lkml.org 
[lkml]   [2022]   [Jun]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] hamradio: 6pack: fix array-index-out-of-bounds in decode_std_command()
Date
Hulk Robot reports incorrect sp->rx_count_cooked value in decode_std_command().
This should be caused by the subtracting from sp->rx_count_cooked before.
It seems that sp->rx_count_cooked value is changed to 0, which bypassed the
previous judgment.
sp->rx_count_cooked is a shared variable but is not protected by a lock.
The same applies to sp->rx_count. This patch adds a lock to fix the bug.

The fail log is shown below:
=======================================================================
UBSAN: array-index-out-of-bounds in drivers/net/hamradio/6pack.c:925:31
index 400 is out of range for type 'unsigned char [400]'
CPU: 3 PID: 7433 Comm: kworker/u10:1 Not tainted 5.18.0-rc5-00163-g4b97bac0756a #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Workqueue: events_unbound flush_to_ldisc
Call Trace:
<TASK>
dump_stack_lvl+0xcd/0x134
ubsan_epilogue+0xb/0x50
__ubsan_handle_out_of_bounds.cold+0x62/0x6c
sixpack_receive_buf+0xfda/0x1330
tty_ldisc_receive_buf+0x13e/0x180
tty_port_default_receive_buf+0x6d/0xa0
flush_to_ldisc+0x213/0x3f0
process_one_work+0x98f/0x1620
worker_thread+0x665/0x1080
kthread+0x2e9/0x3a0
ret_from_fork+0x1f/0x30
...

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Xu Jia <xujia39@huawei.com>
---
drivers/net/hamradio/6pack.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
index 45c3c4a..194f22f 100644
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -100,6 +100,8 @@ struct sixpack {
unsigned int rx_count;
unsigned int rx_count_cooked;

+ spinlock_t rxlock;
+
int mtu; /* Our mtu (to spot changes!) */
int buffsize; /* Max buffers sizes */

@@ -565,6 +567,7 @@ static int sixpack_open(struct tty_struct *tty)
sp->dev = dev;

spin_lock_init(&sp->lock);
+ spin_lock_init(&sp->rxlock);
refcount_set(&sp->refcnt, 1);
init_completion(&sp->dead);

@@ -913,6 +916,7 @@ static void decode_std_command(struct sixpack *sp, unsigned char cmd)
sp->led_state = 0x60;
/* fill trailing bytes with zeroes */
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
+ spin_lock(&sp->rxlock);
rest = sp->rx_count;
if (rest != 0)
for (i = rest; i <= 3; i++)
@@ -930,6 +934,7 @@ static void decode_std_command(struct sixpack *sp, unsigned char cmd)
sp_bump(sp, 0);
}
sp->rx_count_cooked = 0;
+ spin_unlock(&sp->rxlock);
}
break;
case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n");
--
1.8.3.1
\
 
 \ /
  Last update: 2022-06-13 11:13    [W:0.039 / U:0.228 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site