From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
David Howells <dhowells@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Matthew Garrett <mjg59@google.com>,
Kees Cook <keescook@chromium.org>, Jiri Slaby <jslaby@suse.com>,
linux-serial@vger.kernel.org
Subject: [PATCH V40 18/29] lockdown: Lock down TIOCSSERIAL
Date: Mon, 19 Aug 2019 17:17:54 -0700 [thread overview]
Message-ID: <20190820001805.241928-19-matthewgarrett@google.com> (raw)
In-Reply-To: <20190820001805.241928-1-matthewgarrett@google.com>
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>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
---
drivers/tty/serial/serial_core.c | 5 +++++
include/linux/security.h | 1 +
security/lockdown/lockdown.c | 1 +
3 files changed, 7 insertions(+)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 83f4dd0bfd74..bbad407557b9 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -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.
*/
diff --git a/include/linux/security.h b/include/linux/security.h
index 683f0607e6f2..b4a85badb03a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -112,6 +112,7 @@ enum lockdown_reason {
LOCKDOWN_MSR,
LOCKDOWN_ACPI_TABLES,
LOCKDOWN_PCMCIA_CIS,
+ LOCKDOWN_TIOCSSERIAL,
LOCKDOWN_INTEGRITY_MAX,
LOCKDOWN_CONFIDENTIALITY_MAX,
};
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index db3477585972..771c77f9c04a 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -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",
};
--
2.23.0.rc1.153.gdeed80330f-goog
next prev parent reply other threads:[~2019-08-20 0:19 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-20 0:17 [PATCH V40 00/29] Add kernel lockdown functionality Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 01/29] security: Support early LSMs Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 02/29] security: Add a "locked down" LSM hook Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 03/29] security: Add a static lockdown policy LSM Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 04/29] lockdown: Enforce module signatures if the kernel is locked down Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 05/29] lockdown: Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 06/29] kexec_load: Disable at runtime if " Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 07/29] lockdown: Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 08/29] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-08-30 14:26 ` Philipp Rudo
2019-08-20 0:17 ` [PATCH V40 09/29] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 10/29] hibernate: Disable when " Matthew Garrett
2019-08-20 21:43 ` Rafael J. Wysocki
2019-08-25 9:51 ` Pavel Machek
2019-08-20 0:17 ` [PATCH V40 11/29] PCI: Lock down BAR access " Matthew Garrett
2019-08-20 19:45 ` Bjorn Helgaas
2019-08-20 21:04 ` Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 12/29] x86: Lock down IO port " Matthew Garrett
2022-01-05 6:25 ` Kai-Heng Feng
2022-01-05 6:48 ` Matthew Garrett
2022-01-05 6:57 ` Kai-Heng Feng
2022-01-05 7:20 ` Matthew Garrett
2022-01-05 10:05 ` Kai-Heng Feng
2022-01-05 10:14 ` Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 13/29] x86/msr: Restrict MSR " Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 14/29] ACPI: Limit access to custom_method " Matthew Garrett
2019-08-20 22:07 ` Rafael J. Wysocki
2019-08-20 0:17 ` [PATCH V40 15/29] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-08-20 22:08 ` Rafael J. Wysocki
2019-08-20 0:17 ` [PATCH V40 16/29] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-08-20 22:08 ` Rafael J. Wysocki
2019-08-20 0:17 ` [PATCH V40 17/29] lockdown: Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-08-20 0:17 ` Matthew Garrett [this message]
2019-08-20 0:17 ` [PATCH V40 19/29] lockdown: Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-08-20 16:39 ` Jessica Yu
2019-08-20 0:17 ` [PATCH V40 20/29] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 21/29] lockdown: Lock down /proc/kcore Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 22/29] lockdown: Lock down tracing and perf kprobes when in confidentiality mode Matthew Garrett
2019-08-20 0:17 ` [PATCH V40 23/29] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-08-20 0:18 ` [PATCH V40 24/29] lockdown: Lock down perf when " Matthew Garrett
2019-08-20 0:18 ` [PATCH V40 25/29] kexec: Allow kexec_file() with appropriate IMA policy when locked down Matthew Garrett
2019-08-20 0:18 ` [PATCH V40 26/29] debugfs: Restrict debugfs when the kernel is " Matthew Garrett
2019-08-20 0:18 ` [PATCH V40 27/29] tracefs: Restrict tracefs " Matthew Garrett
2019-08-20 0:18 ` [PATCH V40 28/29] efi: Restrict efivar_ssdt_load " Matthew Garrett
2019-08-20 0:18 ` [PATCH V40 29/29] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-08-20 6:45 ` [PATCH V40 00/29] Add kernel lockdown functionality James Morris
2019-08-30 16:28 ` [PATCH V40 03/29] security: Add a static lockdown policy LSM David Howells
2019-09-04 16:51 ` Matthew Garrett
2019-09-10 10:06 ` Matthew Garrett
2019-08-30 16:31 ` [PATCH V40 04/29] lockdown: Enforce module signatures if the kernel is locked down David Howells
2019-09-04 16:57 ` Matthew Garrett
2019-08-30 16:32 ` [PATCH V40 23/29] bpf: Restrict bpf when kernel lockdown is in confidentiality mode David Howells
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