1 files changed, 67 insertions, 0 deletions
diff --git a/include/linux/device_cgroup.h b/include/linux/device_cgroup.h
new file mode 100644
index 000000000..d02f32b75
--- /dev/null
+++ b/include/linux/device_cgroup.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/fs.h>
+
+#define DEVCG_ACC_MKNOD 1
+#define DEVCG_ACC_READ  2
+#define DEVCG_ACC_WRITE 4
+#define DEVCG_ACC_MASK (DEVCG_ACC_MKNOD | DEVCG_ACC_READ | DEVCG_ACC_WRITE)
+
+#define DEVCG_DEV_BLOCK 1
+#define DEVCG_DEV_CHAR  2
+#define DEVCG_DEV_ALL   4  /* this represents all devices */
+
+
+#if defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF)
+int devcgroup_check_permission(short type, u32 major, u32 minor,
+			       short access);
+static inline int devcgroup_inode_permission(struct inode *inode, int mask)
+{
+	short type, access = 0;
+
+	if (likely(!inode->i_rdev))
+		return 0;
+
+	if (S_ISBLK(inode->i_mode))
+		type = DEVCG_DEV_BLOCK;
+	else if (S_ISCHR(inode->i_mode))
+		type = DEVCG_DEV_CHAR;
+	else
+		return 0;
+
+	if (mask & MAY_WRITE)
+		access |= DEVCG_ACC_WRITE;
+	if (mask & MAY_READ)
+		access |= DEVCG_ACC_READ;
+
+	return devcgroup_check_permission(type, imajor(inode), iminor(inode),
+					  access);
+}
+
+static inline int devcgroup_inode_mknod(int mode, dev_t dev)
+{
+	short type;
+
+	if (!S_ISBLK(mode) && !S_ISCHR(mode))
+		return 0;
+
+	if (S_ISCHR(mode) && dev == WHITEOUT_DEV)
+		return 0;
+
+	if (S_ISBLK(mode))
+		type = DEVCG_DEV_BLOCK;
+	else
+		type = DEVCG_DEV_CHAR;
+
+	return devcgroup_check_permission(type, MAJOR(dev), MINOR(dev),
+					  DEVCG_ACC_MKNOD);
+}
+
+#else
+static inline int devcgroup_check_permission(short type, u32 major, u32 minor,
+			       short access)
+{ return 0; }
+static inline int devcgroup_inode_permission(struct inode *inode, int mask)
+{ return 0; }
+static inline int devcgroup_inode_mknod(int mode, dev_t dev)
+{ return 0; }
+#endif