2024-04-07 13:14:08

by Nikita Zhandarovich

[permalink] [raw]
Subject: [PATCH] wifi: carl9170: add a proper sanity check for endpoints

Syzkaller reports [1] hitting a warning which is caused by presence
of a wrong endpoint type at the URB sumbitting stage. While there
was a check for a specific 4th endpoint, since it can switch types
between bulk and interrupt, other endpoints are trusted implicitly.
Similar warning is triggered in a couple of other syzbot issues [2].

Fix the issue by doing a comprehensive check of all endpoints
taking into account difference between high- and full-speed
configuration.

This patch has not been tested on real hardware.

[1] Syzkaller report:
...
WARNING: CPU: 0 PID: 4721 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
...
Call Trace:
<TASK>
carl9170_usb_send_rx_irq_urb+0x273/0x340 drivers/net/wireless/ath/carl9170/usb.c:504
carl9170_usb_init_device drivers/net/wireless/ath/carl9170/usb.c:939 [inline]
carl9170_usb_firmware_finish drivers/net/wireless/ath/carl9170/usb.c:999 [inline]
carl9170_usb_firmware_step2+0x175/0x240 drivers/net/wireless/ath/carl9170/usb.c:1028
request_firmware_work_func+0x130/0x240 drivers/base/firmware_loader/main.c:1107
process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
worker_thread+0x669/0x1090 kernel/workqueue.c:2436
kthread+0x2e8/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>

[2] Related syzkaller crashes:
Link: https://syzkaller.appspot.com/bug?extid=e394db78ae0b0032cb4d
Link: https://syzkaller.appspot.com/bug?extid=9468df99cb63a4a4c4e1

Reported-and-tested-by: [email protected]
Fixes: a84fab3cbfdc ("carl9170: 802.11 rx/tx processing and usb backend")
Signed-off-by: Nikita Zhandarovich <[email protected]>
---
P.S. as AR9170_USB_EP_CMD endpoint can switch between bulk and int,
I failed to find a prettier solution to this problem. Will be glad
to hear if there is a better option...

drivers/net/wireless/ath/carl9170/usb.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/drivers/net/wireless/ath/carl9170/usb.c b/drivers/net/wireless/ath/carl9170/usb.c
index c4edf8355941..66d2ad561fd3 100644
--- a/drivers/net/wireless/ath/carl9170/usb.c
+++ b/drivers/net/wireless/ath/carl9170/usb.c
@@ -1069,6 +1069,33 @@ static int carl9170_usb_probe(struct usb_interface *intf,
ar->usb_ep_cmd_is_bulk = true;
}

+ /* Verify that all expected endpoints are present */
+ if (ar->usb_ep_cmd_is_bulk) {
+ u8 bulk_ep_addr[] = {
+ AR9170_USB_EP_RX | USB_DIR_IN,
+ AR9170_USB_EP_TX | USB_DIR_OUT,
+ AR9170_USB_EP_CMD | USB_DIR_OUT,
+ 0};
+ u8 int_ep_addr[] = {
+ AR9170_USB_EP_IRQ | USB_DIR_IN,
+ 0};
+ if (!usb_check_bulk_endpoints(intf, bulk_ep_addr) ||
+ !usb_check_int_endpoints(intf, int_ep_addr))
+ return -ENODEV;
+ } else {
+ u8 bulk_ep_addr[] = {
+ AR9170_USB_EP_RX | USB_DIR_IN,
+ AR9170_USB_EP_TX | USB_DIR_OUT,
+ 0};
+ u8 int_ep_addr[] = {
+ AR9170_USB_EP_IRQ | USB_DIR_IN,
+ AR9170_USB_EP_CMD | USB_DIR_OUT,
+ 0};
+ if (!usb_check_bulk_endpoints(intf, bulk_ep_addr) ||
+ !usb_check_int_endpoints(intf, int_ep_addr))
+ return -ENODEV;
+ }
+
usb_set_intfdata(intf, ar);
SET_IEEE80211_DEV(ar->hw, &intf->dev);



2024-04-18 18:48:49

by Christian Lamparter

[permalink] [raw]
Subject: Re: [PATCH] wifi: carl9170: add a proper sanity check for endpoints

