From ecf8fecb7828648cba0e42de7464a7e600c93459 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Sun, 5 Nov 2017 08:15:31 -0500 Subject: [PATCH] device_cgroup: prepare code for bpf-based device controller This is non-functional change to prepare the device cgroup code for adding eBPF-based controller for cgroups v2. The patch performs the following changes: 1) __devcgroup_inode_permission() and devcgroup_inode_mknod() are moving to the device-cgroup.h and converting into static inline. 2) __devcgroup_check_permission() is exported. 3) devcgroup_check_permission() wrapper is introduced to be used by both existing and new bpf-based implementations. Signed-off-by: Roman Gushchin Acked-by: Tejun Heo Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/device_cgroup.h | 61 ++++++++++++++++++++++++++++++++--- security/device_cgroup.c | 47 ++------------------------- 2 files changed, 59 insertions(+), 49 deletions(-) diff --git a/include/linux/device_cgroup.h b/include/linux/device_cgroup.h index cdbc344a92e4..2d93d7ecd479 100644 --- a/include/linux/device_cgroup.h +++ b/include/linux/device_cgroup.h @@ -1,17 +1,70 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include +#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 + #ifdef CONFIG_CGROUP_DEVICE -extern int __devcgroup_inode_permission(struct inode *inode, int mask); -extern int devcgroup_inode_mknod(int mode, dev_t dev); +static inline int devcgroup_check_permission(short type, u32 major, u32 minor, + short access) +{ + 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) && !S_ISCHR(inode->i_mode)) + + if (S_ISBLK(inode->i_mode)) + type = DEVCG_DEV_BLOCK; + else if (S_ISCHR(inode->i_mode)) + type = DEVCG_DEV_CHAR; + else return 0; - return __devcgroup_inode_permission(inode, mask); + + 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; } diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 968c21557ba7..c65b39bafdfe 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -15,15 +15,6 @@ #include #include -#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 */ - static DEFINE_MUTEX(devcgroup_mutex); enum devcg_behavior { @@ -810,8 +801,8 @@ struct cgroup_subsys devices_cgrp_subsys = { * * returns 0 on success, -EPERM case the operation is not permitted */ -static int __devcgroup_check_permission(short type, u32 major, u32 minor, - short access) +int __devcgroup_check_permission(short type, u32 major, u32 minor, + short access) { struct dev_cgroup *dev_cgroup; bool rc; @@ -833,37 +824,3 @@ static int __devcgroup_check_permission(short type, u32 major, u32 minor, return 0; } - -int __devcgroup_inode_permission(struct inode *inode, int mask) -{ - short type, access = 0; - - if (S_ISBLK(inode->i_mode)) - type = DEVCG_DEV_BLOCK; - if (S_ISCHR(inode->i_mode)) - type = DEVCG_DEV_CHAR; - 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); -} - -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); - -} -- 2.30.2