[PATCH] usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()

[PATCH] usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()

[Zhou Qingyang]

In cdnsp_endpoint_init(), cdnsp_ring_alloc() is assigned to pep->ring
and there is a dereference of it in cdnsp_endpoint_init(), which could
lead to a NULL pointer dereference on failure of cdnsp_ring_alloc().

Fix this bug by adding a check of pep->ring.

This bug was found by a static analyzer. The analysis employs
differential checking to identify inconsistent security operations
(e.g., checks or kfrees) between two code paths and confirms that the
inconsistent operations are not recovered in the current function or
the callers, so they constitute bugs.

Note that, as a bug found by static analysis, it can be a false
positive or hard to trigger. Multiple researchers have cross-reviewed
the bug.

Builds with CONFIG_USB_CDNSP_GADGET=y show no new warnings,
and our static analyzer no longer warns about this code.

Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
---
 drivers/usb/cdns3/cdnsp-mem.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/cdns3/cdnsp-mem.c b/drivers/usb/cdns3/cdnsp-mem.c
index ad9aee3f1e39..97866bfb2da9 100644
--- a/drivers/usb/cdns3/cdnsp-mem.c
+++ b/drivers/usb/cdns3/cdnsp-mem.c
@@ -987,6 +987,9 @@ int cdnsp_endpoint_init(struct cdnsp_device *pdev,
 
 	/* Set up the endpoint ring. */
 	pep->ring = cdnsp_ring_alloc(pdev, 2, ring_type, max_packet, mem_flags);
+	if (!pep->ring)
+		return -ENOMEM;
+
 	pep->skip = false;
 
 	/* Fill the endpoint context */
-- 
2.25.1

RE: [PATCH] usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()

[Pawel Laszczak]

>
>In cdnsp_endpoint_init(), cdnsp_ring_alloc() is assigned to pep->ring
>and there is a dereference of it in cdnsp_endpoint_init(), which could
>lead to a NULL pointer dereference on failure of cdnsp_ring_alloc().
>
>Fix this bug by adding a check of pep->ring.
>
>This bug was found by a static analyzer. The analysis employs
>differential checking to identify inconsistent security operations
>(e.g., checks or kfrees) between two code paths and confirms that the
>inconsistent operations are not recovered in the current function or
>the callers, so they constitute bugs.
>
>Note that, as a bug found by static analysis, it can be a false
>positive or hard to trigger. Multiple researchers have cross-reviewed
>the bug.
>
>Builds with CONFIG_USB_CDNSP_GADGET=y show no new warnings,
>and our static analyzer no longer warns about this code.
>
>Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
>Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
>---
> drivers/usb/cdns3/cdnsp-mem.c | 3 +++
> 1 file changed, 3 insertions(+)
>
>diff --git a/drivers/usb/cdns3/cdnsp-mem.c b/drivers/usb/cdns3/cdnsp-mem.c
>index ad9aee3f1e39..97866bfb2da9 100644
>--- a/drivers/usb/cdns3/cdnsp-mem.c
>+++ b/drivers/usb/cdns3/cdnsp-mem.c
>@@ -987,6 +987,9 @@ int cdnsp_endpoint_init(struct cdnsp_device *pdev,
>
> 	/* Set up the endpoint ring. */
> 	pep->ring = cdnsp_ring_alloc(pdev, 2, ring_type, max_packet, mem_flags);
>+	if (!pep->ring)
>+		return -ENOMEM;
>+
> 	pep->skip = false;
>
> 	/* Fill the endpoint context */
>--
>2.25.1


Acked-by: Pawel Laszczak <pawell@cadence.com>

--

Thanks,
Pawel Laszczak

RE: [PATCH] usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()

[Pawel Laszczak]

Only fixed Peter Chen address email:
peter.chen@nxp.com  doesn't exist, should be peter.chen@kernel.org

