diff options
| author | David Howells <dhowells@redhat.com> | 2019-08-20 02:17:54 +0200 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2019-08-20 06:54:16 +0200 |
| commit | 794edf30ee6cd088d5f4079b1d4a4cfe5371203e (patch) | |
| tree | 334e6911930274ad592b1620fc0a385f2d532835 | |
| parent | lockdown: Prohibit PCMCIA CIS storage when the kernel is locked down (diff) | |
| download | linux-794edf30ee6cd088d5f4079b1d4a4cfe5371203e.tar.xz linux-794edf30ee6cd088d5f4079b1d4a4cfe5371203e.zip | |
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: 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>
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 5 | ||||
| -rw-r--r-- | include/linux/security.h | 1 | ||||
| -rw-r--r-- | security/lockdown/lockdown.c | 1 |
3 files changed, 7 insertions, 0 deletions
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", }; |