diff mbox series

[RFC,v11,12/19] dm: add finalize hook to target_type

Message ID 1696457386-3010-13-git-send-email-wufan@linux.microsoft.com
State New
Headers
Series Integrity Policy Enforcement LSM (IPE) |

Commit Message

Fan Wu Oct. 4, 2023, 10:09 p.m. UTC 
  This patch adds a target finalize hook.

The hook is triggered just before activating an inactive table of a
mapped device. If it returns an error the __bind get cancelled.

The dm-verity target will use this hook to attach the dm-verity's
roothash metadata to the block_device struct of the mapped device.

Signed-off-by: Fan Wu <wufan@linux.microsoft.com>

---
v1-v10:
  + Not present
---
 drivers/md/dm.c               | 12 ++++++++++++
 include/linux/device-mapper.h |  7 +++++++
 2 files changed, 19 insertions(+)

Comments

Paul Moore Oct. 24, 2023, 3:52 a.m. UTC | #1 
On Oct  4, 2023 Fan Wu <wufan@linux.microsoft.com> wrote:
> 
> This patch adds a target finalize hook.
> 
> The hook is triggered just before activating an inactive table of a
> mapped device. If it returns an error the __bind get cancelled.
> 
> The dm-verity target will use this hook to attach the dm-verity's
> roothash metadata to the block_device struct of the mapped device.
> 
> Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
> ---
> v1-v10:
>   + Not present
> ---
>  drivers/md/dm.c               | 12 ++++++++++++
>  include/linux/device-mapper.h |  7 +++++++
>  2 files changed, 19 insertions(+)

We need an ACK and confirmation from Alasdair and/or Mike that this
is the right approach.

> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 64a1f306c96c..3be9cc35306d 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -2239,6 +2239,18 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
>  		goto out;
>  	}
>  
> +	for (unsigned int i = 0; i < t->num_targets; i++) {
> +		struct dm_target *ti = dm_table_get_target(t, i);
> +
> +		if (ti->type->finalize) {
> +			ret = ti->type->finalize(ti);
> +			if (ret) {
> +				old_map = ERR_PTR(ret);
> +				goto out;
> +			}
> +		}
> +	}
> +
>  	old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
>  	rcu_assign_pointer(md->map, (void *)t);
>  	md->immutable_target_type = dm_table_get_immutable_target_type(t);
> diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
> index 69d0435c7ebb..4040e84a8ec7 100644
> --- a/include/linux/device-mapper.h
> +++ b/include/linux/device-mapper.h
> @@ -160,6 +160,12 @@ typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
>   */
>  typedef size_t (*dm_dax_recovery_write_fn)(struct dm_target *ti, pgoff_t pgoff,
>  		void *addr, size_t bytes, struct iov_iter *i);
> +/*
> + * Returns:
> + *  < 0 : error
> + *  = 0 : success
> + */
> +typedef int (*dm_finalize_fn) (struct dm_target *target);
>  
>  void dm_error(const char *message);
>  
> @@ -209,6 +215,7 @@ struct target_type {
>  	dm_dax_direct_access_fn direct_access;
>  	dm_dax_zero_page_range_fn dax_zero_page_range;
>  	dm_dax_recovery_write_fn dax_recovery_write;
> +	dm_finalize_fn finalize;
>  
>  	/* For internal device-mapper use. */
>  	struct list_head list;
> -- 
> 2.25.1

--
paul-moore.com
Paul Moore Nov. 2, 2023, 12:41 a.m. UTC | #2 
On Mon, Oct 23, 2023 at 11:52 PM Paul Moore <paul@paul-moore.com> wrote:
> On Oct  4, 2023 Fan Wu <wufan@linux.microsoft.com> wrote:
> >
> > This patch adds a target finalize hook.
> >
> > The hook is triggered just before activating an inactive table of a
> > mapped device. If it returns an error the __bind get cancelled.
> >
> > The dm-verity target will use this hook to attach the dm-verity's
> > roothash metadata to the block_device struct of the mapped device.
> >
> > Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
> > ---
> > v1-v10:
> >   + Not present
> > ---
> >  drivers/md/dm.c               | 12 ++++++++++++
> >  include/linux/device-mapper.h |  7 +++++++
> >  2 files changed, 19 insertions(+)
>
> We need an ACK and confirmation from Alasdair and/or Mike that this
> is the right approach.

