1tcpd_selinux(8) SELinux Policy tcpd tcpd_selinux(8)
2
3
4
6 tcpd_selinux - Security Enhanced Linux Policy for the tcpd processes
7
9 Security-Enhanced Linux secures the tcpd processes via flexible manda‐
10 tory access control.
11
12 The tcpd processes execute with the tcpd_t SELinux type. You can check
13 if you have these processes running by executing the ps command with
14 the -Z qualifier.
15
16 For example:
17
18 ps -eZ | grep tcpd_t
19
20
21
23 The tcpd_t SELinux type can be entered via the tcpd_exec_t file type.
24
25 The default entrypoint paths for the tcpd_t domain are the following:
26
27 /usr/sbin/tcpd
28
30 SELinux defines process types (domains) for each process running on the
31 system
32
33 You can see the context of a process using the -Z option to ps
34
35 Policy governs the access confined processes have to files. SELinux
36 tcpd policy is very flexible allowing users to setup their tcpd pro‐
37 cesses in as secure a method as possible.
38
39 The following process types are defined for tcpd:
40
41 tcpd_t
42
43 Note: semanage permissive -a tcpd_t can be used to make the process
44 type tcpd_t permissive. SELinux does not deny access to permissive
45 process types, but the AVC (SELinux denials) messages are still gener‐
46 ated.
47
48
50 SELinux policy is customizable based on least access required. tcpd
51 policy is extremely flexible and has several booleans that allow you to
52 manipulate the policy and run tcpd with the tightest access possible.
53
54
55
56 If you want to allow all domains to execute in fips_mode, you must turn
57 on the fips_mode boolean. Enabled by default.
58
59 setsebool -P fips_mode 1
60
61
62
63 If you want to allow system to run with NIS, you must turn on the
64 nis_enabled boolean. Disabled by default.
65
66 setsebool -P nis_enabled 1
67
68
69
70 If you want to allow sshd to use tcp wrappers, you must turn on the
71 ssh_use_tcpd boolean. Disabled by default.
72
73 setsebool -P ssh_use_tcpd 1
74
75
76
78 The SELinux process type tcpd_t can manage files labeled with the fol‐
79 lowing file types. The paths listed are the default paths for these
80 file types. Note the processes UID still need to have DAC permissions.
81
82 tcpd_tmp_t
83
84
85
87 SELinux requires files to have an extended attribute to define the file
88 type.
89
90 You can see the context of a file using the -Z option to ls
91
92 Policy governs the access confined processes have to these files.
93 SELinux tcpd policy is very flexible allowing users to setup their tcpd
94 processes in as secure a method as possible.
95
96 STANDARD FILE CONTEXT
97
98 SELinux defines the file context types for the tcpd, if you wanted to
99 store files with these types in a diffent paths, you need to execute
100 the semanage command to specify alternate labeling and then use re‐
101 storecon to put the labels on disk.
102
103 semanage fcontext -a -t tcpd_tmp_t '/srv/mytcpd_content(/.*)?'
104 restorecon -R -v /srv/mytcpd_content
105
106 Note: SELinux often uses regular expressions to specify labels that
107 match multiple files.
108
109 The following file types are defined for tcpd:
110
111
112
113 tcpd_exec_t
114
115 - Set files with the tcpd_exec_t type, if you want to transition an ex‐
116 ecutable to the tcpd_t domain.
117
118
119
120 tcpd_tmp_t
121
122 - Set files with the tcpd_tmp_t type, if you want to store tcpd tempo‐
123 rary files in the /tmp directories.
124
125
126
127 Note: File context can be temporarily modified with the chcon command.
128 If you want to permanently change the file context you need to use the
129 semanage fcontext command. This will modify the SELinux labeling data‐
130 base. You will need to use restorecon to apply the labels.
131
132
134 semanage fcontext can also be used to manipulate default file context
135 mappings.
136
137 semanage permissive can also be used to manipulate whether or not a
138 process type is permissive.
139
140 semanage module can also be used to enable/disable/install/remove pol‐
141 icy modules.
142
143 semanage boolean can also be used to manipulate the booleans
144
145
146 system-config-selinux is a GUI tool available to customize SELinux pol‐
147 icy settings.
148
149
151 This manual page was auto-generated using sepolicy manpage .
152
153
155 selinux(8), tcpd(8), semanage(8), restorecon(8), chcon(1), sepolicy(8),
156 setsebool(8)
157
158
159
160tcpd 21-11-19 tcpd_selinux(8)