From patchwork Tue Feb 11 16:57:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 11375947 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C372A17F0 for ; Tue, 11 Feb 2020 16:59:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A19582168B for ; Tue, 11 Feb 2020 16:59:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731024AbgBKQ7r (ORCPT ); Tue, 11 Feb 2020 11:59:47 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:53492 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730986AbgBKQ7p (ORCPT ); Tue, 11 Feb 2020 11:59:45 -0500 Received: from ip5f5bf7ec.dynamic.kabel-deutschland.de ([95.91.247.236] helo=wittgenstein.fritz.box) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1j1Ysf-00014T-4B; Tue, 11 Feb 2020 16:59:25 +0000 From: Christian Brauner To: =?utf-8?q?St=C3=A9phane_Graber?= , "Eric W. Biederman" , Aleksa Sarai , Jann Horn Cc: smbarber@chromium.org, Alexander Viro , Alexey Dobriyan , Serge Hallyn , James Morris , Kees Cook , Jonathan Corbet , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, containers@lists.linux-foundation.org, linux-security-module@vger.kernel.org, linux-api@vger.kernel.org, Christian Brauner Subject: [PATCH 19/24] sys:__sys_setgid(): handle fsid mappings Date: Tue, 11 Feb 2020 17:57:48 +0100 Message-Id: <20200211165753.356508-20-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200211165753.356508-1-christian.brauner@ubuntu.com> References: <20200211165753.356508-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Switch setgid() to lookup fsids in the fsid mappings. If no fsid mappings are setup the behavior is unchanged, i.e. fsids are looked up in the id mappings. Signed-off-by: Christian Brauner --- kernel/sys.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/kernel/sys.c b/kernel/sys.c index afaec8d46bc5..11f41e0a4974 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -416,24 +416,31 @@ long __sys_setgid(gid_t gid) const struct cred *old; struct cred *new; int retval; - kgid_t kgid; + kgid_t kgid, kfsgid; kgid = make_kgid(ns, gid); if (!gid_valid(kgid)) return -EINVAL; + kfsgid = make_kfsgid(ns, gid); + if (!gid_valid(kfsgid)) + return -EINVAL; + new = prepare_creds(); if (!new) return -ENOMEM; old = current_cred(); retval = -EPERM; - if (ns_capable(old->user_ns, CAP_SETGID)) - new->gid = new->egid = new->sgid = new->fsgid = kgid; - else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid)) - new->egid = new->fsgid = kgid; - else + if (ns_capable(old->user_ns, CAP_SETGID)) { + new->gid = new->egid = new->sgid = kgid; + new->fsgid = kfsgid; + } else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid)) { + new->egid = kgid; + new->fsgid = kfsgid; + } else { goto error; + } return commit_creds(new);