From 000bfbc6bc334a93fffca8f5aa9583e7b6356cb5 Mon Sep 17 00:00:00 2001 From: Krzysztof Kozlowski Date: Wed, 18 Jun 2025 09:36:50 +0200 Subject: [PATCH] NFC: nci: uart: Set tty->disc_data only in success path commit fc27ab48904ceb7e4792f0c400f1ef175edf16fe upstream. Setting tty->disc_data before opening the NCI device means we need to clean it up on error paths. This also opens some short window if device starts sending data, even before NCIUARTSETDRIVER IOCTL succeeded (broken hardware?). Close the window by exposing tty->disc_data only on the success path, when opening of the NCI device and try_module_get() succeeds. The code differs in error path in one aspect: tty->disc_data won't be ever assigned thus NULL-ified. This however should not be relevant difference, because of "tty->disc_data=NULL" in nci_uart_tty_open(). Cc: Linus Torvalds Fixes: 9961127d4bce ("NFC: nci: add generic uart support") Cc: Signed-off-by: Krzysztof Kozlowski Reviewed-by: Greg Kroah-Hartman Link: https://patch.msgid.link/20250618073649.25049-2-krzysztof.kozlowski@linaro.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/nfc/nci/uart.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/nfc/nci/uart.c b/net/nfc/nci/uart.c index 1204c438e87dc..03a51bcb9c373 100644 --- a/net/nfc/nci/uart.c +++ b/net/nfc/nci/uart.c @@ -131,22 +131,22 @@ static int nci_uart_set_driver(struct tty_struct *tty, unsigned int driver) memcpy(nu, nci_uart_drivers[driver], sizeof(struct nci_uart)); nu->tty = tty; - tty->disc_data = nu; skb_queue_head_init(&nu->tx_q); INIT_WORK(&nu->write_work, nci_uart_write_work); spin_lock_init(&nu->rx_lock); ret = nu->ops.open(nu); if (ret) { - tty->disc_data = NULL; kfree(nu); + return ret; } else if (!try_module_get(nu->owner)) { nu->ops.close(nu); - tty->disc_data = NULL; kfree(nu); return -ENOENT; } - return ret; + tty->disc_data = nu; + + return 0; } /* ------ LDISC part ------ */ -- 2.47.3