From 252f71190eccba6229e01e75c968e4b3b9aac086 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 24 May 2021 12:07:55 +0000 Subject: [PATCH] USB: cdc-acm: fix unprivileged TIOCCSERIAL stable inclusion from stable-5.10.37 commit 4425c2f32ac9fc7d3699084134a55672361d2fc3 bugzilla: 51868 CVE: NA -------------------------------- [ Upstream commit dd5619582d60007139f0447382d2839f4f9e339b ] TIOCSSERIAL is a horrid, underspecified, legacy interface which for most serial devices is only useful for setting the close_delay and closing_wait parameters. A non-privileged user has only ever been able to set the since long deprecated ASYNC_SPD flags and trying to change any other *supported* feature should result in -EPERM being returned. Setting the current values for any supported features should return success. Fix the cdc-acm implementation which instead indicated that the TIOCSSERIAL ioctl was not even implemented when a non-privileged user set the current values. Fixes: ba2d8ce9db0a ("cdc-acm: implement TIOCSSERIAL to avoid blocking close(2)") Acked-by: Oliver Neukum Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210408131602.27956-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Chen Jun Acked-by: Weilong Chen Signed-off-by: Zheng Zengkai --- drivers/usb/class/cdc-acm.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 0876468c2e7d..63824552e5d0 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -955,8 +955,6 @@ static int set_serial_info(struct tty_struct *tty, struct serial_struct *ss) if ((close_delay != acm->port.close_delay) || (closing_wait != acm->port.closing_wait)) retval = -EPERM; - else - retval = -EOPNOTSUPP; } else { acm->port.close_delay = close_delay; acm->port.closing_wait = closing_wait; -- GitLab