Better IV modes support
This commit is contained in:
Vladimir 'phcoder' Serbinenko
parent
4879d87871
commit
95172af9fa
1 changed files with 151 additions and 115 deletions
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@ -70,12 +70,20 @@ struct grub_luks_phdr
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typedef struct grub_luks_phdr *grub_luks_phdr_t;
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typedef enum
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{
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GRUB_LUKS_MODE_ECB,
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GRUB_LUKS_MODE_CBC_PLAIN,
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GRUB_LUKS_MODE_CBC_ESSIV,
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GRUB_LUKS_MODE_XTS
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} luks_mode_t;
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{
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GRUB_LUKS_MODE_ECB,
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GRUB_LUKS_MODE_CBC,
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GRUB_LUKS_MODE_XTS
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} luks_mode_t;
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typedef enum
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{
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GRUB_LUKS_MODE_IV_NULL,
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GRUB_LUKS_MODE_IV_PLAIN,
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GRUB_LUKS_MODE_IV_PLAIN64,
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GRUB_LUKS_MODE_IV_ESSIV,
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GRUB_LUKS_MODE_IV_BENBI,
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} luks_mode_iv_t;
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struct grub_luks
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{
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@ -85,8 +93,10 @@ struct grub_luks
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int ref;
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grub_crypto_cipher_handle_t cipher;
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grub_crypto_cipher_handle_t secondary_cipher;
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grub_crypto_cipher_handle_t essiv_cipher;
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const gcry_md_spec_t *essiv_hash, *hash;
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luks_mode_t mode;
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luks_mode_iv_t mode_iv;
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unsigned long id, source_id;
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enum grub_disk_dev_id source_dev_id;
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char uuid[sizeof (((struct grub_luks_phdr *) 0)->uuid) + 1];
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@ -112,13 +122,6 @@ static const struct grub_arg_option options[] =
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{0, 0, 0, 0, 0, 0}
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};
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static inline void
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make_iv (grub_uint32_t *iv, grub_size_t sz, grub_disk_addr_t sector)
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{
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grub_memset (iv, 0, sz * sizeof (iv[0]));
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iv[0] = grub_cpu_to_le32 (sector & 0xFFFFFFFF);
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}
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/* Our irreducible polynom is x^128+x^7+x^2+x+1. Lowest byte of it is: */
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#define POLYNOM 0x87
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@ -141,89 +144,83 @@ gf_mul_x (grub_uint8_t *g)
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static gcry_err_code_t
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luks_decrypt (const struct grub_luks *dev,
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grub_uint8_t * data, grub_size_t len, grub_size_t sector)
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grub_uint8_t * data, grub_size_t len, grub_disk_addr_t sector)
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{
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grub_size_t i;
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gcry_err_code_t err;
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switch (dev->mode)
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/* The only mode without IV. */
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if (dev->mode == GRUB_LUKS_MODE_ECB)
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return grub_crypto_ecb_decrypt (dev->cipher, data, data, len);
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for (i = 0; i < len; i += GRUB_DISK_SECTOR_SIZE)
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{
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case GRUB_LUKS_MODE_ECB:
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return grub_crypto_ecb_decrypt (dev->cipher, data, data, len);
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grub_size_t sz = ((dev->cipher->cipher->blocksize
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+ sizeof (grub_uint32_t) - 1)
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/ sizeof (grub_uint32_t));
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grub_uint32_t iv[sz];
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case GRUB_LUKS_MODE_CBC_PLAIN:
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for (i = 0; i < len; i += GRUB_DISK_SECTOR_SIZE)
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grub_memset (iv, 0, sz * sizeof (iv[0]));
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switch (dev->mode_iv)
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{
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grub_size_t sz = ((dev->cipher->cipher->blocksize
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+ sizeof (grub_uint32_t) - 1)
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/ sizeof (grub_uint32_t));
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grub_uint32_t iv[sz];
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make_iv (iv, sz, sector);
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case GRUB_LUKS_MODE_IV_NULL:
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break;
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case GRUB_LUKS_MODE_IV_PLAIN64:
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iv[1] = grub_cpu_to_le32 (sector >> 32);
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case GRUB_LUKS_MODE_IV_PLAIN:
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iv[0] = grub_cpu_to_le32 (sector & 0xFFFFFFFF);
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break;
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case GRUB_LUKS_MODE_IV_BENBI:
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iv[sz - 2] = grub_cpu_to_be32 (sector >> 32);
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iv[sz - 1] = grub_cpu_to_be32 (sector & 0xFFFFFFFF);
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break;
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case GRUB_LUKS_MODE_IV_ESSIV:
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iv[0] = grub_cpu_to_le32 (sector & 0xFFFFFFFF);
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err = grub_crypto_ecb_encrypt (dev->essiv_cipher, iv, iv,
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dev->cipher->cipher->blocksize);
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if (err)
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return err;
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}
