from argparse import ArgumentParser
-drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'
-
# can set to True here, but also use the -d option
debug = False
fork_pid = os.fork()
- # capsh has a --user option starting with f14
- # so if only for f12 we need to fake this one
- #
- # capsh.c does essentially the following when invoked with --user:
- # pwd = getpwnam(user); ...
- # ngroups = MAX_GROUPS;
- # status = getgrouplist(user, pwd->pw_gid, groups, &ngroups); ...
- # status = setgroups(ngroups, groups); ...
- # status = setgid(pwd->pw_gid); ...
- # status = setuid(pwd->pw_uid); ...
- # however we cannot simulate that ourselves because if we did in this process then
- # capsh could not be allowed to mess with caps any more
-
def getuid (slicename):
import pwd
try:
return
if (fork_pid == 0):
- cap_arg = '--drop='+drop_capabilities
-
if (not args.root):
+ setns.drop_caps()
if (args.nosliceuid):
# we still want to drop capabilities, but don't want to switch UIDs
- exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login',]+args.command_to_run
+ exec_args = [arch,'/bin/sh','--login',]+args.command_to_run
else:
uid = getuid (slice_name)
if not uid:
print "lxcsu could not spot %s in /etc/passwd - exiting"%slice_name
exit(1)
- exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--uid=%s'%uid,'--','--login',]+args.command_to_run
+ exec_args = [arch,'/bin/sh','--uid=%s'%uid,'--login',]+args.command_to_run
# once we can drop f12, it would be nicer to instead go for
-# exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--user=%s'%slice_name,'--','--login',]+args.command_to_run
+# exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--user=%s'%slice_name,'--login',]+args.command_to_run
else:
- exec_args = [arch,'/usr/sbin/capsh','--','--login']+args.command_to_run
+ exec_args = [arch,'/bin/sh','--login']+args.command_to_run
os.environ['SHELL'] = '/bin/sh'
if os.path.exists('/etc/planetlab/lib/bind_public.so'):
#include <asm/unistd.h>
#include <sys/mount.h>
#include <errno.h>
+#include <sys/prctl.h>
+#include <linux/capability.h>
+
+static PyObject *
+drop_caps(PyObject *self, PyObject *args)
+{
+ unsigned int to_drop[128] = {CAP_NET_ADMIN,CAP_SYS_ADMIN,CAP_SYS_BOOT,CAP_MKNOD,CAP_MAC_ADMIN,CAP_SYS_MODULE};
+ unsigned int i;
+ for (i = 0;i<6;i++) {
+ if (prctl(PR_CAPBSET_DROP, to_drop[i], 0, 0, 0) == -1) {
+ perror("prctl");
+ return Py_BuildValue("i", 2);
+ }
+ }
+ return Py_BuildValue("i", 0);
+}
static PyObject *
proc_mount(PyObject *self, PyObject *args)
{"proc_mount", proc_mount, METH_VARARGS, "Mount a volume via the mount system call."},
{"proc_umount", proc_umount, METH_VARARGS, "Umount a volume via the umount system call."},
{"chcontext", chcontext, METH_VARARGS, "Switch into an lxc container."},
+ {"drop_caps", drop_caps, METH_VARARGS, "Drop dangerous capabilities."},
{"chfscontext", chfscontext, METH_VARARGS, "Switch into an lxc container."},
{NULL, NULL, 0, NULL}
};