user namespaces: require cap_set{ug}id for CLONE_NEWUSER

While ideally CLONE_NEWUSER will eventually require no
privilege, the required permission checks are currently
not there.  As a result, CLONE_NEWUSER has the same effect
as a setuid(0)+setgroups(1,"0").  While we already require
CAP_SYS_ADMIN, requiring CAP_SETUID and CAP_SETGID seems
appropriate.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Serge E. Hallyn 2008-12-03 13:17:33 -06:00 committed by James Morris
parent c37bbb0fdc
commit 7657d90497

View file

@ -1344,7 +1344,8 @@ long do_fork(unsigned long clone_flags,
/* hopefully this check will go away when userns support is
* complete
*/
if (!capable(CAP_SYS_ADMIN))
if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) ||
!capable(CAP_SETGID))
return -EPERM;
}