Re: [PATCH v5] wifi: mwifiex: Fix OOB and integer underflow when rx packets

[Abhishek Kumar]

Left some comments around the formatting. Did you run checkpatch.pl
before pushing the change , if not please run.
On Fri, Jul 14, 2023 at 5:02 AM Polaris Pi <pinkperfect2021@xxxxxxxxx> wrote:
>
> Make sure mwifiex_process_mgmt_packet and its callers
> mwifiex_process_sta_rx_packet and mwifiex_process_uap_rx_packet
> not out-of-bounds access the skb->data buffer.
>
> Fixes: 2dbaf751b1de ("mwifiex: report received management frames to cfg80211")
> Signed-off-by: Polaris Pi <pinkperfect2021@xxxxxxxxx>
> ---
> V5: Follow chromeos comments: preserve the original flow of mwifiex_process_uap_rx_packet
> ---
>  drivers/net/wireless/marvell/mwifiex/sta_rx.c   |  3 ++-
>  drivers/net/wireless/marvell/mwifiex/uap_txrx.c | 11 +++++++++++
>  drivers/net/wireless/marvell/mwifiex/util.c     |  5 +++++
>  3 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/marvell/mwifiex/sta_rx.c b/drivers/net/wireless/marvell/mwifiex/sta_rx.c
> index 13659b02ba88..88aaec645291 100644
> --- a/drivers/net/wireless/marvell/mwifiex/sta_rx.c
> +++ b/drivers/net/wireless/marvell/mwifiex/sta_rx.c
> @@ -194,7 +194,8 @@ int mwifiex_process_sta_rx_packet(struct mwifiex_private *priv,
>
>         rx_pkt_hdr = (void *)local_rx_pd + rx_pkt_offset;
>
> -       if ((rx_pkt_offset + rx_pkt_length) > (u16) skb->len) {
> +       if ((rx_pkt_offset + rx_pkt_length) > (u16)skb->len ||
formatting issue, space after (u16)
> +           skb->len - rx_pkt_offset < sizeof(*rx_pkt_hdr)) {
>                 mwifiex_dbg(adapter, ERROR,
>                             "wrong rx packet: len=%d, rx_pkt_offset=%d, rx_pkt_length=%d\n",
>                             skb->len, rx_pkt_offset, rx_pkt_length);
> diff --git a/drivers/net/wireless/marvell/mwifiex/uap_txrx.c b/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
> index e495f7eaea03..32f4626a4d76 100644
> --- a/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
> +++ b/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
> @@ -367,6 +367,17 @@ int mwifiex_process_uap_rx_packet(struct mwifiex_private *priv,
>         rx_pkt_type = le16_to_cpu(uap_rx_pd->rx_pkt_type);
>         rx_pkt_hdr = (void *)uap_rx_pd + le16_to_cpu(uap_rx_pd->rx_pkt_offset);
>
> +       if (le16_to_cpu(uap_rx_pd->rx_pkt_offset) > skb->len ||
> +           skb->len - le16_to_cpu(uap_rx_pd->rx_pkt_offset) < sizeof(*rx_pkt_hdr)) {
> +               mwifiex_dbg(adapter, ERROR,
> +                           "wrong rx packet offset: len=%d, offset=%d\n",
> +                           skb->len, le16_to_cpu(uap_rx_pd->rx_pkt_offset));
> +               priv->stats.rx_dropped++;
> +
> +               dev_kfree_skb_any(skb);
> +               return 0;
> +       }
> +
>         ether_addr_copy(ta, rx_pkt_hdr->eth803_hdr.h_source);
>
>         if ((le16_to_cpu(uap_rx_pd->rx_pkt_offset) +
> diff --git a/drivers/net/wireless/marvell/mwifiex/util.c b/drivers/net/wireless/marvell/mwifiex/util.c
> index 94c2d219835d..31e1a82883e4 100644
> --- a/drivers/net/wireless/marvell/mwifiex/util.c
> +++ b/drivers/net/wireless/marvell/mwifiex/util.c
> @@ -399,6 +399,11 @@ mwifiex_process_mgmt_packet(struct mwifiex_private *priv,
>
>         pkt_len = le16_to_cpu(rx_pd->rx_pkt_length);
>
> +       if (pkt_len < sizeof(struct ieee80211_hdr) || skb->len < pkt_len) {
> +               mwifiex_dbg(priv->adapter, ERROR, "invalid rx_pkt_length");
> +               return -1;
why return -1 instead of returning appropriate error code , may be EMSGSIZE

Thanks
Abhishek

> +       }
> +
>         ieee_hdr = (void *)skb->data;
>         if (ieee80211_is_mgmt(ieee_hdr->frame_control)) {
>                 if (mwifiex_parse_mgmt_packet(priv, (u8 *)ieee_hdr,
> --
> 2.25.1
>