From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> [ 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@xxxxxxxxxx> Reported-and-tested-by: syzbot+7dbcd9ff34dc4ed45240@xxxxxxxxxxxxxxxxxxxxxxxxx Reviewed-by: Johan Hovold <johan@xxxxxxxxxx> Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210607152307.GD1768031@xxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 041c68ea329f..7ca908704777 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -647,6 +647,9 @@ 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) { @@ -695,6 +698,9 @@ 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
