Large pkt_len can lead to out-out-bound memcpy. Current
ath9k_hif_usb_rx_stream allows combining the content of two urb
inputs to one pkt. The first input can indicate the size of the
pkt. Any remaining size is saved in hif_dev->rx_remain_len.
While processing the next input, memcpy is used with rx_remain_len.
4-byte pkt_len can go up to 0xffff, while a single input is 0x4000
maximum in size (MAX_RX_BUF_SIZE). Thus, the patch adds a check for
pkt_len which must not exceed 2 * MAX_RX_BUG_SIZE.
BUG: KASAN: slab-out-of-bounds in ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
Read of size 46393 at addr ffff888018798000 by task kworker/0:1/23
CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 5.6.0 #63
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
Workqueue: events request_firmware_work_func
Call Trace:
<IRQ>
dump_stack+0x76/0xa0
print_address_description.constprop.0+0x16/0x200
? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
__kasan_report.cold+0x37/0x7c
? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
kasan_report+0xe/0x20
check_memory_region+0x15a/0x1d0
memcpy+0x20/0x50
ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
? hif_usb_mgmt_cb+0x2d9/0x2d9 [ath9k_htc]
? _raw_spin_lock_irqsave+0x7b/0xd0
? _raw_spin_trylock_bh+0x120/0x120
? __usb_unanchor_urb+0x12f/0x210
__usb_hcd_giveback_urb+0x1e4/0x380
usb_giveback_urb_bh+0x241/0x4f0
? __hrtimer_run_queues+0x316/0x740
? __usb_hcd_giveback_urb+0x380/0x380
tasklet_action_common.isra.0+0x135/0x330
__do_softirq+0x18c/0x634
irq_exit+0x114/0x140
smp_apic_timer_interrupt+0xde/0x380
apic_timer_interrupt+0xf/0x20
Signed-off-by: Zekun Shen <[email protected]>
---
drivers/net/wireless/ath/ath9k/hif_usb.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index 860da13bf..0681bc5fa 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
@@ -589,6 +589,12 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
RX_STAT_INC(skb_dropped);
return;
}
+ if (pkt_len > 2 * MAX_RX_BUF_SIZE) {
+ dev_err(&hif_dev->udev->dev,
+ "ath9k_htc: invalid pkt_len (%x)\n", pkt_len);
+ RX_STAT_INC(skb_dropped);
+ return;
+ }
pad_len = 4 - (pkt_len & 0x3);
if (pad_len == 4)
--
2.25.1
Zekun Shen <[email protected]> writes:
> Large pkt_len can lead to out-out-bound memcpy. Current
> ath9k_hif_usb_rx_stream allows combining the content of two urb
> inputs to one pkt. The first input can indicate the size of the
> pkt. Any remaining size is saved in hif_dev->rx_remain_len.
> While processing the next input, memcpy is used with rx_remain_len.
>
> 4-byte pkt_len can go up to 0xffff, while a single input is 0x4000
> maximum in size (MAX_RX_BUF_SIZE). Thus, the patch adds a check for
> pkt_len which must not exceed 2 * MAX_RX_BUG_SIZE.
>
> BUG: KASAN: slab-out-of-bounds in ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> Read of size 46393 at addr ffff888018798000 by task kworker/0:1/23
>
> CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 5.6.0 #63
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
> Workqueue: events request_firmware_work_func
> Call Trace:
> <IRQ>
> dump_stack+0x76/0xa0
> print_address_description.constprop.0+0x16/0x200
> ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> __kasan_report.cold+0x37/0x7c
> ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> kasan_report+0xe/0x20
> check_memory_region+0x15a/0x1d0
> memcpy+0x20/0x50
> ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> ? hif_usb_mgmt_cb+0x2d9/0x2d9 [ath9k_htc]
> ? _raw_spin_lock_irqsave+0x7b/0xd0
> ? _raw_spin_trylock_bh+0x120/0x120
> ? __usb_unanchor_urb+0x12f/0x210
> __usb_hcd_giveback_urb+0x1e4/0x380
> usb_giveback_urb_bh+0x241/0x4f0
> ? __hrtimer_run_queues+0x316/0x740
> ? __usb_hcd_giveback_urb+0x380/0x380
> tasklet_action_common.isra.0+0x135/0x330
> __do_softirq+0x18c/0x634
> irq_exit+0x114/0x140
> smp_apic_timer_interrupt+0xde/0x380
> apic_timer_interrupt+0xf/0x20
>
> Signed-off-by: Zekun Shen <[email protected]>
How did you test this?
