lkml.org 
[lkml]   [2022]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/2] serdev: ttyport: fix use-after-free on closed TTY
Date
use-after-free is visible in serdev-ttyport, e.g. during system reboot
with Qualcomm Atheros Bluetooth. The TTY is closed, thus "struct
tty_struct" is being released, but the hci_uart_qca driver performs
writes and flushes during system shutdown in qca_serdev_shutdown().

Unable to handle kernel paging request at virtual address 0072662f67726fd7
...
CPU: 6 PID: 1 Comm: systemd-shutdow Tainted: G W 6.1.0-rt5-00325-g8a5f56bcfcca #8
Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
Call trace:
tty_driver_flush_buffer+0x4/0x30
serdev_device_write_flush+0x24/0x34
qca_serdev_shutdown+0x80/0x130 [hci_uart]
device_shutdown+0x15c/0x260
kernel_restart+0x48/0xac

KASAN report:

BUG: KASAN: use-after-free in tty_driver_flush_buffer+0x1c/0x50
Read of size 8 at addr ffff16270c2e0018 by task systemd-shutdow/1

CPU: 7 PID: 1 Comm: systemd-shutdow Not tainted 6.1.0-next-20221220-00014-gb85aaf97fb01-dirty #28
Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
Call trace:
dump_backtrace.part.0+0xdc/0xf0
show_stack+0x18/0x30
dump_stack_lvl+0x68/0x84
print_report+0x188/0x488
kasan_report+0xa4/0xf0
__asan_load8+0x80/0xac
tty_driver_flush_buffer+0x1c/0x50
ttyport_write_flush+0x34/0x44
serdev_device_write_flush+0x48/0x60
qca_serdev_shutdown+0x124/0x274
device_shutdown+0x1e8/0x350
kernel_restart+0x48/0xb0
__do_sys_reboot+0x244/0x2d0
__arm64_sys_reboot+0x54/0x70
invoke_syscall+0x60/0x190
el0_svc_common.constprop.0+0x7c/0x160
do_el0_svc+0x44/0xf0
el0_svc+0x2c/0x6c
el0t_64_sync_handler+0xbc/0x140
el0t_64_sync+0x190/0x194

Fixes: bed35c6dfa6a ("serdev: add a tty port controller driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
drivers/tty/serdev/serdev-ttyport.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index d367803e2044..3d2bab91a988 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -91,6 +91,9 @@ static void ttyport_write_flush(struct serdev_controller *ctrl)
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;

+ if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+ return;
+
tty_driver_flush_buffer(tty);
}

@@ -99,6 +102,9 @@ static int ttyport_write_room(struct serdev_controller *ctrl)
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;

+ if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+ return 0;
+
return tty_write_room(tty);
}

@@ -172,6 +178,9 @@ static unsigned int ttyport_set_baudrate(struct serdev_controller *ctrl, unsigne
struct tty_struct *tty = serport->tty;
struct ktermios ktermios = tty->termios;

+ if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+ return -ENXIO;
+
ktermios.c_cflag &= ~CBAUD;
tty_termios_encode_baud_rate(&ktermios, speed, speed);

@@ -186,6 +195,9 @@ static void ttyport_set_flow_control(struct serdev_controller *ctrl, bool enable
struct tty_struct *tty = serport->tty;
struct ktermios ktermios = tty->termios;

+ if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+ return;
+
if (enable)
ktermios.c_cflag |= CRTSCTS;
else
@@ -201,6 +213,9 @@ static int ttyport_set_parity(struct serdev_controller *ctrl,
struct tty_struct *tty = serport->tty;
struct ktermios ktermios = tty->termios;

+ if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+ return -ENXIO;
+
ktermios.c_cflag &= ~(PARENB | PARODD | CMSPAR);
if (parity != SERDEV_PARITY_NONE) {
ktermios.c_cflag |= PARENB;
@@ -222,6 +237,9 @@ static void ttyport_wait_until_sent(struct serdev_controller *ctrl, long timeout
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;

+ if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+ return;
+
tty_wait_until_sent(tty, timeout);
}

@@ -230,6 +248,9 @@ static int ttyport_get_tiocm(struct serdev_controller *ctrl)
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;

+ if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+ return -ENXIO;
+
if (!tty->ops->tiocmget)
return -ENOTSUPP;

@@ -241,6 +262,9 @@ static int ttyport_set_tiocm(struct serdev_controller *ctrl, unsigned int set, u
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;

+ if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+ return -ENXIO;
+
if (!tty->ops->tiocmset)
return -ENOTSUPP;

--
2.34.1
\
 
 \ /
  Last update: 2023-03-26 23:17    [W:0.035 / U:0.260 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site