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From:   Kees Cook <keescook@chromium.org>
To:     Lee Jones <lee@kernel.org>
Cc:     Kees Cook <keescook@chromium.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev, linux-hardening@vger.kernel.org
Subject: [PATCH] mfd: iqs62x: Annotate struct iqs62x_fw_blk with __counted_by
Date:   Fri, 22 Sep 2023 10:53:38 -0700
Message-Id: <20230922175337.work.150-kees@kernel.org>
MIME-Version: 1.0
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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 iqs62x_fw_blk.

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

Cc: Lee Jones <lee@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/mfd/iqs62x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mfd/iqs62x.c b/drivers/mfd/iqs62x.c
index e03b4d38fbb0..1b465590567c 100644
--- a/drivers/mfd/iqs62x.c
+++ b/drivers/mfd/iqs62x.c
@@ -96,7 +96,7 @@ struct iqs62x_fw_blk {
 	u8 addr;
 	u8 mask;
 	u8 len;
-	u8 data[];
+	u8 data[] __counted_by(len);
 };
 
 struct iqs62x_info {
-- 
2.34.1