>-----Original Message-----
>From: Pawel Laszczak
>Sent: Wednesday, December 1, 2021 8:28 AM
>To: Zhou Qingyang <zhou1615@umn.edu>
>Cc: kjlu@umn.edu; Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Peter Chen <peter.chen@nxp.com>; linux-
>usb@vger.kernel.org; linux-kernel@vger.kernel.org
>Subject: RE: [PATCH] usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()
>
>>
>>In cdnsp_endpoint_init(), cdnsp_ring_alloc() is assigned to pep->ring
>>and there is a dereference of it in cdnsp_endpoint_init(), which could
>>lead to a NULL pointer dereference on failure of cdnsp_ring_alloc().
>>
>>Fix this bug by adding a check of pep->ring.
>>
>>This bug was found by a static analyzer. The analysis employs
>>differential checking to identify inconsistent security operations
>>(e.g., checks or kfrees) between two code paths and confirms that the
>>inconsistent operations are not recovered in the current function or
>>the callers, so they constitute bugs.
>>
>>Note that, as a bug found by static analysis, it can be a false
>>positive or hard to trigger. Multiple researchers have cross-reviewed
>>the bug.
>>
>>Builds with CONFIG_USB_CDNSP_GADGET=y show no new warnings,
>>and our static analyzer no longer warns about this code.
>>
>>Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
>>Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
>>---
>> drivers/usb/cdns3/cdnsp-mem.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>>diff --git a/drivers/usb/cdns3/cdnsp-mem.c b/drivers/usb/cdns3/cdnsp-mem.c
>>index ad9aee3f1e39..97866bfb2da9 100644
>>--- a/drivers/usb/cdns3/cdnsp-mem.c
>>+++ b/drivers/usb/cdns3/cdnsp-mem.c
>>@@ -987,6 +987,9 @@ int cdnsp_endpoint_init(struct cdnsp_device *pdev,
>>
>> 	/* Set up the endpoint ring. */
>> 	pep->ring = cdnsp_ring_alloc(pdev, 2, ring_type, max_packet, mem_flags);
>>+	if (!pep->ring)
>>+		return -ENOMEM;
>>+
>> 	pep->skip = false;
>>
>> 	/* Fill the endpoint context */
>>--
>>2.25.1
>
>
>Acked-by: Pawel Laszczak <pawell@cadence.com>
>
>--
>
>Thanks,
>Pawel Laszczak

Re: [PATCH] usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()

[Peter Chen]

On 21-12-01 07:39:05, Pawel Laszczak wrote:
> Only fixed Peter Chen address email:
> peter.chen@nxp.com  doesn't exist, should be peter.chen@kernel.org
> 
> >-----Original Message-----
> >From: Pawel Laszczak
> >Sent: Wednesday, December 1, 2021 8:28 AM
> >To: Zhou Qingyang <zhou1615@umn.edu>
> >Cc: kjlu@umn.edu; Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Peter Chen <peter.chen@nxp.com>; linux-
> >usb@vger.kernel.org; linux-kernel@vger.kernel.org
> >Subject: RE: [PATCH] usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()
> >
> >>
> >>In cdnsp_endpoint_init(), cdnsp_ring_alloc() is assigned to pep->ring
> >>and there is a dereference of it in cdnsp_endpoint_init(), which could
> >>lead to a NULL pointer dereference on failure of cdnsp_ring_alloc().
> >>
> >>Fix this bug by adding a check of pep->ring.
> >>
> >>This bug was found by a static analyzer. The analysis employs
> >>differential checking to identify inconsistent security operations
> >>(e.g., checks or kfrees) between two code paths and confirms that the
> >>inconsistent operations are not recovered in the current function or
> >>the callers, so they constitute bugs.
> >>
> >>Note that, as a bug found by static analysis, it can be a false
> >>positive or hard to trigger. Multiple researchers have cross-reviewed
> >>the bug.
> >>
> >>Builds with CONFIG_USB_CDNSP_GADGET=y show no new warnings,
> >>and our static analyzer no longer warns about this code.
> >>
> >>Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
> >>Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
> >>---
> >> drivers/usb/cdns3/cdnsp-mem.c | 3 +++
> >> 1 file changed, 3 insertions(+)
> >>
> >>diff --git a/drivers/usb/cdns3/cdnsp-mem.c b/drivers/usb/cdns3/cdnsp-mem.c
> >>index ad9aee3f1e39..97866bfb2da9 100644
> >>--- a/drivers/usb/cdns3/cdnsp-mem.c
> >>+++ b/drivers/usb/cdns3/cdnsp-mem.c
> >>@@ -987,6 +987,9 @@ int cdnsp_endpoint_init(struct cdnsp_device *pdev,
> >>
> >> 	/* Set up the endpoint ring. */
> >> 	pep->ring = cdnsp_ring_alloc(pdev, 2, ring_type, max_packet, mem_flags);
> >>+	if (!pep->ring)
> >>+		return -ENOMEM;
> >>+
> >> 	pep->skip = false;
> >>
> >> 	/* Fill the endpoint context */
> >>--
> >>2.25.1
> >
> >
> >Acked-by: Pawel Laszczak <pawell@cadence.com>

Acked-by: Peter Chen <peter.chen@kernel.org>

> >
> >--
> >
> >Thanks,
> >Pawel Laszczak

-- 

Thanks,
Peter Chen