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trace/bpf: remove helper bpf_perf_prog_read_value from tracepoint type programs
Commit4bebdc7a85
("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>
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@ -661,32 +661,6 @@ static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
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.arg3_type = ARG_ANYTHING,
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};
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BPF_CALL_3(bpf_perf_prog_read_value_tp, struct bpf_perf_event_data_kern *, ctx,
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struct bpf_perf_event_value *, buf, u32, size)
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{
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int err = -EINVAL;
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if (unlikely(size != sizeof(struct bpf_perf_event_value)))
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goto clear;
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err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled,
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&buf->running);
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if (unlikely(err))
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goto clear;
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return 0;
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clear:
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memset(buf, 0, size);
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return err;
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}
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static const struct bpf_func_proto bpf_perf_prog_read_value_proto_tp = {
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.func = bpf_perf_prog_read_value_tp,
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.gpl_only = true,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_PTR_TO_CTX,
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.arg2_type = ARG_PTR_TO_UNINIT_MEM,
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.arg3_type = ARG_CONST_SIZE,
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};
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static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
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{
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switch (func_id) {
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@ -694,8 +668,6 @@ static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
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return &bpf_perf_event_output_proto_tp;
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case BPF_FUNC_get_stackid:
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return &bpf_get_stackid_proto_tp;
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case BPF_FUNC_perf_prog_read_value:
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return &bpf_perf_prog_read_value_proto_tp;
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default:
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return tracing_func_proto(func_id);
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}
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@ -723,6 +695,46 @@ const struct bpf_verifier_ops tracepoint_verifier_ops = {
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const struct bpf_prog_ops tracepoint_prog_ops = {
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};
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BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx,
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struct bpf_perf_event_value *, buf, u32, size)
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{
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int err = -EINVAL;
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if (unlikely(size != sizeof(struct bpf_perf_event_value)))
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goto clear;
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err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled,
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&buf->running);
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if (unlikely(err))
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goto clear;
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return 0;
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clear:
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memset(buf, 0, size);
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return err;
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}
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static const struct bpf_func_proto bpf_perf_prog_read_value_proto = {
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.func = bpf_perf_prog_read_value,
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.gpl_only = true,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_PTR_TO_CTX,
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.arg2_type = ARG_PTR_TO_UNINIT_MEM,
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.arg3_type = ARG_CONST_SIZE,
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};
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static const struct bpf_func_proto *pe_prog_func_proto(enum bpf_func_id func_id)
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{
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switch (func_id) {
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case BPF_FUNC_perf_event_output:
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return &bpf_perf_event_output_proto_tp;
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case BPF_FUNC_get_stackid:
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return &bpf_get_stackid_proto_tp;
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case BPF_FUNC_perf_prog_read_value:
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return &bpf_perf_prog_read_value_proto;
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default:
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return tracing_func_proto(func_id);
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}
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}
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static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
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struct bpf_insn_access_aux *info)
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{
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@ -779,7 +791,7 @@ static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
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}
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const struct bpf_verifier_ops perf_event_verifier_ops = {
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.get_func_proto = tp_prog_func_proto,
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.get_func_proto = pe_prog_func_proto,
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.is_valid_access = pe_prog_is_valid_access,
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.convert_ctx_access = pe_prog_convert_ctx_access,
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};
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