From: Jakub Kicinski <kuba@kernel.org>
To: Stefan Wahren <wahrenst@gmx.net>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Dan Carpenter <dan.carpenter@linaro.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH net] net: vertexcom: mse102x: Fix possible double free of TX skb
Date: Tue, 29 Oct 2024 12:10:28 -0700 [thread overview]
Message-ID: <20241029121028.127f89b3@kernel.org> (raw)
In-Reply-To: <20241022155242.33729-1-wahrenst@gmx.net>
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.
next prev parent reply other threads:[~2024-10-29 19:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-22 15:52 [PATCH net] net: vertexcom: mse102x: Fix possible double free of TX skb Stefan Wahren
2024-10-24 9:49 ` Simon Horman
2024-10-29 19:10 ` Jakub Kicinski [this message]
2024-10-29 21:15 ` Stefan Wahren
2024-10-29 22:01 ` Jakub Kicinski
2024-10-29 23:06 ` Stefan Wahren
2024-10-30 0:36 ` Jakub Kicinski
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