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geli v5 (including rekeying support)

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This commit is contained in:
Vladimir 'phcoder' Serbinenko 2011-04-24 17:15:55 +02:00
parent 3e90811d88
commit 88ac3146d6
5 changed files with 79 additions and 11 deletions
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20
grub-core/disk/cryptodisk.c
View file

@ -178,7 +178,7 @@ lrw_xor (const struct lrw_sector *sec,
}
gcry_err_code_t
grub_cryptodisk_decrypt (const struct grub_cryptodisk *dev,
grub_cryptodisk_decrypt (struct grub_cryptodisk *dev,
grub_uint8_t * data, grub_size_t len,
grub_disk_addr_t sector)
{
@ -186,7 +186,7 @@ grub_cryptodisk_decrypt (const struct grub_cryptodisk *dev,
gcry_err_code_t err;
/* The only mode without IV. */
if (dev->mode == GRUB_CRYPTODISK_MODE_ECB)
if (dev->mode == GRUB_CRYPTODISK_MODE_ECB && !dev->rekey)
return grub_crypto_ecb_decrypt (dev->cipher, data, data, len);
for (i = 0; i < len; i += (1U << dev->log_sector_size))
@ -196,6 +196,18 @@ grub_cryptodisk_decrypt (const struct grub_cryptodisk *dev,
/ sizeof (grub_uint32_t));
grub_uint32_t iv[sz];
if (dev->rekey)
{
grub_uint64_t zone = sector >> dev->rekey_shift;
if (zone != dev->last_rekey)
{
err = dev->rekey (dev, zone);
if (err)
return err;
dev->last_rekey = zone;
}
}
grub_memset (iv, 0, sz * sizeof (iv[0]));
switch (dev->mode_iv)
{
@ -291,6 +303,10 @@ grub_cryptodisk_decrypt (const struct grub_cryptodisk *dev,
lrw_xor (&sec, dev, data + i);
}
break;
case GRUB_CRYPTODISK_MODE_ECB:
grub_crypto_ecb_decrypt (dev->cipher, data + i, data + i,
(1U << dev->log_sector_size));
break;
default:
return GPG_ERR_NOT_IMPLEMENTED;
}

45
grub-core/disk/geli.c
View file

@ -104,6 +104,28 @@ static const struct grub_arg_option options[] =
static int check_uuid, have_it;
static char *search_uuid;
static gcry_err_code_t
geli_rekey (struct grub_cryptodisk *dev, grub_uint64_t zoneno)
{
gcry_err_code_t gcry_err;
const struct {
char magic[4];
grub_uint64_t zone;
} __attribute__ ((packed)) tohash
= { {'e', 'k', 'e', 'y'}, grub_cpu_to_le64 (zoneno) };
grub_uint64_t key[(dev->hash->mdlen + 7) / 8];
grub_dprintf ("geli", "rekeying %" PRIuGRUB_UINT64_T " keysize=%d\n",
zoneno, dev->rekey_derived_size);
gcry_err = grub_crypto_hmac_buffer (dev->hash, dev->rekey_key, 64,
&tohash, sizeof (tohash), key);
if (gcry_err)
return grub_crypto_gcry_error (gcry_err);
return grub_cryptodisk_setkey (dev, (grub_uint8_t *) key,
dev->rekey_derived_size);
}
static grub_cryptodisk_t
configure_ciphers (const struct grub_geli_phdr *header)
{
@ -115,8 +137,8 @@ configure_ciphers (const struct grub_geli_phdr *header)
/* Look for GELI magic sequence. */
if (grub_memcmp (header->magic, GELI_MAGIC, sizeof (GELI_MAGIC))
|| grub_le_to_cpu32 (header->version) > 3
|| grub_le_to_cpu32 (header->version) < 2)
|| grub_le_to_cpu32 (header->version) > 5
|| grub_le_to_cpu32 (header->version) < 1)
{
grub_dprintf ("geli", "wrong magic %02x\n", header->magic[0]);
return NULL;
@ -212,6 +234,12 @@ configure_ciphers (const struct grub_geli_phdr *header)
for (newdev->log_sector_size = 0;
(1U << newdev->log_sector_size) < grub_le_to_cpu32 (header->sector_size);
newdev->log_sector_size++);
if (grub_le_to_cpu32 (header->version) >= 5)
{
newdev->rekey = geli_rekey;
newdev->rekey_shift = 20;
}
#if 0
grub_memcpy (newdev->uuid, uuid, sizeof (newdev->uuid));
#endif
@ -325,10 +353,23 @@ recover_key (grub_cryptodisk_t dev, const struct grub_geli_phdr *header,
grub_printf ("Slot %d opened\n", i);
/* Set the master key. */
if (!dev->rekey)
{
gcry_err = grub_cryptodisk_setkey (dev, candidate_key.cipher_key,
keysize);
if (gcry_err)
return grub_crypto_gcry_error (gcry_err);
}
else
{
/* For a reason I don't know, the IV key is used in rekeying. */
grub_memcpy (dev->rekey_key, candidate_key.iv_key,
sizeof (candidate_key.iv_key));
dev->rekey_derived_size = keysize;
dev->last_rekey = -1;
COMPILE_TIME_ASSERT (sizeof (dev->rekey_key)
>= sizeof (candidate_key.iv_key));
}
dev->iv_prefix_len = sizeof (candidate_key.iv_key);
grub_memcpy (dev->iv_prefix, candidate_key.iv_key,

