From: Frode Isaksen <frode@meta.com>
Date: Thu, 3 Apr 2025 07:28:03 +0000 (+0200)
Subject: usb: dwc3: gadget: check that event count does not exceed event buffer length
X-Git-Tag: v6.15-rc4~21^2~9
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=63ccd26cd1f6600421795f6ca3e625076be06c9f;p=thirdparty%2Fkernel%2Flinux.git

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

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: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver")
Cc: stable <stable@kernel.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20250403072907.448524-1-fisaksen@baylibre.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 47e73c4ed62d3..8c30d86cc4e3a 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4617,6 +4617,12 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
 	if (!count)
 		return IRQ_NONE;
 
+	if (count > evt->length) {
+		dev_err_ratelimited(dwc->dev, "invalid count(%u) > evt->length(%u)\n",
+			count, evt->length);
+		return IRQ_NONE;
+	}
+
 	evt->count = count;
 	evt->flags |= DWC3_EVENT_PENDING;