Messages in this thread | | | From | Pkshih <> | Subject | RE: [PATCH] rtw88: Fix out-of-bounds write | Date | Mon, 12 Jul 2021 01:43:16 +0000 |
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> -----Original Message----- > From: Len Baker [mailto:len.baker@gmx.com] > Sent: Sunday, July 11, 2021 10:17 PM > To: Yan-Hsuan Chuang; Kalle Valo; David S. Miller; Jakub Kicinski > Cc: Len Baker; Stanislaw Gruszka; Brian Norris; 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 > > 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> > --- > 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/wireless/realtek/rtw88/pci.c > index e7d17ab8f113..b9d8c049e776 100644 > --- 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,
I think "if (len > TRX_BD_IDX_MASK)" you mentioned is
if (len > TRX_BD_IDX_MASK) { rtw_err(rtwdev, "len %d exceeds maximum RX entries\n", len); return -EINVAL; }
This statement is used to ensure the length doesn't exceed hardware capability.
To prevent the 'len' argument from exceeding the array size of rx_ring->buff, I suggest to add another checking statement, like
if (len > ARRAY_SIZE(rx_ring->buf)) { rtw_err(rtwdev, "len %d exceeds maximum RX ring buffer\n", len); return -EINVAL; }
But, I wonder if this a false alarm because 'len' is equal to ARRAY_SIZE(rx_ring->buf) for now.
> } > rx_ring->r.head = head; > > - for (i = 0; i < len; i++) { > + for (i = 0; i < ARRAY_SIZE(rx_ring->buf); i++) { > skb = dev_alloc_skb(buf_sz); > if (!skb) { > allocated = i; > -- > 2.25.1
-- Ping-Ke
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