diff options
Diffstat (limited to 'crypto/block-luks.c')
| -rw-r--r-- | crypto/block-luks.c | 228 |
1 files changed, 98 insertions, 130 deletions
diff --git a/crypto/block-luks.c b/crypto/block-luks.c index f62be6836b..df2b4105d6 100644 --- a/crypto/block-luks.c +++ b/crypto/block-luks.c @@ -23,6 +23,7 @@ #include "qemu/bswap.h" #include "block-luks.h" +#include "block-luks-priv.h" #include "crypto/hash.h" #include "crypto/afsplit.h" @@ -46,37 +47,6 @@ */ typedef struct QCryptoBlockLUKS QCryptoBlockLUKS; -typedef struct QCryptoBlockLUKSHeader QCryptoBlockLUKSHeader; -typedef struct QCryptoBlockLUKSKeySlot QCryptoBlockLUKSKeySlot; - - -/* The following constants are all defined by the LUKS spec */ -#define QCRYPTO_BLOCK_LUKS_VERSION 1 - -#define QCRYPTO_BLOCK_LUKS_MAGIC_LEN 6 -#define QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN 32 -#define QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN 32 -#define QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN 32 -#define QCRYPTO_BLOCK_LUKS_DIGEST_LEN 20 -#define QCRYPTO_BLOCK_LUKS_SALT_LEN 32 -#define QCRYPTO_BLOCK_LUKS_UUID_LEN 40 -#define QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS 8 -#define QCRYPTO_BLOCK_LUKS_STRIPES 4000 -#define QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS 1000 -#define QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS 1000 -#define QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET 4096 - -#define QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED 0x0000DEAD -#define QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED 0x00AC71F3 - -#define QCRYPTO_BLOCK_LUKS_SECTOR_SIZE 512LL - -#define QCRYPTO_BLOCK_LUKS_DEFAULT_ITER_TIME_MS 2000 -#define QCRYPTO_BLOCK_LUKS_ERASE_ITERATIONS 40 - -static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = { - 'L', 'U', 'K', 'S', 0xBA, 0xBE -}; typedef struct QCryptoBlockLUKSNameMap QCryptoBlockLUKSNameMap; struct QCryptoBlockLUKSNameMap { @@ -134,69 +104,7 @@ qcrypto_block_luks_cipher_name_map[] = { { "twofish", qcrypto_block_luks_cipher_size_map_twofish }, }; - -/* - * This struct is written to disk in big-endian format, - * but operated upon in native-endian format. - */ -struct QCryptoBlockLUKSKeySlot { - /* state of keyslot, enabled/disable */ - uint32_t active; - /* iterations for PBKDF2 */ - uint32_t iterations; - /* salt for PBKDF2 */ - uint8_t salt[QCRYPTO_BLOCK_LUKS_SALT_LEN]; - /* start sector of key material */ - uint32_t key_offset_sector; - /* number of anti-forensic stripes */ - uint32_t stripes; -}; - QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSKeySlot) != 48); - - -/* - * This struct is written to disk in big-endian format, - * but operated upon in native-endian format. - */ -struct QCryptoBlockLUKSHeader { - /* 'L', 'U', 'K', 'S', '0xBA', '0xBE' */ - char magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN]; - - /* LUKS version, currently 1 */ - uint16_t version; - - /* cipher name specification (aes, etc) */ - char cipher_name[QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN]; - - /* cipher mode specification (cbc-plain, xts-essiv:sha256, etc) */ - char cipher_mode[QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN]; - - /* hash specification (sha256, etc) */ - char hash_spec[QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN]; - - /* start offset of the volume data (in 512 byte sectors) */ - uint32_t payload_offset_sector; - - /* Number of key bytes */ - uint32_t master_key_len; - - /* master key checksum after PBKDF2 */ - uint8_t master_key_digest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN]; - - /* salt for master key PBKDF2 */ - uint8_t master_key_salt[QCRYPTO_BLOCK_LUKS_SALT_LEN]; - - /* iterations for master key PBKDF2 */ - uint32_t master_key_iterations; - - /* UUID of the partition in standard ASCII representation */ - uint8_t uuid[QCRYPTO_BLOCK_LUKS_UUID_LEN]; - - /* key slots */ - QCryptoBlockLUKSKeySlot key_slots[QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS]; -}; - QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSHeader) != 592); @@ -254,7 +162,7 @@ static int qcrypto_block_luks_cipher_name_lookup(const char *name, } } - error_setg(errp, "Algorithm %s with key size %d bytes not supported", + error_setg(errp, "Algorithm '%s' with key size %d bytes not supported", name, key_bytes); return 0; } @@ -290,7 +198,7 @@ static int qcrypto_block_luks_name_lookup(const char *name, int ret = qapi_enum_parse(map, name, -1, NULL); if (ret < 0) { - error_setg(errp, "%s %s not