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From:   Kees Cook <keescook@chromium.org>
To:     Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc:     Kees Cook <keescook@chromium.org>,
        Jeremy Kerr <jk@codeconstruct.com.au>,
        Joel Stanley <joel@jms.id.au>, linux-i3c@lists.infradead.org,
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        Tom Rix <trix@redhat.com>,
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        <u.kleine-koenig@pengutronix.de>,
        Matt Johnston <matt@codeconstruct.com.au>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Jack Chen <zenghuchen@google.com>,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        linux-hardening@vger.kernel.org
Subject: [PATCH] i3c: dw: Annotate struct dw_i3c_xfer with __counted_by
Date:   Fri, 22 Sep 2023 10:50:11 -0700
Message-Id: <20230922175011.work.800-kees@kernel.org>
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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 dw_i3c_xfer.

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

Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Jeremy Kerr <jk@codeconstruct.com.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: linux-i3c@lists.infradead.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/i3c/master/dw-i3c-master.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index 9332ae5f6419..ef5751e91cc9 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -233,7 +233,7 @@ struct dw_i3c_xfer {
 	struct completion comp;
 	int ret;
 	unsigned int ncmds;
-	struct dw_i3c_cmd cmds[];
+	struct dw_i3c_cmd cmds[] __counted_by(ncmds);
 };
 
 struct dw_i3c_i2c_dev_data {
-- 
2.34.1