329 lines
12 KiB
Diff
329 lines
12 KiB
Diff
From 3e2ffefe1edbbd874ca18ac397a14465d1ac49be Mon Sep 17 00:00:00 2001
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From: John Lane <john@lane.uk.net>
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Date: Fri, 26 Jun 2015 13:49:58 +0100
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Subject: [PATCH 3/5] Cryptomount luks allow multiple passphrase attempts
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---
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grub-core/disk/luks.c | 278 ++++++++++++++++++++++++++------------------------
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1 file changed, 143 insertions(+), 135 deletions(-)
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diff --git a/grub-core/disk/luks.c b/grub-core/disk/luks.c
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index 5882368..11e437e 100644
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--- a/grub-core/disk/luks.c
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+++ b/grub-core/disk/luks.c
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@@ -321,10 +321,10 @@ configure_ciphers (grub_disk_t disk, const char *check_uuid,
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static grub_err_t
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luks_recover_key (grub_disk_t source,
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- grub_cryptodisk_t dev,
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- grub_file_t hdr,
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- grub_uint8_t *keyfile_bytes,
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- grub_size_t keyfile_bytes_size)
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+ grub_cryptodisk_t dev,
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+ grub_file_t hdr,
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+ grub_uint8_t *keyfile_bytes,
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+ grub_size_t keyfile_bytes_size)
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{
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struct grub_luks_phdr header;
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grub_size_t keysize;
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@@ -339,6 +339,7 @@ luks_recover_key (grub_disk_t source,
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grub_size_t max_stripes = 1;
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char *tmp;
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grub_uint32_t sector;
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+ unsigned attempts = 2;
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err = GRUB_ERR_NONE;
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@@ -361,151 +362,158 @@ luks_recover_key (grub_disk_t source,
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for (i = 0; i < ARRAY_SIZE (header.keyblock); i++)
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if (grub_be_to_cpu32 (header.keyblock[i].active) == LUKS_KEY_ENABLED
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- && grub_be_to_cpu32 (header.keyblock[i].stripes) > max_stripes)
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+ && grub_be_to_cpu32 (header.keyblock[i].stripes) > max_stripes)
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max_stripes = grub_be_to_cpu32 (header.keyblock[i].stripes);
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split_key = grub_malloc (keysize * max_stripes);
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if (!split_key)
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return grub_errno;
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- if (keyfile_bytes)
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+ while (attempts)
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{
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- /* Use bytestring from key file as passphrase */
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- passphrase = keyfile_bytes;
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- passphrase_length = keyfile_bytes_size;
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- }
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- else
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- {
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- /* Get the passphrase from the user. */
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- tmp = NULL;
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- if (source->partition)
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- tmp = grub_partition_get_name (source->partition);
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- grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "), source->name,
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- source->partition ? "," : "", tmp ? : "", dev->uuid);
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- grub_free (tmp);
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- if (!grub_password_get (interactive_passphrase, MAX_PASSPHRASE))
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+ if (keyfile_bytes)
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{
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- grub_free (split_key);
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- return grub_error (GRUB_ERR_BAD_ARGUMENT, "Passphrase not supplied");
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- }
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-
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- passphrase = (grub_uint8_t *)interactive_passphrase;
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- passphrase_length = grub_strlen (interactive_passphrase);
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-
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- }
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-
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- /* Try to recover master key from each active keyslot. */
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- for (i = 0; i < ARRAY_SIZE (header.keyblock); i++)
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- {
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- gcry_err_code_t gcry_err;
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- grub_uint8_t candidate_key[GRUB_CRYPTODISK_MAX_KEYLEN];
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- grub_uint8_t digest[GRUB_CRYPTODISK_MAX_KEYLEN];
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-
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- /* Check if keyslot is enabled. */
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- if (grub_be_to_cpu32 (header.keyblock[i].active) != LUKS_KEY_ENABLED)
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- continue;
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-
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- grub_dprintf ("luks", "Trying keyslot %d\n", i);
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-
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- /* Calculate the PBKDF2 of the user supplied passphrase. */
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- gcry_err = grub_crypto_pbkdf2 (dev->hash, (grub_uint8_t *) passphrase,
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- passphrase_length,
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- header.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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-
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- if (gcry_err)
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- {
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- grub_free (split_key);
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- return grub_crypto_gcry_error (gcry_err);
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- }
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-
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- grub_dprintf ("luks", "PBKDF2 done\n");
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-
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- gcry_err = grub_cryptodisk_setkey (dev, digest, keysize);
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- if (gcry_err)
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- {
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- grub_free (split_key);
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- return grub_crypto_gcry_error (gcry_err);
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- }
