Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 794edf30 authored by David Howells's avatar David Howells Committed by James Morris
Browse files

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: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarMatthew Garrett <mjg59@google.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 3f19cad3

drivers/tty/serial/serial_core.c

+5 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <linux/serial_core.h>

#include <linux/delay.h>

#include <linux/mutex.h>

#include <linux/security.h>



#include <linux/irq.h>

#include <linux/uaccess.h>
@@ -862,6 +863,10 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, 
		goto check_and_exit;

	}



	retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);

	if (retval && (change_irq || change_port))

		goto exit;



	/*

	 * Ask the low level driver to verify the settings.

	 */

include/linux/security.h

+1 −0
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ enum lockdown_reason { 
	LOCKDOWN_MSR,

	LOCKDOWN_ACPI_TABLES,

	LOCKDOWN_PCMCIA_CIS,

	LOCKDOWN_TIOCSSERIAL,

	LOCKDOWN_INTEGRITY_MAX,

	LOCKDOWN_CONFIDENTIALITY_MAX,

};

security/lockdown/lockdown.c

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = { 
	[LOCKDOWN_MSR] = "raw MSR access",

	[LOCKDOWN_ACPI_TABLES] = "modifying ACPI tables",

	[LOCKDOWN_PCMCIA_CIS] = "direct PCMCIA CIS storage",

	[LOCKDOWN_TIOCSSERIAL] = "reconfiguration of serial port IO",

	[LOCKDOWN_INTEGRITY_MAX] = "integrity",

	[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",

};