[PATCH AUTOSEL 4.14 299/371] ath10k: adjust skb length in ath10k_sdio_mbox_rx_packet

Sasha Levin
2020-01-16T17:29:39Z

From: Nicolas Boichat <drinkcat@chromium.org>

[ Upstream commit b7139960832eb56fa15d390a4b5c8c5739bd0d1a ]

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@chromium.org>
Signed-off-by: Wen Gong <wgong@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/ath/ath10k/sdio.c | 29 +++++++++++++++++++-------
1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c
index 0a1248ebccf5..f49b21b137c1 100644
--- a/drivers/net/wireless/ath/ath10k/sdio.c
+++ b/drivers/net/wireless/ath/ath10k/sdio.c
@@ -392,16 +392,11 @@ static int ath10k_sdio_mbox_rx_process_packet(struct ath10k *ar,
struct ath10k_htc_hdr *htc_hdr = (struct ath10k_htc_hdr *)skb->data;
bool trailer_present = htc_hdr->flags & ATH10K_HTC_FLAG_TRAILER_PRESENT;
enum ath10k_htc_ep_id eid;
- u16 payload_len;
u8 *trailer;
int ret;

- payload_len = le16_to_cpu(htc_hdr->len);
- skb->len = payload_len + sizeof(struct ath10k_htc_hdr);
-
if (trailer_present) {
- trailer = skb->data + sizeof(*htc_hdr) +
- payload_len - htc_hdr->trailer_len;
+ trailer = skb->data + skb->len - htc_hdr->trailer_len;

eid = pipe_id_to_eid(htc_hdr->eid);

@@ -635,13 +630,31 @@ 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)
+ goto out;
+
+ /* 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) {
+ ath10k_warn(ar, "rx packet too large (%zu > %zu)\n",
+ pkt->act_len, pkt->alloc_len);
+ ret = -EMSGSIZE;
+ goto out;
+ }
+
+ skb_put(skb, pkt->act_len);
+
+out:
pkt->status = ret;
- if (!ret)
- skb_put(skb, pkt->act_len);

return ret;
}
--
2.20.1