From edf2431697649d37bf00335d8ff6b7da43ccf044 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 27 Mar 2020 16:58:53 +0100 Subject: [PATCH] UPSTREAM: bpf: Allow to retrieve cgroup v1 classid from v2 hooks Today, Kubernetes is still operating on cgroups v1, however, it is possible to retrieve the task's classid based on 'current' out of connect(), sendmsg(), recvmsg() and bind-related hooks for orchestrators which attach to the root cgroup v2 hook in a mixed env like in case of Cilium, for example, in order to then correlate certain pod traffic and use it as part of the key for BPF map lookups. Change-Id: I7568d1aa68f2349900554383a5422c105f957bd6 Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/555e1c69db7376c0947007b4951c260e1074efc3.1585323121.git.daniel@iogearbox.net --- include/net/cls_cgroup.h | 7 ++++++- net/core/filter.c | 21 +++++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/include/net/cls_cgroup.h b/include/net/cls_cgroup.h index 7c2ead6cdc53..668aeee9b3f6 100644 --- a/include/net/cls_cgroup.h +++ b/include/net/cls_cgroup.h @@ -45,9 +45,14 @@ static inline void sock_update_classid(struct sock_cgroup_data *skcd) sock_cgroup_set_classid(skcd, classid); } +static inline u32 __task_get_classid(struct task_struct *task) +{ + return task_cls_state(task)->classid; +} + static inline u32 task_get_classid(const struct sk_buff *skb) { - u32 classid = task_cls_state(current)->classid; + u32 classid = __task_get_classid(current); /* Due to the nature of the classifier it is required to ignore all * packets originating from softirq context as accessing `current' diff --git a/net/core/filter.c b/net/core/filter.c index 288851a58a96..78e5a754f5fc 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2694,6 +2694,19 @@ static const struct bpf_func_proto bpf_msg_pop_data_proto = { .arg4_type = ARG_ANYTHING, }; +#ifdef CONFIG_CGROUP_NET_CLASSID +BPF_CALL_0(bpf_get_cgroup_classid_curr) +{ + return __task_get_classid(current); +} + +static const struct bpf_func_proto bpf_get_cgroup_classid_curr_proto = { + .func = bpf_get_cgroup_classid_curr, + .gpl_only = false, + .ret_type = RET_INTEGER, +}; +#endif + BPF_CALL_1(bpf_get_cgroup_classid, const struct sk_buff *, skb) { return task_get_classid(skb); @@ -6117,6 +6130,10 @@ sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_netns_cookie_sock_proto; case BPF_FUNC_perf_event_output: return &bpf_event_output_data_proto; +#ifdef CONFIG_CGROUP_NET_CLASSID + case BPF_FUNC_get_cgroup_classid: + return &bpf_get_cgroup_classid_curr_proto; +#endif default: return bpf_base_func_proto(func_id); } @@ -6147,6 +6164,10 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_local_storage_proto; case BPF_FUNC_perf_event_output: return &bpf_event_output_data_proto; +#ifdef CONFIG_CGROUP_NET_CLASSID + case BPF_FUNC_get_cgroup_classid: + return &bpf_get_cgroup_classid_curr_proto; +#endif #ifdef CONFIG_INET case BPF_FUNC_sk_lookup_tcp: return &bpf_sock_addr_sk_lookup_tcp_proto;