Commit 0456ea17 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Alexei Starovoitov
Browse files

bpf: Enable more helpers for BPF_PROG_TYPE_CGROUP_{DEVICE,SYSCTL,SOCKOPT} 



Currently the following prog types don't fall back to bpf_base_func_proto()
(instead they have cgroup_base_func_proto which has a limited set of
helpers from bpf_base_func_proto):
* BPF_PROG_TYPE_CGROUP_DEVICE
* BPF_PROG_TYPE_CGROUP_SYSCTL
* BPF_PROG_TYPE_CGROUP_SOCKOPT

I don't see any specific reason why we shouldn't use bpf_base_func_proto(),
every other type of program (except bpf-lirc and, understandably, tracing)
use it, so let's fall back to bpf_base_func_proto for those prog types
as well.

This basically boils down to adding access to the following helpers:
* BPF_FUNC_get_prandom_u32
* BPF_FUNC_get_smp_processor_id
* BPF_FUNC_get_numa_node_id
* BPF_FUNC_tail_call
* BPF_FUNC_ktime_get_ns
* BPF_FUNC_spin_lock (CAP_SYS_ADMIN)
* BPF_FUNC_spin_unlock (CAP_SYS_ADMIN)
* BPF_FUNC_jiffies64 (CAP_SYS_ADMIN)

I've also added bpf_perf_event_output() because it's really handy for
logging and debugging.

Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200420174610.77494-1-sdf@google.com
parent 93e51689

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -1523,6 +1523,7 @@ extern const struct bpf_func_proto bpf_strtoul_proto; 
extern const struct bpf_func_proto bpf_tcp_sock_proto;

extern const struct bpf_func_proto bpf_jiffies64_proto;

extern const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto;

extern const struct bpf_func_proto bpf_event_output_data_proto;



const struct bpf_func_proto *bpf_tracing_func_proto(

	enum bpf_func_id func_id, const struct bpf_prog *prog);

kernel/bpf/cgroup.c

+3 −17
Original line number Diff line number Diff line
@@ -1060,30 +1060,16 @@ static const struct bpf_func_proto * 
cgroup_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)

{

	switch (func_id) {

	case BPF_FUNC_map_lookup_elem:

		return &bpf_map_lookup_elem_proto;

	case BPF_FUNC_map_update_elem:

		return &bpf_map_update_elem_proto;

	case BPF_FUNC_map_delete_elem:

		return &bpf_map_delete_elem_proto;

	case BPF_FUNC_map_push_elem:

		return &bpf_map_push_elem_proto;

	case BPF_FUNC_map_pop_elem:

		return &bpf_map_pop_elem_proto;

	case BPF_FUNC_map_peek_elem:

		return &bpf_map_peek_elem_proto;

	case BPF_FUNC_get_current_uid_gid:

		return &bpf_get_current_uid_gid_proto;

	case BPF_FUNC_get_local_storage:

		return &bpf_get_local_storage_proto;

	case BPF_FUNC_get_current_cgroup_id:

		return &bpf_get_current_cgroup_id_proto;

	case BPF_FUNC_trace_printk:

		if (capable(CAP_SYS_ADMIN))

			return bpf_get_trace_printk_proto();

		/* fall through */

	case BPF_FUNC_perf_event_output:

		return &bpf_event_output_data_proto;

	default:

		return NULL;

		return bpf_base_func_proto(func_id);

	}

}

net/core/filter.c

+1 −1
Original line number Diff line number Diff line
@@ -4214,7 +4214,7 @@ BPF_CALL_5(bpf_event_output_data, void *, ctx, struct bpf_map *, map, u64, flags 
	return bpf_event_output(map, flags, data, size, NULL, 0, NULL);

}



static const struct bpf_func_proto bpf_event_output_data_proto =  {

const struct bpf_func_proto bpf_event_output_data_proto =  {

	.func		= bpf_event_output_data,

	.gpl_only       = true,

	.ret_type       = RET_INTEGER,

tools/testing/selftests/bpf/verifier/event_output.c

+24 −0
Original line number Diff line number Diff line
@@ -92,3 +92,27 @@ 
	.result = ACCEPT,

	.retval = 1,

},

{

	"perfevent for cgroup dev",

	.insns =  { __PERF_EVENT_INSNS__ },

	.prog_type = BPF_PROG_TYPE_CGROUP_DEVICE,

	.fixup_map_event_output = { 4 },

	.result = ACCEPT,

	.retval = 1,

},

{

	"perfevent for cgroup sysctl",

	.insns =  { __PERF_EVENT_INSNS__ },

	.prog_type = BPF_PROG_TYPE_CGROUP_SYSCTL,

	.fixup_map_event_output = { 4 },

	.result = ACCEPT,

	.retval = 1,

},

{

	"perfevent for cgroup sockopt",

	.insns =  { __PERF_EVENT_INSNS__ },

	.prog_type = BPF_PROG_TYPE_CGROUP_SOCKOPT,

	.fixup_map_event_output = { 4 },

	.result = ACCEPT,

	.retval = 1,

},

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