diff mbox

[21/27] Lock down TIOCSSERIAL

Message ID 150842479208.7923.3429065489239605709.stgit@warthog.procyon.org.uk (mailing list archive)
State New, archived
Headers show

Commit Message

David Howells Oct. 19, 2017, 2:53 p.m. UTC
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>
cc: Jiri Slaby <jslaby@suse.com>
---

 drivers/tty/serial/serial_core.c |    6 ++++++
 1 file changed, 6 insertions(+)


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diff mbox

Patch

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 3a14cccbd7ff..41f0922ad842 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -842,6 +842,12 @@  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 ||