From 97c41e99830a5a79f589196f289eae15f05e0fd8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 24 May 2017 14:56:06 +0100 Subject: [PATCH] UBUNTU: SAUCE: (efi-lockdown) Lock down TIOCSSERIAL Lock down TIOCSSERIAL as that can be used to change the ioport and irq settings on a serial port. This only appears to be an issue for the serial drivers that use the core serial code. All other drivers seem to either ignore attempts to change port/irq or give an error. Reported-by: Greg Kroah-Hartman Signed-off-by: David Howells cc: Jiri Slaby (cherry picked from commit 8d8c1da752c5ea837f1dbe06fa21d4ca891fcd83 git://git.kernel.org/pub/scm/linux/kernel/git/jwboyer/fedora.git) Signed-off-by: Seth Forshee --- drivers/tty/serial/serial_core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 854995e1cae7..89fed5294c76 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -829,6 +829,12 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, new_flags = (__force upf_t)new_info->flags; old_custom_divisor = uport->custom_divisor; + if ((change_port || change_irq) && + kernel_is_locked_down("Using TIOCSSERIAL to change device addresses, irqs and dma channels")) { + retval = -EPERM; + goto exit; + } + if (!capable(CAP_SYS_ADMIN)) { retval = -EPERM; if (change_irq || change_port || -- 2.39.2