Wen Gong <wgong@xxxxxxxxxxxxxx> writes:
> From: Nicolas Boichat <drinkcat@xxxxxxxxxxxx>
>
> When the FW bundles multiple packets, pkt->act_len may be incorrect
> as it refers to the first packet only (however, the FW will only
> bundle packets that fit into the same pkt->alloc_len).
>
> Before this patch, the skb length would be set (incorrectly) to
> pkt->act_len in ath10k_sdio_mbox_rx_packet, and then later manually
> adjusted in ath10k_sdio_mbox_rx_process_packet.
>
> The first problem is that ath10k_sdio_mbox_rx_process_packet does not
> use proper skb_put commands to adjust the length (it directly changes
> skb->len), so we end up with a mismatch between skb->head + skb->tail
> and skb->data + skb->len. This is quite serious, and causes corruptions
> in the TCP stack, as the stack tries to coalesce packets, and relies
> on skb->tail being correct (that is, skb_tail_pointer must point to
> the first byte_after_ the data).
>
> Instead of re-adjusting the size in ath10k_sdio_mbox_rx_process_packet,
> this moves the code to ath10k_sdio_mbox_rx_packet, and also add a
> bounds check, as skb_put would crash the kernel if not enough space is
> available.
>
> Tested with QCA6174 SDIO with firmware
> WLAN.RMH.4.4.1-00007-QCARMSWP-1.
>
> Fixes: 8530b4e7b22bc3b ("ath10k: sdio: set skb len for all rx packets")
> Signed-off-by: Nicolas Boichat <drinkcat@xxxxxxxxxxxx>
> Signed-off-by: Wen Gong <wgong@xxxxxxxxxxxxxx>
[...]
> @@ -632,13 +627,29 @@ static int ath10k_sdio_mbox_rx_packet(struct ath10k *ar,
> {
> struct ath10k_sdio *ar_sdio = ath10k_sdio_priv(ar);
> struct sk_buff *skb = pkt->skb;
> + struct ath10k_htc_hdr *htc_hdr;
> int ret;
>
> ret = ath10k_sdio_readsb(ar, ar_sdio->mbox_info.htc_addr,
> skb->data, pkt->alloc_len);
> +
> + if (!ret) {
> + /* Update actual length. The original length may be incorrect,
> + * as the FW will bundle multiple packets as long as their sizes
> + * fit within the same aligned length (pkt->alloc_len).
> + */
> + htc_hdr = (struct ath10k_htc_hdr *)skb->data;
> + pkt->act_len = le16_to_cpu(htc_hdr->len) + sizeof(*htc_hdr);
> + if (pkt->act_len <= pkt->alloc_len) {
> + skb_put(skb, pkt->act_len);
> + } else {
> + ath10k_warn(ar, "rx packet too large (%zu > %zu)\n",
> + pkt->act_len, pkt->alloc_len);
> + ret = -EMSGSIZE;
> + }
> + }
> +
> pkt->status = ret;
> - if (!ret)
> - skb_put(skb, pkt->act_len);
>
> return ret;
> }
I simplified the error handling in this function to follow the ath10k
style, please check carefully that I didn't create any bugs:
https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git/commit/?h=pending&id=6e4d2cc5
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