[PATCH] mtd: rawnand: meson: Annotate struct meson_nfc_nand_chip with __counted_by

[Kees Cook]

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct meson_nfc_nand_chip.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Liang Yang <liang.yang at amlogic.com>
Cc: Miquel Raynal <miquel.raynal at bootlin.com>
Cc: Richard Weinberger <richard at nod.at>
Cc: Vignesh Raghavendra <vigneshr at ti.com>
Cc: Neil Armstrong <neil.armstrong at linaro.org>
Cc: Kevin Hilman <khilman at baylibre.com>
Cc: Jerome Brunet <jbrunet at baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl at googlemail.com>
Cc: linux-mtd at lists.infradead.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-amlogic at lists.infradead.org
Signed-off-by: Kees Cook <keescook at chromium.org>
---
 drivers/mtd/nand/raw/meson_nand.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index 25e3c1cb605e..378f28ce6a74 100644
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -128,7 +128,7 @@ struct meson_nfc_nand_chip {
 	u8 *data_buf;
 	__le64 *info_buf;
 	u32 nsels;
-	u8 sels[];
+	u8 sels[] __counted_by(nsels);
 };
 
 struct meson_nand_ecc {
-- 
2.34.1