From: "Serge E. Hallyn" <serge@hallyn.com> To: "Mickaël Salaün" <mic@digikod.net> Cc: "Serge E. Hallyn" <serge@hallyn.com>, "James Morris" <jmorris@namei.org>, "Jann Horn" <jannh@google.com>, "Al Viro" <viro@zeniv.linux.org.uk>, "Andrew Morton" <akpm@linux-foundation.org>, "Andy Lutomirski" <luto@amacapital.net>, "Anton Ivanov" <anton.ivanov@cambridgegreys.com>, "Arnd Bergmann" <arnd@arndb.de>, "Casey Schaufler" <casey@schaufler-ca.com>, "Jeff Dike" <jdike@addtoit.com>, "Jonathan Corbet" <corbet@lwn.net>, "Kees Cook" <keescook@chromium.org>, "Michael Kerrisk" <mtk.manpages@gmail.com>, "Richard Weinberger" <richard@nod.at>, "Shuah Khan" <shuah@kernel.org>, "Vincent Dagonneau" <vincent.dagonneau@ssi.gouv.fr>, 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, "Mickaël Salaün" <mic@linux.microsoft.com> Subject: Re: [PATCH v28 06/12] fs,security: Add sb_delete hook Date: Sat, 6 Feb 2021 22:18:14 -0600 [thread overview] Message-ID: <20210207041814.GA7955@mail.hallyn.com> (raw) In-Reply-To: <92e6a8a6-19da-0b1f-c1cf-01dc0af61299@digikod.net> On Fri, Feb 05, 2021 at 03:57:37PM +0100, Mickaël Salaün wrote: > > 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 <mic@linux.microsoft.com> > >> > >> 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 <viro@zeniv.linux.org.uk> > >> Cc: James Morris <jmorris@namei.org> > >> Cc: Kees Cook <keescook@chromium.org> > >> Cc: Serge E. Hallyn <serge@hallyn.com> > > > > One note below, but > > > > Acked-by: Serge Hallyn <serge@hallyn.com> > > > >> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> > >> Reviewed-by: Jann Horn <jannh@google.com> > >> --- > >> > >> Changes since v22: > >> * Add Reviewed-by: Jann Horn <jannh@google.com> > >> > >> 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."? That's good. Thanks. > > > >> * @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
next prev parent reply other threads:[~2021-02-07 4:19 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-02 16:26 [PATCH v28 00/12] Landlock LSM Mickaël Salaün 2021-02-02 16:26 ` [PATCH v28 01/12] landlock: Add object management Mickaël Salaün 2021-02-03 14:21 ` Serge E. Hallyn 2021-02-03 15:27 ` Mickaël Salaün 2021-02-02 16:27 ` [PATCH v28 02/12] landlock: Add ruleset and domain management Mickaël Salaün 2021-02-04 3:30 ` Serge E. Hallyn 2021-02-02 16:27 ` [PATCH v28 03/12] landlock: Set up the security framework and manage credentials Mickaël Salaün 2021-02-04 3:46 ` Serge E. Hallyn 2021-02-02 16:27 ` [PATCH v28 04/12] landlock: Add ptrace restrictions Mickaël Salaün 2021-02-05 13:48 ` Serge E. Hallyn 2021-02-02 16:27 ` [PATCH v28 05/12] LSM: Infrastructure management of the superblock Mickaël Salaün 2021-02-05 14:17 ` Serge E. Hallyn 2021-02-05 16:51 ` Casey Schaufler 2021-02-05 16:51 ` Casey Schaufler 2021-02-02 16:27 ` [PATCH v28 06/12] fs,security: Add sb_delete hook Mickaël Salaün 2021-02-05 14:21 ` Serge E. Hallyn 2021-02-05 14:57 ` Mickaël Salaün 2021-02-07 4:18 ` Serge E. Hallyn [this message] 2021-02-02 16:27 ` [PATCH v28 07/12] landlock: Support filesystem access-control Mickaël Salaün 2021-02-10 19:36 ` Serge E. Hallyn 2021-02-10 20:17 ` Mickaël Salaün 2021-02-19 15:34 ` Serge E. Hallyn 2021-02-02 16:27 ` [PATCH v28 08/12] landlock: Add syscall implementations Mickaël Salaün 2021-02-03 15:04 ` Serge E. Hallyn 2021-02-02 16:27 ` [PATCH v28 09/12] arch: Wire up Landlock syscalls Mickaël Salaün 2021-02-02 16:27 ` [PATCH v28 10/12] selftests/landlock: Add user space tests Mickaël Salaün 2021-02-02 16:27 ` [PATCH v28 11/12] samples/landlock: Add a sandbox manager example Mickaël Salaün 2021-02-02 16:27 ` [PATCH v28 12/12] landlock: Add user and kernel documentation Mickaël Salaün
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