patch "usb: dwc3: ep0: Fix mem corruption on OUT transfers of more than 512" added to usb-next

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    usb: dwc3: ep0: Fix mem corruption on OUT transfers of more than 512

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


>From b2fb5b1a0f50d3ebc12342c8d8dead245e9c9d4e Mon Sep 17 00:00:00 2001
From: Kishon Vijay Abraham I <kishon@ti.com>
Date: Mon, 27 Jul 2015 12:25:27 +0530
Subject: usb: dwc3: ep0: Fix mem corruption on OUT transfers of more than 512
 bytes

DWC3 uses bounce buffer to handle non max packet aligned OUT transfers and
the size of bounce buffer is 512 bytes. However if the host initiates OUT
transfers of size more than 512 bytes (and non max packet aligned), the
driver throws a WARN dump but still programs the TRB to receive more than
512 bytes. This will cause bounce buffer to overflow and corrupt the
adjacent memory locations which can be fatal.

Fix it by programming the TRB to receive a maximum of DWC3_EP0_BOUNCE_SIZE
(512) bytes.

Cc: <stable@vger.kernel.org> # 3.4+
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
---
 drivers/usb/dwc3/ep0.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 69e769c35cf5..06ecd1e6871c 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -820,6 +820,11 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
 		unsigned maxp = ep0->endpoint.maxpacket;
 
 		transfer_size += (maxp - (transfer_size % maxp));
+
+		/* Maximum of DWC3_EP0_BOUNCE_SIZE can only be received */
+		if (transfer_size > DWC3_EP0_BOUNCE_SIZE)
+			transfer_size = DWC3_EP0_BOUNCE_SIZE;
+
 		transferred = min_t(u32, ur->length,
 				transfer_size - length);
 		memcpy(ur->buf, dwc->ep0_bounce, transferred);
@@ -941,11 +946,14 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
 			return;
 		}
 
-		WARN_ON(req->request.length > DWC3_EP0_BOUNCE_SIZE);
-
 		maxpacket = dep->endpoint.maxpacket;
 		transfer_size = roundup(req->request.length, maxpacket);
 
+		if (transfer_size > DWC3_EP0_BOUNCE_SIZE) {
+			dev_WARN(dwc->dev, "bounce buf can't handle req len\n");
+			transfer_size = DWC3_EP0_BOUNCE_SIZE;
+		}
+
 		dwc->ep0_bounced = true;
 
 		/*
-- 
2.5.0