1getcon(3)                  SELinux API documentation                 getcon(3)
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NAME

6       getcon,  getprevcon,  getpidcon  -  get  SELinux  security context of a
7       process
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9       freecon, freeconary - free memory associated with SELinux security con‐
10       texts
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12       getpeercon - get security context of a peer socket
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14       setcon - set current security context of a process
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SYNOPSIS

18       #include <selinux/selinux.h>
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20       int getcon(char **context);
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22       int getcon_raw(char **context);
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24       int getprevcon(char **context);
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26       int getprevcon_raw(char **context);
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28       int getpidcon(pid_t pid, char **context);
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30       int getpidcon_raw(pid_t pid, char **context);
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32       int getpidprevcon(pid_t pid, char **context);
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34       int getpidprevcon_raw(pid_t pid, char **context);
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36       int getpeercon(int fd, char **context);
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38       int getpeercon_raw(int fd, char **context);
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40       void freecon(char *con);
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42       void freeconary(char **con);
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44       int setcon(const char *context);
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46       int setcon_raw(const char *context);
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DESCRIPTION

50       getcon()
51              retrieves  the  context  of  the  current process, which must be
52              free'd with freecon().
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55       getprevcon()
56              same as getcon but gets the context before the last exec.
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59       getpidcon()
60              returns the process context for the specified PID, which must be
61              free'd with freecon().
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64       getpidprevcon()
65              returns  the process context before the last exec for the speci‐
66              fied PID, which must be free'd with freecon().
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69       getpeercon()
70              retrieves the context of the peer socket, which must  be  free'd
71              with freecon().
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74       freecon()
75              frees the memory allocated for a security context.
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77              If con is NULL, no operation is performed.
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80       freeconary()
81              frees the memory allocated for a context array.
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83              If con is NULL, no operation is performed.
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86       setcon()
87              sets the current security context of the process to a new value.
88              Note that use of this function requires that the entire applica‐
89              tion  be  trusted to maintain any desired separation between the
90              old and new security  contexts,  unlike  exec-based  transitions
91              performed  via setexeccon(3).  When possible, decompose your ap‐
92              plication and use setexeccon(3) and execve(3) instead.
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94              Since access to file descriptors  is  revalidated  upon  use  by
95              SELinux,  the  new  context must be explicitly authorized in the
96              policy to use the descriptors opened by the old context if  that
97              is  desired.   Otherwise, attempts by the process to use any ex‐
98              isting descriptors (including stdin, stdout, and  stderr)  after
99              performing the setcon() will fail.
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101              A  multi-threaded  application  can  perform a setcon() prior to
102              creating any child threads, in  which  case  all  of  the  child
103              threads  will  inherit the new context.  However, prior to Linux
104              2.6.28, setcon() would fail if there are any other threads  run‐
105              ning in the same process since this would yield an inconsistency
106              among the security contexts of threads sharing the  same  memory
107              space.   Since  Linux  2.6.28, setcon() is permitted for threads
108              within a multi-threaded process if the new security  context  is
109              bounded  by the old security context, where the bounded relation
110              is defined through typebounds statements in the policy and guar‐
111              antees that the new security context has a subset of the permis‐
112              sions of the old security context.
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114              If the process was being ptraced at the time of the setcon() op‐
115              eration,  ptrace  permission will be revalidated against the new
116              context and the setcon() will fail if it is not allowed by  pol‐
117              icy.
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120       *_raw()
121              getcon_raw(),   getprevcon_raw(),   getpidcon_raw(),  getpidpre‐
122              vcon_raw(), getpeercon_raw() and setcon_raw() behave identically
123              to  their non-raw counterparts but do not perform context trans‐
124              lation.
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RETURN VALUE

128       On error -1 is returned with errno set.  On success 0 is returned.
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NOTES

132       The retrieval functions might return success and set *context  to  NULL
133       if and only if SELinux is not enabled.
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135       Querying  a foreign process via its PID, e.g. getpidcon() or getpidpre‐
136       vcon(), is inherently racy and therefore should never  be  relied  upon
137       for security purposes.
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SEE ALSO

141       selinux(8), setexeccon(3)
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145russell@coker.com.au           21 December 2011                      getcon(3)
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