diff options
| author | Andrii Nakryiko | 2020-07-31 11:28:26 -0700 |
|---|---|---|
| committer | Alexei Starovoitov | 2020-08-01 20:38:28 -0700 |
| commit | 73b11c2ab072d5b0599d1e12cc126f55ee306daf (patch) | |
| tree | 0b005d7d70f073d7d908e0d2a1fb263405f3971b /net | |
| 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 'net')
| -rw-r--r-- | net/core/dev.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index a2a57988880a..c8b911b10187 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8979,12 +8979,20 @@ static void bpf_xdp_link_release(struct bpf_link *link) /* if racing with net_device's tear down, xdp_link->dev might be * already NULL, in which case link was already auto-detached */ - if (xdp_link->dev) + if (xdp_link->dev) { WARN_ON(dev_xdp_detach_link(xdp_link->dev, NULL, xdp_link)); + xdp_link->dev = NULL; + } rtnl_unlock(); } +static int bpf_xdp_link_detach(struct bpf_link *link) +{ + bpf_xdp_link_release(link); + return 0; +} + static void bpf_xdp_link_dealloc(struct bpf_link *link) { struct bpf_xdp_link *xdp_link = container_of(link, struct bpf_xdp_link, link); @@ -9066,6 +9074,7 @@ out_unlock: static const struct bpf_link_ops bpf_xdp_link_lops = { .release = bpf_xdp_link_release, .dealloc = bpf_xdp_link_dealloc, + .detach = bpf_xdp_link_detach, .show_fdinfo = bpf_xdp_link_show_fdinfo, .fill_link_info = bpf_xdp_link_fill_link_info, .update_prog = bpf_xdp_link_update, |