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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 */
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#include <linux/fs.h>
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#include <linux/bpf-cgroup.h>
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#define DEVCG_ACC_MKNOD 1
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#define DEVCG_ACC_READ 2
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#define DEVCG_ACC_WRITE 4
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#define DEVCG_ACC_MASK (DEVCG_ACC_MKNOD | DEVCG_ACC_READ | DEVCG_ACC_WRITE)
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#define DEVCG_DEV_BLOCK 1
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#define DEVCG_DEV_CHAR 2
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#define DEVCG_DEV_ALL 4 /* this represents all devices */
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#ifdef CONFIG_CGROUP_DEVICE
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extern int __devcgroup_check_permission(short type, u32 major, u32 minor,
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short access);
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#else
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static inline int __devcgroup_check_permission(short type, u32 major, u32 minor,
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short access)
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{ return 0; }
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#endif
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#if defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF)
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static inline int devcgroup_check_permission(short type, u32 major, u32 minor,
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short access)
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{
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int rc = BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type, major, minor, access);
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if (rc)
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return -EPERM;
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return __devcgroup_check_permission(type, major, minor, access);
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}
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static inline int devcgroup_inode_permission(struct inode *inode, int mask)
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{
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short type, access = 0;
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if (likely(!inode->i_rdev))
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return 0;
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if (S_ISBLK(inode->i_mode))
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type = DEVCG_DEV_BLOCK;
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else if (S_ISCHR(inode->i_mode))
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type = DEVCG_DEV_CHAR;
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else
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return 0;
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if (mask & MAY_WRITE)
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access |= DEVCG_ACC_WRITE;
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if (mask & MAY_READ)
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access |= DEVCG_ACC_READ;
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return devcgroup_check_permission(type, imajor(inode), iminor(inode),
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access);
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}
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static inline int devcgroup_inode_mknod(int mode, dev_t dev)
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{
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short type;
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if (!S_ISBLK(mode) && !S_ISCHR(mode))
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return 0;
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if (S_ISBLK(mode))
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type = DEVCG_DEV_BLOCK;
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else
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type = DEVCG_DEV_CHAR;
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return devcgroup_check_permission(type, MAJOR(dev), MINOR(dev),
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DEVCG_ACC_MKNOD);
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}
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#else
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static inline int devcgroup_inode_permission(struct inode *inode, int mask)
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{ return 0; }
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static inline int devcgroup_inode_mknod(int mode, dev_t dev)
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{ return 0; }
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#endif
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