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luks: Move configuration of ciphers into cryptodisk 

The luks module contains quite a lot of logic to parse cipher and
cipher-mode strings like aes-xts-plain64 into constants to apply them
to the grub_cryptodisk_t structure. This code will be required by the
upcoming luks2 module, as well, which is why this commit moves it into
its own function grub_cryptodisk_setcipher in the cryptodisk module.
While the strings are probably rather specific to the LUKS modules, it
certainly does make sense that the cryptodisk module houses code to set
up its own internal ciphers instead of hosting that code in the luks
module.

Except for necessary adjustments around error handling, this commit does
an exact move of the cipher configuration logic from luks.c to
cryptodisk.c. Any behavior changes are unintentional.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Patrick Steinhardt 2019-12-27 16:18:38 +01:00 committed by Daniel Kiper
parent 5324c335b1
commit dd3f49b106
3 changed files with 181 additions and 175 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

163
grub-core/disk/cryptodisk.c
View File

@ -1,6 +1,6 @@
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2003,2007,2010,2011 Free Software Foundation, Inc.
* Copyright (C) 2003,2007,2010,2011,2019 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@ -404,6 +404,167 @@ grub_cryptodisk_decrypt (struct grub_cryptodisk *dev,
return grub_cryptodisk_endecrypt (dev, data, len, sector, 0);
}
grub_err_t
grub_cryptodisk_setcipher (grub_cryptodisk_t crypt, const char *ciphername, const char *ciphermode)
{
const char *cipheriv = NULL;
grub_crypto_cipher_handle_t cipher = NULL, secondary_cipher = NULL;
grub_crypto_cipher_handle_t essiv_cipher = NULL;
const gcry_md_spec_t *essiv_hash = NULL;
const struct gcry_cipher_spec *ciph;
grub_cryptodisk_mode_t mode;
grub_cryptodisk_mode_iv_t mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN64;
int benbi_log = 0;
grub_err_t ret = GRUB_ERR_NONE;
ciph = grub_crypto_lookup_cipher_by_name (ciphername);
if (!ciph)
{
ret = grub_error (GRUB_ERR_FILE_NOT_FOUND, "Cipher %s isn't available",
ciphername);
goto err;
}
/* Configure the cipher used for the bulk data. */
cipher = grub_crypto_cipher_open (ciph);
if (!cipher)
{
ret = grub_error (GRUB_ERR_FILE_NOT_FOUND, "Cipher %s could not be initialized",
ciphername);
goto err;
}
/* Configure the cipher mode. */
if (grub_strcmp (ciphermode, "ecb") == 0)
{
mode = GRUB_CRYPTODISK_MODE_ECB;
mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN;
cipheriv = NULL;
}
else if (grub_strcmp (ciphermode, "plain") == 0)
{
mode = GRUB_CRYPTODISK_MODE_CBC;
mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN;
cipheriv = NULL;
}
else if (grub_memcmp (ciphermode, "cbc-", sizeof ("cbc-") - 1) == 0)
{
mode = GRUB_CRYPTODISK_MODE_CBC;
cipheriv = ciphermode + sizeof ("cbc-") - 1;
}
else if (grub_memcmp (ciphermode, "pcbc-", sizeof ("pcbc-") - 1) == 0)
{
mode = GRUB_CRYPTODISK_MODE_PCBC;
cipheriv = ciphermode + sizeof ("pcbc-") - 1;
