[PATCH V34 17/29] Prohibit PCMCIA CIS storage when the kernel is locked down

Matthew Garrett
2019-06-22T00:04:50Z

From: David Howells <dhowells@redhat.com>

Prohibit replacement of the PCMCIA Card Information Structure when the
kernel is locked down.

Suggested-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
---
drivers/pcmcia/cistpl.c | 5 +++++
include/linux/security.h | 1 +
security/lockdown/lockdown.c | 1 +
3 files changed, 7 insertions(+)

diff --git a/drivers/pcmcia/cistpl.c b/drivers/pcmcia/cistpl.c
index ac0672b8dfca..379c53610102 100644
--- a/drivers/pcmcia/cistpl.c
+++ b/drivers/pcmcia/cistpl.c
@@ -24,6 +24,7 @@
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/io.h>
+#include <linux/security.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>

@@ -1578,6 +1579,10 @@ static ssize_t pccard_store_cis(struct file *filp, struct kobject *kobj,
struct pcmcia_socket *s;
int error;

+ error = security_locked_down(LOCKDOWN_PCMCIA_CIS);
+ if (error)
+ return error;
+
s = to_socket(container_of(kobj, struct device, kobj));

if (off)
diff --git a/include/linux/security.h b/include/linux/security.h
index cc2b5ee4cadd..03c125b277ca 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -90,6 +90,7 @@ enum lockdown_reason {
LOCKDOWN_IOPORT,
LOCKDOWN_MSR,
LOCKDOWN_ACPI_TABLES,
+ LOCKDOWN_PCMCIA_CIS,
LOCKDOWN_INTEGRITY_MAX,
LOCKDOWN_CONFIDENTIALITY_MAX,
};
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index 1725224f0024..7be3e8fb5847 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -26,6 +26,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
[LOCKDOWN_IOPORT] = "raw io port access",
[LOCKDOWN_MSR] = "raw MSR access",
[LOCKDOWN_ACPI_TABLES] = "modified ACPI tables",
+ [LOCKDOWN_PCMCIA_CIS] = "direct PCMCIA CIS storage",
[LOCKDOWN_INTEGRITY_MAX] = "integrity",
[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
};
--
2.22.0.410.gd8fdbe21b5-goog