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);
devcgroup_inode_permission(struct inode * inode,int mask)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 
devcgroup_inode_mknod(int mode,dev_t dev)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
devcgroup_check_permission(short type,u32 major,u32 minor,short access)60 static inline int devcgroup_check_permission(short type, u32 major, u32 minor,
61 			       short access)
62 { return 0; }
devcgroup_inode_permission(struct inode * inode,int mask)63 static inline int devcgroup_inode_permission(struct inode *inode, int mask)
64 { return 0; }
devcgroup_inode_mknod(int mode,dev_t dev)65 static inline int devcgroup_inode_mknod(int mode, dev_t dev)
66 { return 0; }
67 #endif
68