Hi! > commit e7b931bee739e8a77ae216e613d3b99342b6dec0 upstream. > > The driver would happily overwrite its write buffer with user data in > 256 byte increments due to a removed buffer-space sanity check. > +++ b/drivers/usb/serial/iuu_phoenix.c > @@ -697,14 +697,16 @@ static int iuu_uart_write(struct tty_str > struct iuu_private *priv = usb_get_serial_port_data(port); > unsigned long flags; > > - if (count > 256) > - return -ENOMEM; > - > spin_lock_irqsave(&priv->lock, flags); > > + count = min(count, 256 - priv->writelen); > + if (count == 0) > + goto out; > + > /* fill the buffer */ > memcpy(priv->writebuf + priv->writelen, buf, count); > priv->writelen += count; > +out: > spin_unlock_irqrestore(&priv->lock, flags); > > return count; Ok, so... goto and label is unneccessary, memcpy will do the right thing with count == 0. But what is worse, this changes return value in the error case; returning 0 instead of -ENOMEM. I don't believe 0 is appropriate return code here. (It should block on the write buffer if blocking or return -EAGAIN if nonblocking, right?) Best regards, Pavel -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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