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switch (dev->mode)
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{
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case GRUB_LUKS_MODE_CBC:
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err = grub_crypto_cbc_decrypt (dev->cipher, data + i, data + i,
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GRUB_DISK_SECTOR_SIZE, iv);
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if (err)
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return err;
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sector++;
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break;
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case GRUB_LUKS_MODE_XTS:
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{
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int j;
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err = grub_crypto_ecb_encrypt (dev->secondary_cipher, iv, iv,
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dev->cipher->cipher->blocksize);
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if (err)
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return err;
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for (j = 0; j < GRUB_DISK_SECTOR_SIZE;
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j += dev->cipher->cipher->blocksize)
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{
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grub_crypto_xor (data + i + j, data + i + j, iv,
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dev->cipher->cipher->blocksize);
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err = grub_crypto_ecb_decrypt (dev->cipher, data + i + j,
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data + i + j,
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dev->cipher->cipher->blocksize);
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if (err)
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return err;
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grub_crypto_xor (data + i + j, data + i + j, iv,
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dev->cipher->cipher->blocksize);
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gf_mul_x ((grub_uint8_t *) iv);
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}
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}
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break;
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default:
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return GPG_ERR_NOT_IMPLEMENTED;
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}
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return GPG_ERR_NO_ERROR;
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case GRUB_LUKS_MODE_CBC_ESSIV:
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for (i = 0; i < len; i += GRUB_DISK_SECTOR_SIZE)
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{
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grub_size_t sz = ((dev->cipher->cipher->blocksize
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+ sizeof (grub_uint32_t) - 1)
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/ sizeof (grub_uint32_t));
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grub_uint32_t iv[sz];
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make_iv (iv, sz, sector);
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err = grub_crypto_ecb_encrypt (dev->secondary_cipher, iv, iv,
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dev->cipher->cipher->blocksize);
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if (err)
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return err;
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err = grub_crypto_cbc_decrypt (dev->cipher, data + i, data + i,
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GRUB_DISK_SECTOR_SIZE, iv);
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if (err)
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return err;
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sector++;
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}
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return GPG_ERR_NO_ERROR;
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case GRUB_LUKS_MODE_XTS:
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for (i = 0; i < len; i += GRUB_DISK_SECTOR_SIZE)
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{
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grub_size_t sz = ((dev->cipher->cipher->blocksize
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+ sizeof (grub_uint32_t) - 1)
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/ sizeof (grub_uint32_t));
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grub_uint32_t iv[sz];
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int j;
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make_iv (iv, sz, sector);
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err = grub_crypto_ecb_encrypt (dev->secondary_cipher, iv, iv,
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dev->cipher->cipher->blocksize);
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if (err)
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return err;
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for (j = 0; j < GRUB_DISK_SECTOR_SIZE;
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j += dev->cipher->cipher->blocksize)
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{
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grub_crypto_xor (data + i + j, data + i + j, iv,
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dev->cipher->cipher->blocksize);
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err = grub_crypto_ecb_decrypt (dev->cipher, data + i + j,
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data + i + j,
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dev->cipher->cipher->blocksize);
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if (err)
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return err;
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grub_crypto_xor (data + i + j, data + i + j, iv,
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dev->cipher->cipher->blocksize);
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gf_mul_x ((grub_uint8_t *) iv);
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}
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sector++;
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}
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return GPG_ERR_NO_ERROR;
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default:
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return GPG_ERR_NOT_IMPLEMENTED;
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sector++;
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}
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return GPG_ERR_NO_ERROR;
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}
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static int check_uuid, have_it;
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@ -238,11 +235,14 @@ configure_ciphers (const struct grub_luks_phdr *header)
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char uuid[sizeof (header->uuid) + 1];
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char ciphername[sizeof (header->cipherName) + 1];
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char ciphermode[sizeof (header->cipherMode) + 1];
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char *cipheriv = NULL;
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char hashspec[sizeof (header->hashSpec) + 1];
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grub_crypto_cipher_handle_t cipher = NULL, secondary_cipher = NULL;
