forked from mirrors/linux
ebc614f687
Cgroup v2 lacks the device controller, provided by cgroup v1. This patch adds a new eBPF program type, which in combination of previously added ability to attach multiple eBPF programs to a cgroup, will provide a similar functionality, but with some additional flexibility. This patch introduces a BPF_PROG_TYPE_CGROUP_DEVICE program type. A program takes major and minor device numbers, device type (block/character) and access type (mknod/read/write) as parameters and returns an integer which defines if the operation should be allowed or terminated with -EPERM. Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
79 lines
1.9 KiB
C
79 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#include <linux/fs.h>
|
|
#include <linux/bpf-cgroup.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 */
|
|
|
|
#ifdef CONFIG_CGROUP_DEVICE
|
|
extern int __devcgroup_check_permission(short type, u32 major, u32 minor,
|
|
short access);
|
|
#else
|
|
static inline int __devcgroup_check_permission(short type, u32 major, u32 minor,
|
|
short access)
|
|
{ return 0; }
|
|
#endif
|
|
|
|
#if defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF)
|
|
static inline int devcgroup_check_permission(short type, u32 major, u32 minor,
|
|
short access)
|
|
{
|
|
int rc = BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type, major, minor, access);
|
|
|
|
if (rc)
|
|
return -EPERM;
|
|
|
|
return __devcgroup_check_permission(type, major, minor, 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_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_inode_permission(struct inode *inode, int mask)
|
|
{ return 0; }
|
|
static inline int devcgroup_inode_mknod(int mode, dev_t dev)
|
|
{ return 0; }
|
|
#endif
|