supported", type, name); + error_setg(errp, "%s '%s' not supported", type, name); return 0; } return ret; @@ -440,6 +348,51 @@ qcrypto_block_luks_splitkeylen_sectors(const QCryptoBlockLUKS *luks, return ROUND_UP(splitkeylen_sectors, header_sectors); } + +void +qcrypto_block_luks_to_disk_endian(QCryptoBlockLUKSHeader *hdr) +{ + size_t i; + + /* + * Everything on disk uses Big Endian (tm), so flip header fields + * before writing them + */ + cpu_to_be16s(&hdr->version); + cpu_to_be32s(&hdr->payload_offset_sector); + cpu_to_be32s(&hdr->master_key_len); + cpu_to_be32s(&hdr->master_key_iterations); + + for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { + cpu_to_be32s(&hdr->key_slots[i].active); + cpu_to_be32s(&hdr->key_slots[i].iterations); + cpu_to_be32s(&hdr->key_slots[i].key_offset_sector); + cpu_to_be32s(&hdr->key_slots[i].stripes); + } +} + +void +qcrypto_block_luks_from_disk_endian(QCryptoBlockLUKSHeader *hdr) +{ + size_t i; + + /* + * The header is always stored in big-endian format, so + * convert everything to native + */ + be16_to_cpus(&hdr->version); + be32_to_cpus(&hdr->payload_offset_sector); + be32_to_cpus(&hdr->master_key_len); + be32_to_cpus(&hdr->master_key_iterations); + + for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { + be32_to_cpus(&hdr->key_slots[i].active); + be32_to_cpus(&hdr->key_slots[i].iterations); + be32_to_cpus(&hdr->key_slots[i].key_offset_sector); + be32_to_cpus(&hdr->key_slots[i].stripes); + } +} + /* * Stores the main LUKS header, taking care of endianess */ @@ -451,28 +404,13 @@ qcrypto_block_luks_store_header(QCryptoBlock *block, { const QCryptoBlockLUKS *luks = block->opaque; Error *local_err = NULL; - size_t i; g_autofree QCryptoBlockLUKSHeader *hdr_copy = NULL; /* Create a copy of the header */ hdr_copy = g_new0(QCryptoBlockLUKSHeader, 1); memcpy(hdr_copy, &luks->header, sizeof(QCryptoBlockLUKSHeader)); - /* - * Everything on disk uses Big Endian (tm), so flip header fields - * before writing them - */ - cpu_to_be16s(&hdr_copy->version); - cpu_to_be32s(&hdr_copy->payload_offset_sector); - cpu_to_be32s(&hdr_copy->master_key_len); - cpu_to_be32s(&hdr_copy->master_key_iterations); - - for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { - cpu_to_be32s(&hdr_copy->key_slots[i].active); - cpu_to_be32s(&hdr_copy->key_slots[i].iterations); - cpu_to_be32s(&hdr_copy->key_slots[i].key_offset_sector); - cpu_to_be32s(&hdr_copy->key_slots[i].stripes); - } + qcrypto_block_luks_to_disk_endian(hdr_copy); /* Write out the partition header and key slot headers */ writefunc(block, 0, (const uint8_t *)hdr_copy, sizeof(*hdr_copy), @@ -496,7 +434,6 @@ qcrypto_block_luks_load_header(QCryptoBlock *block, Error **errp) { int rv; - size_t i; QCryptoBlockLUKS *luks = block->opaque; /* @@ -512,21 +449,7 @@ qcrypto_block_luks_load_header(QCryptoBlock *block, return rv; } - /* - * The header is always stored in big-endian format, so - * convert everything to native - */ - be16_to_cpus(&luks->header.version); - be32_to_cpus(&luks->header.payload_offset_sector); - be32_to_cpus(&luks->header.master_key_len); - be32_to_cpus(&luks->header.master_key_iterations); - - for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { - be32_to_cpus(&luks->header.key_slots[i].active); - be32_to_cpus(&luks->header.key_slots[i].iterations); - be32_to_cpus(&luks->header.key_slots[i].key_offset_sector); - be32_to_cpus(&luks->header.key_slots[i].stripes); - } + qcrypto_block_luks_from_disk_endian(&luks->header); return 0; } @@ -554,6 +477,36 @@ qcrypto_block_luks_check_header(const QCryptoBlockLUKS *luks, Error **errp) return -1; } + if (!memchr(luks->header.cipher_name, '\0', + sizeof(luks->header.cipher_name))) { + error_setg(errp, "LUKS header cipher name is not NUL terminated"); + return -1; + } + + if (!memchr(luks->header.cipher_mode, '\0', + sizeof(luks->header.cipher_mode))) { + error_setg(errp, "LUKS header cipher mode is not NUL terminated"); + return -1; + } + + if (!memchr(luks->header.hash_spec, '\0', + sizeof(luks->header.hash_spec))) { + error_setg(errp, "LUKS header hash spec is not NUL terminated"); + return -1; + } + + if (luks->header.payload_offset_sector < + DIV_ROUND_UP(QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET, + QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) { + error_setg(errp, "LUKS payload is overlapping with the header"); + return -1; + } + + if (luks->header.master_key_iterations == 0) { + error_setg(errp, "LUKS key iteration count is zero"); + return -1; + } + /* