On 05/18/2017 12:47 PM, Gilad Ben-Yossef wrote:
> DM-Verity has an (undocumented) mode where no salt is used.
> This was never handled directly by the DM-Verity code, instead working due
> to the fact that calling crypto_shash_update() with a zero length data is
> an implicit noop.
>
> This is no longer the case now that we have switched to
> crypto_ahash_update(). Fix the issue by introducing an explicit handling
> of the no salt use case to DM-Verity.
>
> Signed-off-by: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
> Reported-by: Marian Csontos <mcsontos@xxxxxxxxxx>
> Fixes: d1ac3ff ("dm verity: switch to using asynchronous hash crypto API")
> CC: Milan Broz <gmazyland@xxxxxxxxx>
Tested-by: Milan Broz <gmazyland@xxxxxxxxx>
Thanks for quick fix!
Mike: this must go to 4.12rc (only).
m.
> ---
> drivers/md/dm-verity-target.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
> index 97de961..1ec9b2c 100644
> --- a/drivers/md/dm-verity-target.c
> +++ b/drivers/md/dm-verity-target.c
> @@ -166,7 +166,7 @@ static int verity_hash_init(struct dm_verity *v, struct ahash_request *req,
> return r;
> }
>
> - if (likely(v->version >= 1))
> + if (likely(v->salt_size && (v->version >= 1)))
> r = verity_hash_update(v, req, v->salt, v->salt_size, res);
>
> return r;
> @@ -177,7 +177,7 @@ static int verity_hash_final(struct dm_verity *v, struct ahash_request *req,
> {
> int r;
>
> - if (unlikely(!v->version)) {
> + if (unlikely(v->salt_size && (!v->version))) {
> r = verity_hash_update(v, req, v->salt, v->salt_size, res);
>
> if (r < 0) {
>
--
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