7f67763337
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>
92 lines
2.7 KiB
C
92 lines
2.7 KiB
C
#ifndef _BPF_CGROUP_H
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#define _BPF_CGROUP_H
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#include <linux/jump_label.h>
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#include <uapi/linux/bpf.h>
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struct sock;
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struct cgroup;
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struct sk_buff;
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#ifdef CONFIG_CGROUP_BPF
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extern struct static_key_false cgroup_bpf_enabled_key;
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#define cgroup_bpf_enabled static_branch_unlikely(&cgroup_bpf_enabled_key)
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struct cgroup_bpf {
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/*
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* Store two sets of bpf_prog pointers, one for programs that are
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* pinned directly to this cgroup, and one for those that are effective
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* when this cgroup is accessed.
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*/
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struct bpf_prog *prog[MAX_BPF_ATTACH_TYPE];
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struct bpf_prog __rcu *effective[MAX_BPF_ATTACH_TYPE];
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bool disallow_override[MAX_BPF_ATTACH_TYPE];
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};
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void cgroup_bpf_put(struct cgroup *cgrp);
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void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent);
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int __cgroup_bpf_update(struct cgroup *cgrp, struct cgroup *parent,
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struct bpf_prog *prog, enum bpf_attach_type type,
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bool overridable);
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/* Wrapper for __cgroup_bpf_update() protected by cgroup_mutex */
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int cgroup_bpf_update(struct cgroup *cgrp, struct bpf_prog *prog,
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enum bpf_attach_type type, bool overridable);
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int __cgroup_bpf_run_filter_skb(struct sock *sk,
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struct sk_buff *skb,
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enum bpf_attach_type type);
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int __cgroup_bpf_run_filter_sk(struct sock *sk,
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enum bpf_attach_type type);
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/* Wrappers for __cgroup_bpf_run_filter_skb() guarded by cgroup_bpf_enabled. */
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#define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk, skb) \
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({ \
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int __ret = 0; \
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if (cgroup_bpf_enabled) \
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__ret = __cgroup_bpf_run_filter_skb(sk, skb, \
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BPF_CGROUP_INET_INGRESS); \
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\
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__ret; \
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})
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#define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb) \
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({ \
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int __ret = 0; \
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if (cgroup_bpf_enabled && sk && sk == skb->sk) { \
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typeof(sk) __sk = sk_to_full_sk(sk); \
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if (sk_fullsock(__sk)) \
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__ret = __cgroup_bpf_run_filter_skb(__sk, skb, \
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BPF_CGROUP_INET_EGRESS); \
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} \
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__ret; \
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})
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#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) \
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({ \
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int __ret = 0; \
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if (cgroup_bpf_enabled && sk) { \
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__ret = __cgroup_bpf_run_filter_sk(sk, \
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BPF_CGROUP_INET_SOCK_CREATE); \
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} \
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__ret; \
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})
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#else
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struct cgroup_bpf {};
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static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
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static inline void cgroup_bpf_inherit(struct cgroup *cgrp,
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struct cgroup *parent) {}
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#define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; })
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#define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk,skb) ({ 0; })
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#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) ({ 0; })
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#endif /* CONFIG_CGROUP_BPF */
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#endif /* _BPF_CGROUP_H */
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