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
On Fri, Oct 29, 2021 at 06:52:31AM +0300, Kalle Valo wrote:
> Zekun Shen <[email protected]> writes:
>
> > Large pkt_len can lead to out-out-bound memcpy. Current
> > ath9k_hif_usb_rx_stream allows combining the content of two urb
> > inputs to one pkt. The first input can indicate the size of the
> > pkt. Any remaining size is saved in hif_dev->rx_remain_len.
> > While processing the next input, memcpy is used with rx_remain_len.
> >
> > 4-byte pkt_len can go up to 0xffff, while a single input is 0x4000
> > maximum in size (MAX_RX_BUF_SIZE). Thus, the patch adds a check for
> > pkt_len which must not exceed 2 * MAX_RX_BUG_SIZE.
> >
> > BUG: KASAN: slab-out-of-bounds in ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> > Read of size 46393 at addr ffff888018798000 by task kworker/0:1/23
> >
> > CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 5.6.0 #63
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> > BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
> > Workqueue: events request_firmware_work_func
> > Call Trace:
> > <IRQ>
> > dump_stack+0x76/0xa0
> > print_address_description.constprop.0+0x16/0x200
> > ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> > ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> > __kasan_report.cold+0x37/0x7c
> > ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> > kasan_report+0xe/0x20
> > check_memory_region+0x15a/0x1d0
> > memcpy+0x20/0x50
> > ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> > ? hif_usb_mgmt_cb+0x2d9/0x2d9 [ath9k_htc]
> > ? _raw_spin_lock_irqsave+0x7b/0xd0
> > ? _raw_spin_trylock_bh+0x120/0x120
> > ? __usb_unanchor_urb+0x12f/0x210
> > __usb_hcd_giveback_urb+0x1e4/0x380
> > usb_giveback_urb_bh+0x241/0x4f0
> > ? __hrtimer_run_queues+0x316/0x740
> > ? __usb_hcd_giveback_urb+0x380/0x380
> > tasklet_action_common.isra.0+0x135/0x330
> > __do_softirq+0x18c/0x634
> > irq_exit+0x114/0x140
> > smp_apic_timer_interrupt+0xde/0x380
> > apic_timer_interrupt+0xf/0x20
> >
> > Signed-off-by: Zekun Shen <[email protected]>
>
> How did you test this?
I found the bug using a custome USBFuzz port. It's a research work
to fuzz USB stack/drivers. I modified it to fuzz ath9k driver only,
providing hand-crafted usb descriptors to QEMU.
After fixing the value of pkt_tag to ATH_USB_RX_STREAM_MODE_TAG in QEMU
emulation, I found the KASAN report. The bug is triggerable whenever
pkt_len is above two MAX_RX_BUG_SIZE. I used the same input that crashes
to test the driver works when applying the patch.
>
> --
> https://patchwork.kernel.org/project/linux-wireless/list/
>
> https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
Zekun Shen <[email protected]> wrote:
> Large pkt_len can lead to out-out-bound memcpy. Current
> ath9k_hif_usb_rx_stream allows combining the content of two urb
> inputs to one pkt. The first input can indicate the size of the
> pkt. Any remaining size is saved in hif_dev->rx_remain_len.
> While processing the next input, memcpy is used with rx_remain_len.
>
> 4-byte pkt_len can go up to 0xffff, while a single input is 0x4000
> maximum in size (MAX_RX_BUF_SIZE). Thus, the patch adds a check for
> pkt_len which must not exceed 2 * MAX_RX_BUG_SIZE.
