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

Message ID 20250401125350.221910-1-fisaksen@baylibre.com
State New
Headers show
Series [v2] usb: dwc3: gadget: check that event count does not exceed event buffer length | expand

Commit Message

Frode Isaksen April 1, 2025, 12:53 p.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 error log

 drivers/usb/dwc3/gadget.c | 6 ++++++
 1 file changed, 6 insertions(+)
diff mbox series

Patch

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 89a4dc8ebf94..923737776d82 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4564,6 +4564,12 @@  static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
 	if (!count)
 		return IRQ_NONE;
 
+	if (count > evt->length) {
+		dev_err(dwc->dev, "invalid count(%u) > evt->length(%u)\n",
+			count, evt->length);
+		return IRQ_NONE;
+	}
+
 	evt->count = count;
 	evt->flags |= DWC3_EVENT_PENDING;