[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20241029121028.127f89b3@kernel.org>
Date: Tue, 29 Oct 2024 12:10:28 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Stefan Wahren <wahrenst@....net>
Cc: Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller"
<davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Paolo Abeni
<pabeni@...hat.com>, Dan Carpenter <dan.carpenter@...aro.org>,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Subject: Re: [PATCH net] net: vertexcom: mse102x: Fix possible double free
of TX skb
On Tue, 22 Oct 2024 17:52:42 +0200 Stefan Wahren wrote:
> -static int mse102x_tx_frame_spi(struct mse102x_net *mse, struct sk_buff *txp,
> +static int mse102x_tx_frame_spi(struct mse102x_net *mse, struct sk_buff **txp,
> unsigned int pad)
> {
> struct mse102x_net_spi *mses = to_mse102x_spi(mse);
> @@ -226,29 +226,29 @@ static int mse102x_tx_frame_spi(struct mse102x_net *mse, struct sk_buff *txp,
> int ret;
>
> netif_dbg(mse, tx_queued, mse->ndev, "%s: skb %p, %d@%p\n",
> - __func__, txp, txp->len, txp->data);
> + __func__, *txp, (*txp)->len, (*txp)->data);
>
> - if ((skb_headroom(txp) < DET_SOF_LEN) ||
> - (skb_tailroom(txp) < DET_DFT_LEN + pad)) {
> - tskb = skb_copy_expand(txp, DET_SOF_LEN, DET_DFT_LEN + pad,
> + if ((skb_headroom(*txp) < DET_SOF_LEN) ||
> + (skb_tailroom(*txp) < DET_DFT_LEN + pad)) {
> + tskb = skb_copy_expand(*txp, DET_SOF_LEN, DET_DFT_LEN + pad,
> GFP_KERNEL);
> if (!tskb)
> return -ENOMEM;
>
> - dev_kfree_skb(txp);
> - txp = tskb;
> + dev_kfree_skb(*txp);
> + *txp = tskb;
> }
>
> - mse102x_push_header(txp);
> + mse102x_push_header(*txp);
>
> if (pad)
> - skb_put_zero(txp, pad);
> + skb_put_zero(*txp, pad);
>
> - mse102x_put_footer(txp);
> + mse102x_put_footer(*txp);
>
> - xfer->tx_buf = txp->data;
> + xfer->tx_buf = (*txp)->data;
> xfer->rx_buf = NULL;
> - xfer->len = txp->len;
> + xfer->len = (*txp)->len;
>
> ret = spi_sync(mses->spidev, msg);
> if (ret < 0) {
> @@ -368,7 +368,7 @@ static void mse102x_rx_pkt_spi(struct mse102x_net *mse)
> mse->ndev->stats.rx_bytes += rxlen;
Isn't it easier to change this function to free the copy rather than
the original? That way the original will remain valid for the callers.
Powered by blists - more mailing lists