| Message ID | 20210202162710.657398-7-mic@digikod.net (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Landlock LSM | expand |
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. > * @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
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."? > >> * @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
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
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). * @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);