Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
SETRESUID(2)		   Linux Programmer's Manual		  SETRESUID(2)

NAME
       setresuid, setresgid - set real,	effective and saved user or group ID

SYNOPSIS
       #define _GNU_SOURCE	   /* See feature_test_macros(7) */
       #include	<unistd.h>

       int setresuid(uid_t ruid, uid_t euid, uid_t suid);
       int setresgid(gid_t rgid, gid_t egid, gid_t sgid);

DESCRIPTION
       setresuid() sets	the real user ID, the effective	user ID, and the saved
       set-user-ID of the calling process.

       Unprivileged user processes may change the real UID, effective UID, and
       saved  set-user-ID,  each  to one of: the current real UID, the current
       effective UID or	the current saved set-user-ID.

       Privileged processes (on	Linux, those having the	CAP_SETUID capability)
       may set the real	UID, effective UID, and	saved set-user-ID to arbitrary
       values.

       If one of the arguments equals  -1,  the	 corresponding	value  is  not
       changed.

       Regardless of what changes are made to the real UID, effective UID, and
       saved set-user-ID, the filesystem UID is	always set to the  same	 value
       as the (possibly	new) effective UID.

       Completely  analogously,	 setresgid() sets the real GID,	effective GID,
       and saved set-group-ID of the calling process (and always modifies  the
       filesystem  GID to be the same as the effective GID), with the same re-
       strictions for unprivileged processes.

RETURN VALUE
       On success, zero	is returned.  On error,	-1 is returned,	and  errno  is
       set appropriately.

       Note:  there  are cases where setresuid() can fail even when the	caller
       is UID 0; it is a grave security	error to omit checking for  a  failure
       return from setresuid().

ERRORS
       EAGAIN The call would change the	caller's real UID (i.e., ruid does not
	      match the	caller's real UID), but	there was a temporary  failure
	      allocating the necessary kernel data structures.

       EAGAIN ruid  does  not  match the caller's real UID and this call would
	      bring the	number of processes belonging to the real user ID ruid
	      over the caller's	RLIMIT_NPROC resource limit.  Since Linux 3.1,
	      this error case no longer	occurs (but robust applications	should
	      check  for  this	error);	 see  the description of EAGAIN	in ex-
	      ecve(2).

       EINVAL One or more of the target	user or	group IDs is not valid in this
	      user namespace.

       EPERM  The  calling process is not privileged (did not have the CAP_SE-
	      TUID capability) and tried to change the IDs to values that  are
	      not permitted.

VERSIONS
       These calls are available under Linux since Linux 2.1.44.

CONFORMING TO
       These  calls are	nonstandard; they also appear on HP-UX and some	of the
       BSDs.

NOTES
       Under HP-UX and FreeBSD,	the prototype is found in  _unistd.h_.	 Under
       Linux, the prototype is provided	by glibc since version 2.3.2.

       The  original  Linux setresuid()	and setresgid()	system calls supported
       only 16-bit user	and group IDs.	Subsequently, Linux 2.4	 added	setre-
       suid32()	 and  setresgid32(),  supporting 32-bit	IDs.  The glibc	setre-
       suid() and setresgid() wrapper functions	transparently  deal  with  the
       variations across kernel	versions.

SEE ALSO
       getresuid(2),  getuid(2),  setfsgid(2),	setfsuid(2),  setreuid(2), se-
       tuid(2),	capabilities(7), credentials(7), user_namespaces(7)

COLOPHON
       This page is part of release 3.74 of the	Linux  man-pages  project.   A
       description  of	the project, information about reporting bugs, and the
       latest	 version    of	  this	  page,	   can	   be	  found	    at
       http://www.kernel.org/doc/man-pages/.

Linux				  2014-09-21			  SETRESUID(2)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=setresgid&sektion=2&manpath=Debian+8.1.0>

home | help