From cce7fc8b29961b64fadb1ce398dc5ff32a79643b Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: Fri, 1 Sep 2023 01:25:55 +0300
Subject: [PATCH] serial: 8250_port: Check IRQ data before use
Git-commit: cce7fc8b29961b64fadb1ce398dc5ff32a79643b
Patch-mainline: v6.6-rc4
References: git-fixes CVE-2023-52567 bsc#1220839
In case the leaf driver wants to use IRQ polling (irq = 0) and
IIR register shows that an interrupt happened in the 8250 hardware
the IRQ data can be NULL. In such a case we need to skip the wake
event as we came to this path from the timer interrupt and quite
likely system is already awake.
Without this fix we have got an Oops:
serial8250: ttyS0 at I/O 0x3f8 (irq = 0, base_baud = 115200) is a 16550A
...
BUG: kernel NULL pointer dereference, address: 0000000000000010
RIP: 0010:serial8250_handle_irq+0x7c/0x240
Call Trace:
? serial8250_handle_irq+0x7c/0x240
? __pfx_serial8250_timeout+0x10/0x10
Fixes: 0ba9e3a13c6a ("serial: 8250: Add missing wakeup event reporting")
Cc: stable <stable@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20230831222555.614426-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/tty/serial/8250/8250_port.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index fb891b67968f..141627370aab 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1936,7 +1936,10 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
skip_rx = true;
if (status & (UART_LSR_DR | UART_LSR_BI) && !skip_rx) {
- if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
+ struct irq_data *d;
+
+ d = irq_get_irq_data(port->irq);
+ if (d && irqd_is_wakeup_set(d))
pm_wakeup_event(tport->tty->dev, 0);
if (!up->dma || handle_rx_dma(up, iir))
status = serial8250_rx_chars(up, status);
--
2.35.3