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From:   Len Baker <len.baker@gmx.com>
To:     Yan-Hsuan Chuang <tony0620emma@gmail.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
Cc:     Len Baker <len.baker@gmx.com>,
        Stanislaw Gruszka <sgruszka@redhat.com>,
        Brian Norris <briannorris@chromium.org>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: [PATCH] rtw88: Fix out-of-bounds write
Date:   Sun, 11 Jul 2021 16:16:34 +0200
Message-Id: <20210711141634.6133-1-len.baker@gmx.com>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

In the rtw_pci_init_rx_ring function the "if (len > TRX_BD_IDX_MASK)"
statement guarantees that len is less than or equal to GENMASK(11, 0) or
in other words that len is less than or equal to 4095. However the
rx_ring->buf has a size of RTK_MAX_RX_DESC_NUM (defined as 512). This
way it is possible an out-of-bounds write in the for statement due to
the i variable can exceed the rx_ring->buff size.

Fix it using the ARRAY_SIZE macro.

Cc: stable@vger.kernel.org
Addresses-Coverity-ID: 1461515 ("Out-of-bounds write")
Fixes: e3037485c68ec ("rtw88: new Realtek 802.11ac driver")
Signed-off-by: Len Baker <len.baker@gmx.com>
=2D--
 drivers/net/wireless/realtek/rtw88/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wirele=
ss/realtek/rtw88/pci.c
index e7d17ab8f113..b9d8c049e776 100644
=2D-- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -280,7 +280,7 @@ static int rtw_pci_init_rx_ring(struct rtw_dev *rtwdev=
,
 	}
 	rx_ring->r.head =3D head;

-	for (i =3D 0; i < len; i++) {
+	for (i =3D 0; i < ARRAY_SIZE(rx_ring->buf); i++) {
 		skb =3D dev_alloc_skb(buf_sz);
 		if (!skb) {
 			allocated =3D i;
=2D-
2.25.1