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-
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- sector = grub_be_to_cpu32 (header.keyblock[i].keyMaterialOffset);
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- length = (keysize * grub_be_to_cpu32 (header.keyblock[i].stripes));
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-
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- /* Read and decrypt the key material from the disk. */
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- if (hdr)
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- {
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- grub_file_seek (hdr, sector * 512);
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- if (grub_file_read (hdr, split_key, length) != (grub_ssize_t)length)
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- err = GRUB_ERR_READ_ERROR;
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+ /* Use bytestring from key file as passphrase */
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+ passphrase = keyfile_bytes;
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+ passphrase_length = keyfile_bytes_size;
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+ keyfile_bytes = NULL; /* use it only once */
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}
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else
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- err = grub_disk_read (source, sector, 0, length, split_key);
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- if (err)
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- {
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- grub_free (split_key);
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- return err;
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- }
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-
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- gcry_err = grub_cryptodisk_decrypt (dev, split_key, length, 0);
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- if (gcry_err)
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- {
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- grub_free (split_key);
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- return grub_crypto_gcry_error (gcry_err);
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- }
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-
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- /* Merge the decrypted key material to get the candidate master key. */
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- gcry_err = AF_merge (dev->hash, split_key, candidate_key, keysize,
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- grub_be_to_cpu32 (header.keyblock[i].stripes));
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- if (gcry_err)
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- {
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- grub_free (split_key);
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- return grub_crypto_gcry_error (gcry_err);
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- }
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-
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- grub_dprintf ("luks", "candidate key recovered\n");
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-
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- /* Calculate the PBKDF2 of the candidate master key. */
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- gcry_err = grub_crypto_pbkdf2 (dev->hash, candidate_key,
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- grub_be_to_cpu32 (header.keyBytes),
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- header.mkDigestSalt,
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- sizeof (header.mkDigestSalt),
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- grub_be_to_cpu32
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- (header.mkDigestIterations),
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- candidate_digest,
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- sizeof (candidate_digest));
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- if (gcry_err)
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- {
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- grub_free (split_key);
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- return grub_crypto_gcry_error (gcry_err);
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- }
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-
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- /* Compare the calculated PBKDF2 to the digest stored
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- in the header to see if it's correct. */
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- if (grub_memcmp (candidate_digest, header.mkDigest,
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- sizeof (header.mkDigest)) != 0)
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- {
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- grub_dprintf ("luks", "bad digest\n");
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- continue;
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- }
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+ {
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+ /* Get the passphrase from the user. */
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+ tmp = NULL;
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+ if (source->partition)
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+ tmp = grub_partition_get_name (source->partition);
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+ grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "), source->name,
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+ source->partition ? "," : "", tmp ? : "", dev->uuid);
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+ grub_free (tmp);
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+ if (!grub_password_get (interactive_passphrase, MAX_PASSPHRASE))
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+ {
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+ grub_free (split_key);
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+ return grub_error (GRUB_ERR_BAD_ARGUMENT, "Passphrase not supplied");
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+ }
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+
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+ passphrase = (grub_uint8_t *)interactive_passphrase;
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+ passphrase_length = grub_strlen (interactive_passphrase);
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- /* TRANSLATORS: It's a cryptographic key slot: one element of an array
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- where each element is either empty or holds a key. */
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- grub_printf_ (N_("Slot %d opened\n"), i);
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+ }
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- /* Set the master key. */
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- gcry_err = grub_cryptodisk_setkey (dev, candidate_key, keysize);
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- if (gcry_err)
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- {
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- grub_free (split_key);
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- return grub_crypto_gcry_error (gcry_err);
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- }
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+ /* Try to recover master key from each active keyslot. */
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+ for (i = 0; i < ARRAY_SIZE (header.keyblock); i++)
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+ {
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+ gcry_err_code_t gcry_err;
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+ grub_uint8_t candidate_key[GRUB_CRYPTODISK_MAX_KEYLEN];
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+ grub_uint8_t digest[GRUB_CRYPTODISK_MAX_KEYLEN];
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+
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+ /* Check if keyslot is enabled. */
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+ if (grub_be_to_cpu32 (header.keyblock[i].active) != LUKS_KEY_ENABLED)
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+ continue;
