Reviewed-by: Sarthak Kukreti <sarthakkukr...@chromium.org>
On Wed, Sep 7, 2022 at 1:31 PM Matthias Kaehlcke <m...@chromium.org> wrote:
>
> Verity targets can be configured to ignore corrupted data blocks.
> LoadPin must only trust verity targets that are configured to
> perform some kind of enforcement when data corruption is detected,
> like returning an error, restarting the system or triggering a
> panic.
>
> Fixes: b6c1c5745ccc ("dm: Add verity helpers for LoadPin")
> Reported-by: Sarthak Kukreti <sarthakkukr...@chromium.org>
> Signed-off-by: Matthias Kaehlcke <m...@chromium.org>
> ---
>
> drivers/md/dm-verity-loadpin.c | 8 ++++++++
> drivers/md/dm-verity-target.c | 16 ++++++++++++++++
> drivers/md/dm-verity.h | 1 +
> 3 files changed, 25 insertions(+)
>
> diff --git a/drivers/md/dm-verity-loadpin.c b/drivers/md/dm-verity-loadpin.c
> index 387ec43aef72..4f78cc55c251 100644
> --- a/drivers/md/dm-verity-loadpin.c
> +++ b/drivers/md/dm-verity-loadpin.c
> @@ -14,6 +14,7 @@ LIST_HEAD(dm_verity_loadpin_trusted_root_digests);
>
> static bool is_trusted_verity_target(struct dm_target *ti)
> {
> + int verity_mode;
> u8 *root_digest;
> unsigned int digest_size;
> struct dm_verity_loadpin_trusted_root_digest *trd;
> @@ -22,6 +23,13 @@ static bool is_trusted_verity_target(struct dm_target *ti)
> if (!dm_is_verity_target(ti))
> return false;
>
> + verity_mode = dm_verity_get_mode(ti);
> +
> + if ((verity_mode != DM_VERITY_MODE_EIO) &&
> + (verity_mode != DM_VERITY_MODE_RESTART) &&
> + (verity_mode != DM_VERITY_MODE_PANIC))
> + return false;
> +
> if (dm_verity_get_root_digest(ti, &root_digest, &digest_size))
> return false;
>
> diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
> index 94b6cb599db4..8a00cc42e498 100644
> --- a/drivers/md/dm-verity-target.c
> +++ b/drivers/md/dm-verity-target.c
> @@ -1446,6 +1446,22 @@ bool dm_is_verity_target(struct dm_target *ti)
> return ti->type->module == THIS_MODULE;
> }
>
> +/*
> + * Get the verity mode (error behavior) of a verity target.
> + *
> + * Returns the verity mode of the target, or -EINVAL if 'ti' is not a verity
> + * target.
> + */
> +int dm_verity_get_mode(struct dm_target *ti)
nit: It might be cleaner to combine the mode check above into this
function; eg. dm_verity_is_enforcing_mode(struct dm_target *ti).
> +{
> + struct dm_verity *v = ti->private;
> +
> + if (!dm_is_verity_target(ti))
> + return -EINVAL;
> +
> + return v->mode;
> +}
> +
> /*
> * Get the root digest of a verity target.
> *
> diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h
> index 45455de1b4bc..98f306ec6a33 100644
> --- a/drivers/md/dm-verity.h
> +++ b/drivers/md/dm-verity.h
> @@ -134,6 +134,7 @@ extern int verity_hash_for_block(struct dm_verity *v,
> struct dm_verity_io *io,
> sector_t block, u8 *digest, bool *is_zero);
>
> extern bool dm_is_verity_target(struct dm_target *ti);
> +extern int dm_verity_get_mode(struct dm_target *ti);
> extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest,
> unsigned int *digest_size);
>
> --
> 2.37.2.789.g6183377224-goog
>
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