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.TH "chcontext" "8" "0.1.0" "Klavs Klavsen <kl@vsen.dk>" "System Administration" |
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.SH "NAME" |
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.LP |
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chcontext \- chcontext allocates a new security context and executes a command in that context. |
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.SH "SYNTAX" |
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.LP |
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chcontext [\fIoptions\fP] <\fIcommand arguments\fP> |
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.SH "DESCRIPTION" |
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.LP |
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chcontext allocates a new security context and executes a command in that context. |
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By default, a new/unused context is allocated |
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.SH "OPTIONS" |
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.LP |
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.TP |
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\fB\-\-cap\fR CAP_NAME |
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Add a capability from the command. This option may be repeated several time. See /usr/include/linux/capability.h In general, this option is used with the \-\-secure option. \-\-secure removes most critical capabilities and \-\-cap adds specific ones. |
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.TP |
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\fB\-\-cap\fR !CAP_NAME |
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Remove a capability from the command. This option may be repeated several time. See /usr/include/linux/capability.h |
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.TP |
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\fB\-\-ctx\fR num |
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Select the context. Only root in context 0 is allowed to select a specific context. |
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Context number 1 is special. It can see all processes in any contexts, but can't kill them though. |
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.TP |
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\fB\-\-disconnect\fR |
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Start the command in background and make the process a child of process 1. |
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.TP |
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\fB\-\-domainname\fR new_domainname |
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Set the domainname (NIS) in the new security context. |
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Use "none" to unset the domainname. |
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.TP |
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\fB\-\-flag\fR |
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Set one flag in the new or current security context. The following flags are supported. The option may be used several time. |
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lock: The new process is trapped and can't use |
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chcontext anymore. |
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sched: The new process and its children will |
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share a common execution priority. |
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nproc: Limit the number of process in the |
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vserver according to ulimit setting. |
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Normally, ulimit is a per user thing. |
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With this flag, it becomes a per vserver |
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thing. |
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private: No one can join this security context |
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once created. |
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.TP |
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\fB\-\-hostname\fR new_hostname |
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Set the hostname in the new security context. |
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This is needed because if you create a less privileged security context, it may be unable to change its hostname. |
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.TP |
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\fB\-\-secure\fR |
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Remove all the capabilities to make a virtual server trustable. |
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.TP |
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\fB\-\-silent\fR |
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Do not print the allocated context number. |
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.LP |
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Information about context is found in /proc/self/status |
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.SH "FILES" |
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.LP |
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\fI/usr/sbin/chcontext\fP |
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|
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.SH "EXAMPLES" |
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.LP |
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# You must be root, running X. |
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# We start an xterm in another security context |
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/usr/sbin/chcontext xterm & |
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# We check, there is no xterm running, yet we can |
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# see it. |
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ps ax | grep xterm |
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|
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# Are we running in security context 0 |
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# We check the s_context line in /proc/self/status |
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cat /proc/self/status |
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# Ok we in security context 0 |
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# Try the security context 1 |
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/usr/sbin/chcontext \-\-ctx 1 ps ax | grep xterm |
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# Ok, we see the xterm, we try to kill it |
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/usr/sbin/chcontext \-\-ctx 1 killall xterm |
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|
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# No, security context 1 can see, but can't kill |
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# let's find out in which security context this |
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# xterm is running |
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/usr/sbin/chcontext \-\-ctx 1 ps ax | grep xterm |
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|
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# Ok, this is PID XX. We need the security context |
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/usr/sbin/chcontext \-\-ctx 1 cat /proc/XX/status |
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|
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# We see the s_context, this is SS. |
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# We want to kill this process |
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/usr/sbin/chcontext \-\-ctx SS killall xterm |
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.LP |
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Please contribute some, if you feel it's important. |
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.SH "AUTHORS" |
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.LP |
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This Man page was written by Klavs Klavsen <kl@vsen.dk> and based upon the helpful output from the program itself and the documentation on the Virtual Server site <http://www.solucorp.qc.ca/miscprj/s_context.hc?prjstate=1&nodoc=0> |
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.SH "SEE ALSO" |
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.LP |
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chbind(8) rebootmgr(8) reducecap(8) |
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vps(8) vpstree(8) vrpm(8) vserver(8) |
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vserver\-stat(8) vtop(8) |
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