lkml.org 
[lkml]   [2021]   [Jul]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH AUTOSEL 4.4 09/23] USB: core: Avoid WARNings for 0-length descriptor requests
Date
From: Alan Stern <stern@rowland.harvard.edu>

[ Upstream commit 60dfe484cef45293e631b3a6e8995f1689818172 ]

The USB core has utility routines to retrieve various types of
descriptors. These routines will now provoke a WARN if they are asked
to retrieve 0 bytes (USB "receive" requests must not have zero
length), so avert this by checking the size argument at the start.

CC: Johan Hovold <johan@kernel.org>
Reported-and-tested-by: syzbot+7dbcd9ff34dc4ed45240@syzkaller.appspotmail.com
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20210607152307.GD1768031@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/core/message.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index e568325cb6e1..8b6e25f11d87 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -643,6 +643,9 @@ int usb_get_descriptor(struct usb_device *dev, unsigned char type,
int i;
int result;

+ if (size <= 0) /* No point in asking for no data */
+ return -EINVAL;
+
memset(buf, 0, size); /* Make sure we parse really received data */

for (i = 0; i < 3; ++i) {
@@ -691,6 +694,9 @@ static int usb_get_string(struct usb_device *dev, unsigned short langid,
int i;
int result;

+ if (size <= 0) /* No point in asking for no data */
+ return -EINVAL;
+
for (i = 0; i < 3; ++i) {
/* retry on length 0 or stall; some devices are flakey */
result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
--
2.30.2
\
 
 \ /
  Last update: 2021-07-10 04:43    [W:0.051 / U:0.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site