2
grub-core/lib/crypto.c
View file

@ -388,7 +388,7 @@ grub_crypto_hmac_fini (struct grub_crypto_hmac_handle *hnd, void *out)
gcry_err_code_t
grub_crypto_hmac_buffer (const struct gcry_md_spec *md,
const void *key, grub_size_t keylen,
void *data, grub_size_t datalen, void *out)
const void *data, grub_size_t datalen, void *out)
{
struct grub_crypto_hmac_handle *hnd;

2
include/grub/crypto.h
View file

@ -244,7 +244,7 @@ grub_crypto_hmac_fini (struct grub_crypto_hmac_handle *hnd, void *out);
gcry_err_code_t
grub_crypto_hmac_buffer (const struct gcry_md_spec *md,
const void *key, grub_size_t keylen,
void *data, grub_size_t datalen, void *out);
const void *data, grub_size_t datalen, void *out);
extern gcry_md_spec_t _gcry_digest_spec_md5;
extern gcry_md_spec_t _gcry_digest_spec_sha1;

13
include/grub/cryptodisk.h
View file

@ -48,6 +48,12 @@ typedef enum
#define GRUB_CRYPTODISK_GF_LOG_BYTES (GRUB_CRYPTODISK_GF_LOG_SIZE - 3)
#define GRUB_CRYPTODISK_GF_BYTES (1U << GRUB_CRYPTODISK_GF_LOG_BYTES)
struct grub_cryptodisk;
typedef gcry_err_code_t
(*grub_cryptodisk_rekey_func_t) (struct grub_cryptodisk *dev,
grub_uint64_t zoneno);
struct grub_cryptodisk
{
char *source;
@ -74,6 +80,11 @@ struct grub_cryptodisk
int cheat_fd;
#endif
int log_sector_size;
grub_cryptodisk_rekey_func_t rekey;
int rekey_shift;
grub_uint8_t rekey_key[64];
grub_uint64_t last_rekey;
int rekey_derived_size;
struct grub_cryptodisk *next;
};
typedef struct grub_cryptodisk *grub_cryptodisk_t;
@ -82,7 +93,7 @@ gcry_err_code_t
grub_cryptodisk_setkey (grub_cryptodisk_t dev,
grub_uint8_t *key, grub_size_t keysize);
gcry_err_code_t
grub_cryptodisk_decrypt (const struct grub_cryptodisk *dev,
grub_cryptodisk_decrypt (struct grub_cryptodisk *dev,
grub_uint8_t * data, grub_size_t len,
grub_disk_addr_t sector);
grub_err_t