diff -up util-linux-2.23.2/sys-utils/nsenter.1.kzak util-linux-2.23.2/sys-utils/nsenter.1
--- util-linux-2.23.2/sys-utils/nsenter.1.kzak	2014-03-12 12:39:19.283577293 +0100
+++ util-linux-2.23.2/sys-utils/nsenter.1	2014-03-12 12:42:08.930336415 +0100
@@ -47,12 +47,7 @@ flag).
 will fork by default if changing the PID namespace, so that the new program
 and its children share the same PID namespace and are visible to each other.
 If \-\-no\-fork is used, the new program will be exec'ed without forking.
-.TP
-.B user namespace
-process will have distinct set of UIDs, GIDs and capabilities
-.RB ( CLONE_\:NEWUSER
-flag).
-.TP
+.PP
 See the
 .BR clone (2)
 for exact semantics of the flags.
@@ -88,9 +83,6 @@ the network namespace
 /proc/\fIpid\fR/ns/pid
 the PID namespace
 .TP
-/proc/\fIpid\fR/ns/user
-the user namespace
-.TP
 /proc/\fIpid\fR/root
 the root directory
 .TP
@@ -124,11 +116,6 @@ Enter the PID namespace.  If no file is
 the target process.  If file is specified enter the PID namespace specified by
 file.
 .TP
-\fB\-U\fR, \fB\-\-user\fR [\fIfile\fR]
-Enter the user namespace.  If no file is specified enter the user namespace of
-the target process.  If file is specified enter the user namespace specified by
-file.
-.TP
 \fB\-r\fR, \fB\-\-root\fR [\fIdirectory\fR]
 Set the root directory.  If no directory is specified set the root directory to
 the root directory of the target process.  If directory is specified set the
diff -up util-linux-2.23.2/sys-utils/nsenter.c.kzak util-linux-2.23.2/sys-utils/nsenter.c
--- util-linux-2.23.2/sys-utils/nsenter.c.kzak	2014-03-12 12:39:10.402485179 +0100
+++ util-linux-2.23.2/sys-utils/nsenter.c	2014-03-12 12:44:07.986570461 +0100
@@ -42,12 +42,7 @@ static struct namespace_file {
 	int fd;
 } namespace_files[] = {
 	/* Careful the order is significant in this array.
-	 *
-	 * The user namespace comes first, so that it is entered
-	 * first.  This gives an unprivileged user the potential to
-	 * enter the other namespaces.
 	 */
-	{ .nstype = CLONE_NEWUSER, .name = "ns/user", .fd = -1 },
 	{ .nstype = CLONE_NEWIPC,  .name = "ns/ipc",  .fd = -1 },
 	{ .nstype = CLONE_NEWUTS,  .name = "ns/uts",  .fd = -1 },
 	{ .nstype = CLONE_NEWNET,  .name = "ns/net",  .fd = -1 },
@@ -71,7 +66,6 @@ static void usage(int status)
 	fputs(_(" -i, --ipc   [=<file>]  enter System V IPC namespace\n"), out);
 	fputs(_(" -n, --net   [=<file>]  enter network namespace\n"), out);
 	fputs(_(" -p, --pid   [=<file>]  enter pid namespace\n"), out);
-	fputs(_(" -U, --user  [=<file>]  enter user namespace\n"), out);
 	fputs(_(" -r, --root  [=<dir>]   set the root directory\n"), out);
 	fputs(_(" -w, --wd    [=<dir>]   set the working directory\n"), out);
 	fputs(_(" -F, --no-fork          do not fork before exec'ing <program>\n"), out);
@@ -168,7 +162,6 @@ int main(int argc, char *argv[])
 		{ "ipc", optional_argument, NULL, 'i' },
 		{ "net", optional_argument, NULL, 'n' },
 		{ "pid", optional_argument, NULL, 'p' },
-		{ "user", optional_argument, NULL, 'U' },
 		{ "root", optional_argument, NULL, 'r' },
 		{ "wd", optional_argument, NULL, 'w' },
 		{ "no-fork", no_argument, NULL, 'F' },
@@ -186,7 +179,7 @@ int main(int argc, char *argv[])
 	atexit(close_stdout);
 
