lockdown: Prohibit PCMCIA CIS storage when the kernel is locked down

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>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <jmorris@namei.org>

diff --git a/drivers/pcmcia/cistpl.c b/drivers/pcmcia/cistpl.c
index abd0299..629359f 100644 (file)
--- a/drivers/pcmcia/cistpl.c
+++ b/drivers/pcmcia/cistpl.c
@@ -21,6 +21,7 @@
 #include <linux/pci.h>
 #include <linux/ioport.h>
 #include <linux/io.h>
+#include <linux/security.h>
 #include <asm/byteorder.h>
 #include <asm/unaligned.h>
 
@@ -1575,6 +1576,10 @@ 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 390e393..683f060 100644 (file)
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -111,6 +111,7 @@ 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 6d44db0..db34775 100644 (file)
--- 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] = "modifying ACPI tables",
+       [LOCKDOWN_PCMCIA_CIS] = "direct PCMCIA CIS storage",
        [LOCKDOWN_INTEGRITY_MAX] = "integrity",
        [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
 };