On 4/7/24 3:11 PM, Nikita Zhandarovich wrote:
> Syzkaller reports [1] hitting a warning which is caused by presence
> of a wrong endpoint type at the URB sumbitting stage. While there
> was a check for a specific 4th endpoint, since it can switch types
> between bulk and interrupt, other endpoints are trusted implicitly.
> Similar warning is triggered in a couple of other syzbot issues [2].
>
> Fix the issue by doing a comprehensive check of all endpoints
> taking into account difference between high- and full-speed
> configuration.
>
> This patch has not been tested on real hardware.
>
> [1] Syzkaller report:
> ...
> WARNING: CPU: 0 PID: 4721 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
> ...
> Call Trace:
> <TASK>
> carl9170_usb_send_rx_irq_urb+0x273/0x340 drivers/net/wireless/ath/carl9170/usb.c:504
> carl9170_usb_init_device drivers/net/wireless/ath/carl9170/usb.c:939 [inline]
> carl9170_usb_firmware_finish drivers/net/wireless/ath/carl9170/usb.c:999 [inline]
> carl9170_usb_firmware_step2+0x175/0x240 drivers/net/wireless/ath/carl9170/usb.c:1028
> request_firmware_work_func+0x130/0x240 drivers/base/firmware_loader/main.c:1107
> process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
> worker_thread+0x669/0x1090 kernel/workqueue.c:2436
> kthread+0x2e8/0x3a0 kernel/kthread.c:376
> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
> </TASK>
>
> [2] Related syzkaller crashes:
> Link: https://syzkaller.appspot.com/bug?extid=e394db78ae0b0032cb4d
> Link: https://syzkaller.appspot.com/bug?extid=9468df99cb63a4a4c4e1
>
> Reported-and-tested-by: [email protected]
> Fixes: a84fab3cbfdc ("carl9170: 802.11 rx/tx processing and usb backend")
> Signed-off-by: Nikita Zhandarovich <[email protected]>

This was tricky. USB 2.0 works and was easy to test.
But I had to hunt down a FULLSPEED USB Host for this.
The driver loads on with a OHCI Host (Silicon Image, Inc. USB0673 (rev 06))

So, I think this would work. But see my comments below.

> ---
> P.S. as AR9170_USB_EP_CMD endpoint can switch between bulk and int,
> I failed to find a prettier solution to this problem. Will be glad
> to hear if there is a better option...
>
> drivers/net/wireless/ath/carl9170/usb.c | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/drivers/net/wireless/ath/carl9170/usb.c b/drivers/net/wireless/ath/carl9170/usb.c
> index c4edf8355941..66d2ad561fd3 100644
> --- a/drivers/net/wireless/ath/carl9170/usb.c
> +++ b/drivers/net/wireless/ath/carl9170/usb.c
> @@ -1069,6 +1069,33 @@ static int carl9170_usb_probe(struct usb_interface *intf,
> ar->usb_ep_cmd_is_bulk = true;
> }
>
> + /* Verify that all expected endpoints are present */
> + if (ar->usb_ep_cmd_is_bulk) {
> + u8 bulk_ep_addr[] = {
> + AR9170_USB_EP_RX | USB_DIR_IN,
> + AR9170_USB_EP_TX | USB_DIR_OUT,
> + AR9170_USB_EP_CMD | USB_DIR_OUT,
> + 0};
> + u8 int_ep_addr[] = {
> + AR9170_USB_EP_IRQ | USB_DIR_IN,
> + 0};
> + if (!usb_check_bulk_endpoints(intf, bulk_ep_addr) ||
> + !usb_check_int_endpoints(intf, int_ep_addr))
> + return -ENODEV;

Please call carl9170_free(ar); before returning here.
Otherwise the "ar" will memleak'ed.

> + } else {
> + u8 bulk_ep_addr[] = {
> + AR9170_USB_EP_RX | USB_DIR_IN,
> + AR9170_USB_EP_TX | USB_DIR_OUT,
> + 0};
> + u8 int_ep_addr[] = {
> + AR9170_USB_EP_IRQ | USB_DIR_IN,
> + AR9170_USB_EP_CMD | USB_DIR_OUT,
> + 0};
> + if (!usb_check_bulk_endpoints(intf, bulk_ep_addr) ||
> + !usb_check_int_endpoints(intf, int_ep_addr))
> + return -ENODEV;

Same here.

> + }
> +
> usb_set_intfdata(intf, ar);
> SET_IEEE80211_DEV(ar->hw, &intf->dev);
>