Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753766AbbGOTrd (ORCPT ); Wed, 15 Jul 2015 15:47:33 -0400 Received: from mail-oi0-f45.google.com ([209.85.218.45]:34694 "EHLO mail-oi0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753666AbbGOTrX (ORCPT ); Wed, 15 Jul 2015 15:47:23 -0400 From: Seth Forshee To: "Eric W. Biederman" , Alexander Viro , Paul Moore , Stephen Smalley , Eric Paris Cc: Serge Hallyn , Andy Lutomirski , Seth Forshee , linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, linux-kernel@vger.kernel.org, James Morris , "Serge E. Hallyn" Subject: [PATCH 6/7] selinux: Ignore security labels on user namespace mounts Date: Wed, 15 Jul 2015 14:46:07 -0500 Message-Id: <1436989569-69582-7-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1436989569-69582-1-git-send-email-seth.forshee@canonical.com> References: <1436989569-69582-1-git-send-email-seth.forshee@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1676 Lines: 52 Unprivileged users should not be able to supply security labels in filesystems, nor should they be able to supply security contexts in unprivileged mounts. For any mount where s_user_ns is not init_user_ns, force the use of SECURITY_FS_USE_NONE behavior and return EPERM if any contexts are supplied in the mount options. Signed-off-by: Seth Forshee --- security/selinux/hooks.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 459e71ddbc9d..eeb71e45ab82 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -732,6 +732,19 @@ static int selinux_set_mnt_opts(struct super_block *sb, !strcmp(sb->s_type->name, "pstore")) sbsec->flags |= SE_SBGENFS; + /* + * If this is a user namespace mount, no contexts are allowed + * on the command line and security labels mus be ignored. + */ + if (sb->s_user_ns != &init_user_ns) { + if (context_sid || fscontext_sid || rootcontext_sid || + defcontext_sid) + return -EPERM; + sbsec->behavior = SECURITY_FS_USE_NONE; + goto out_set_opts; + } + + if (!sbsec->behavior) { /* * Determine the labeling behavior to use for this @@ -813,6 +826,7 @@ static int selinux_set_mnt_opts(struct super_block *sb, sbsec->def_sid = defcontext_sid; } +out_set_opts: rc = sb_finish_set_opts(sb); out: mutex_unlock(&sbsec->lock); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/