| Message ID | 1655112337-48005-1-git-send-email-xujia39@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | hamradio: 6pack: fix array-index-out-of-bounds in decode_std_command() | expand |
On Mon, 2022-06-13 at 17:25 +0800, Xu Jia wrote: > 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. It's not clear to me how multiple process could access it concurrently, could you please elaborate more? > 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); It looks like 'sp->rx_count' and 'sp->rx_count_cooked' are touched also in decode_data(). Do we need to protect such accesses, too? Thanks! Paolo
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");
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(+)