Subject: [BISECTED REGRESSION] ath9k: Fix general protection fault in ath9k_hif_usb_rx_cb

From: Roman Mamedov <[email-masked]>
Date: Sun, 21 Jun 2020 02:04:28 +0500

On Sat,  4 Apr 2020 12:18:38 +0800
Qiujun Huang <[email-masked]> wrote:

> In ath9k_hif_usb_rx_cb interface number is assumed to be 0.
> usb_ifnum_to_if(urb->dev, 0)
> But it isn't always true.
> 
> The case reported by syzbot:
> https://lore.kernel.org/linux-usb/[email-masked]
> usb 2-1: new high-speed USB device number 2 using dummy_hcd
> usb 2-1: config 1 has an invalid interface number: 2 but max is 0
> usb 2-1: config 1 has no interface number 0
> usb 2-1: New USB device found, idVendor=0cf3, idProduct=9271, bcdDevice=
> 1.08
> usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
> general protection fault, probably for non-canonical address
> 0xdffffc0000000015: 0000 [#1] SMP KASAN
> KASAN: null-ptr-deref in range [0x00000000000000a8-0x00000000000000af]
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc5-syzkaller #0
> 
> Call Trace
> __usb_hcd_giveback_urb+0x29a/0x550 drivers/usb/core/hcd.c:1650
> usb_hcd_giveback_urb+0x368/0x420 drivers/usb/core/hcd.c:1716
> dummy_timer+0x1258/0x32ae drivers/usb/gadget/udc/dummy_hcd.c:1966
> call_timer_fn+0x195/0x6f0 kernel/time/timer.c:1404
> expire_timers kernel/time/timer.c:1449 [inline]
> __run_timers kernel/time/timer.c:1773 [inline]
> __run_timers kernel/time/timer.c:1740 [inline]
> run_timer_softirq+0x5f9/0x1500 kernel/time/timer.c:1786
> __do_softirq+0x21e/0x950 kernel/softirq.c:292
> invoke_softirq kernel/softirq.c:373 [inline]
> irq_exit+0x178/0x1a0 kernel/softirq.c:413
> exiting_irq arch/x86/include/asm/apic.h:546 [inline]
> smp_apic_timer_interrupt+0x141/0x540 arch/x86/kernel/apic/apic.c:1146
> apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
> 
> Reported-and-tested-by: [email-masked]
> Signed-off-by: Qiujun Huang <[email-masked]>

This causes complete breakage of ath9k operation across all the stable kernel
series it got backported to, and I guess the mainline as well. Please see:
https://bugzilla.kernel.org/show_bug.cgi?id=208251
https://bugzilla.redhat.com/show_bug.cgi?id=1848631

