adds BPF_PROG_GET_NEXT_ID and BPF_MAP_GET_NEXT_ID
to allow userspace to iterate all bpf_prog IDs and bpf_map IDs.
The API is trying to be consistent with the existing
BPF_MAP_GET_NEXT_KEY.
It is currently limited to CAP_SYS_ADMIN which we can
consider to lift it in followup patches.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/uapi/linux/bpf.h | 7 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 38 |
2 files changed, 45 insertions, 0 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index e78aece03628..629747a3f273 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -82,6 +82,8 @@ enum bpf_cmd { BPF_PROG_ATTACH, BPF_PROG_DETACH, BPF_PROG_TEST_RUN, + BPF_PROG_GET_NEXT_ID, + BPF_MAP_GET_NEXT_ID, }; enum bpf_map_type { @@ -209,6 +211,11 @@ union bpf_attr { __u32 repeat; __u32 duration; } test; + + struct { /* anonymous struct used by BPF_*_GET_NEXT_ID */ + __u32 start_id; + __u32 next_id; + }; } __attribute__((aligned(8))); /* BPF helper function descriptions: diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 4c3075b5d840..2405feedb8c1 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -166,6 +166,7 @@ static void bpf_map_put_uref(struct bpf_map *map) void bpf_map_put(struct bpf_map *map) { if (atomic_dec_and_test(&map->refcnt)) { + /* bpf_map_free_id() must be called first */ bpf_map_free_id(map); INIT_WORK(&map->work, bpf_map_free_deferred); schedule_work(&map->work); @@ -726,6 +727,7 @@ void bpf_prog_put(struct bpf_prog *prog) { if (atomic_dec_and_test(&prog->aux->refcnt)) { trace_bpf_prog_put_rcu(prog); + /* bpf_prog_free_id() must be called first */ bpf_prog_free_id(prog); bpf_prog_kallsyms_del(prog); call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu); @@ -1069,6 +1071,34 @@ static int bpf_prog_test_run(const union bpf_attr *attr, return ret; } +#define BPF_OBJ_GET_NEXT_ID_LAST_FIELD next_id + +static int bpf_obj_get_next_id(const union bpf_attr *attr, + union bpf_attr __user *uattr, + struct idr *idr, + spinlock_t *lock) +{ + u32 next_id = attr->start_id; + int err = 0; + + if (CHECK_ATTR(BPF_OBJ_GET_NEXT_ID) || next_id >= INT_MAX) + return -EINVAL; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + next_id++; + spin_lock_bh(lock); + if (!idr_get_next(idr, &next_id)) + err = -ENOENT; + spin_unlock_bh(lock); + + if (!err) + err = put_user(next_id, &uattr->next_id); + + return err; +} + SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) { union bpf_attr attr = {}; @@ -1146,6 +1176,14 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz case BPF_PROG_TEST_RUN: err = bpf_prog_test_run(&attr, uattr); break; + case BPF_PROG_GET_NEXT_ID: + err = bpf_obj_get_next_id(&attr, uattr, + &prog_idr, &prog_idr_lock); + break; + case BPF_MAP_GET_NEXT_ID: + err = bpf_obj_get_next_id(&attr, uattr, + &map_idr, &map_idr_lock); + break; default: err = -EINVAL; break; |