[PATCH 08/17] bpf: disable CFI in dispatcher functions

Sami Tolvanen
2021-03-12T00:50:21Z

BPF dispatcher functions are patched at runtime to perform direct
instead of indirect calls. Disable CFI for the dispatcher functions to
avoid conflicts.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
include/linux/bpf.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index cccaef1088ea..9acdca574527 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -635,7 +635,7 @@ struct bpf_dispatcher {
struct bpf_ksym ksym;
};

-static __always_inline unsigned int bpf_dispatcher_nop_func(
+static __always_inline __nocfi unsigned int bpf_dispatcher_nop_func(
const void *ctx,
const struct bpf_insn *insnsi,
unsigned int (*bpf_func)(const void *,
@@ -663,7 +663,7 @@ void bpf_trampoline_put(struct bpf_trampoline *tr);
}

#define DEFINE_BPF_DISPATCHER(name) \
- noinline unsigned int bpf_dispatcher_##name##_func( \
+ noinline __nocfi unsigned int bpf_dispatcher_##name##_func( \
const void *ctx, \
const struct bpf_insn *insnsi, \
unsigned int (*bpf_func)(const void *, \
--
2.31.0.rc2.261.g7f71774620-goog