From 129d868ede1ea835ac97f0a9f2cf3f4ed00d8ea7 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 5 Jan 2023 11:26:47 -0800 Subject: [PATCH] bpf: Replace 0-length arrays with flexible arrays Zero-length arrays are deprecated [1]. Replace struct bpf_array's union of 0-length arrays with flexible arrays. Detected with GCC 13, by using -fstrict-flex-arrays=3: arch/x86/net/bpf_jit_comp.c: In function 'bpf_tail_call_direct_fixup': arch/x86/net/bpf_jit_comp.c:606:37: warning: array subscript is outside array bounds of 'void *[0]' [-Warray-bounds=] 606 | target = array->ptrs[poke->tail_call.key]; | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/filter.h:9, from arch/x86/net/bpf_jit_comp.c:9: include/linux/bpf.h:1527:23: note: while referencing 'ptrs' 1527 | void *ptrs[0] __aligned(8); | ^~~~ [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays Signed-off-by: Kees Cook Signed-off-by: Daniel Borkmann Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20230105192646.never.154-kees@kernel.org --- include/linux/bpf.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 1697bd8..ae7771c 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1523,9 +1523,9 @@ struct bpf_array { u32 index_mask; struct bpf_array_aux *aux; union { - char value[0] __aligned(8); - void *ptrs[0] __aligned(8); - void __percpu *pptrs[0] __aligned(8); + DECLARE_FLEX_ARRAY(char, value) __aligned(8); + DECLARE_FLEX_ARRAY(void *, ptrs) __aligned(8); + DECLARE_FLEX_ARRAY(void __percpu *, pptrs) __aligned(8); }; }; -- 2.7.4