1kernel_selinux(8) SELinux Policy kernel kernel_selinux(8)
2
3
4
6 kernel_selinux - Security Enhanced Linux Policy for the kernel pro‐
7 cesses
8
10 Security-Enhanced Linux secures the kernel processes via flexible
11 mandatory access control.
12
13 The kernel processes execute with the kernel_t SELinux type. You can
14 check if you have these processes running by executing the ps command
15 with the -Z qualifier.
16
17 For example:
18
19 ps -eZ | grep kernel_t
20
21
22
24 SELinux defines process types (domains) for each process running on the
25 system
26
27 You can see the context of a process using the -Z option to ps
28
29 Policy governs the access confined processes have to files. SELinux
30 kernel policy is very flexible allowing users to setup their kernel
31 processes in as secure a method as possible.
32
33 The following process types are defined for kernel:
34
35 kernel_t
36
37 Note: semanage permissive -a kernel_t can be used to make the process
38 type kernel_t permissive. SELinux does not deny access to permissive
39 process types, but the AVC (SELinux denials) messages are still gener‐
40 ated.
41
42
44 SELinux policy is customizable based on least access required. kernel
45 policy is extremely flexible and has several booleans that allow you to
46 manipulate the policy and run kernel with the tightest access possible.
47
48
49
50 If you want to deny user domains applications to map a memory region as
51 both executable and writable, this is dangerous and the executable
52 should be reported in bugzilla, you must turn on the deny_execmem bool‐
53 ean. Enabled by default.
54
55 setsebool -P deny_execmem 1
56
57
58
59 If you want to control the ability to mmap a low area of the address
60 space, as configured by /proc/sys/vm/mmap_min_addr, you must turn on
61 the mmap_low_allowed boolean. Disabled by default.
62
63 setsebool -P mmap_low_allowed 1
64
65
66
67 If you want to disable kernel module loading, you must turn on the se‐
68 cure_mode_insmod boolean. Enabled by default.
69
70 setsebool -P secure_mode_insmod 1
71
72
73
74 If you want to allow unconfined executables to make their heap memory
75 executable. Doing this is a really bad idea. Probably indicates a
76 badly coded executable, but could indicate an attack. This executable
77 should be reported in bugzilla, you must turn on the selinuxuser_ex‐
78 echeap boolean. Disabled by default.
79
80 setsebool -P selinuxuser_execheap 1
81
82
83
84 If you want to allow unconfined executables to make their stack exe‐
85 cutable. This should never, ever be necessary. Probably indicates a
86 badly coded executable, but could indicate an attack. This executable
87 should be reported in bugzilla, you must turn on the selinuxuser_exec‐
88 stack boolean. Enabled by default.
89
90 setsebool -P selinuxuser_execstack 1
91
92
93
95 The SELinux process type kernel_t can manage files labeled with the
96 following file types. The paths listed are the default paths for these
97 file types. Note the processes UID still need to have DAC permissions.
98
99 file_type
100
101 all files on the system
102
103
105 semanage fcontext can also be used to manipulate default file context
106 mappings.
107
108 semanage permissive can also be used to manipulate whether or not a
109 process type is permissive.
110
111 semanage module can also be used to enable/disable/install/remove pol‐
112 icy modules.
113
114 semanage boolean can also be used to manipulate the booleans
115
116
117 system-config-selinux is a GUI tool available to customize SELinux pol‐
118 icy settings.
119
120
122 This manual page was auto-generated using sepolicy manpage .
123
124
126 selinux(8), kernel(8), semanage(8), restorecon(8), chcon(1), sepol‐
127 icy(8), setsebool(8)
128
129
130
131kernel 23-02-03 kernel_selinux(8)