shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-09 04:10:18 +09:00
Code Issues Packages Projects Releases Wiki Activity

userns: Don't allow unprivileged creation of gid mappings

Browse Source 
commit be7c6dba23 upstream.

As any gid mapping will allow and must allow for backwards
compatibility dropping groups don't allow any gid mappings to be
established without CAP_SETGID in the parent user namespace.

For a small class of applications this change breaks userspace
and removes useful functionality.  This small class of applications
includes tools/testing/selftests/mount/unprivilged-remount-test.c

Most of the removed functionality will be added back with the addition
of a one way knob to disable setgroups.  Once setgroups is disabled
setting the gid_map becomes as safe as setting the uid_map.

For more common applications that set the uid_map and the gid_map
with privilege this change will have no affect.

This is part of a fix for CVE-2014-8989.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eric W. Biederman
2014-12-05 18:14:19 -06:00
committed by Greg Kroah-Hartman
parent fc9b65e3d7
commit ba0922adbd
1 changed files with 0 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
kernel/user_namespace.c
View File

@@ -810,11 +810,6 @@ static bool new_idmap_permitted(const struct file *file,
if (uid_eq(uid, file->f_cred->fsuid))
return true;
}
else if (cap_setid == CAP_SETGID) {
kgid_t gid = make_kgid(ns->parent, id);
if (gid_eq(gid, file->f_cred->fsgid))
return true;
}
}
/* Allow anyone to set a mapping that doesn't require privilege */