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 X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 4960AC4321A for ; Fri, 5 Feb 2021 23:13:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2733B64FF6 for ; Fri, 5 Feb 2021 23:13:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231891AbhBEXMB (ORCPT ); Fri, 5 Feb 2021 18:12:01 -0500 Received: from smtp-bc08.mail.infomaniak.ch ([45.157.188.8]:35753 "EHLO smtp-bc08.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232653AbhBEObV (ORCPT ); Fri, 5 Feb 2021 09:31:21 -0500 Received: from smtp-3-0001.mail.infomaniak.ch (unknown [10.4.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DXJRw6S0qzMqPtr; Fri, 5 Feb 2021 15:57:32 +0100 (CET) Received: from ns3096276.ip-94-23-54.eu (unknown [23.97.221.149]) by smtp-3-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4DXJRs4xvlzlh8TC; Fri, 5 Feb 2021 15:57:29 +0100 (CET) Subject: Re: [PATCH v28 06/12] fs,security: Add sb_delete hook To: "Serge E. Hallyn" Cc: James Morris , Jann Horn , Al Viro , Andrew Morton , Andy Lutomirski , Anton Ivanov , Arnd Bergmann , Casey Schaufler , Jeff Dike , Jonathan Corbet , Kees Cook , Michael Kerrisk , Richard Weinberger , Shuah Khan , Vincent Dagonneau , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-security-module@vger.kernel.org, x86@kernel.org, =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= References: <20210202162710.657398-1-mic@digikod.net> <20210202162710.657398-7-mic@digikod.net> <20210205142143.GA18451@mail.hallyn.com> From: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= Message-ID: <92e6a8a6-19da-0b1f-c1cf-01dc0af61299@digikod.net> Date: Fri, 5 Feb 2021 15:57:37 +0100 User-Agent: MIME-Version: 1.0 In-Reply-To: <20210205142143.GA18451@mail.hallyn.com> Content-Type: text/plain; charset=iso-8859-15 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/02/2021 15:21, Serge E. Hallyn wrote: > On Tue, Feb 02, 2021 at 05:27:04PM +0100, Mickaël Salaün wrote: >> From: Mickaël Salaün >> >> The sb_delete security hook is called when shutting down a superblock, >> which may be useful to release kernel objects tied to the superblock's >> lifetime (e.g. inodes). >> >> This new hook is needed by Landlock to release (ephemerally) tagged >> struct inodes. This comes from the unprivileged nature of Landlock >> described in the next commit. >> >> Cc: Al Viro >> Cc: James Morris >> Cc: Kees Cook >> Cc: Serge E. Hallyn > > One note below, but > > Acked-by: Serge Hallyn > >> Signed-off-by: Mickaël Salaün >> Reviewed-by: Jann Horn >> --- >> >> Changes since v22: >> * Add Reviewed-by: Jann Horn >> >> Changes since v17: >> * Initial patch to replace the direct call to landlock_release_inodes() >> (requested by James Morris). >> https://lore.kernel.org/lkml/alpine.LRH.2.21.2005150536440.7929@namei.org/ >> --- >> fs/super.c | 1 + >> include/linux/lsm_hook_defs.h | 1 + >> include/linux/lsm_hooks.h | 2 ++ >> include/linux/security.h | 4 ++++ >> security/security.c | 5 +++++ >> 5 files changed, 13 insertions(+) >> >> diff --git a/fs/super.c b/fs/super.c >> index 2c6cdea2ab2d..c3c5178cde65 100644 >> --- a/fs/super.c >> +++ b/fs/super.c >> @@ -454,6 +454,7 @@ void generic_shutdown_super(struct super_block *sb) >> evict_inodes(sb); >> /* only nonzero refcount inodes can have marks */ >> fsnotify_sb_delete(sb); >> + security_sb_delete(sb); >> >> if (sb->s_dio_done_wq) { >> destroy_workqueue(sb->s_dio_done_wq); >> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h >> index 7aaa753b8608..32472b3849bc 100644 >> --- a/include/linux/lsm_hook_defs.h >> +++ b/include/linux/lsm_hook_defs.h >> @@ -59,6 +59,7 @@ LSM_HOOK(int, 0, fs_context_dup, struct fs_context *fc, >> LSM_HOOK(int, -ENOPARAM, fs_context_parse_param, struct fs_context *fc, >> struct fs_parameter *param) >> LSM_HOOK(int, 0, sb_alloc_security, struct super_block *sb) >> +LSM_HOOK(void, LSM_RET_VOID, sb_delete, struct super_block *sb) >> LSM_HOOK(void, LSM_RET_VOID, sb_free_security, struct super_block *sb) >> LSM_HOOK(void, LSM_RET_VOID, sb_free_mnt_opts, void *mnt_opts) >> LSM_HOOK(int, 0, sb_eat_lsm_opts, char *orig, void **mnt_opts) >> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h >> index 970106d98306..e339b201f79b 100644 >> --- a/include/linux/lsm_hooks.h >> +++ b/include/linux/lsm_hooks.h >> @@ -108,6 +108,8 @@ >> * allocated. >> * @sb contains the super_block structure to be modified. >> * Return 0 if operation was successful. >> + * @sb_delete: >> + * Release objects tied to a superblock (e.g. inodes). > > It's customary here to add the line detailing the @sb argument. What about "@sb contains the super_block structure being released."? > >> * @sb_free_security: >> * Deallocate and clear the sb->s_security field. >> * @sb contains the super_block structure to be modified. >> diff --git a/include/linux/security.h b/include/linux/security.h >> index c35ea0ffccd9..c41a94e29b62 100644 >> --- a/include/linux/security.h >> +++ b/include/linux/security.h >> @@ -288,6 +288,7 @@ void security_bprm_committed_creds(struct linux_binprm *bprm); >> int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc); >> int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param); >> int security_sb_alloc(struct super_block *sb); >> +void security_sb_delete(struct super_block *sb); >> void security_sb_free(struct super_block *sb); >> void security_free_mnt_opts(void **mnt_opts); >> int security_sb_eat_lsm_opts(char *options, void **mnt_opts); >> @@ -620,6 +621,9 @@ static inline int security_sb_alloc(struct super_block *sb) >> return 0; >> } >> >> +static inline void security_sb_delete(struct super_block *sb) >> +{ } >> + >> static inline void security_sb_free(struct super_block *sb) >> { } >> >> diff --git a/security/security.c b/security/security.c >> index 9f979d4afe6c..1b4a73b2549a 100644 >> --- a/security/security.c >> +++ b/security/security.c >> @@ -900,6 +900,11 @@ int security_sb_alloc(struct super_block *sb) >> return rc; >> } >> >> +void security_sb_delete(struct super_block *sb) >> +{ >> + call_void_hook(sb_delete, sb); >> +} >> + >> void security_sb_free(struct super_block *sb) >> { >> call_void_hook(sb_free_security, sb); >> -- >> 2.30.0