From: Johan Hovold johan@kernel.org
[ Upstream commit 496960274153bdeb9d1f904ff1ea875cef8232c1 ]
TIOCSSERIAL is a horrid, underspecified, legacy interface which for most serial devices is only useful for setting the close_delay and closing_wait parameters.
The xmit_fifo_size parameter could be used to set the hardware transmit fifo size of a legacy UART when it could not be detected, but the interface is limited to eight bits and should be left unset when it is not used.
Similarly, baud_base could be used to set the UART base clock when it could not be detected, but might as well be left unset when it is not known (which is the case for CDC).
Fix the cdc-acm TIOCGSERIAL implementation by dropping its custom interpretation of the unused xmit_fifo_size and baud_base fields, which overflowed the former with the URB buffer size and set the latter to the current line speed. Also return the port line number, which is the only other value used besides the close parameters.
Note that the current line speed can still be retrieved through the standard termios interfaces.
Fixes: 18c75720e667 ("USB: allow users to run setserial with cdc-acm") Acked-by: Oliver Neukum oneukum@suse.com Signed-off-by: Johan Hovold johan@kernel.org Link: https://lore.kernel.org/r/20210408131602.27956-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/class/cdc-acm.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 63824552e5d0..6fbabf56dbb7 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -929,8 +929,7 @@ static int get_serial_info(struct tty_struct *tty, struct serial_struct *ss) { struct acm *acm = tty->driver_data;
- ss->xmit_fifo_size = acm->writesize; - ss->baud_base = le32_to_cpu(acm->line.dwDTERate); + ss->line = acm->minor; ss->close_delay = jiffies_to_msecs(acm->port.close_delay) / 10; ss->closing_wait = acm->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ? ASYNC_CLOSING_WAIT_NONE :