oracular (3) selinux_set_mapping.3.gz

NAME

       selinux_set_mapping - establish dynamic object class and permission mapping

SYNOPSIS

       #include <selinux/selinux.h>

       struct security_class_mapping {
            const char *name;
            const char *perms[];
       };

       int selinux_set_mapping(struct security_class_mapping *map);

DESCRIPTION

       selinux_set_mapping()  establishes  a  mapping  from  a  user-provided  ordering  of  object  classes and
       permissions to the  numbers  actually  used  by  the  loaded  system  policy.  If  using  this  function,
       applications should also set a SELINUX_CB_POLICYLOAD callback via selinux_set_callback(3) that calls this
       function again upon a policy reload to re-create the mapping in  case  the  class  or  permission  values
       change  in  the  new policy.  Generally it is preferred to instead use selinux_check_access(3) instead of
       avc_has_perm(3) or security_compute_av(3) and not use this function at all.

       After the mapping is established, all libselinux functions that operate on class  and  permission  values
       take the user-provided numbers, which are determined as follows:

       The map argument consists of an array of security_class_mapping structures, which must be terminated by a
       structure having a NULL name field.  Except for this last structure, the name field should refer  to  the
       string  name of an object class, and the corresponding perms field should refer to an array of permission
       bit names terminated by a NULL string.

       The object classes named in the mapping and the bit indexes of each set of permission bits named  in  the
       mapping  are  numbered  in  order starting from 1.  These numbers are the values that should be passed to
       subsequent libselinux calls.

RETURN VALUE

       Zero is returned on success.  On error, -1 is returned and errno is set appropriately.

ERRORS

       EINVAL One of the class or permission names requested in the mapping is not present in the loaded policy.

       ENOMEM An attempt to allocate memory failed.

EXAMPLE

              struct security_class_mapping map[] = {
                  { "file", { "create", "unlink", "read", "write", NULL } },
                  { "socket", { "bind", NULL } },
                  { "process", { "signal", NULL } },
                  { NULL }
              };

              if (selinux_set_mapping(map) < 0)
                  exit(1);

       In this example, after the call has succeeded, classes file, socket, and process will be identified by 1,
       2  and  3,  respectively.   Permissions  create,  unlink,  read,  and  write (for the file class) will be
       identified by 1, 2, 4, and 8 respectively.  Classes and permissions not listed in the mapping  cannot  be
       used.

AUTHOR

       Originally Eamon Walsh.  Updated by Stephen Smalley <sds@tycho.nsa.gov>

SEE ALSO

       selinux_check_access(3), selinux_set_callback(3), avc_has_perm(3), selinux(8)

                                                   12 Jun 2008                            selinux_set_mapping(3)