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grub_crypto_cipher_handle_t essiv_cipher = NULL;
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const gcry_md_spec_t *hash = NULL, *essiv_hash = NULL;
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const struct gcry_cipher_spec *ciph;
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luks_mode_t mode;
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luks_mode_iv_t mode_iv;
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/* Look for LUKS magic sequence. */
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if (grub_memcmp (header->magic, LUKS_MAGIC, sizeof (header->magic))
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@ -294,35 +294,26 @@ configure_ciphers (const struct grub_luks_phdr *header)
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/* Configure the cipher mode. */
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if (grub_strcmp (ciphermode, "ecb") == 0)
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mode = GRUB_LUKS_MODE_ECB;
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else if (grub_strcmp (ciphermode, "cbc-plain") == 0
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|| grub_strcmp (ciphermode, "plain") == 0)
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mode = GRUB_LUKS_MODE_CBC_PLAIN;
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else if (grub_memcmp (ciphermode, "cbc-essiv:", sizeof ("cbc-essiv:") - 1)
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== 0)
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{
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mode = GRUB_LUKS_MODE_CBC_ESSIV;
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char *hash_str = ciphermode + 10;
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/* Configure the hash and cipher used for ESSIV. */
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essiv_hash = grub_crypto_lookup_md_by_name (hash_str);
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if (!essiv_hash)
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{
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grub_crypto_cipher_close (cipher);
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grub_error (GRUB_ERR_FILE_NOT_FOUND,
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"Couldn't load %s hash", hash_str);
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return NULL;
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}
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secondary_cipher = grub_crypto_cipher_open (ciph);
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if (!secondary_cipher)
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{
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grub_crypto_cipher_close (cipher);
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return NULL;
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}
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mode = GRUB_LUKS_MODE_ECB;
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mode_iv = GRUB_LUKS_MODE_IV_PLAIN;
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cipheriv = NULL;
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}
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else if (grub_strcmp (ciphermode, "xts-plain") == 0)
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else if (grub_strcmp (ciphermode, "plain") == 0)
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{
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mode = GRUB_LUKS_MODE_CBC;
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mode_iv = GRUB_LUKS_MODE_IV_PLAIN;
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cipheriv = NULL;
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}
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else if (grub_memcmp (ciphermode, "cbc-", sizeof ("cbc-") - 1) == 0)
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{
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mode = GRUB_LUKS_MODE_CBC;
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cipheriv = ciphermode + sizeof ("cbc-") - 1;
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}
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else if (grub_memcmp (ciphermode, "xts-", sizeof ("xts-") - 1) == 0)
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{
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mode = GRUB_LUKS_MODE_XTS;
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cipheriv = ciphermode + sizeof ("xts-") - 1;
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secondary_cipher = grub_crypto_cipher_open (ciph);
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if (!secondary_cipher)
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{
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@ -350,11 +341,51 @@ configure_ciphers (const struct grub_luks_phdr *header)
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return NULL;
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}
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if (cipheriv == NULL);
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else if (grub_memcmp (cipheriv, "plain", sizeof ("plain") - 1) == 0)
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mode_iv = GRUB_LUKS_MODE_IV_PLAIN;
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else if (grub_memcmp (cipheriv, "plain64", sizeof ("plain64") - 1) == 0)
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mode_iv = GRUB_LUKS_MODE_IV_PLAIN64;
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else if (grub_memcmp (cipheriv, "benbi", sizeof ("benbi") - 1) == 0)
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mode_iv = GRUB_LUKS_MODE_IV_BENBI;
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else if (grub_memcmp (cipheriv, "null", sizeof ("null") - 1) == 0)
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mode_iv = GRUB_LUKS_MODE_IV_NULL;
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else if (grub_memcmp (cipheriv, "essiv:", sizeof ("essiv:") - 1) == 0)
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{
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char *hash_str = cipheriv + 6;
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mode_iv = GRUB_LUKS_MODE_IV_ESSIV;
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/* Configure the hash and cipher used for ESSIV. */
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essiv_hash = grub_crypto_lookup_md_by_name (hash_str);
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if (!essiv_hash)
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{
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grub_crypto_cipher_close (cipher);
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grub_error (GRUB_ERR_FILE_NOT_FOUND,
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"Couldn't load %s hash", hash_str);
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return NULL;
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}
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essiv_cipher = grub_crypto_cipher_open (ciph);
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if (!essiv_cipher)
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{
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grub_crypto_cipher_close (cipher);
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return NULL;
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}
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}
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else
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{
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grub_crypto_cipher_close (cipher);
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grub_error (GRUB_ERR_BAD_ARGUMENT, "Unknown IV mode: %s",
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cipheriv);
