Although the usb_alloc_urb uses GFP_ATOMIC, tring to make sure the memory
allocated not to be NULL. But in some low-memory situation, it's still
possible to return NULL. It'll pass urb as argument in
usb_fill_bulk_urb, which will finally lead to a NULL pointer dereference.
Fix it by adding additional check.
Note that, as a bug found by static analysis, it can be a false
positive or hard to trigger.
Fixes: 68d57a07bfe5 ("wireless: add plfxlc driver for pureLiFi X, XL, XC devices")
Signed-off-by: Zheng Wang <[email protected]>
---
drivers/net/wireless/purelifi/plfxlc/usb.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/net/wireless/purelifi/plfxlc/usb.c b/drivers/net/wireless/purelifi/plfxlc/usb.c
index 76d0a778636a..ac149aa64908 100644
--- a/drivers/net/wireless/purelifi/plfxlc/usb.c
+++ b/drivers/net/wireless/purelifi/plfxlc/usb.c
@@ -496,10 +496,17 @@ int plfxlc_usb_wreq_async(struct plfxlc_usb *usb, const u8 *buffer,
struct urb *urb = usb_alloc_urb(0, GFP_ATOMIC);
int r;
+ if (!urb) {
+ r = -ENOMEM;
+ kfree(urb);
+ goto out;
+ }
usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT),
(void *)buffer, buffer_len, complete_fn, context);
r = usb_submit_urb(urb, GFP_ATOMIC);
+
+out:
if (r)
dev_err(&udev->dev, "Async write submit failed (%d)\n", r);
--
2.25.1
Le 03/02/2023 à 05:16, Zheng Wang a écrit :
> Although the usb_alloc_urb uses GFP_ATOMIC, tring to make sure the memory
> allocated not to be NULL. But in some low-memory situation, it's still
> possible to return NULL. It'll pass urb as argument in
> usb_fill_bulk_urb, which will finally lead to a NULL pointer dereference.
>
> Fix it by adding additional check.
>
> Note that, as a bug found by static analysis, it can be a false
> positive or hard to trigger.
>
> Fixes: 68d57a07bfe5 ("wireless: add plfxlc driver for pureLiFi X, XL, XC devices")
>
> Signed-off-by: Zheng Wang <[email protected]>
> ---
> drivers/net/wireless/purelifi/plfxlc/usb.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/net/wireless/purelifi/plfxlc/usb.c b/drivers/net/wireless/purelifi/plfxlc/usb.c
> index 76d0a778636a..ac149aa64908 100644
> --- a/drivers/net/wireless/purelifi/plfxlc/usb.c
> +++ b/drivers/net/wireless/purelifi/plfxlc/usb.c
> @@ -496,10 +496,17 @@ int plfxlc_usb_wreq_async(struct plfxlc_usb *usb, const u8 *buffer,
> struct urb *urb = usb_alloc_urb(0, GFP_ATOMIC);
> int r;
>
> + if (!urb) {
> + r = -ENOMEM;
> + kfree(urb);
Hi,
why kfree() in such a case?
CJ
> + goto out;
> + }
> usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT),
> (void *)buffer, buffer_len, complete_fn, context);
>
> r = usb_submit_urb(urb, GFP_ATOMIC);
> +
> +out:
> if (r)
> dev_err(&udev->dev, "Async write submit failed (%d)\n", r);
>
At 2023-02-03 13:25:45, "Christophe JAILLET" <[email protected]> wrote:
>Le 03/02/2023 à 05:16, Zheng Wang a écrit :
>> Although the usb_alloc_urb uses GFP_ATOMIC, tring to make sure the memory
>> allocated not to be NULL. But in some low-memory situation, it's still
>> possible to return NULL. It'll pass urb as argument in
>> usb_fill_bulk_urb, which will finally lead to a NULL pointer dereference.
>>
>> Fix it by adding additional check.
>>
>> Note that, as a bug found by static analysis, it can be a false
>> positive or hard to trigger.
>>
>> Fixes: 68d57a07bfe5 ("wireless: add plfxlc driver for pureLiFi X, XL, XC devices")
>>
>> Signed-off-by: Zheng Wang <[email protected]>
>> ---
>> drivers/net/wireless/purelifi/plfxlc/usb.c | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/drivers/net/wireless/purelifi/plfxlc/usb.c b/drivers/net/wireless/purelifi/plfxlc/usb.c
>> index 76d0a778636a..ac149aa64908 100644
>> --- a/drivers/net/wireless/purelifi/plfxlc/usb.c
>> +++ b/drivers/net/wireless/purelifi/plfxlc/usb.c
>> @@ -496,10 +496,17 @@ int plfxlc_usb_wreq_async(struct plfxlc_usb *usb, const u8 *buffer,
>> struct urb *urb = usb_alloc_urb(0, GFP_ATOMIC);
>> int r;
>>
>> + if (!urb) {
>> + r = -ENOMEM;
>> + kfree(urb);
>
>Hi,
>why kfree() in such a case?
Hello CJ,
Thanks for pointing that out. Kfree is unnecessary in such case, we can just return.
Regards,
Zheng Wang
>
>> + goto out;
>> + }
>> usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT),
>> (void *)buffer, buffer_len, complete_fn, context);
>>
>> r = usb_submit_urb(urb, GFP_ATOMIC);
>> +
>> +out:
>> if (r)
>> dev_err(&udev->dev, "Async write submit failed (%d)\n", r);
>>