2019-10-22 09:34:05

by Suwan Kim

Subject: [PATCH v2] usbip: Fix free of unallocated memory in vhci tx

iso_buffer should be set to NULL after use and free in the while loop.
In the case of isochronous URB in the while loop, iso_buffer is
allocated and after sending it to server, buffer is deallocated. And
then, if the next URB in the while loop is not a isochronous pipe,
iso_buffer still holds the previously deallocated buffer address and
kfree tries to free wrong buffer address.

Fixes: ea44d190764b ("usbip: Implement SG support to vhci-hcd and stub driver")
Reported-by: kbuild test robot <[email protected]>
Reported-by: Julia Lawall <[email protected]>
Signed-off-by: Suwan Kim <[email protected]>
---
v1 - v2: Move the setting NULL after kfree() and add the comment
---
drivers/usb/usbip/vhci_tx.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/usb/usbip/vhci_tx.c b/drivers/usb/usbip/vhci_tx.c
index c3803785f6ef..0ae40a13a9fe 100644
--- a/drivers/usb/usbip/vhci_tx.c
+++ b/drivers/usb/usbip/vhci_tx.c
@@ -147,7 +147,10 @@ static int vhci_send_cmd_submit(struct vhci_device *vdev)
}

kfree(iov);
+ /* This is only for isochronous case */
kfree(iso_buffer);
+ iso_buffer = NULL;
+
usbip_dbg_vhci_tx("send txdata\n");

total_size += txsize;
--
2.20.1

2019-10-22 09:53:17

by Julia Lawall

Subject: Re: [PATCH v2] usbip: Fix free of unallocated memory in vhci tx

On Tue, 22 Oct 2019, Suwan Kim wrote:

> iso_buffer should be set to NULL after use and free in the while loop.
> In the case of isochronous URB in the while loop, iso_buffer is
> allocated and after sending it to server, buffer is deallocated. And
> then, if the next URB in the while loop is not a isochronous pipe,
> iso_buffer still holds the previously deallocated buffer address and
> kfree tries to free wrong buffer address.
>
> Fixes: ea44d190764b ("usbip: Implement SG support to vhci-hcd and stub driver")
> Reported-by: kbuild test robot <[email protected]>
> Reported-by: Julia Lawall <[email protected]>
> Signed-off-by: Suwan Kim <[email protected]>

Reviewed-by: Julia Lawall <[email protected]>

> ---
> v1 - v2: Move the setting NULL after kfree() and add the comment
> ---
> drivers/usb/usbip/vhci_tx.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/usb/usbip/vhci_tx.c b/drivers/usb/usbip/vhci_tx.c
> index c3803785f6ef..0ae40a13a9fe 100644
> --- a/drivers/usb/usbip/vhci_tx.c
> +++ b/drivers/usb/usbip/vhci_tx.c
> @@ -147,7 +147,10 @@ static int vhci_send_cmd_submit(struct vhci_device *vdev)
> }
>
> kfree(iov);
> + /* This is only for isochronous case */
> kfree(iso_buffer);
> + iso_buffer = NULL;
> +
> usbip_dbg_vhci_tx("send txdata\n");
>
> total_size += txsize;
> --
> 2.20.1
>
>

2019-10-24 05:33:50

by Shuah Khan

Subject: Re: [PATCH v2] usbip: Fix free of unallocated memory in vhci tx

On 10/22/19 3:51 AM, Julia Lawall wrote:
>
>
> On Tue, 22 Oct 2019, Suwan Kim wrote:
>
>> iso_buffer should be set to NULL after use and free in the while loop.
>> In the case of isochronous URB in the while loop, iso_buffer is
>> allocated and after sending it to server, buffer is deallocated. And
>> then, if the next URB in the while loop is not a isochronous pipe,
>> iso_buffer still holds the previously deallocated buffer address and
>> kfree tries to free wrong buffer address.
>>
>> Fixes: ea44d190764b ("usbip: Implement SG support to vhci-hcd and stub driver")
>> Reported-by: kbuild test robot <[email protected]>
>> Reported-by: Julia Lawall <[email protected]>
>> Signed-off-by: Suwan Kim <[email protected]>
>
> Reviewed-by: Julia Lawall <[email protected]>
>
>> ---
>> v1 - v2: Move the setting NULL after kfree() and add the comment
>> ---

Thanks.

Acked-by: Shuah Khan <[email protected]>

thanks,
-- Shuah