diff options
| author | Andrii Nakryiko <andriin@fb.com> | 2020-07-31 11:28:26 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-08-01 20:38:28 -0700 |
| commit | 73b11c2ab072d5b0599d1e12cc126f55ee306daf (patch) | |
| tree | 0b005d7d70f073d7d908e0d2a1fb263405f3971b /kernel/bpf/net_namespace.c | |
| parent | 4939b2847d26c025e2e2118744226967f239a1ac (diff) | |
bpf: Add support for forced LINK_DETACH command
Add LINK_DETACH command to force-detach bpf_link without destroying it. It has
the same behavior as auto-detaching of bpf_link due to cgroup dying for
bpf_cgroup_link or net_device being destroyed for bpf_xdp_link. In such case,
bpf_link is still a valid kernel object, but is defuncts and doesn't hold BPF
program attached to corresponding BPF hook. This functionality allows users
with enough access rights to manually force-detach attached bpf_link without
killing respective owner process.
This patch implements LINK_DETACH for cgroup, xdp, and netns links, mostly
re-using existing link release handling code.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200731182830.286260-2-andriin@fb.com
Diffstat (limited to 'kernel/bpf/net_namespace.c')
| -rw-r--r-- | kernel/bpf/net_namespace.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c index 71405edd667c..542f275bf252 100644 --- a/kernel/bpf/net_namespace.c +++ b/kernel/bpf/net_namespace.c @@ -142,9 +142,16 @@ static void bpf_netns_link_release(struct bpf_link *link) 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 = @@ -228,6 +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, |