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 <gregkh@linuxfoundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
(cherry picked from commit
83bd921f9ac911f2644bdc5abd31dd4d56cfeb4e
git://git.kernel.org/pub/scm/linux/kernel/git/jwboyer/fedora.git)
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
new_flags = new_info->flags;
old_custom_divisor = uport->custom_divisor;
+ if ((change_port || change_irq) && kernel_is_locked_down()) {
+ pr_err("Using TIOCSSERIAL to change device addresses, irqs and dma channels is not permitted when the kernel is locked down\n");
+ retval = -EPERM;
+ goto exit;
+ }
+
if (!capable(CAP_SYS_ADMIN)) {
retval = -EPERM;
if (change_irq || change_port ||