include/linux/device_cgroup.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #include <linux/fs.h>
   3
   4 #define DEVCG_ACC_MKNOD 1
   5 #define DEVCG_ACC_READ  2
   6 #define DEVCG_ACC_WRITE 4
   7 #define DEVCG_ACC_MASK (DEVCG_ACC_MKNOD | DEVCG_ACC_READ | DEVCG_ACC_WRITE)
   8
   9 #define DEVCG_DEV_BLOCK 1
  10 #define DEVCG_DEV_CHAR  2
  11 #define DEVCG_DEV_ALL   4  /* this represents all devices */
  12
  13
  14 #if defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF)
  15 int devcgroup_check_permission(short type, u32 major, u32 minor,
  16                                short access);
  17 static inline int devcgroup_inode_permission(struct inode *inode, int mask)
  18 {
  19         short type, access = 0;
  20
  21         if (likely(!inode->i_rdev))
  22                 return 0;
  23
  24         if (S_ISBLK(inode->i_mode))
  25                 type = DEVCG_DEV_BLOCK;
  26         else if (S_ISCHR(inode->i_mode))
  27                 type = DEVCG_DEV_CHAR;
  28         else
  29                 return 0;
  30
  31         if (mask & MAY_WRITE)
  32                 access |= DEVCG_ACC_WRITE;
  33         if (mask & MAY_READ)
  34                 access |= DEVCG_ACC_READ;
  35
  36         return devcgroup_check_permission(type, imajor(inode), iminor(inode),
  37                                           access);
  38 }
  39
  40 static inline int devcgroup_inode_mknod(int mode, dev_t dev)
  41 {
  42         short type;
  43
  44         if (!S_ISBLK(mode) && !S_ISCHR(mode))
  45                 return 0;
  46
  47         if (S_ISCHR(mode) && dev == WHITEOUT_DEV)
  48                 return 0;
  49
  50         if (S_ISBLK(mode))
  51                 type = DEVCG_DEV_BLOCK;
  52         else
  53                 type = DEVCG_DEV_CHAR;
  54
  55         return devcgroup_check_permission(type, MAJOR(dev), MINOR(dev),
  56                                           DEVCG_ACC_MKNOD);
  57 }
  58
  59 #else
  60 static inline int devcgroup_check_permission(short type, u32 major, u32 minor,
  61                                short access)
  62 { return 0; }
  63 static inline int devcgroup_inode_permission(struct inode *inode, int mask)
  64 { return 0; }
  65 static inline int devcgroup_inode_mknod(int mode, dev_t dev)
  66 { return 0; }
  67 #endif