diff mbox series

[v2] usb: dwc3: gadget: check that event count does not exceed event buffer length

Message ID 20250328104930.2179123-1-fisaksen@baylibre.com (mailing list archive)
State New
Headers show
Series [v2] usb: dwc3: gadget: check that event count does not exceed event buffer length | expand

Commit Message

Frode Isaksen March 28, 2025, 10:44 a.m. UTC 
From: Frode Isaksen <frode@meta.com>

The event count is read from register DWC3_GEVNTCOUNT.
There is a check for the count being zero, but not for exceeding the
event buffer length.
Check that event count does not exceed event buffer length,
avoiding an out-of-bounds access when memcpy'ing the event.
Crash log:
Unable to handle kernel paging request at virtual address ffffffc0129be000
pc : __memcpy+0x114/0x180
lr : dwc3_check_event_buf+0xec/0x348
x3 : 0000000000000030 x2 : 000000000000dfc4
x1 : ffffffc0129be000 x0 : ffffff87aad60080
Call trace:
__memcpy+0x114/0x180
dwc3_interrupt+0x24/0x34

Signed-off-by: Frode Isaksen <frode@meta.com>
Fixes: ebbb2d59398f ("usb: dwc3: gadget: use evt->cache for processing events")
Cc: stable@vger.kernel.org
---
v1 -> v2: Added Fixes and Cc tag.

This bug was discovered, tested and fixed (no more crashes seen) on Meta Quest 3 device.
Also tested on T.I. AM62x board.

 drivers/usb/dwc3/gadget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 63fef4a1a498..548e112167f3 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4564,7 +4564,7 @@  static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
 
 	count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(0));
 	count &= DWC3_GEVNTCOUNT_MASK;
-	if (!count)
+	if (!count || count > evt->length)
 		return IRQ_NONE;
 
 	evt->count = count;