>
> BUG: KASAN: slab-out-of-bounds in ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> Read of size 46393 at addr ffff888018798000 by task kworker/0:1/23
>
> CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 5.6.0 #63
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
> Workqueue: events request_firmware_work_func
> Call Trace:
> <IRQ>
> dump_stack+0x76/0xa0
> print_address_description.constprop.0+0x16/0x200
> ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> __kasan_report.cold+0x37/0x7c
> ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> kasan_report+0xe/0x20
> check_memory_region+0x15a/0x1d0
> memcpy+0x20/0x50
> ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> ? hif_usb_mgmt_cb+0x2d9/0x2d9 [ath9k_htc]
> ? _raw_spin_lock_irqsave+0x7b/0xd0
> ? _raw_spin_trylock_bh+0x120/0x120
> ? __usb_unanchor_urb+0x12f/0x210
> __usb_hcd_giveback_urb+0x1e4/0x380
> usb_giveback_urb_bh+0x241/0x4f0
> ? __hrtimer_run_queues+0x316/0x740
> ? __usb_hcd_giveback_urb+0x380/0x380
> tasklet_action_common.isra.0+0x135/0x330
> __do_softirq+0x18c/0x634
> irq_exit+0x114/0x140
> smp_apic_timer_interrupt+0xde/0x380
> apic_timer_interrupt+0xf/0x20
>
> Signed-off-by: Zekun Shen <[email protected]>
I need to test this myself.
Patch set to Deferred.
--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
Zekun Shen <[email protected]> wrote:
> Large pkt_len can lead to out-out-bound memcpy. Current
> ath9k_hif_usb_rx_stream allows combining the content of two urb
> inputs to one pkt. The first input can indicate the size of the
> pkt. Any remaining size is saved in hif_dev->rx_remain_len.
> While processing the next input, memcpy is used with rx_remain_len.
>
> 4-byte pkt_len can go up to 0xffff, while a single input is 0x4000
> maximum in size (MAX_RX_BUF_SIZE). Thus, the patch adds a check for
> pkt_len which must not exceed 2 * MAX_RX_BUG_SIZE.
>
> BUG: KASAN: slab-out-of-bounds in ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> Read of size 46393 at addr ffff888018798000 by task kworker/0:1/23
>
> CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 5.6.0 #63
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
> Workqueue: events request_firmware_work_func
> Call Trace:
> <IRQ>
> dump_stack+0x76/0xa0
> print_address_description.constprop.0+0x16/0x200
> ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> __kasan_report.cold+0x37/0x7c
> ? ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> kasan_report+0xe/0x20
> check_memory_region+0x15a/0x1d0
> memcpy+0x20/0x50
> ath9k_hif_usb_rx_cb+0x490/0xed7 [ath9k_htc]
> ? hif_usb_mgmt_cb+0x2d9/0x2d9 [ath9k_htc]
> ? _raw_spin_lock_irqsave+0x7b/0xd0
> ? _raw_spin_trylock_bh+0x120/0x120
> ? __usb_unanchor_urb+0x12f/0x210
> __usb_hcd_giveback_urb+0x1e4/0x380
> usb_giveback_urb_bh+0x241/0x4f0
> ? __hrtimer_run_queues+0x316/0x740
> ? __usb_hcd_giveback_urb+0x380/0x380
> tasklet_action_common.isra.0+0x135/0x330
> __do_softirq+0x18c/0x634
> irq_exit+0x114/0x140
> smp_apic_timer_interrupt+0xde/0x380
> apic_timer_interrupt+0xf/0x20
>
> I found the bug using a custome USBFuzz port. It's a research work
> to fuzz USB stack/drivers. I modified it to fuzz ath9k driver only,
> providing hand-crafted usb descriptors to QEMU.
>
> After fixing the value of pkt_tag to ATH_USB_RX_STREAM_MODE_TAG in QEMU
> emulation, I found the KASAN report. The bug is triggerable whenever
> pkt_len is above two MAX_RX_BUG_SIZE. I used the same input that crashes
> to test the driver works when applying the patch.
>
> Signed-off-by: Zekun Shen <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>
Patch applied to ath-next branch of ath.git, thanks.
6ce708f54cc8 ath9k: Fix out-of-bound memcpy in ath9k_hif_usb_rx_stream
--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches