linux-hardening - [PATCH] mtd: rawnand: rockchip: Use struct

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <481721c2c7fe570b4027dbe231d523961c953d5a.1696146232.git.christophe.jaillet@wanadoo.fr>
Date: Sun,  1 Oct 2023 09:44:04 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Miquel Raynal <miquel.raynal@...tlin.com>,
	Richard Weinberger <richard@....at>,
	Vignesh Raghavendra <vigneshr@...com>,
	Heiko Stuebner <heiko@...ech.de>,
	Kees Cook <keescook@...omium.org>,
	"Gustavo A. R. Silva" <gustavoars@...nel.org>,
	Nathan Chancellor <nathan@...nel.org>,
	Nick Desaulniers <ndesaulniers@...gle.com>,
	Tom Rix <trix@...hat.com>
Cc: linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org,
	Christophe JAILLET <christophe.jaillet@...adoo.fr>,
	linux-mtd@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-rockchip@...ts.infradead.org,
	linux-hardening@...r.kernel.org,
	llvm@...ts.linux.dev
Subject: [PATCH] mtd: rawnand: rockchip: Use struct_size()

Use struct_size() instead of hand writing it.
This is less verbose and more robust.

While at it, 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).

Also remove a useless comment about the position of a flex-array in a
structure.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
This patch is part of a work done in parallel of what is currently worked
on by Kees Cook.

My patches are only related to corner cases that do NOT match the
semantic of his Coccinelle script[1].

In this case, struct_size() was not used to compute the size needed for the
structure and its flex array.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
---
 drivers/mtd/nand/raw/rockchip-nand-controller.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/raw/rockchip-nand-controller.c b/drivers/mtd/nand/raw/rockchip-nand-controller.c
index 5bc90ffa721f..596cf9a78274 100644
--- a/drivers/mtd/nand/raw/rockchip-nand-controller.c
+++ b/drivers/mtd/nand/raw/rockchip-nand-controller.c
@@ -158,8 +158,7 @@ struct rk_nfc_nand_chip {
 	u32 timing;
 
 	u8 nsels;
-	u8 sels[];
-	/* Nothing after this field. */
+	u8 sels[] __counted_by(nsels);
 };
 
 struct rk_nfc {
@@ -1119,7 +1118,7 @@ static int rk_nfc_nand_chip_init(struct device *dev, struct rk_nfc *nfc,
 		return -EINVAL;
 	}
 
-	rknand = devm_kzalloc(dev, sizeof(*rknand) + nsels * sizeof(u8),
+	rknand = devm_kzalloc(dev, struct_size(rknand, sels, nsels),
 			      GFP_KERNEL);
 	if (!rknand)
 		return -ENOMEM;
-- 
2.34.1