linux_dsm_epyc7002/security/selinux
Ondrej Mosnacek 53e0c2aa9a selinux: do not override context on context mounts
Ignore all selinux_inode_notifysecctx() calls on mounts with SBLABEL_MNT
flag unset. This is achived by returning -EOPNOTSUPP for this case in
selinux_inode_setsecurtity() (because that function should not be called
in such case anyway) and translating this error to 0 in
selinux_inode_notifysecctx().

This fixes behavior of kernfs-based filesystems when mounted with the
'context=' option. Before this patch, if a node's context had been
explicitly set to a non-default value and later the filesystem has been
remounted with the 'context=' option, then this node would show up as
having the manually-set context and not the mount-specified one.

Steps to reproduce:
    # mount -t cgroup2 cgroup2 /sys/fs/cgroup/unified
    # chcon unconfined_u:object_r:user_home_t:s0 /sys/fs/cgroup/unified/cgroup.stat
    # ls -lZ /sys/fs/cgroup/unified
    total 0
    -r--r--r--. 1 root root system_u:object_r:cgroup_t:s0        0 Dec 13 10:41 cgroup.controllers
    -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0        0 Dec 13 10:41 cgroup.max.depth
    -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0        0 Dec 13 10:41 cgroup.max.descendants
    -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0        0 Dec 13 10:41 cgroup.procs
    -r--r--r--. 1 root root unconfined_u:object_r:user_home_t:s0 0 Dec 13 10:41 cgroup.stat
    -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0        0 Dec 13 10:41 cgroup.subtree_control
    -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0        0 Dec 13 10:41 cgroup.threads
    # umount /sys/fs/cgroup/unified
    # mount -o context=system_u:object_r:tmpfs_t:s0 -t cgroup2 cgroup2 /sys/fs/cgroup/unified

Result before:
    # ls -lZ /sys/fs/cgroup/unified
    total 0
    -r--r--r--. 1 root root system_u:object_r:tmpfs_t:s0         0 Dec 13 10:41 cgroup.controllers
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0         0 Dec 13 10:41 cgroup.max.depth
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0         0 Dec 13 10:41 cgroup.max.descendants
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0         0 Dec 13 10:41 cgroup.procs
    -r--r--r--. 1 root root unconfined_u:object_r:user_home_t:s0 0 Dec 13 10:41 cgroup.stat
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0         0 Dec 13 10:41 cgroup.subtree_control
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0         0 Dec 13 10:41 cgroup.threads

Result after:
    # ls -lZ /sys/fs/cgroup/unified
    total 0
    -r--r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.controllers
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.max.depth
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.max.descendants
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.procs
    -r--r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.stat
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.subtree_control
    -rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.threads

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-10 21:24:43 -05:00
..
include selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link 2019-01-10 20:34:37 -05:00
ss selinux/stable-4.21 PR 20181224 2018-12-27 12:01:58 -08:00
.gitignore SELinux: add .gitignore files for dynamic classes 2009-10-24 09:42:27 +08:00
avc.c selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link 2019-01-10 20:34:37 -05:00
exports.c selinux: sparse fix: include selinux.h in exports.c 2011-09-09 16:56:32 -07:00
hooks.c selinux: do not override context on context mounts 2019-01-10 21:24:43 -05:00
ibpkey.c selinux: wrap global selinux state 2018-03-01 18:48:02 -05:00
Kconfig security: introduce CONFIG_SECURITY_WRITABLE_HOOKS 2017-03-06 11:00:12 +11:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
netif.c selinux: Cleanup printk logging in netif 2018-06-19 13:45:31 -04:00
netlabel.c selinux: wrap AVC state 2018-03-20 16:58:17 -04:00
netlink.c selinux: Cleanup printk logging in netlink 2018-06-19 13:33:05 -04:00
netnode.c selinux: Cleanup printk logging in netnode 2018-06-19 13:49:10 -04:00
netport.c selinux: Cleanup printk logging in netport 2018-06-19 13:43:01 -04:00
nlmsgtab.c selinux: add support for RTM_NEWCHAIN, RTM_DELCHAIN, and RTM_GETCHAIN 2018-11-29 11:32:02 -05:00
selinuxfs.c selinux/stable-4.18 PR 20180814 2018-08-15 10:39:06 -07:00
xfrm.c net: use skb_sec_path helper in more places 2018-12-19 11:21:37 -08:00