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return NULL;
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}
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/* Configure the hash used for the AF splitter and HMAC. */
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hash = grub_crypto_lookup_md_by_name (hashspec);
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if (!hash)
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{
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grub_crypto_cipher_close (cipher);
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grub_crypto_cipher_close (essiv_cipher);
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grub_crypto_cipher_close (secondary_cipher);
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grub_error (GRUB_ERR_FILE_NOT_FOUND, "Couldn't load %s hash",
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hashspec);
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@ -368,7 +399,9 @@ configure_ciphers (const struct grub_luks_phdr *header)
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newdev->offset = grub_be_to_cpu32 (header->payloadOffset);
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newdev->source_disk = NULL;
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newdev->mode = mode;
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newdev->mode_iv = mode_iv;
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newdev->secondary_cipher = secondary_cipher;
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newdev->essiv_cipher = essiv_cipher;
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newdev->essiv_hash = essiv_hash;
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newdev->hash = hash;
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newdev->id = n++;
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@ -392,7 +425,7 @@ luks_recover_key (grub_luks_t dev, const struct grub_luks_phdr *header,
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grub_size_t length;
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grub_err_t err;
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if (dev->mode == GRUB_LUKS_MODE_CBC_ESSIV)
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if (dev->mode_iv == GRUB_LUKS_MODE_IV_ESSIV)
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{
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essiv_keysize = dev->essiv_hash->mdlen;
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hashed_key = grub_malloc (dev->essiv_hash->mdlen);
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@ -433,8 +466,7 @@ luks_recover_key (grub_luks_t dev, const struct grub_luks_phdr *header,
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gcry_err = grub_crypto_pbkdf2 (dev->hash, (grub_uint8_t *) passphrase,
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grub_strlen (passphrase),
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header->keyblock[i].passwordSalt,
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sizeof (header->
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keyblock[i].passwordSalt),
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sizeof (header->keyblock[i].passwordSalt),
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grub_be_to_cpu32 (header->keyblock[i].
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passwordIterations),
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digest, keysize);
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@ -460,10 +492,10 @@ luks_recover_key (grub_luks_t dev, const struct grub_luks_phdr *header,
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}
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/* Configure ESSIV if necessary. */
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if (dev->mode == GRUB_LUKS_MODE_CBC_ESSIV)
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if (dev->mode_iv == GRUB_LUKS_MODE_IV_ESSIV)
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{
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grub_crypto_hash (dev->essiv_hash, hashed_key, digest, keysize);
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gcry_err = grub_crypto_cipher_set_key (dev->secondary_cipher,
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gcry_err = grub_crypto_cipher_set_key (dev->essiv_cipher,
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hashed_key,
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essiv_keysize);
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if (gcry_err)
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@ -562,12 +594,12 @@ luks_recover_key (grub_luks_t dev, const struct grub_luks_phdr *header,
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}
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/* Configure ESSIV if necessary. */
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if (dev->mode == GRUB_LUKS_MODE_CBC_ESSIV)
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if (dev->mode_iv == GRUB_LUKS_MODE_IV_ESSIV)
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{
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grub_crypto_hash (dev->essiv_hash, hashed_key,
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candidate_key, keysize);
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gcry_err =
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grub_crypto_cipher_set_key (dev->secondary_cipher, hashed_key,
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grub_crypto_cipher_set_key (dev->essiv_cipher, hashed_key,
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essiv_keysize);
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if (gcry_err)
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{
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@ -604,6 +636,7 @@ luks_close (grub_luks_t luks)
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{
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grub_crypto_cipher_close (luks->cipher);
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grub_crypto_cipher_close (luks->secondary_cipher);
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grub_crypto_cipher_close (luks->essiv_cipher);
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grub_free (luks);
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}
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@ -888,6 +921,8 @@ grub_util_luks_print_ciphers (grub_disk_t disk)
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grub_printf ("%s ", dev->cipher->cipher->modname);
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if (dev->secondary_cipher)
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grub_printf ("%s ", dev->secondary_cipher->cipher->modname);
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if (dev->essiv_cipher)
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grub_printf ("%s ", dev->essiv_cipher->cipher->modname);
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if (dev->hash)
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grub_printf ("%s ", dev->hash->modname);
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if (dev->essiv_hash)
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@ -913,6 +948,7 @@ luks_cleanup (void)
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grub_free (dev->source);
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grub_free (dev->cipher);
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grub_free (dev->secondary_cipher);
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grub_free (dev->essiv_cipher);
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tmp = dev->next;
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grub_free (dev);
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dev = tmp;
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