From eec8fd0277e37cf447b88c6be181e81df867bcf1 Mon Sep 17 00:00:00 2001 From: Odin Ugedal Date: Fri, 3 Apr 2020 19:55:28 +0200 Subject: device_cgroup: Cleanup cgroup eBPF device filter code 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 4b7d4d453fc4 ("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 Acked-by: Roman Gushchin Signed-off-by: Tejun Heo --- include/linux/device_cgroup.h | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) (limited to 'include/linux/device_cgroup.h') diff --git a/include/linux/device_cgroup.h b/include/linux/device_cgroup.h index fa35b52e0002..9a72214496e5 100644 --- a/include/linux/device_cgroup.h +++ b/include/linux/device_cgroup.h @@ -1,6 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include -#include #define DEVCG_ACC_MKNOD 1 #define DEVCG_ACC_READ 2 @@ -11,16 +10,10 @@ #define DEVCG_DEV_CHAR 2 #define DEVCG_DEV_ALL 4 /* this represents all devices */ -#ifdef CONFIG_CGROUP_DEVICE -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) +int devcgroup_check_permission(short type, u32 major, u32 minor, + short access); static inline int devcgroup_inode_permission(struct inode *inode, int mask) { short type, access = 0; @@ -61,6 +54,9 @@ static inline int devcgroup_inode_mknod(int mode, dev_t dev) } #else +static inline int devcgroup_check_permission(short type, u32 major, u32 minor, + short access) +{ return 0; } static inline int devcgroup_inode_permission(struct inode *inode, int mask) { return 0; } static inline int devcgroup_inode_mknod(int mode, dev_t dev) -- cgit v1.2.3-59-g8ed1b