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From: Franky Lin <franky.lin@broadcom.com>
Date: Fri, 2 Jun 2017 11:52:29 -0700
Message-ID: <CA+8PC_e8HdkBw4DfGUPO0BbM-W5wftK=i6_vjwFTmS7=axyFUw@mail.gmail.com> (sfid-20170602_205321_580527_CA5810E5)
Subject: Re: [PATCH] brcmfmac: Fix glob_skb leak in brcmf_sdiod_recv_chain
To: "Peter S. Housel" <housel@acm.org>
Cc: Arend van Spriel <arend.vanspriel@broadcom.com>,
        Hante Meuleman <hante.meuleman@broadcom.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        Christian Daudt <csd@broadcom.com>,
        Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER"
        <linux-wireless@vger.kernel.org>,
        "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER"
        <brcm80211-dev-list.pdl@broadcom.com>,
        "open list:NETWORKING DRIVERS" <netdev@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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Sender: linux-wireless-owner@vger.kernel.org

On Fri, Jun 2, 2017 at 10:22 AM, Peter S. Housel <housel@acm.org> wrote:
> An earlier change to this function (3bdae810721b) fixed a leak in the
> case of an unsuccessful call to brcmf_sdiod_buffrw(). However, the
> glob_skb buffer, used for emulating a scattering read, is never used
> or referenced after its contents are copied into the destination
> buffers, and therefore always needs to be freed by the end of the
> function.
>
> Signed-off-by: Peter S. Housel <housel@acm.org>
> ---
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c
> index 9b970dc..4c5064f 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c
> @@ -727,15 +727,16 @@ int brcmf_sdiod_recv_chain(struct brcmf_sdio_dev *sdiodev,
>                         return -ENOMEM;
>                 err = brcmf_sdiod_buffrw(sdiodev, SDIO_FUNC_2, false, addr,
>                                          glom_skb);
> -               if (err) {
> -                       brcmu_pkt_buf_free_skb(glom_skb);
> -                       goto done;
> -               }
> +               if (err)
> +                       goto free_glom_skb;
>
>                 skb_queue_walk(pktq, skb) {
>                         memcpy(skb->data, glom_skb->data, skb->len);
>                         skb_pull(glom_skb, skb->len);
>                 }
> +
> +free_glom_skb:
> +               brcmu_pkt_buf_free_skb(glom_skb);

What about
        if (!err) {
            skb_queue_walk(pktq, skb) {
                memcpy(skb->data, glom_skb->data, skb->len);
                skb_pull(glom_skb, skb->len);
            }
        }
        brcmu_pkt_buf_free_skb(glom_skb);

Then no goto is needed.

Thanks,
Franky

>         } else
>                 err = brcmf_sdiod_sglist_rw(sdiodev, SDIO_FUNC_2, false, addr,
>                                             pktq);
> --
> 2.7.4
>