diff options
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/syscall.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 5439e05e3d25..1c213a730502 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3713,6 +3713,48 @@ out_put_link: return ret; } +static int bpf_link_inc_not_zero(struct bpf_link *link) +{ + return atomic64_fetch_add_unless(&link->refcnt, 1, 0) ? 0 : -ENOENT; +} + +#define BPF_LINK_GET_FD_BY_ID_LAST_FIELD link_id + +static int bpf_link_get_fd_by_id(const union bpf_attr *attr) +{ + struct bpf_link *link; + u32 id = attr->link_id; + int fd, err; + + if (CHECK_ATTR(BPF_LINK_GET_FD_BY_ID)) + return -EINVAL; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + spin_lock_bh(&link_idr_lock); + link = idr_find(&link_idr, id); + /* before link is "settled", ID is 0, pretend it doesn't exist yet */ + if (link) { + if (link->id) + err = bpf_link_inc_not_zero(link); + else + err = -EAGAIN; + } else { + err = -ENOENT; + } + spin_unlock_bh(&link_idr_lock); + + if (err) + return err; + + fd = bpf_link_new_fd(link); + if (fd < 0) + bpf_link_put(link); + + return fd; +} + SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) { union bpf_attr attr; @@ -3830,6 +3872,13 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz case BPF_LINK_UPDATE: err = link_update(&attr); break; + case BPF_LINK_GET_FD_BY_ID: + err = bpf_link_get_fd_by_id(&attr); + break; + case BPF_LINK_GET_NEXT_ID: + err = bpf_obj_get_next_id(&attr, uattr, + &link_idr, &link_idr_lock); + break; default: err = -EINVAL; break; |