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eec8fd0277
Original cgroup v2 eBPF code for filtering device access made it
possible to compile with CONFIG_CGROUP_DEVICE=n and still use the eBPF
filtering. Change
commit 4b7d4d453f ("device_cgroup: Export devcgroup_check_permission")
reverted this, making it required to set it to y.
Since the device filtering (and all the docs) for cgroup v2 is no longer
a "device controller" like it was in v1, someone might compile their
kernel with CONFIG_CGROUP_DEVICE=n. Then (for linux 5.5+) the eBPF
filter will not be invoked, and all processes will be allowed access
to all devices, no matter what the eBPF filter says.
Signed-off-by: Odin Ugedal <odin@ugedal.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#include <linux/fs.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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#if defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF)
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int devcgroup_check_permission(short type, u32 major, u32 minor,
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short access);
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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_check_permission(short type, u32 major, u32 minor,
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short access)
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{ return 0; }
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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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