diff options
| author | Pengpeng Hou <pengpeng@iscas.ac.cn> | 2026-04-05 08:40:00 +0800 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2026-04-09 13:54:37 +0200 |
| commit | c71ba669b570c7b3f86ec875be222ea11dacb352 (patch) | |
| tree | 8c40916d8c87f40f5e8ff38ddfe03dd27a3f857a /drivers | |
| parent | ebe560ea5f54134279356703e73b7f867c89db13 (diff) | |
nfc: pn533: allocate rx skb before consuming bytes
pn532_receive_buf() reports the number of accepted bytes to the serdev
core. The current code consumes bytes into recv_skb and may already hand
a complete frame to pn533_recv_frame() before allocating a fresh receive
buffer.
If that alloc_skb() fails, the callback returns 0 even though it has
already consumed bytes, and it leaves recv_skb as NULL for the next
receive callback. That breaks the receive_buf() accounting contract and
can also lead to a NULL dereference on the next skb_put_u8().
Allocate the receive skb lazily before consuming the next byte instead.
If allocation fails, return the number of bytes already accepted.
Fixes: c656aa4c27b1 ("nfc: pn533: add UART phy driver")
Cc: stable@vger.kernel.org
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Link: https://patch.msgid.link/20260405094003.3-pn533-v2-pengpeng@iscas.ac.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/nfc/pn533/uart.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/nfc/pn533/uart.c b/drivers/nfc/pn533/uart.c index 1b82b7b2a5fa..e0d67cd2ac9b 100644 --- a/drivers/nfc/pn533/uart.c +++ b/drivers/nfc/pn533/uart.c @@ -211,6 +211,13 @@ static size_t pn532_receive_buf(struct serdev_device *serdev, timer_delete(&dev->cmd_timeout); for (i = 0; i < count; i++) { + if (!dev->recv_skb) { + dev->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, + GFP_KERNEL); + if (!dev->recv_skb) + return i; + } + if (unlikely(!skb_tailroom(dev->recv_skb))) skb_trim(dev->recv_skb, 0); @@ -219,9 +226,7 @@ static size_t pn532_receive_buf(struct serdev_device *serdev, continue; pn533_recv_frame(dev->priv, dev->recv_skb, 0); - dev->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL); - if (!dev->recv_skb) - return 0; + dev->recv_skb = NULL; } return i; |