Thread (19 messages) 19 messages, 2 authors, 2021-03-31

[PATCH v4 08/17] bpf: disable CFI in dispatcher functions

flat view
STALE2014d REVIEWED: 1 (0M)

From: Sami Tolvanen <samitolvanen@google.com>
Date: 2021-03-31 21:29:25
Also in: bpf, linux-arch, linux-hardening, linux-kbuild, linux-pci, lkml
Subsystem: bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds

Revision v4 of 6 in this series; 1 review trailer.

Revisions (6)
  1. v1 [diff vs current]
  2. v2 [diff vs current]
  3. v3 [diff vs current]
  4. v4 current
  5. v5 [diff vs current]
  6. v6 [diff vs current]
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>
Reviewed-by: Kees Cook <redacted>
---
 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 3625f019767d..2f46f98479e1 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -650,7 +650,7 @@ 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 *,
@@ -678,7 +678,7 @@ 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 *,			\
-- 
2.31.0.291.g576ba9dcdaf-goog


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help