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trace/bpf: remove helper bpf_perf_prog_read_value from tracepoint type programs 

Commit 4bebdc7a85 ("bpf: add helper bpf_perf_prog_read_value")
added helper bpf_perf_prog_read_value so that perf_event type program
can read event counter and enabled/running time.
This commit, however, introduced a bug which allows this helper
for tracepoint type programs. This is incorrect as bpf_perf_prog_read_value
needs to access perf_event through its bpf_perf_event_data_kern type context,
which is not available for tracepoint type program.

This patch fixed the issue by separating bpf_func_proto between tracepoint
and perf_event type programs and removed bpf_perf_prog_read_value
from tracepoint func prototype.

Fixes: 4bebdc7a85 ("bpf: add helper bpf_perf_prog_read_value")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
hifive-unleashed-5.1
Yonghong Song 2018-03-20 11:19:17 -07:00 committed by Daniel Borkmann
parent 52fda36d63
commit f005afede9
1 changed files with 41 additions and 29 deletions
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70
kernel/trace/bpf_trace.c
View File

@ -661,32 +661,6 @@ static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
.arg3_type = ARG_ANYTHING,
};
BPF_CALL_3(bpf_perf_prog_read_value_tp, struct bpf_perf_event_data_kern *, ctx,
struct bpf_perf_event_value *, buf, u32, size)
{
int err = -EINVAL;
if (unlikely(size != sizeof(struct bpf_perf_event_value)))
goto clear;
err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled,
&buf->running);
if (unlikely(err))
goto clear;
return 0;
clear:
memset(buf, 0, size);
return err;
}
static const struct bpf_func_proto bpf_perf_prog_read_value_proto_tp = {
.func = bpf_perf_prog_read_value_tp,
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_PTR_TO_UNINIT_MEM,
.arg3_type = ARG_CONST_SIZE,
};
static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
{
switch (func_id) {
@ -694,8 +668,6 @@ static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
return &bpf_perf_event_output_proto_tp;
case BPF_FUNC_get_stackid:
return &bpf_get_stackid_proto_tp;
case BPF_FUNC_perf_prog_read_value:
return &bpf_perf_prog_read_value_proto_tp;
default:
return tracing_func_proto(func_id);
}
@ -723,6 +695,46 @@ const struct bpf_verifier_ops tracepoint_verifier_ops = {
const struct bpf_prog_ops tracepoint_prog_ops = {
};
BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx,
struct bpf_perf_event_value *, buf, u32, size)
{
int err = -EINVAL;
if (unlikely(size != sizeof(struct bpf_perf_event_value)))
goto clear;
err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled,
&buf->running);
if (unlikely(err))
goto clear;
return 0;
clear:
memset(buf, 0, size);
return err;
}
static const struct bpf_func_proto bpf_perf_prog_read_value_proto = {
.func = bpf_perf_prog_read_value,
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_PTR_TO_UNINIT_MEM,
.arg3_type = ARG_CONST_SIZE,
};
static const struct bpf_func_proto *pe_prog_func_proto(enum bpf_func_id func_id)
{
switch (func_id) {
case BPF_FUNC_perf_event_output:
return &bpf_perf_event_output_proto_tp;
case BPF_FUNC_get_stackid:
return &bpf_get_stackid_proto_tp;
case BPF_FUNC_perf_prog_read_value:
return &bpf_perf_prog_read_value_proto;
default:
return tracing_func_proto(func_id);
}
}
static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
struct bpf_insn_access_aux *info)
{
@ -779,7 +791,7 @@ static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
}
const struct bpf_verifier_ops perf_event_verifier_ops = {
.get_func_proto = tp_prog_func_proto,
.get_func_proto = pe_prog_func_proto,
.is_valid_access = pe_prog_is_valid_access,
.convert_ctx_access = pe_prog_convert_ctx_access,
};