From a8f9e3dcece89c179e89414abe89985c7ab1e03f Mon Sep 17 00:00:00 2001 From: John Lane Date: Fri, 26 Jun 2015 22:09:52 +0100 Subject: [PATCH 4/7] Cryptomount support plain dm-crypt Patch modified to take into account a change to context brought about by c93d3e694713b8230fa2cf88414fabe005b56782 grub-core/disk/cryptodisk.c 142c142 < if (disklast) --- > --- grub-core/disk/cryptodisk.c | 298 +++++++++++++++++++++++++++++++++++++++++++- grub-core/disk/luks.c | 195 +---------------------------- include/grub/cryptodisk.h | 8 ++ 3 files changed, 310 insertions(+), 191 deletions(-) diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c index 5261af547..7f656f75c 100644 --- a/grub-core/disk/cryptodisk.c +++ b/grub-core/disk/cryptodisk.c @@ -45,6 +45,12 @@ static const struct grub_arg_option options[] = {"keyfile", 'k', 0, N_("Key file"), 0, ARG_TYPE_STRING}, {"keyfile-offset", 'O', 0, N_("Key file offset (bytes)"), 0, ARG_TYPE_INT}, {"keyfile-size", 'S', 0, N_("Key file data size (bytes)"), 0, ARG_TYPE_INT}, + {"plain", 'p', 0, N_("Plain (no LUKS header)"), 0, ARG_TYPE_NONE}, + {"cipher", 'c', 0, N_("Plain mode cipher"), 0, ARG_TYPE_STRING}, + {"digest", 'd', 0, N_("Plain mode passphrase digest (hash)"), 0, ARG_TYPE_STRING}, + {"offset", 'o', 0, N_("Plain mode data sector offset"), 0, ARG_TYPE_INT}, + {"size", 's', 0, N_("Size of raw device (sectors, defaults to whole device)"), 0, ARG_TYPE_INT}, + {"key-size", 'K', 0, N_("Set key size (bits)"), 0, ARG_TYPE_INT}, {0, 0, 0, 0, 0, 0} }; @@ -933,6 +939,48 @@ grub_cryptodisk_scan_device (const char *name, return have_it && search_uuid ? 1 : 0; } +/* Hashes a passphrase into a key and stores it with cipher. */ +static gcry_err_code_t +set_passphrase (grub_cryptodisk_t dev, grub_size_t keysize, const char *passphrase) +{ + grub_uint8_t derived_hash[GRUB_CRYPTODISK_MAX_KEYLEN * 2], *dh = derived_hash; + char *p; + unsigned int round, i; + unsigned int len, size; + + /* Need no passphrase if there's no key */ + if (keysize == 0) + return GPG_ERR_INV_KEYLEN; + + /* Hack to support the "none" hash */ + if (dev->hash) + len = dev->hash->mdlen; + else + len = grub_strlen (passphrase); + + if (keysize > GRUB_CRYPTODISK_MAX_KEYLEN || len > GRUB_CRYPTODISK_MAX_KEYLEN) + return GPG_ERR_INV_KEYLEN; + + p = grub_malloc (grub_strlen (passphrase) + 2 + keysize / len); + if (!p) + return grub_errno; + + for (round = 0, size = keysize; size; round++, dh += len, size -= len) + { + for (i = 0; i < round; i++) + p[i] = 'A'; + + grub_strcpy (p + i, passphrase); + + if (len > size) + len = size; + + grub_crypto_hash (dev->hash, dh, p, grub_strlen (p)); + } + + return grub_cryptodisk_setkey (dev, derived_hash, keysize); +} + static grub_err_t grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) { @@ -1060,7 +1108,63 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) return GRUB_ERR_NONE; } - err = grub_cryptodisk_scan_device_real (diskname, disk); + if (state[7].set) /* Plain mode */ + { + char *cipher; + char *mode; + char *digest; + int offset, size, key_size; + + cipher = grub_strdup (state[8].set ? state[8].arg : GRUB_CRYPTODISK_PLAIN_CIPHER); + digest = grub_strdup (state[9].set ? state[9].arg : GRUB_CRYPTODISK_PLAIN_DIGEST); + offset = state[10].set ? grub_strtoul (state[10].arg, 0, 0) : 0; + size = state[11].set ? grub_strtoul (state[11].arg, 0, 0) : 0; + key_size = ( state[12].set ? grub_strtoul (state[12].arg, 0, 0) \ + : GRUB_CRYPTODISK_PLAIN_KEYSIZE ) / 8; + + /* no strtok, do it manually */ + mode = grub_strchr(cipher,'-'); + if (!mode) + return GRUB_ERR_BAD_ARGUMENT; + else + *mode++ = 0; + + dev = grub_cryptodisk_create (disk, NULL, cipher, mode, digest); + + dev->offset_sectors = offset; + if (size) dev->total_sectors = size; + + if (key) + { + err = grub_cryptodisk_setkey (dev, key, key_size); + if (err) + return err; + } + else + { + char passphrase[GRUB_CRYPTODISK_MAX_PASSPHRASE] = ""; + + grub_printf_ (N_("Enter passphrase for %s: "), diskname); + if (!grub_password_get (passphrase, GRUB_CRYPTODISK_MAX_PASSPHRASE)) + return grub_error (GRUB_ERR_BAD_ARGUMENT, "Passphrase not supplied"); + + err = set_passphrase (dev, key_size, passphrase); + if (err) + { + grub_crypto_cipher_close (dev->cipher); + return err; + } + } + + grub_cryptodisk_insert (dev, diskname, disk); + + grub_free (cipher); + grub_free (digest); + + err = GRUB_ERR_NONE; + } + else + err = grub_cryptodisk_scan_device_real (diskname, disk); grub_disk_close (disk); if (disklast) @@ -1193,13 +1297,203 @@ struct grub_procfs_entry luks_script = .get_contents = luks_script_get }; +grub_cryptodisk_t +grub_cryptodisk_create (grub_disk_t disk, char *uuid, + char *ciphername, char *ciphermode, char *hashspec) +{ + grub_cryptodisk_t newdev; + 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 *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; + + if (!uuid) + uuid = (char*)"00000000000000000000000000000000"; + + ciph = grub_crypto_lookup_cipher_by_name (ciphername); + if (!ciph) + { + grub_error (GRUB_ERR_FILE_NOT_FOUND, "Cipher %s isn't available", + ciphername); + return NULL; + } + + /* Configure the cipher used for the bulk data. */ + cipher = grub_crypto_cipher_open (ciph); + if (!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; + } + + /* Configure the passphrase hash (LUKS also uses AF splitter and HMAC). */ + hash = grub_crypto_lookup_md_by_name (hashspec); + if (!hash) + { + grub_crypto_cipher_close (cipher); + grub_crypto_cipher_close (essiv_cipher); + grub_crypto_cipher_close (secondary_cipher); + grub_error (GRUB_ERR_FILE_NOT_FOUND, "Couldn't load %s hash", + hashspec); + return NULL; + } + + newdev = grub_zalloc (sizeof (struct grub_cryptodisk)); + if (!newdev) + { + grub_crypto_cipher_close (cipher); + grub_crypto_cipher_close (essiv_cipher); + grub_crypto_cipher_close (secondary_cipher); + return NULL; + } + newdev->cipher = cipher; + newdev->offset_sectors = 0; + 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_sectors = grub_disk_native_sectors (disk) - newdev->offset_sectors; + grub_memcpy (newdev->uuid, uuid, sizeof (newdev->uuid)); + COMPILE_TIME_ASSERT (sizeof (newdev->uuid) >= sizeof (uuid)); + + return newdev; +} + static grub_extcmd_t cmd; GRUB_MOD_INIT (cryptodisk) { grub_disk_dev_register (&grub_cryptodisk_dev); cmd = grub_register_extcmd ("cryptomount", grub_cmd_cryptomount, 0, - N_("SOURCE|-u UUID|-a|-b|-H file"), + N_("SOURCE|-u UUID|-a|-b|-H file|-p -c cipher -d digest"), N_("Mount a crypto device."), options); grub_procfs_register ("luks_script", &luks_script); } diff --git a/grub-core/disk/luks.c b/grub-core/disk/luks.c index 11e437edb..4ebe21b4e 100644 --- a/grub-core/disk/luks.c +++ b/grub-core/disk/luks.c @@ -329,7 +146,7 @@ luks_recover_key (grub_disk_t source, struct grub_luks_phdr header; grub_size_t keysize; grub_uint8_t *split_key = NULL; - char interactive_passphrase[MAX_PASSPHRASE] = ""; + char interactive_passphrase[GRUB_CRYPTODISK_MAX_PASSPHRASE] = ""; grub_uint8_t *passphrase; grub_size_t passphrase_length; grub_uint8_t candidate_digest[sizeof (header.mkDigest)]; @@ -387,7 +204,7 @@ luks_recover_key (grub_disk_t source, grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "), source->name, source->partition ? "," : "", tmp ? : "", dev->uuid); grub_free (tmp); - if (!grub_password_get (interactive_passphrase, MAX_PASSPHRASE)) + if (!grub_password_get (interactive_passphrase, GRUB_CRYPTODISK_MAX_PASSPHRASE)) { grub_free (split_key); return grub_error (GRUB_ERR_BAD_ARGUMENT, "Passphrase not supplied"); diff --git a/include/grub/cryptodisk.h b/include/grub/cryptodisk.h index 67f6b0b59..bb25ab730 100644 --- a/include/grub/cryptodisk.h +++ b/include/grub/cryptodisk.h @@ -54,9 +54,14 @@ 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) #define GRUB_CRYPTODISK_MAX_KEYLEN 128 +#define GRUB_CRYPTODISK_MAX_PASSPHRASE 256 #define GRUB_CRYPTODISK_MAX_KEYFILE_SIZE 8192 +#define GRUB_CRYPTODISK_PLAIN_CIPHER "aes-cbc-essiv:sha256" +#define GRUB_CRYPTODISK_PLAIN_DIGEST "ripemd160" +#define GRUB_CRYPTODISK_PLAIN_KEYSIZE 256 + struct grub_cryptodisk; typedef gcry_err_code_t @@ -160,4 +165,7 @@ grub_util_get_geli_uuid (const char *dev); grub_cryptodisk_t grub_cryptodisk_get_by_uuid (const char *uuid); grub_cryptodisk_t grub_cryptodisk_get_by_source_disk (grub_disk_t disk); +grub_cryptodisk_t grub_cryptodisk_create (grub_disk_t disk, char *uuid, + char *ciphername, char *ciphermode, char *digest); + #endif -- 2.16.2