CVE-2022-48871

In the Linux kernel, the following vulnerability has been resolved:

tty: serial: qcom-geni-serial: fix slab-out-of-bounds on RX FIFO buffer

Driver's probe allocates memory for RX FIFO (port->rx_fifo) based on

default RX FIFO depth, e.g. 16. Later during serial startup the

qcom_geni_serial_port_setup() updates the RX FIFO depth

(port->rx_fifo_depth) to match real device capabilities, e.g. to 32.

The RX UART handle code will read "port->rx_fifo_depth" number of words

into "port->rx_fifo" buffer, thus exceeding the bounds. This can be

observed in certain configurations with Qualcomm Bluetooth HCI UART

device and KASAN:

Bluetooth: hci0: QCA Product ID :0x00000010

Bluetooth: hci0: QCA SOC Version :0x400a0200

Bluetooth: hci0: QCA ROM Version :0x00000200

Bluetooth: hci0: QCA Patch Version:0x00000d2b

Bluetooth: hci0: QCA controller version 0x02000200

Bluetooth: hci0: QCA Downloading qca/htbtfw20.tlv

bluetooth hci0: Direct firmware load for qca/htbtfw20.tlv failed with error -2

Bluetooth: hci0: QCA Failed to request file: qca/htbtfw20.tlv (-2)

Bluetooth: hci0: QCA Failed to download patch (-2)

==================================================================

BUG: KASAN: slab-out-of-bounds in handle_rx_uart+0xa8/0x18c

Write of size 4 at addr ffff279347d578c0 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.0-rt5-00350-gb2450b7e00be-dirty #26

Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)

Call trace:

dump_backtrace.part.0+0xe0/0xf0

show_stack+0x18/0x40

dump_stack_lvl+0x8c/0xb8

print_report+0x188/0x488

kasan_report+0xb4/0x100

__asan_store4+0x80/0xa4

handle_rx_uart+0xa8/0x18c

qcom_geni_serial_handle_rx+0x84/0x9c

qcom_geni_serial_isr+0x24c/0x760

__handle_irq_event_percpu+0x108/0x500

handle_irq_event+0x6c/0x110

handle_fasteoi_irq+0x138/0x2cc

generic_handle_domain_irq+0x48/0x64

If the RX FIFO depth changes after probe, be sure to resize the buffer.