netdev - [PATCH bpf-next 09/10] bpf: disallow bpf_probe_read[

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Date:   Fri, 4 Oct 2019 22:03:13 -0700
From:   Alexei Starovoitov <ast@...nel.org>
To:     <davem@...emloft.net>
CC:     <daniel@...earbox.net>, <x86@...nel.org>, <netdev@...r.kernel.org>,
        <bpf@...r.kernel.org>, <kernel-team@...com>
Subject: [PATCH bpf-next 09/10] bpf: disallow bpf_probe_read[_str] helpers

Disallow bpf_probe_read() and bpf_probe_read_str() helpers in
raw_tracepoint bpf programs that use in-kernel BTF to track
types of memory accesses.

Signed-off-by: Alexei Starovoitov <ast@...nel.org>
---
 kernel/trace/bpf_trace.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 52f7e9d8c29b..7c607f79f1bb 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -700,6 +700,8 @@ tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	case BPF_FUNC_map_peek_elem:
 		return &bpf_map_peek_elem_proto;
 	case BPF_FUNC_probe_read:
+		if (prog->expected_attach_type)
+			return NULL;
 		return &bpf_probe_read_proto;
 	case BPF_FUNC_ktime_get_ns:
 		return &bpf_ktime_get_ns_proto;
@@ -728,6 +730,8 @@ tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	case BPF_FUNC_get_prandom_u32:
 		return &bpf_get_prandom_u32_proto;
 	case BPF_FUNC_probe_read_str:
+		if (prog->expected_attach_type)
+			return NULL;
 		return &bpf_probe_read_str_proto;
 #ifdef CONFIG_CGROUPS
 	case BPF_FUNC_get_current_cgroup_id:
-- 
2.20.0