}
else if (grub_memcmp (ciphermode, "xts-", sizeof ("xts-") - 1) == 0)
{
mode = GRUB_CRYPTODISK_MODE_XTS;
cipheriv = ciphermode + sizeof ("xts-") - 1;
secondary_cipher = grub_crypto_cipher_open (ciph);
if (!secondary_cipher)
{
ret = grub_error (GRUB_ERR_FILE_NOT_FOUND, "Secondary cipher %s isn't available",
secondary_cipher);
goto err;
}
if (cipher->cipher->blocksize != GRUB_CRYPTODISK_GF_BYTES)
{
ret = grub_error (GRUB_ERR_BAD_ARGUMENT, "Unsupported XTS block size: %d",
cipher->cipher->blocksize);
goto err;
}
if (secondary_cipher->cipher->blocksize != GRUB_CRYPTODISK_GF_BYTES)
{
ret = grub_error (GRUB_ERR_BAD_ARGUMENT, "Unsupported XTS block size: %d",
secondary_cipher->cipher->blocksize);
goto err;
}
}
else if (grub_memcmp (ciphermode, "lrw-", sizeof ("lrw-") - 1) == 0)
{
mode = GRUB_CRYPTODISK_MODE_LRW;
cipheriv = ciphermode + sizeof ("lrw-") - 1;
if (cipher->cipher->blocksize != GRUB_CRYPTODISK_GF_BYTES)
{
ret = grub_error (GRUB_ERR_BAD_ARGUMENT, "Unsupported LRW block size: %d",
cipher->cipher->blocksize);
goto err;
}
}
else
{
ret = grub_error (GRUB_ERR_BAD_ARGUMENT, "Unknown cipher mode: %s",
ciphermode);
goto err;
}
if (cipheriv == NULL)
;
else if (grub_memcmp (cipheriv, "plain", sizeof ("plain") - 1) == 0)
mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN;
else if (grub_memcmp (cipheriv, "plain64", sizeof ("plain64") - 1) == 0)
mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN64;
else if (grub_memcmp (cipheriv, "benbi", sizeof ("benbi") - 1) == 0)
{
if (cipher->cipher->blocksize & (cipher->cipher->blocksize - 1)
|| cipher->cipher->blocksize == 0)
grub_error (GRUB_ERR_BAD_ARGUMENT, "Unsupported benbi blocksize: %d",
cipher->cipher->blocksize);
/* FIXME should we return an error here? */
for (benbi_log = 0;
(cipher->cipher->blocksize << benbi_log) < GRUB_DISK_SECTOR_SIZE;
benbi_log++);
mode_iv = GRUB_CRYPTODISK_MODE_IV_BENBI;
}
else if (grub_memcmp (cipheriv, "null", sizeof ("null") - 1) == 0)
mode_iv = GRUB_CRYPTODISK_MODE_IV_NULL;
else if (grub_memcmp (cipheriv, "essiv:", sizeof ("essiv:") - 1) == 0)
{
const char *hash_str = cipheriv + 6;
mode_iv = GRUB_CRYPTODISK_MODE_IV_ESSIV;
/* Configure the hash and cipher used for ESSIV. */
essiv_hash = grub_crypto_lookup_md_by_name (hash_str);
if (!essiv_hash)
{
ret = grub_error (GRUB_ERR_FILE_NOT_FOUND,
"Couldn't load %s hash", hash_str);
goto err;
}
essiv_cipher = grub_crypto_cipher_open (ciph);
if (!essiv_cipher)
{
ret = grub_error (GRUB_ERR_FILE_NOT_FOUND,
"Couldn't load %s cipher", ciphername);
goto err;
}
}
else
{
ret = grub_error (GRUB_ERR_BAD_ARGUMENT, "Unknown IV mode: %s",
cipheriv);
goto err;
}
crypt->cipher = cipher;
crypt->benbi_log = benbi_log;
crypt->mode = mode;
crypt->mode_iv = mode_iv;
crypt->secondary_cipher = secondary_cipher;
crypt->essiv_cipher = essiv_cipher;
crypt->essiv_hash = essiv_hash;
err:
if (ret)
{
grub_crypto_cipher_close (cipher);
grub_crypto_cipher_close (secondary_cipher);
}
return ret;
}
gcry_err_code_t
grub_cryptodisk_setkey (grub_cryptodisk_t dev, grub_uint8_t *key, grub_size_t keysize)
{

190
grub-core/disk/luks.c
View File

@ -1,6 +1,6 @@
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2003,2007,2010,2011 Free Software Foundation, Inc.
* Copyright (C) 2003,2007,2010,2011,2019 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@ -75,15 +75,7 @@ configure_ciphers (grub_disk_t disk, const char *check_uuid,
char uuid[sizeof (header.uuid) + 1];
char ciphername[sizeof (header.cipherName) + 1];
char ciphermode[sizeof (header.cipherMode) + 1];
char *cipheriv = NULL;
char hashspec[sizeof (header.hashSpec) + 1];
grub_crypto_cipher_handle_t cipher = NULL, secondary_cipher = NULL;
grub_crypto_cipher_handle_t essiv_cipher = NULL;
const gcry_md_spec_t *hash = NULL, *essiv_hash = NULL;
const struct gcry_cipher_spec *ciph;
grub_cryptodisk_mode_t mode;
grub_cryptodisk_mode_iv_t mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN64;
int benbi_log = 0;
grub_err_t err;
if (check_boot)
@ -126,183 +118,33 @@ configure_ciphers (grub_disk_t disk, const char *check_uuid,
grub_memcpy (hashspec, header.hashSpec, sizeof (header.hashSpec));
hashspec[sizeof (header.hashSpec)] = 0;
ciph = grub_crypto_lookup_cipher_by_name (ciphername);
if (!ciph)
{
grub_error (GRUB_ERR_FILE_NOT_FOUND, "Cipher %s isn't available",
ciphername);
newdev = grub_zalloc (sizeof (struct grub_cryptodisk));
if (!newdev)
return NULL;
}
/* Configure the cipher used for the bulk data. */
cipher = grub_crypto_cipher_open (ciph);
if (!cipher)
return NULL;
if (grub_be_to_cpu32 (header.keyBytes) > 1024)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "invalid keysize %d",
grub_be_to_cpu32 (header.keyBytes));
grub_crypto_cipher_close (cipher);
return NULL;
}
/* Configure the cipher mode. */
if (grub_strcmp (ciphermode, "ecb") == 0)
{
mode = GRUB_CRYPTODISK_MODE_ECB;
mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN;
cipheriv = NULL;
}
else if (grub_strcmp (ciphermode, "plain") == 0)
{
mode = GRUB_CRYPTODISK_MODE_CBC;
mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN;
cipheriv = NULL;
}
else if (grub_memcmp (ciphermode, "cbc-", sizeof ("cbc-") - 1) == 0)
{
mode = GRUB_CRYPTODISK_MODE_CBC;
cipheriv = ciphermode + sizeof ("cbc-") - 1;
}
else if (grub_memcmp (ciphermode, "pcbc-", sizeof ("pcbc-") - 1) == 0)
{
mode = GRUB_CRYPTODISK_MODE_PCBC;
cipheriv = ciphermode + sizeof ("pcbc-") - 1;
}
else if (grub_memcmp (ciphermode, "xts-", sizeof ("xts-") - 1) == 0)
{
mode = GRUB_CRYPTODISK_MODE_XTS;
cipheriv = ciphermode + sizeof ("xts-") - 1;
secondary_cipher = grub_crypto_cipher_open (ciph);
if (!secondary_cipher)
{
grub_crypto_cipher_close (cipher);
return NULL;
}
if (cipher->cipher->blocksize != GRUB_CRYPTODISK_GF_BYTES)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "Unsupported XTS block size: %d",
cipher->cipher->blocksize);
grub_crypto_cipher_close (cipher);
grub_crypto_cipher_close (secondary_cipher);
return NULL;
}
if (secondary_cipher->cipher->blocksize != GRUB_CRYPTODISK_GF_BYTES)
{
grub_crypto_cipher_close (cipher);
grub_error (GRUB_ERR_BAD_ARGUMENT, "Unsupported XTS block size: %d",
secondary_cipher->cipher->blocksize);
grub_crypto_cipher_close (secondary_cipher);
return NULL;
}
}
else if (grub_memcmp (ciphermode, "lrw-", sizeof ("lrw-") - 1) == 0)
{
mode = GRUB_CRYPTODISK_MODE_LRW;
cipheriv = ciphermode + sizeof ("lrw-") - 1;
if (cipher->cipher->blocksize != GRUB_CRYPTODISK_GF_BYTES)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "Unsupported LRW block size: %d",
cipher->cipher->blocksize);
grub_crypto_cipher_close (cipher);
return NULL;
}
}
else
{
grub_crypto_cipher_close (cipher);
grub_error (GRUB_ERR_BAD_ARGUMENT, "Unknown cipher mode: %s",
ciphermode);
