From patchwork Thu Dec 10 22:16:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: James Morris X-Patchwork-Id: 11966851 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-23.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, INCLUDES_PULL_REQUEST,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE, SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3BA8C3526B for ; Thu, 10 Dec 2020 23:08:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC6BF23BA7 for ; Thu, 10 Dec 2020 23:08:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394167AbgLJWbW (ORCPT ); Thu, 10 Dec 2020 17:31:22 -0500 Received: from namei.org ([65.99.196.166]:60274 "EHLO mail.namei.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405118AbgLJWYm (ORCPT ); Thu, 10 Dec 2020 17:24:42 -0500 Received: from localhost (localhost [127.0.0.1]) by mail.namei.org (Postfix) with ESMTPS id 28F6DDBF; Thu, 10 Dec 2020 22:16:53 +0000 (UTC) Date: Fri, 11 Dec 2020 09:16:53 +1100 (AEDT) From: James Morris To: Linus Torvalds cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, "Serge E. Hallyn" Subject: [SECURITY] fix namespaced fscaps when !CONFIG_SECURITY Message-ID: MIME-Version: 1.0 Precedence: bulk List-ID: Please apply this config bugfix from Serge Hallyn. The following changes since commit bbf5c979011a099af5dc76498918ed7df445635b: Linux 5.9 (2020-10-11 14:15:50 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git tags/fixes-v5.10a for you to fetch changes up to ed9b25d1970a4787ac6a39c2091e63b127ecbfc1: [SECURITY] fix namespaced fscaps when !CONFIG_SECURITY (2020-12-04 16:24:11 -0800) ---------------------------------------------------------------- Fix namespaced fscaps when !CONFIG_SECURITY from Serge Hallyn. ---------------------------------------------------------------- Serge Hallyn (1): [SECURITY] fix namespaced fscaps when !CONFIG_SECURITY include/linux/security.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) commit ed9b25d1970a4787ac6a39c2091e63b127ecbfc1 Author: Serge Hallyn Date: Sun Nov 15 21:55:31 2020 -0600 [SECURITY] fix namespaced fscaps when !CONFIG_SECURITY Namespaced file capabilities were introduced in 8db6c34f1dbc . When userspace reads an xattr for a namespaced capability, a virtualized representation of it is returned if the caller is in a user namespace owned by the capability's owning rootid. The function which performs this virtualization was not hooked up if CONFIG_SECURITY=n. Therefore in that case the original xattr was shown instead of the virtualized one. To test this using libcap-bin (*1), $ v=$(mktemp) $ unshare -Ur setcap cap_sys_admin-eip $v $ unshare -Ur setcap -v cap_sys_admin-eip $v /tmp/tmp.lSiIFRvt8Y: OK "setcap -v" verifies the values instead of setting them, and will check whether the rootid value is set. Therefore, with this bug un-fixed, and with CONFIG_SECURITY=n, setcap -v will fail: $ v=$(mktemp) $ unshare -Ur setcap cap_sys_admin=eip $v $ unshare -Ur setcap -v cap_sys_admin=eip $v nsowner[got=1000, want=0],/tmp/tmp.HHDiOOl9fY differs in [] Fix this bug by calling cap_inode_getsecurity() in security_inode_getsecurity() instead of returning -EOPNOTSUPP, when CONFIG_SECURITY=n. *1 - note, if libcap is too old for getcap to have the '-n' option, then use verify-caps instead. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=209689 Cc: Hervé Guillemet Acked-by: Casey Schaufler Signed-off-by: Serge Hallyn Signed-off-by: Andrew G. Morgan Signed-off-by: James Morris diff --git a/include/linux/security.h b/include/linux/security.h index 0a0a03b36a3b..2befc0a25eb3 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -864,7 +864,7 @@ static inline int security_inode_killpriv(struct dentry *dentry) static inline int security_inode_getsecurity(struct inode *inode, const char *name, void **buffer, bool alloc) { - return -EOPNOTSUPP; + return cap_inode_getsecurity(inode, name, buffer, alloc); } static inline int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags)