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Message-Id: <20210824165908.709932-15-sashal@kernel.org>
Date: Tue, 24 Aug 2021 12:57:44 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Alan Stern <stern@...land.harvard.edu>,
Johan Hovold <johan@...nel.org>,
syzbot+7dbcd9ff34dc4ed45240@...kaller.appspotmail.com,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 14/98] USB: core: Avoid WARNings for 0-length descriptor requests
From: Alan Stern <stern@...land.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@...nel.org>
Reported-and-tested-by: syzbot+7dbcd9ff34dc4ed45240@...kaller.appspotmail.com
Reviewed-by: Johan Hovold <johan@...nel.org>
Signed-off-by: Alan Stern <stern@...land.harvard.edu>
Link: https://lore.kernel.org/r/20210607152307.GD1768031@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.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 19ebb542befc..dba2baca486e 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -785,6 +785,9 @@ 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) {
@@ -833,6 +836,9 @@ 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
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