return NULL;
}
if (cipheriv == NULL);
else if (grub_memcmp (cipheriv, "plain", sizeof ("plain") - 1) == 0)
mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN;
else if (grub_memcmp (cipheriv, "plain64", sizeof ("plain64") - 1) == 0)
mode_iv = GRUB_CRYPTODISK_MODE_IV_PLAIN64;
else if (grub_memcmp (cipheriv, "benbi", sizeof ("benbi") - 1) == 0)
{
if (cipher->cipher->blocksize & (cipher->cipher->blocksize - 1)
|| cipher->cipher->blocksize == 0)
grub_error (GRUB_ERR_BAD_ARGUMENT, "Unsupported benbi blocksize: %d",
cipher->cipher->blocksize);
/* FIXME should we return an error here? */
for (benbi_log = 0;
(cipher->cipher->blocksize << benbi_log) < GRUB_DISK_SECTOR_SIZE;
benbi_log++);
mode_iv = GRUB_CRYPTODISK_MODE_IV_BENBI;
}
else if (grub_memcmp (cipheriv, "null", sizeof ("null") - 1) == 0)
mode_iv = GRUB_CRYPTODISK_MODE_IV_NULL;
else if (grub_memcmp (cipheriv, "essiv:", sizeof ("essiv:") - 1) == 0)
{
char *hash_str = cipheriv + 6;
mode_iv = GRUB_CRYPTODISK_MODE_IV_ESSIV;
/* Configure the hash and cipher used for ESSIV. */
essiv_hash = grub_crypto_lookup_md_by_name (hash_str);
if (!essiv_hash)
{
grub_crypto_cipher_close (cipher);
grub_crypto_cipher_close (secondary_cipher);
grub_error (GRUB_ERR_FILE_NOT_FOUND,
"Couldn't load %s hash", hash_str);
return NULL;
}
essiv_cipher = grub_crypto_cipher_open (ciph);
if (!essiv_cipher)
{
grub_crypto_cipher_close (cipher);
grub_crypto_cipher_close (secondary_cipher);
return NULL;
}
}
else
{
grub_crypto_cipher_close (cipher);
grub_crypto_cipher_close (secondary_cipher);
grub_error (GRUB_ERR_BAD_ARGUMENT, "Unknown IV mode: %s",
cipheriv);
return NULL;
}
newdev->offset = grub_be_to_cpu32 (header.payloadOffset);
newdev->source_disk = NULL;
newdev->log_sector_size = 9;
newdev->total_length = grub_disk_get_size (disk) - newdev->offset;
grub_memcpy (newdev->uuid, uuid, sizeof (newdev->uuid));
newdev->modname = "luks";
/* Configure the hash used for the AF splitter and HMAC. */
hash = grub_crypto_lookup_md_by_name (hashspec);
if (!hash)
newdev->hash = grub_crypto_lookup_md_by_name (hashspec);
if (!newdev->hash)
{
grub_crypto_cipher_close (cipher);
grub_crypto_cipher_close (essiv_cipher);
grub_crypto_cipher_close (secondary_cipher);
grub_free (newdev);
grub_error (GRUB_ERR_FILE_NOT_FOUND, "Couldn't load %s hash",
hashspec);
return NULL;
}
newdev = grub_zalloc (sizeof (struct grub_cryptodisk));
if (!newdev)
err = grub_cryptodisk_setcipher (newdev, ciphername, ciphermode);
if (err)
{
grub_crypto_cipher_close (cipher);
grub_crypto_cipher_close (essiv_cipher);
grub_crypto_cipher_close (secondary_cipher);
grub_free (newdev);
return NULL;
}
newdev->cipher = cipher;
newdev->offset = grub_be_to_cpu32 (header.payloadOffset);
newdev->source_disk = NULL;
newdev->benbi_log = benbi_log;
newdev->mode = mode;
newdev->mode_iv = mode_iv;
newdev->secondary_cipher = secondary_cipher;
newdev->essiv_cipher = essiv_cipher;
newdev->essiv_hash = essiv_hash;
newdev->hash = hash;
newdev->log_sector_size = 9;
newdev->total_length = grub_disk_get_size (disk) - newdev->offset;
grub_memcpy (newdev->uuid, uuid, sizeof (newdev->uuid));
newdev->modname = "luks";
COMPILE_TIME_ASSERT (sizeof (newdev->uuid) >= sizeof (uuid));
return newdev;
}

3
include/grub/cryptodisk.h
View File

@ -130,6 +130,9 @@ grub_cryptodisk_dev_unregister (grub_cryptodisk_dev_t cr)
#define FOR_CRYPTODISK_DEVS(var) FOR_LIST_ELEMENTS((var), (grub_cryptodisk_list))
grub_err_t
grub_cryptodisk_setcipher (grub_cryptodisk_t crypt, const char *ciphername, const char *ciphermode);
gcry_err_code_t
grub_cryptodisk_setkey (grub_cryptodisk_t dev,
grub_uint8_t *key, grub_size_t keysize);