linux/kernel/bpf
Alexei Starovoitov 7f67763337 bpf: introduce BPF_F_ALLOW_OVERRIDE flag
If BPF_F_ALLOW_OVERRIDE flag is used in BPF_PROG_ATTACH command
to the given cgroup the descendent cgroup will be able to override
effective bpf program that was inherited from this cgroup.
By default it's not passed, therefore override is disallowed.

Examples:
1.
prog X attached to /A with default
prog Y fails to attach to /A/B and /A/B/C
Everything under /A runs prog X

2.
prog X attached to /A with allow_override.
prog Y fails to attach to /A/B with default (non-override)
prog M attached to /A/B with allow_override.
Everything under /A/B runs prog M only.

3.
prog X attached to /A with allow_override.
prog Y fails to attach to /A with default.
The user has to detach first to switch the mode.

In the future this behavior may be extended with a chain of
non-overridable programs.

Also fix the bug where detach from cgroup where nothing is attached
was not throwing error. Return ENOENT in such case.

Add several testcases and adjust libbpf.

Fixes: 3007098494 ("cgroup: add support for eBPF programs")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-12 21:52:19 -05:00
..
arraymap.c bpf: don't trigger OOM killer under pressure with map alloc 2017-01-18 17:12:26 -05:00
bpf_lru_list.c bpf: Fix compilation warning in __bpf_lru_list_rotate_inactive 2016-11-16 11:30:56 -05:00
bpf_lru_list.h bpf: Add percpu LRU list 2016-11-15 11:50:20 -05:00
cgroup.c bpf: introduce BPF_F_ALLOW_OVERRIDE flag 2017-02-12 21:52:19 -05:00
core.c bpf: rework prog_digest into prog_tag 2017-01-16 14:03:31 -05:00
hashtab.c bpf: don't trigger OOM killer under pressure with map alloc 2017-01-18 17:12:26 -05:00
helpers.c bpf: add helper for retrieving current numa node id 2016-10-22 17:05:52 -04:00
inode.c bpf: allow for mount options to specify permissions 2016-11-27 20:38:47 -05:00
Makefile cgroup: add support for eBPF programs 2016-11-25 16:25:52 -05:00
percpu_freelist.c bpf: introduce percpu_freelist 2016-03-08 15:28:31 -05:00
percpu_freelist.h bpf: introduce percpu_freelist 2016-03-08 15:28:31 -05:00
stackmap.c bpf: don't trigger OOM killer under pressure with map alloc 2017-01-18 17:12:26 -05:00
syscall.c bpf: introduce BPF_F_ALLOW_OVERRIDE flag 2017-02-12 21:52:19 -05:00
verifier.c bpf: rework prog_digest into prog_tag 2017-01-16 14:03:31 -05:00