Messages in this thread Patch in this message | | | From | Xu Jia <> | Subject | [PATCH] hamradio: 6pack: fix array-index-out-of-bounds in decode_std_command() | Date | Mon, 13 Jun 2022 17:25:37 +0800 |
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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
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