From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 695A4C25B0E for ; Tue, 16 Aug 2022 15:47:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235323AbiHPPrx (ORCPT ); Tue, 16 Aug 2022 11:47:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229607AbiHPPra (ORCPT ); Tue, 16 Aug 2022 11:47:30 -0400 Received: from us-smtp-delivery-44.mimecast.com (us-smtp-delivery-44.mimecast.com [205.139.111.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E325545063 for ; Tue, 16 Aug 2022 08:44:01 -0700 (PDT) Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-654-tOBIA_5-OvaFM29i4NZM_g-1; Tue, 16 Aug 2022 11:43:55 -0400 X-MC-Unique: tOBIA_5-OvaFM29i4NZM_g-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 168D5811E76; Tue, 16 Aug 2022 15:43:55 +0000 (UTC) Received: from comp-core-i7-2640m-0182e6.redhat.com (unknown [10.40.208.6]) by smtp.corp.redhat.com (Postfix) with ESMTP id AAEB52166B26; Tue, 16 Aug 2022 15:43:53 +0000 (UTC) From: Alexey Gladkov To: LKML , Linux Containers Cc: Andrew Morton , Christian Brauner , "Eric W . Biederman" , Kees Cook , Manfred Spraul Subject: [PATCH v1 2/3] sysctl: Allow to change limits for posix messages queues Date: Tue, 16 Aug 2022 17:42:44 +0200 Message-Id: <0e095acd72553868925b116d778357eb019796a2.1660664258.git.legion@kernel.org> In-Reply-To: References: <87wnc1i2wo.fsf@email.froward.int.ebiederm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org All parameters of posix messages queues (queues_max/msg_max/msgsize_max) end up being limited by RLIMIT_MSGQUEUE. The code in mqueue_get_inode is where that limiting happens. The RLIMIT_MSGQUEUE is bound to the user namespace and is counted hierarchically. We can allow root in the user namespace to modify the posix messages queues parameters. Signed-off-by: Alexey Gladkov --- ipc/mq_sysctl.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/ipc/mq_sysctl.c b/ipc/mq_sysctl.c index fbf6a8b93a26..39dcf086b7c2 100644 --- a/ipc/mq_sysctl.c +++ b/ipc/mq_sysctl.c @@ -12,6 +12,7 @@ #include #include #include +#include static int msg_max_limit_min = MIN_MSGMAX; static int msg_max_limit_max = HARD_MSGMAX; @@ -76,8 +77,43 @@ static int set_is_seen(struct ctl_table_set *set) return ¤t->nsproxy->ipc_ns->mq_set == set; } +static int mq_permissions(struct ctl_table_header *head, struct ctl_table *table) +{ + struct ipc_namespace *ns = + container_of(head->set, struct ipc_namespace, mq_set); + + if (ns->user_ns != &init_user_ns) { + kuid_t ns_root_uid = make_kuid(ns->user_ns, 0); + kgid_t ns_root_gid = make_kgid(ns->user_ns, 0); + + if (uid_valid(ns_root_uid) && uid_eq(current_euid(), ns_root_uid)) + return table->mode >> 6; + + if (gid_valid(ns_root_gid) && in_egroup_p(ns_root_gid)) + return table->mode >> 3; + } + + return table->mode; +} + +static void mq_set_ownership(struct ctl_table_header *head, + struct ctl_table *table, + kuid_t *uid, kgid_t *gid) +{ + struct ipc_namespace *ns = + container_of(head->set, struct ipc_namespace, mq_set); + + kuid_t ns_root_uid = make_kuid(ns->user_ns, 0); + kgid_t ns_root_gid = make_kgid(ns->user_ns, 0); + + *uid = uid_valid(ns_root_uid) ? ns_root_uid : GLOBAL_ROOT_UID; + *gid = gid_valid(ns_root_gid) ? ns_root_gid : GLOBAL_ROOT_GID; +} + static struct ctl_table_root set_root = { .lookup = set_lookup, + .permissions = mq_permissions, + .set_ownership = mq_set_ownership, }; bool setup_mq_sysctls(struct ipc_namespace *ns) -- 2.33.4