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Re: [PATCH v2 04/10] luks2: grub_cryptodisk_t->total_length is the max n
From: |
Patrick Steinhardt |
Subject: |
Re: [PATCH v2 04/10] luks2: grub_cryptodisk_t->total_length is the max number of device native sectors |
Date: |
Fri, 9 Oct 2020 11:45:59 +0200 |
On Sat, Oct 03, 2020 at 05:55:28PM -0500, Glenn Washburn wrote:
> The total_length field is named confusingly because length usually refers to
> bytes, whereas in this case its really the total number of sectors on the
> device. Also counter-intuitively, grub_disk_get_size returns the total
> number of device native sectors sectors. We need to convert the sectors from
^~~~~~~~~~~~~~~
Nit: there's a duplicate word here.
Patrick
> the size of the underlying device to the cryptodisk sector size. And
> segment.size is in bytes which need to be converted to cryptodisk sectors.
>
> Also, removed an empty statement.
>
> Signed-off-by: Glenn Washburn <development@efficientek.com>
> ---
> grub-core/disk/luks2.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/grub-core/disk/luks2.c b/grub-core/disk/luks2.c
> index db251cce0..9f7d6e12b 100644
> --- a/grub-core/disk/luks2.c
> +++ b/grub-core/disk/luks2.c
> @@ -424,7 +424,7 @@ luks2_decrypt_key (grub_uint8_t *out_key,
> grub_uint8_t salt[GRUB_CRYPTODISK_MAX_KEYLEN];
> grub_uint8_t *split_key = NULL;
> grub_size_t saltlen = sizeof (salt);
> - char cipher[32], *p;;
> + char cipher[32], *p;
> const gcry_md_spec_t *hash;
> gcry_err_code_t gcry_ret;
> grub_err_t ret;
> @@ -611,9 +611,10 @@ luks2_recover_key (grub_disk_t disk,
> crypt->log_sector_size = sizeof (unsigned int) * 8
> - __builtin_clz ((unsigned int) segment.sector_size) - 1;
> if (grub_strcmp (segment.size, "dynamic") == 0)
> - crypt->total_length = grub_disk_get_size (disk) - crypt->offset;
> + crypt->total_length = (grub_disk_get_size (disk) >>
> (crypt->log_sector_size - disk->log_sector_size))
> + - crypt->offset;
> else
> - crypt->total_length = grub_strtoull (segment.size, NULL, 10);
> + crypt->total_length = grub_strtoull (segment.size, NULL, 10) >>
> crypt->log_sector_size;
>
> ret = luks2_decrypt_key (candidate_key, disk, crypt, &keyslot,
> (const grub_uint8_t *) passphrase, grub_strlen
> (passphrase));
> --
> 2.27.0
>
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- [PATCH 10/10] luks2: Rename source disk variabled named 'disk' to 'source' as in luks.c., (continued)
- [PATCH 10/10] luks2: Rename source disk variabled named 'disk' to 'source' as in luks.c., Glenn Washburn, 2020/10/03
- [PATCH v2 00/10] Cryptodisk fixes for v2.06 redux, Glenn Washburn, 2020/10/03
- [PATCH v2 05/10] cryptodisk: Fix cipher IV mode 'plain64' always being set as 'plain'., Glenn Washburn, 2020/10/03
- [PATCH v2 04/10] luks2: grub_cryptodisk_t->total_length is the max number of device native sectors, Glenn Washburn, 2020/10/03
- Re: [PATCH v2 04/10] luks2: grub_cryptodisk_t->total_length is the max number of device native sectors,
Patrick Steinhardt <=
- [PATCH v2 06/10] cryptodisk: Properly handle non-512 byte sized sectors., Glenn Washburn, 2020/10/03
- [PATCH v2 08/10] cryptodisk: Rename total_length field in grub_cryptodisk_t to total_sectors., Glenn Washburn, 2020/10/03
- [PATCH v2 07/10] cryptodisk: Replace some literals with constants in grub_cryptodisk_endecrypt., Glenn Washburn, 2020/10/03
[PATCH v2 09/10] cryptodisk: Rename offset in grub_cryptodisk_t to offset_sectors., Glenn Washburn, 2020/10/03