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+
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+ grub_dprintf ("luks", "Trying keyslot %d\n", i);
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+
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+ /* Calculate the PBKDF2 of the user supplied passphrase. */
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+ gcry_err = grub_crypto_pbkdf2 (dev->hash, (grub_uint8_t *) passphrase,
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+ passphrase_length,
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+ header.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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+
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+ if (gcry_err)
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+ {
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+ grub_free (split_key);
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+ return grub_crypto_gcry_error (gcry_err);
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+ }
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+
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+ grub_dprintf ("luks", "PBKDF2 done\n");
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+
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+ gcry_err = grub_cryptodisk_setkey (dev, digest, keysize);
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+ if (gcry_err)
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+ {
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+ grub_free (split_key);
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+ return grub_crypto_gcry_error (gcry_err);
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+ }
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+
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+ sector = grub_be_to_cpu32 (header.keyblock[i].keyMaterialOffset);
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+ length = (keysize * grub_be_to_cpu32 (header.keyblock[i].stripes));
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+
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+ /* Read and decrypt the key material from the disk. */
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+ if (hdr)
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+ {
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+ grub_file_seek (hdr, sector * 512);
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+ if (grub_file_read (hdr, split_key, length) != (grub_ssize_t)length)
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+ err = GRUB_ERR_READ_ERROR;
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+ }
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+ else
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+ err = grub_disk_read (source, sector, 0, length, split_key);
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+ if (err)
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+ {
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+ grub_free (split_key);
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+ return err;
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+ }
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+
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+ gcry_err = grub_cryptodisk_decrypt (dev, split_key, length, 0);
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+ if (gcry_err)
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+ {
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+ grub_free (split_key);
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+ return grub_crypto_gcry_error (gcry_err);
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+ }
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+
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+ /* Merge the decrypted key material to get the candidate master key. */
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+ gcry_err = AF_merge (dev->hash, split_key, candidate_key, keysize,
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+ grub_be_to_cpu32 (header.keyblock[i].stripes));
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+ if (gcry_err)
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+ {
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+ grub_free (split_key);
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+ return grub_crypto_gcry_error (gcry_err);
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+ }
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+
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+ grub_dprintf ("luks", "candidate key recovered\n");
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+
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+ /* Calculate the PBKDF2 of the candidate master key. */
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+ gcry_err = grub_crypto_pbkdf2 (dev->hash, candidate_key,
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+ grub_be_to_cpu32 (header.keyBytes),
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+ header.mkDigestSalt,
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+ sizeof (header.mkDigestSalt),
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+ grub_be_to_cpu32
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+ (header.mkDigestIterations),
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+ candidate_digest,
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+ sizeof (candidate_digest));
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+ if (gcry_err)
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+ {
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+ grub_free (split_key);
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+ return grub_crypto_gcry_error (gcry_err);
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+ }
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+
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+ /* Compare the calculated PBKDF2 to the digest stored
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+ in the header to see if it's correct. */
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+ if (grub_memcmp (candidate_digest, header.mkDigest,
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+ sizeof (header.mkDigest)) != 0)
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+ {
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+ grub_dprintf ("luks", "bad digest\n");
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+ continue;
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+ }
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+
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+ /* TRANSLATORS: It's a cryptographic key slot: one element of an array
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+ where each element is either empty or holds a key. */
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+ grub_printf_ (N_("Slot %d opened\n"), i);
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+
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+ /* Set the master key. */
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+ gcry_err = grub_cryptodisk_setkey (dev, candidate_key, keysize);
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+ if (gcry_err)
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+ {
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+ grub_free (split_key);
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+ return grub_crypto_gcry_error (gcry_err);
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+ }
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- grub_free (split_key);
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+ grub_free (split_key);
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- return GRUB_ERR_NONE;
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+ return GRUB_ERR_NONE;
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+ }
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+ grub_printf_ (N_("Failed to decrypt master key.\n"));
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+ if (--attempts) grub_printf_ (N_("%u attempt%s remaining.\n"), attempts,
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+ (attempts==1) ? "" : "s");
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}
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grub_free (split_key);
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--
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2.1.2
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