diff mbox series

[5.15,193/207] usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()

Message ID 20211206145616.961913284@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Dec. 6, 2021, 2:57 p.m. UTC 
From: Zhou Qingyang <zhou1615@umn.edu>

commit 37307f7020ab38dde0892a578249bf63d00bca64 upstream.

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")
Cc: stable <stable@vger.kernel.org>
Acked-by: Pawel Laszczak <pawell@cadence.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
Link: https://lore.kernel.org/r/20211130172700.206650-1-zhou1615@umn.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/cdns3/cdnsp-mem.c |    3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

--- a/drivers/usb/cdns3/cdnsp-mem.c
+++ b/drivers/usb/cdns3/cdnsp-mem.c
@@ -987,6 +987,9 @@  int cdnsp_endpoint_init(struct cdnsp_dev
 
 	/* 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 */