Re: [PATCH v7 06/17] luks2: Use more intuitive slot key instead of index in user messages

[Daniel Kiper]

On Fri, Dec 04, 2020 at 10:43:35AM -0600, Glenn Washburn wrote:
> Use the slot key name in the json array rather than the 0 based index in the
> json array for keyslots, segments, and digests. This is less confusing for
> the end user. For example, say you have a LUKS2 device with a key in slot 1
> and slot 4. When using the password for slot 4 to unlock the device, the
> messages using the index of the keyslot will mention keyslot 1 (its a
> zero-based index). Furthermore, with this change the keyslot number will
> align with the number used to reference the keyslot when using the
> --key-slot argument to cryptsetup.
>
> Signed-off-by: Glenn Washburn <development@efficientek.com>
> ---
>  grub-core/disk/luks2.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/grub-core/disk/luks2.c b/grub-core/disk/luks2.c
> index 437c1da07..ea1065bcf 100644
> --- a/grub-core/disk/luks2.c
> +++ b/grub-core/disk/luks2.c
> @@ -284,13 +284,13 @@ luks2_get_keyslot (grub_luks2_keyslot_t *k, 
> grub_luks2_digest_t *d, grub_luks2_s
>         grub_json_getuint64 (&d->json_slot_key, &digest, NULL) ||
>            grub_json_getchild (&digest, &digest, 0) ||
>            luks2_parse_digest (d, &digest))
> -     return grub_error (GRUB_ERR_BAD_ARGUMENT, "Could not parse digest 
> %"PRIuGRUB_SIZE, i);
> +     return grub_error (GRUB_ERR_BAD_ARGUMENT, "Could not parse digest index 
> %"PRIuGRUB_SIZE, i);

Does not this change belong to next patch?

>        if ((d->keyslots & (1 << k->json_slot_key)))
>       break;
>      }
>    if (i == size)
> -      return grub_error (GRUB_ERR_FILE_NOT_FOUND, "No digest for keyslot 
> %"PRIuGRUB_SIZE, keyslot_idx);
> +      return grub_error (GRUB_ERR_FILE_NOT_FOUND, "No digest for keyslot 
> \"%"PRIuGRUB_UINT64_T"\"", k->slot_key);

I am afraid this does not build. The slot_key seems a remnant from v6.

>    /* Get segment that matches the digest. */
>    if (grub_json_getvalue (&segments, root, "segments") ||
> @@ -308,7 +308,7 @@ luks2_get_keyslot (grub_luks2_keyslot_t *k, 
> grub_luks2_digest_t *d, grub_luks2_s
>       break;
>      }
>    if (i == size)
> -    return grub_error (GRUB_ERR_FILE_NOT_FOUND, "No segment for digest 
> %"PRIuGRUB_SIZE);
> +    return grub_error (GRUB_ERR_FILE_NOT_FOUND, "No segment for digest 
> \"%"PRIuGRUB_UINT64_T"\"", d->slot_key);

Ditto and below...

>    return GRUB_ERR_NONE;
>  }
> @@ -604,11 +604,11 @@ luks2_recover_key (grub_disk_t source,
>
>        if (keyslot.priority == 0)
>       {
> -       grub_dprintf ("luks2", "Ignoring keyslot %"PRIuGRUB_SIZE" due to 
> priority\n", i);
> +       grub_dprintf ("luks2", "Ignoring keyslot \"%"PRIuGRUB_UINT64_T"\" due 
> to priority\n", keyslot.slot_key);
>         continue;
>          }
>
> -      grub_dprintf ("luks2", "Trying keyslot %"PRIuGRUB_SIZE"\n", i);
> +      grub_dprintf ("luks2", "Trying keyslot \"%"PRIuGRUB_UINT64_T"\"\n", 
> keyslot.slot_key);
>
>        /* Set up disk according to keyslot's segment. */
>        crypt->offset_sectors = grub_divmod64 (segment.offset, 
> segment.sector_size, NULL);
> @@ -623,16 +623,16 @@ luks2_recover_key (grub_disk_t source,
>                              (const grub_uint8_t *) passphrase, grub_strlen 
> (passphrase));
>        if (ret)
>       {
> -       grub_dprintf ("luks2", "Decryption with keyslot %"PRIuGRUB_SIZE" 
> failed: %s\n",
> -                     i, grub_errmsg);
> +       grub_dprintf ("luks2", "Decryption with keyslot 
> \"%"PRIuGRUB_UINT64_T"\" failed: %s\n",
> +                     keyslot.slot_key, grub_errmsg);
>         continue;
>       }
>
>        ret = luks2_verify_key (&digest, candidate_key, keyslot.key_size);
>        if (ret)
>       {
> -       grub_dprintf ("luks2", "Could not open keyslot %"PRIuGRUB_SIZE": 
> %s\n",
> -                     i, grub_errmsg);
> +       grub_dprintf ("luks2", "Could not open keyslot 
> \"%"PRIuGRUB_UINT64_T"\": %s\n",
> +                     keyslot.slot_key, grub_errmsg);
>         continue;
>       }
>
> @@ -640,7 +640,7 @@ luks2_recover_key (grub_disk_t source,
>         * TRANSLATORS: It's a cryptographic key slot: one element of an array
>         * where each element is either empty or holds a key.
>         */
> -      grub_printf_ (N_("Slot %"PRIuGRUB_SIZE" opened\n"), i);
> +      grub_printf_ (N_("Slot \"%"PRIuGRUB_UINT64_T"\" opened\n"), 
> keyslot.slot_key);
>
>        candidate_key_len = keyslot.key_size;
>        break;

Daniel