From:   Jacob Keller <jacob.e.keller@intel.com>
To:     Kalle Valo <kvalo@kernel.org>
Cc:     Johannes Berg <johannes@sipsolutions.net>,
        linux-wireless@vger.kernel.org,
        Jacob Keller <jacob.e.keller@intel.com>,
        Igor Mitsyanko <imitsyanko@quantenna.com>,
        Sergey Matyukevich <geomatsi@gmail.com>
Subject: [PATCH v2] wifi: qtnfmac: use struct_size and size_sub for payload length
Date:   Tue,  7 Mar 2023 15:02:12 -0800
Message-Id: <20230307230212.3735818-1-jacob.e.keller@intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Replace the calculations for the payload length in
qtnf_cmd_band_fill_iftype with struct_size() and size_sub(). While
the payload length does not get directly passed to an allocation function,
the performed calculation is still calculating the size of a flexible array
structure (minus the size of a header structure).

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Cc: Igor Mitsyanko <imitsyanko@quantenna.com>
Cc: Sergey Matyukevich <geomatsi@gmail.com>
---
This was discovered by a coccinelle patch I developed, and submitted at:
  https://lore.kernel.org/all/20230227202428.3657443-1-jacob.e.keller@intel.com/

V1: https://lore.kernel.org/linux-wireless/99a9d4a2-d032-1c9d-90c6-3a68f6b3a092@intel.com/
Changes since v1
* Split series into individual postings to avoid confusion about dependency
* Fixed subject line

 drivers/net/wireless/quantenna/qtnfmac/commands.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/quantenna/qtnfmac/commands.c b/drivers/net/wireless/quantenna/qtnfmac/commands.c
index b1b73478d89b..68ae9c7ea95a 100644
--- a/drivers/net/wireless/quantenna/qtnfmac/commands.c
+++ b/drivers/net/wireless/quantenna/qtnfmac/commands.c
@@ -1325,9 +1325,10 @@ static int qtnf_cmd_band_fill_iftype(const u8 *data,
 	struct ieee80211_sband_iftype_data *iftype_data;
 	const struct qlink_tlv_iftype_data *tlv =
 		(const struct qlink_tlv_iftype_data *)data;
-	size_t payload_len = tlv->n_iftype_data * sizeof(*tlv->iftype_data) +
-		sizeof(*tlv) -
-		sizeof(struct qlink_tlv_hdr);
+	size_t payload_len;
+
+	payload_len = struct_size(tlv, iftype_data, tlv->n_iftype_data);
+	payload_len = size_sub(payload_len, sizeof(struct qlink_tlv_hdr));
 
 	if (tlv->hdr.len != cpu_to_le16(payload_len)) {
 		pr_err("bad IFTYPE_DATA TLV len %u\n", tlv->hdr.len);

base-commit: 8f9850dd8d23c1290cb642ce9548a440da5771ec
-- 
2.39.1.405.gd4c25cc71f83