A gentle ping with a reminder ...

For reference, the full patchset can be found on lore at the link below:

https://lore.kernel.org/linux-security-module/1696457386-3010-1-git-send-email-wufan@linux.microsoft.com/

> > diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> > index 64a1f306c96c..3be9cc35306d 100644
> > --- a/drivers/md/dm.c
> > +++ b/drivers/md/dm.c
> > @@ -2239,6 +2239,18 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
> >               goto out;
> >       }
> >
> > +     for (unsigned int i = 0; i < t->num_targets; i++) {
> > +             struct dm_target *ti = dm_table_get_target(t, i);
> > +
> > +             if (ti->type->finalize) {
> > +                     ret = ti->type->finalize(ti);
> > +                     if (ret) {
> > +                             old_map = ERR_PTR(ret);
> > +                             goto out;
> > +                     }
> > +             }
> > +     }
> > +
> >       old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
> >       rcu_assign_pointer(md->map, (void *)t);
> >       md->immutable_target_type = dm_table_get_immutable_target_type(t);
> > diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
> > index 69d0435c7ebb..4040e84a8ec7 100644
> > --- a/include/linux/device-mapper.h
> > +++ b/include/linux/device-mapper.h
> > @@ -160,6 +160,12 @@ typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
> >   */
> >  typedef size_t (*dm_dax_recovery_write_fn)(struct dm_target *ti, pgoff_t pgoff,
> >               void *addr, size_t bytes, struct iov_iter *i);
> > +/*
> > + * Returns:
> > + *  < 0 : error
> > + *  = 0 : success
> > + */
> > +typedef int (*dm_finalize_fn) (struct dm_target *target);
> >
> >  void dm_error(const char *message);
> >
> > @@ -209,6 +215,7 @@ struct target_type {
> >       dm_dax_direct_access_fn direct_access;
> >       dm_dax_zero_page_range_fn dax_zero_page_range;
> >       dm_dax_recovery_write_fn dax_recovery_write;
> > +     dm_finalize_fn finalize;
> >
> >       /* For internal device-mapper use. */
> >       struct list_head list;
> > --
> > 2.25.1
diff mbox series

Patch

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 64a1f306c96c..3be9cc35306d 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2239,6 +2239,18 @@  static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
 		goto out;
 	}
 
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+
+		if (ti->type->finalize) {
+			ret = ti->type->finalize(ti);
+			if (ret) {
+				old_map = ERR_PTR(ret);
+				goto out;
+			}
+		}
+	}
+
 	old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
 	rcu_assign_pointer(md->map, (void *)t);
 	md->immutable_target_type = dm_table_get_immutable_target_type(t);
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 69d0435c7ebb..4040e84a8ec7 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -160,6 +160,12 @@  typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
  */
 typedef size_t (*dm_dax_recovery_write_fn)(struct dm_target *ti, pgoff_t pgoff,
 		void *addr, size_t bytes, struct iov_iter *i);
+/*
+ * Returns:
+ *  < 0 : error
+ *  = 0 : success
+ */
+typedef int (*dm_finalize_fn) (struct dm_target *target);
 
 void dm_error(const char *message);
 
@@ -209,6 +215,7 @@  struct target_type {
 	dm_dax_direct_access_fn direct_access;
 	dm_dax_zero_page_range_fn dax_zero_page_range;
 	dm_dax_recovery_write_fn dax_recovery_write;
+	dm_finalize_fn finalize;
 
 	/* For internal device-mapper use. */
 	struct list_head list;