Thanks

> ---
>  drivers/net/wireless/ath/ath9k/hif_usb.c | 48 ++++++++++++++++++------
>  drivers/net/wireless/ath/ath9k/hif_usb.h |  5 +++
>  2 files changed, 42 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
> index 6049d3766c64..4ed21dad6a8e 100644
> --- a/drivers/net/wireless/ath/ath9k/hif_usb.c
> +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
> @@ -643,9 +643,9 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
>  
>  static void ath9k_hif_usb_rx_cb(struct urb *urb)
>  {
> -	struct sk_buff *skb = (struct sk_buff *) urb->context;
> -	struct hif_device_usb *hif_dev =
> -		usb_get_intfdata(usb_ifnum_to_if(urb->dev, 0));
> +	struct rx_buf *rx_buf = (struct rx_buf *)urb->context;
> +	struct hif_device_usb *hif_dev = rx_buf->hif_dev;
> +	struct sk_buff *skb = rx_buf->skb;
>  	int ret;
>  
>  	if (!skb)
> @@ -685,14 +685,15 @@ static void ath9k_hif_usb_rx_cb(struct urb *urb)
>  	return;
>  free:
>  	kfree_skb(skb);
> +	kfree(rx_buf);
>  }
>  
>  static void ath9k_hif_usb_reg_in_cb(struct urb *urb)
>  {
> -	struct sk_buff *skb = (struct sk_buff *) urb->context;
> +	struct rx_buf *rx_buf = (struct rx_buf *)urb->context;
> +	struct hif_device_usb *hif_dev = rx_buf->hif_dev;
> +	struct sk_buff *skb = rx_buf->skb;
>  	struct sk_buff *nskb;
> -	struct hif_device_usb *hif_dev =
> -		usb_get_intfdata(usb_ifnum_to_if(urb->dev, 0));
>  	int ret;
>  
>  	if (!skb)
> @@ -750,6 +751,7 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb)
>  	return;
>  free:
>  	kfree_skb(skb);
> +	kfree(rx_buf);
>  	urb->context = NULL;
>  }
>  
> @@ -795,7 +797,7 @@ static int ath9k_hif_usb_alloc_tx_urbs(struct hif_device_usb *hif_dev)
>  	init_usb_anchor(&hif_dev->mgmt_submitted);
>  
>  	for (i = 0; i < MAX_TX_URB_NUM; i++) {
> -		tx_buf = kzalloc(sizeof(struct tx_buf), GFP_KERNEL);
> +		tx_buf = kzalloc(sizeof(*tx_buf), GFP_KERNEL);
>  		if (!tx_buf)
>  			goto err;
>  
> @@ -832,8 +834,9 @@ static void ath9k_hif_usb_dealloc_rx_urbs(struct hif_device_usb *hif_dev)
>  
>  static int ath9k_hif_usb_alloc_rx_urbs(struct hif_device_usb *hif_dev)
>  {
> -	struct urb *urb = NULL;
> +	struct rx_buf *rx_buf = NULL;
>  	struct sk_buff *skb = NULL;
> +	struct urb *urb = NULL;
>  	int i, ret;
>  
>  	init_usb_anchor(&hif_dev->rx_submitted);
> @@ -841,6 +844,12 @@ static int ath9k_hif_usb_alloc_rx_urbs(struct hif_device_usb *hif_dev)
>  
>  	for (i = 0; i < MAX_RX_URB_NUM; i++) {
>  
> +		rx_buf = kzalloc(sizeof(*rx_buf), GFP_KERNEL);
> +		if (!rx_buf) {
> +			ret = -ENOMEM;
> +			goto err_rxb;
> +		}
> +
>  		/* Allocate URB */
>  		urb = usb_alloc_urb(0, GFP_KERNEL);
>  		if (urb == NULL) {
> @@ -855,11 +864,14 @@ static int ath9k_hif_usb_alloc_rx_urbs(struct hif_device_usb *hif_dev)
>  			goto err_skb;
>  		}
>  
> +		rx_buf->hif_dev = hif_dev;
> +		rx_buf->skb = skb;
> +
>  		usb_fill_bulk_urb(urb, hif_dev->udev,
>  				  usb_rcvbulkpipe(hif_dev->udev,
>  						  USB_WLAN_RX_PIPE),
>  				  skb->data, MAX_RX_BUF_SIZE,
> -				  ath9k_hif_usb_rx_cb, skb);
> +				  ath9k_hif_usb_rx_cb, rx_buf);
>  
>  		/* Anchor URB */
>  		usb_anchor_urb(urb, &hif_dev->rx_submitted);
> @@ -885,6 +897,8 @@ static int ath9k_hif_usb_alloc_rx_urbs(struct hif_device_usb *hif_dev)
>  err_skb:
>  	usb_free_urb(urb);
>  err_urb:
> +	kfree(rx_buf);
> +err_rxb:
>  	ath9k_hif_usb_dealloc_rx_urbs(hif_dev);
>  	return ret;
>  }
> @@ -896,14 +910,21 @@ static void ath9k_hif_usb_dealloc_reg_in_urbs(struct hif_device_usb *hif_dev)
>  
>  static int ath9k_hif_usb_alloc_reg_in_urbs(struct hif_device_usb *hif_dev)
>  {
> -	struct urb *urb = NULL;
> +	struct rx_buf *rx_buf = NULL;
>  	struct sk_buff *skb = NULL;
> +	struct urb *urb = NULL;
>  	int i, ret;
>  
>  	init_usb_anchor(&hif_dev->reg_in_submitted);
>  
>  	for (i = 0; i < MAX_REG_IN_URB_NUM; i++) {
>  
> +		rx_buf = kzalloc(sizeof(*rx_buf), GFP_KERNEL);
> +		if (!rx_buf) {
> +			ret = -ENOMEM;
> +			goto err_rxb;
> +		}
> +
>  		/* Allocate URB */
>  		urb = usb_alloc_urb(0, GFP_KERNEL);
>  		if (urb == NULL) {
> @@ -918,11 +939,14 @@ static int ath9k_hif_usb_alloc_reg_in_urbs(struct hif_device_usb *hif_dev)
>  			goto err_skb;
>  		}
>  
> +		rx_buf->hif_dev = hif_dev;
> +		rx_buf->skb = skb;
> +
>  		usb_fill_int_urb(urb, hif_dev->udev,
>  				  usb_rcvintpipe(hif_dev->udev,
>  						  USB_REG_IN_PIPE),
>  				  skb->data, MAX_REG_IN_BUF_SIZE,
> -				  ath9k_hif_usb_reg_in_cb, skb, 1);
> +				  ath9k_hif_usb_reg_in_cb, rx_buf, 1);
>  
>  		/* Anchor URB */
>  		usb_anchor_urb(urb, &hif_dev->reg_in_submitted);
> @@ -948,6 +972,8 @@ static int ath9k_hif_usb_alloc_reg_in_urbs(struct hif_device_usb *hif_dev)
>  err_skb:
>  	usb_free_urb(urb);
>  err_urb:
> +	kfree(rx_buf);
> +err_rxb:
>  	ath9k_hif_usb_dealloc_reg_in_urbs(hif_dev);
>  	return ret;
>  }
> diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.h b/drivers/net/wireless/ath/ath9k/hif_usb.h
> index a94e7e1c86e9..5985aa15ca93 100644
> --- a/drivers/net/wireless/ath/ath9k/hif_usb.h
> +++ b/drivers/net/wireless/ath/ath9k/hif_usb.h
> @@ -86,6 +86,11 @@ struct tx_buf {
>  	struct list_head list;
>  };
>  
> +struct rx_buf {
> +	struct sk_buff *skb;
> +	struct hif_device_usb *hif_dev;
> +};
> +
>  #define HIF_USB_TX_STOP  BIT(0)
>  #define HIF_USB_TX_FLUSH BIT(1)
>  

-- 
With respect,
Roman