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)
15int devcgroup_check_permission(short type, u32 major, u32 minor,
16			       short access);
17static inline int devcgroup_inode_permission(struct inode *inode, int mask)
18{
19	short type, access = 0;
20
21	if (likely(!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode)))
22		return 0;
23
24	if (!inode->i_rdev)
25		return 0;
26
27	if (S_ISBLK(inode->i_mode))
28		type = DEVCG_DEV_BLOCK;
29	else /* S_ISCHR by the test above */
30		type = DEVCG_DEV_CHAR;
31
32	if (mask & MAY_WRITE)
33		access |= DEVCG_ACC_WRITE;
34	if (mask & MAY_READ)
35		access |= DEVCG_ACC_READ;
36
37	return devcgroup_check_permission(type, imajor(inode), iminor(inode),
38					  access);
39}
40
41static inline int devcgroup_inode_mknod(int mode, dev_t dev)
42{
43	short type;
44
45	if (!S_ISBLK(mode) && !S_ISCHR(mode))
46		return 0;
47
48	if (S_ISCHR(mode) && dev == WHITEOUT_DEV)
49		return 0;
50
51	if (S_ISBLK(mode))
52		type = DEVCG_DEV_BLOCK;
53	else
54		type = DEVCG_DEV_CHAR;
55
56	return devcgroup_check_permission(type, MAJOR(dev), MINOR(dev),
57					  DEVCG_ACC_MKNOD);
58}
59
60#else
61static inline int devcgroup_check_permission(short type, u32 major, u32 minor,
62			       short access)
63{ return 0; }
64static inline int devcgroup_inode_permission(struct inode *inode, int mask)
65{ return 0; }
66static inline int devcgroup_inode_mknod(int mode, dev_t dev)
67{ return 0; }
68#endif