On Thu, 12 Nov 2020 17:22:04 -0800
James Bottomley <j...@linux.ibm.com> wrote:
> For AMD SEV environments, the grub boot password has to be retrieved
> from a given memory location rather than prompted for. This means
> that the standard password getter needs to be replaced with one that
> gets the passphrase from the SEV area and uses that instead. Adding
> the password getter as a passed in argument to recover_key() makes
> this possible.
>
> Signed-off-by: James Bottomley <j...@linux.ibm.com>
> ---
> grub-core/disk/cryptodisk.c | 2 +-
> grub-core/disk/geli.c | 5 +++--
> grub-core/disk/luks.c | 12 +++++++-----
> grub-core/disk/luks2.c | 12 +++++++-----
> include/grub/cryptodisk.h | 6 +++++-
> 5 files changed, 23 insertions(+), 14 deletions(-)
>
> diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
> index a3d672f68..682f5a55d 100644
> --- a/grub-core/disk/cryptodisk.c
> +++ b/grub-core/disk/cryptodisk.c
> @@ -997,7 +997,7 @@ grub_cryptodisk_scan_device_real (const char
> *name, grub_disk_t source) if (!dev)
> continue;
>
> - err = cr->recover_key (source, dev);
> + err = cr->recover_key (source, dev, grub_password_get);
> if (err)
> {
> cryptodisk_close (dev);
> diff --git a/grub-core/disk/geli.c b/grub-core/disk/geli.c
> index e9d23299a..5514c16a3 100644
> --- a/grub-core/disk/geli.c
> +++ b/grub-core/disk/geli.c
> @@ -398,7 +398,8 @@ configure_ciphers (grub_disk_t disk, const char
> *check_uuid, }
>
> static grub_err_t
> -recover_key (grub_disk_t source, grub_cryptodisk_t dev)
> +recover_key (grub_disk_t source, grub_cryptodisk_t dev,
> + grub_passwd_cb *password_get)
> {
> grub_size_t keysize;
> grub_uint8_t digest[GRUB_CRYPTO_MAX_MDLEN];
> @@ -442,7 +443,7 @@ recover_key (grub_disk_t source,
> grub_cryptodisk_t dev) source->partition ? "," : "", tmp ? : "",
> dev->uuid);
> grub_free (tmp);
In luks.c and luks2.c below, grub_printf_ is made conditional, but not
here. It probably should be.
> - if (!grub_password_get (passphrase, MAX_PASSPHRASE))
> + if (!password_get (passphrase, MAX_PASSPHRASE))
> return grub_error (GRUB_ERR_BAD_ARGUMENT, "Passphrase not
> supplied");
> /* Calculate the PBKDF2 of the user supplied passphrase. */
> diff --git a/grub-core/disk/luks.c b/grub-core/disk/luks.c
> index 59702067a..165f4a6bd 100644
> --- a/grub-core/disk/luks.c
> +++ b/grub-core/disk/luks.c
> @@ -152,7 +152,8 @@ configure_ciphers (grub_disk_t disk, const char
> *check_uuid,
> static grub_err_t
> luks_recover_key (grub_disk_t source,
> - grub_cryptodisk_t dev)
> + grub_cryptodisk_t dev,
> + grub_passwd_cb *password_get)
> {
> struct grub_luks_phdr header;
> grub_size_t keysize;
> @@ -187,11 +188,12 @@ luks_recover_key (grub_disk_t source,
> tmp = NULL;
> if (source->partition)
> tmp = grub_partition_get_name (source->partition);
> - grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "),
> source->name,
> - source->partition ? "," : "", tmp ? : "",
> - dev->uuid);
> + if (password_get == grub_password_get)
> + grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "),
> source->name,
> + source->partition ? "," : "", tmp ? : "",
> + dev->uuid);
> grub_free (tmp);
> - if (!grub_password_get (passphrase, MAX_PASSPHRASE))
> + if (!password_get (passphrase, MAX_PASSPHRASE))
> {
> grub_free (split_key);
> return grub_error (GRUB_ERR_BAD_ARGUMENT, "Passphrase not
> supplied"); diff --git a/grub-core/disk/luks2.c
> b/grub-core/disk/luks2.c index 31d7166fc..984182aa9 100644
> --- a/grub-core/disk/luks2.c
> +++ b/grub-core/disk/luks2.c
> @@ -531,7 +531,8 @@ luks2_decrypt_key (grub_uint8_t *out_key,
>
> static grub_err_t
> luks2_recover_key (grub_disk_t disk,
> - grub_cryptodisk_t crypt)
> + grub_cryptodisk_t crypt,
> + grub_passwd_cb *password_get)
> {
> grub_uint8_t candidate_key[GRUB_CRYPTODISK_MAX_KEYLEN];
> char passphrase[MAX_PASSPHRASE], cipher[32];
> @@ -573,10 +574,11 @@ luks2_recover_key (grub_disk_t disk,
> /* Get the passphrase from the user. */
> if (disk->partition)
> part = grub_partition_get_name (disk->partition);
> - grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "), disk->name,
> - disk->partition ? "," : "", part ? : "",
> - crypt->uuid);
> - if (!grub_password_get (passphrase, MAX_PASSPHRASE))
> + if (password_get == grub_password_get)
> + grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "),
> disk->name,
> + disk->partition ? "," : "", part ? : "",
> + crypt->uuid);
> + if (!password_get (passphrase, MAX_PASSPHRASE))
> {
> ret = grub_error (GRUB_ERR_BAD_ARGUMENT, "Passphrase not
> supplied"); goto err;
> diff --git a/include/grub/cryptodisk.h b/include/grub/cryptodisk.h
> index e1b21e785..45dae5483 100644
> --- a/include/grub/cryptodisk.h
> +++ b/include/grub/cryptodisk.h
> @@ -101,6 +101,9 @@ struct grub_cryptodisk
> };
> typedef struct grub_cryptodisk *grub_cryptodisk_t;
>
> +/* must match prototype for grub_password_get */
> +typedef int (grub_passwd_cb)(char buf[], unsigned buf_size);
> +
> struct grub_cryptodisk_dev
> {
> struct grub_cryptodisk_dev *next;
> @@ -108,7 +111,8 @@ struct grub_cryptodisk_dev
>
> grub_cryptodisk_t (*scan) (grub_disk_t disk, const char
> *check_uuid, int boot_only);
> - grub_err_t (*recover_key) (grub_disk_t disk, grub_cryptodisk_t
> dev);
> + grub_err_t (*recover_key) (grub_disk_t disk, grub_cryptodisk_t dev,
> + grub_passwd_cb *get_password);
> };
> typedef struct grub_cryptodisk_dev *grub_cryptodisk_dev_t;
>
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