From: Matteo Croce <teknoraver@xxxxxxxx> The helper bpf_current_task_under_cgroup() currently is only allowed for tracing programs. Allow its usage also in the BPF_CGROUP_* program types. Move the code from kernel/trace/bpf_trace.c to kernel/bpf/helpers.c, so it compiles also without CONFIG_BPF_EVENTS. This will be used in systemd-networkd to monitor the sysctl writes, and filter it's own writes from others: https://github.com/systemd/systemd/pull/32212 Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Signed-off-by: Matteo Croce <teknoraver@xxxxxxxx> --- include/linux/bpf.h | 1 + kernel/bpf/cgroup.c | 2 ++ kernel/bpf/helpers.c | 23 +++++++++++++++++++++++ kernel/trace/bpf_trace.c | 23 ----------------------- 4 files changed, 26 insertions(+), 23 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 7ad37cbdc815..3820fcf360b6 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3202,6 +3202,7 @@ extern const struct bpf_func_proto bpf_sock_hash_update_proto; extern const struct bpf_func_proto bpf_get_current_cgroup_id_proto; extern const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto; extern const struct bpf_func_proto bpf_get_cgroup_classid_curr_proto; +extern const struct bpf_func_proto bpf_current_task_under_cgroup_proto; extern const struct bpf_func_proto bpf_msg_redirect_hash_proto; extern const struct bpf_func_proto bpf_msg_redirect_map_proto; extern const struct bpf_func_proto bpf_sk_redirect_hash_proto; diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 8ba73042a239..e7113d700b87 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -2581,6 +2581,8 @@ cgroup_current_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_get_cgroup_classid: return &bpf_get_cgroup_classid_curr_proto; #endif + case BPF_FUNC_current_task_under_cgroup: + return &bpf_current_task_under_cgroup_proto; default: return NULL; } diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 0d1d97d968b0..8502cfed2926 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2458,6 +2458,29 @@ __bpf_kfunc long bpf_task_under_cgroup(struct task_struct *task, return ret; } +BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) +{ + struct bpf_array *array = container_of(map, struct bpf_array, map); + struct cgroup *cgrp; + + if (unlikely(idx >= array->map.max_entries)) + return -E2BIG; + + cgrp = READ_ONCE(array->ptrs[idx]); + if (unlikely(!cgrp)) + return -EAGAIN; + + return task_under_cgroup_hierarchy(current, cgrp); +} + +const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { + .func = bpf_current_task_under_cgroup, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_ANYTHING, +}; + /** * bpf_task_get_cgroup1 - Acquires the associated cgroup of a task within a * specific cgroup1 hierarchy. The cgroup1 hierarchy is identified by its diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index cd098846e251..cc9301054f84 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -798,29 +798,6 @@ const struct bpf_func_proto bpf_task_pt_regs_proto = { .ret_btf_id = &bpf_task_pt_regs_ids[0], }; -BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) -{ - struct bpf_array *array = container_of(map, struct bpf_array, map); - struct cgroup *cgrp; - - if (unlikely(idx >= array->map.max_entries)) - return -E2BIG; - - cgrp = READ_ONCE(array->ptrs[idx]); - if (unlikely(!cgrp)) - return -EAGAIN; - - return task_under_cgroup_hierarchy(current, cgrp); -} - -static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { - .func = bpf_current_task_under_cgroup, - .gpl_only = false, - .ret_type = RET_INTEGER, - .arg1_type = ARG_CONST_MAP_PTR, - .arg2_type = ARG_ANYTHING, -}; - struct send_signal_irq_work { struct irq_work irq_work; struct task_struct *task; -- 2.45.2
