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authorJohan Hovold <johan@kernel.org>2021-04-07 13:23:29 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-04-07 18:22:07 +0300
commitdc8c8437658667be9b11ec25c4b5482ed2becdaa (patch)
treed26574381e2d997c7c8b8a3a36949ae66322562a /drivers/tty/moxa.c
parent6e70b73ca5240c0059a1fbf8ccd4276d6cf71956 (diff)
downloadlinux-dc8c8437658667be9b11ec25c4b5482ed2becdaa.tar.xz
tty: moxa: fix TIOCSSERIAL permission check
Changing the port close delay or type are privileged operations so make sure to return -EPERM if a regular user tries to change them. Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210407102334.32361-12-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/moxa.c')
-rw-r--r--drivers/tty/moxa.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/tty/moxa.c b/drivers/tty/moxa.c
index 5b7bc7af8b1e..63e440d900ff 100644
--- a/drivers/tty/moxa.c
+++ b/drivers/tty/moxa.c
@@ -2048,6 +2048,7 @@ static int moxa_set_serial_info(struct tty_struct *tty,
struct serial_struct *ss)
{
struct moxa_port *info = tty->driver_data;
+ unsigned int close_delay;
if (tty->index == MAX_PORTS)
return -EINVAL;
@@ -2059,19 +2060,24 @@ static int moxa_set_serial_info(struct tty_struct *tty,
ss->baud_base != 921600)
return -EPERM;
+ close_delay = msecs_to_jiffies(ss->close_delay * 10);
+
mutex_lock(&info->port.mutex);
if (!capable(CAP_SYS_ADMIN)) {
- if (((ss->flags & ~ASYNC_USR_MASK) !=
+ if (close_delay != info->port.close_delay ||
+ ss->type != info->type ||
+ ((ss->flags & ~ASYNC_USR_MASK) !=
(info->port.flags & ~ASYNC_USR_MASK))) {
mutex_unlock(&info->port.mutex);
return -EPERM;
}
- }
- info->port.close_delay = msecs_to_jiffies(ss->close_delay * 10);
+ } else {
+ info->port.close_delay = close_delay;
- MoxaSetFifo(info, ss->type == PORT_16550A);
+ MoxaSetFifo(info, ss->type == PORT_16550A);
- info->type = ss->type;
+ info->type = ss->type;
+ }
mutex_unlock(&info->port.mutex);
return 0;
}