From patchwork Mon Mar 15 13:55:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 401401 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=-24.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 80862C433E6 for ; Mon, 15 Mar 2021 14:03:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 426D664F2F for ; Mon, 15 Mar 2021 14:03:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233517AbhCOOBy (ORCPT ); Mon, 15 Mar 2021 10:01:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:35904 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232814AbhCON75 (ORCPT ); Mon, 15 Mar 2021 09:59:57 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id CCE8064F18; Mon, 15 Mar 2021 13:59:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1615816767; bh=/Ddd2zPl42t0KPISs+Dxeg/qgBi4KA8gGxKbfY4SnUE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U7vyhzPXR1hXVWbOjatxr+DMmeLXQoxDH8GtB8xmIsVvdbxp7i0xhpesD0/SWc0tO CYd3Ut5fRIREZ/Mtx0on9OmieBEJf7D4rsfW9SsldTDlV0o+PWVIhqQC7H1vCkD7sM JTLTF+zng2i7DhnCQsUMFX3MKB23Nc7BiHNlA1UU= From: gregkh@linuxfoundation.org To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Eric W. Biederman" Subject: [PATCH 5.4 096/168] Revert 95ebabde382c ("capabilities: Dont allow writing ambiguous v3 file capabilities") Date: Mon, 15 Mar 2021 14:55:28 +0100 Message-Id: <20210315135553.525307621@linuxfoundation.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210315135550.333963635@linuxfoundation.org> References: <20210315135550.333963635@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Greg Kroah-Hartman From: Eric W. Biederman commit 3b0c2d3eaa83da259d7726192cf55a137769012f upstream. It turns out that there are in fact userspace implementations that care and this recent change caused a regression. https://github.com/containers/buildah/issues/3071 As the motivation for the original change was future development, and the impact is existing real world code just revert this change and allow the ambiguity in v3 file caps. Cc: stable@vger.kernel.org Fixes: 95ebabde382c ("capabilities: Don't allow writing ambiguous v3 file capabilities") Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman --- security/commoncap.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) --- a/security/commoncap.c +++ b/security/commoncap.c @@ -500,8 +500,7 @@ int cap_convert_nscap(struct dentry *den __u32 magic, nsmagic; struct inode *inode = d_backing_inode(dentry); struct user_namespace *task_ns = current_user_ns(), - *fs_ns = inode->i_sb->s_user_ns, - *ancestor; + *fs_ns = inode->i_sb->s_user_ns; kuid_t rootid; size_t newsize; @@ -524,15 +523,6 @@ int cap_convert_nscap(struct dentry *den if (nsrootid == -1) return -EINVAL; - /* - * Do not allow allow adding a v3 filesystem capability xattr - * if the rootid field is ambiguous. - */ - for (ancestor = task_ns->parent; ancestor; ancestor = ancestor->parent) { - if (from_kuid(ancestor, rootid) == 0) - return -EINVAL; - } - newsize = sizeof(struct vfs_ns_cap_data); nscap = kmalloc(newsize, GFP_ATOMIC); if (!nscap)