 	while ((c =
-		getopt_long(argc, argv, "hVt:m::u::i::n::p::U::r::w::F",
+		getopt_long(argc, argv, "hVt:m::u::i::n::p::r::w::F",
 			    longopts, NULL)) != -1) {
 		switch (c) {
 		case 'h':
@@ -228,12 +221,6 @@ int main(int argc, char *argv[])
 			else
 				namespaces |= CLONE_NEWPID;
 			break;
-		case 'U':
-			if (optarg)
-				open_namespace_fd(CLONE_NEWUSER, optarg);
-			else
-				namespaces |= CLONE_NEWUSER;
-			break;
 		case 'F':
 			do_fork = 0;
 			break;
diff -up util-linux-2.23.2/sys-utils/unshare.1.kzak util-linux-2.23.2/sys-utils/unshare.1
--- util-linux-2.23.2/sys-utils/unshare.1.kzak	2014-03-12 12:39:41.367806340 +0100
+++ util-linux-2.23.2/sys-utils/unshare.1	2014-03-12 12:40:25.186260760 +0100
@@ -34,9 +34,6 @@ etc. (\fBCLONE_NEWNET\fP flag).
 .BR "pid namespace"
 children will have a distinct set of pid to process mappings than their parent.
 (\fBCLONE_NEWPID\fP flag).
-.TP
-.BR "user namespace"
-process will have distinct set of uids, gids and capabilities. (\fBCLONE_NEWUSER\fP flag).
 .PP
 See the \fBclone\fR(2) for exact semantics of the flags.
 .SH OPTIONS
@@ -58,9 +55,6 @@ Unshare the network namespace.
 .TP
 .BR \-p , " \-\-pid"
 Unshare the pid namespace.
-.TP
-.BR \-U , " \-\-user"
-Unshare the user namespace.
 .SH SEE ALSO
 .BR unshare (2),
 .BR clone (2)
diff -up util-linux-2.23.2/sys-utils/unshare.c.kzak util-linux-2.23.2/sys-utils/unshare.c
--- util-linux-2.23.2/sys-utils/unshare.c.kzak	2014-03-12 12:39:46.385858383 +0100
+++ util-linux-2.23.2/sys-utils/unshare.c	2014-03-12 12:44:49.955005384 +0100
@@ -45,7 +45,6 @@ static void usage(int status)
 	fputs(_(" -i, --ipc         unshare System V IPC namespace\n"), out);
 	fputs(_(" -n, --net         unshare network namespace\n"), out);
 	fputs(_(" -p, --pid         unshare pid namespace\n"), out);
-	fputs(_(" -U, --user        unshare user namespace\n"), out);
 
 	fputs(USAGE_SEPARATOR, out);
 	fputs(USAGE_HELP, out);
@@ -65,7 +64,6 @@ int main(int argc, char *argv[])
 		{ "ipc", no_argument, 0, 'i' },
 		{ "net", no_argument, 0, 'n' },
 		{ "pid", no_argument, 0, 'p' },
-		{ "user", no_argument, 0, 'U' },
 		{ NULL, 0, 0, 0 }
 	};
 
@@ -78,7 +76,7 @@ int main(int argc, char *argv[])
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	while ((c = getopt_long(argc, argv, "hVmuinpU", longopts, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "hVmuinp", longopts, NULL)) != -1) {
 		switch (c) {
 		case 'h':
 			usage(EXIT_SUCCESS);
@@ -100,9 +98,6 @@ int main(int argc, char *argv[])
 		case 'p':
 			unshare_flags |= CLONE_NEWPID;
 			break;
-		case 'U':
-			unshare_flags |= CLONE_NEWUSER;
-			break;
 		default:
 			usage(EXIT_FAILURE);
 		}