Subject: [PATCH v2 bpf-next 11/12] bpf: disallow bpf_probe_read[_str] helpers

From: Alexei Starovoitov <[email-masked]>
Date: Wed, 9 Oct 2019 21:15:02 -0700

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 <[email-masked]>
---
 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..fa5743abf842 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->aux->attach_btf_id)
+			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->aux->attach_btf_id)
+			return NULL;
 		return &bpf_probe_read_str_proto;
 #ifdef CONFIG_CGROUPS
 	case BPF_FUNC_get_current_cgroup_id:
-- 
2.23.0