[3.19.y-ckt stable] Patch "usb: dwc3: ep0: Fix mem corruption on OUT transfers of more than 512 bytes" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

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

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt8.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From b57678242a74887b733ad31b48e6777ae463d0c3 Mon Sep 17 00:00:00 2001
From: Kishon Vijay Abraham I <kishon at 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

commit b2fb5b1a0f50d3ebc12342c8d8dead245e9c9d4e upstream.

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.

Signed-off-by: Kishon Vijay Abraham I <kishon at ti.com>
Signed-off-by: Felipe Balbi <balbi at ti.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.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 98f3605..5502da3 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;

 		/*
--
1.9.1