[V31,17/25] Lock down TIOCSSERIAL

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Message ID	20190326182742.16950-18-matthewgarrett@google.com
State	New, archived
Headers	show Return-Path: <SRS0=4nbc=R5=vger.kernel.org=linux-kernel-owner@kernel.org> Date: Tue, 26 Mar 2019 11:27:33 -0700 In-Reply-To: <20190326182742.16950-1-matthewgarrett@google.com> Message-Id: <20190326182742.16950-18-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190326182742.16950-1-matthewgarrett@google.com> Subject: [PATCH V31 17/25] Lock down TIOCSSERIAL From: Matthew Garrett <matthewgarrett@google.com> To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-api@vger.kernel.org, luto@kernel.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Matthew Garrett <mjg59@google.com>, Jiri Slaby <jslaby@suse.com>, linux-serial@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk
Series	Add support for kernel lockdown
Related	show [V31,00/25] Add support for kernel lockdown [V31,01/25] Add the ability to lock down access to the running kernel image [V31,02/25] Enforce module signatures if the kernel is locked down [V31,03/25] Restrict /dev/{mem,kmem,port} when the kernel is locked down [V31,04/25] kexec_load: Disable at runtime if the kernel is locked down [V31,05/25] Copy secure_boot flag in boot params across kexec reboot [V31,06/25] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE [V31,07/25] kexec_file: Restrict at runtime if the kernel is locked down [V31,08/25] hibernate: Disable when the kernel is locked down [V31,09/25] uswsusp: Disable when the kernel is locked down [V31,10/25] PCI: Lock down BAR access when the kernel is locked down [V31,11/25] x86: Lock down IO port access when the kernel is locked down [V31,12/25] x86/msr: Restrict MSR access when the kernel is locked down [V31,13/25] ACPI: Limit access to custom_method when the kernel is locked down [V31,14/25] acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down [V31,15/25] acpi: Disable ACPI table override if the kernel is locked down [V31,16/25] Prohibit PCMCIA CIS storage when the kernel is locked down [V31,17/25] Lock down TIOCSSERIAL [V31,18/25] Lock down module params that specify hardware parameters (eg. ioport) [V31,19/25] x86/mmiotrace: Lock down the testmmiotrace module [V31,20/25] Lock down /proc/kcore [V31,21/25] Lock down kprobes when in confidentiality mode [V31,22/25] bpf: Restrict bpf when kernel lockdown is in confidentiality mode [V31,23/25] Lock down perf when in confidentiality mode [V31,24/25] lockdown: Print current->comm in restriction messages [V31,25/25] debugfs: Disable open() when kernel is locked down

Message ID

20190326182742.16950-18-matthewgarrett@google.com

State

New, archived

Headers

Date: Tue, 26 Mar 2019 11:27:33 -0700
In-Reply-To: <20190326182742.16950-1-matthewgarrett@google.com>
Message-Id: <20190326182742.16950-18-matthewgarrett@google.com>
Mime-Version: 1.0
References: <20190326182742.16950-1-matthewgarrett@google.com>
Subject: [PATCH V31 17/25] Lock down TIOCSSERIAL
From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, dhowells@redhat.com,
        linux-api@vger.kernel.org, luto@kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Matthew Garrett <mjg59@google.com>,
        Jiri Slaby <jslaby@suse.com>, linux-serial@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Series

Add support for kernel lockdown

show

Commit Message

Matthew Garrett March 26, 2019, 6:27 p.m. UTC

From: David Howells <dhowells@redhat.com>

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>
Signed-off-by: Matthew Garrett <mjg59@google.com>
cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
---
 drivers/tty/serial/serial_core.c | 6 ++++++
 1 file changed, 6 insertions(+)

Patch

diff mbox series

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index d4cca5bdaf1c..65b67f0d4386 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", LOCKDOWN_INTEGRITY)) {
+		retval = -EPERM;
+		goto exit;
+	}
+
 	if (!capable(CAP_SYS_ADMIN)) {
 		retval = -EPERM;
 		if (change_irq || change_port ||

[V31,17/25] Lock down TIOCSSERIAL 1055064 diff mbox series

Commit Message

Patch 1055064 diff mbox series

[V31,17/25] Lock down TIOCSSERIAL
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Patch
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