[PATCH 10/20] alpha/PCI: Add security_locked_down() check to pci_mmap_resource()

Krzysztof Wilczyński
2026-04-10T07:14:50Z

Currently, Alpha's pci_mmap_resource() does not check
security_locked_down(LOCKDOWN_PCI_ACCESS) before allowing
userspace to mmap PCI BARs.

The generic version has had this check since commit eb627e17727e
("PCI: Lock down BAR access when the kernel is locked down") to
prevent DMA attacks when the kernel is locked down.

Add the same check to Alpha's pci_mmap_resource().

Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
---
arch/alpha/kernel/pci-sysfs.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/alpha/kernel/pci-sysfs.c b/arch/alpha/kernel/pci-sysfs.c
index 3048758304b5..2324720c3e83 100644
--- a/arch/alpha/kernel/pci-sysfs.c
+++ b/arch/alpha/kernel/pci-sysfs.c
@@ -11,6 +11,7 @@
*/

#include <linux/sched.h>
+#include <linux/security.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/pci.h>
@@ -71,7 +72,11 @@ static int pci_mmap_resource(struct kobject *kobj,
struct resource *res = attr->private;
enum pci_mmap_state mmap_type;
struct pci_bus_region bar;
- int i;
+ int i, ret;
+
+ ret = security_locked_down(LOCKDOWN_PCI_ACCESS);
+ if (ret)
+ return ret;

for (i = 0; i < PCI_STD_NUM_BARS; i++)
if (res == &pdev->resource[i])
--
2.53.0