getcon(3) SELinux API documentation getcon(3)
NAME
getcon, getprevcon, getpidcon - get SELinux security context of a
process
freecon, freeconary - free memory associated with SELinux security con-
texts
getpeercon - get security context of a peer socket
setcon - set current security context of a process
SYNOPSIS
#include <selinux/selinux.h>
int getcon(char **context);
int getcon_raw(char **context);
int getprevcon(char **context);
int getprevcon_raw(char **context);
int getpidcon(pid_t pid, char **context);
int getpidcon_raw(pid_t pid, char **context);
int getpeercon(int fd, char **context);
int getpeercon_raw(int fd, char **context);
void freecon(char *con);
void freeconary(char **con);
int setcon(const char *context);
int setcon_raw(const char *context);
DESCRIPTION
getcon()
retrieves the context of the current process, which must be
free'd with freecon().
getprevcon()
same as getcon but gets the context before the last exec.
getpidcon()
returns the process context for the specified PID, which must be
free'd with freecon().
getpeercon()
retrieves the context of the peer socket, which must be free'd
with freecon().
freecon()
frees the memory allocated for a security context.
If con is NULL, no operation is performed.
freeconary()
frees the memory allocated for a context array.
If con is NULL, no operation is performed.
setcon()
sets the current security context of the process to a new value.
Note that use of this function requires that the entire applica-
tion be trusted to maintain any desired separation between the
old and new security contexts, unlike exec-based transitions
performed via setexeccon(3). When possible, decompose your ap-
plication and use setexeccon(3) and execve(3) instead.
Since access to file descriptors is revalidated upon use by
SELinux, the new context must be explicitly authorized in the
policy to use the descriptors opened by the old context if that
is desired. Otherwise, attempts by the process to use any ex-
isting descriptors (including stdin, stdout, and stderr) after
performing the setcon() will fail.
A multi-threaded application can perform a setcon() prior to
creating any child threads, in which case all of the child
threads will inherit the new context. However, prior to Linux
2.6.28, setcon() would fail if there are any other threads run-
ning in the same process since this would yield an inconsistency
among the security contexts of threads sharing the same memory
space. Since Linux 2.6.28, setcon() is permitted for threads
within a multi-threaded process if the new security context is
bounded by the old security context, where the bounded relation
is defined through typebounds statements in the policy and guar-
antees that the new security context has a subset of the permis-
sions of the old security context.
If the process was being ptraced at the time of the setcon() op-
eration, ptrace permission will be revalidated against the new
context and the setcon() will fail if it is not allowed by pol-
icy.
*_raw()
getcon_raw(), getprevcon_raw(), getpidcon_raw(), getpeer-
con_raw() and setcon_raw() behave identically to their non-raw
counterparts but do not perform context translation.
RETURN VALUE
On error -1 is returned with errno set. On success 0 is returned.
NOTES
The retrieval functions might return success and set *context to NULL
if and only if SELinux is not enabled.
SEE ALSO
selinux(8), setexeccon(3)
russell@coker.com.au 21 December 2011 getcon(3)
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