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From:   Kees Cook <keescook@chromium.org>
To:     Ping-Ke Shih <pkshih@realtek.com>
Cc:     Kees Cook <keescook@chromium.org>, Kalle Valo <kvalo@kernel.org>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        linux-wireless@vger.kernel.org, linux-hardening@vger.kernel.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
Subject: [PATCH] wifi: rtw89: coex: Annotate struct rtw89_btc_btf_set_slot_table with __counted_by
Date:   Fri,  6 Oct 2023 13:17:15 -0700
Message-Id: <20231006201715.work.239-kees@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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 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
rtw89_btc_btf_set_slot_table.

Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: linux-wireless@vger.kernel.org
Cc: linux-hardening@vger.kernel.org
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/net/wireless/realtek/rtw89/coex.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw89/coex.c b/drivers/net/wireless/realtek/rtw89/coex.c
index 4ba8b3df70ae..d66a1152c3f5 100644
--- a/drivers/net/wireless/realtek/rtw89/coex.c
+++ b/drivers/net/wireless/realtek/rtw89/coex.c
@@ -237,7 +237,7 @@ struct rtw89_btc_btf_set_report {
 struct rtw89_btc_btf_set_slot_table {
 	u8 fver;
 	u8 tbl_num;
-	u8 buf[];
+	u8 buf[] __counted_by(tbl_num);
 } __packed;
 
 struct rtw89_btc_btf_set_mon_reg {
-- 
2.34.1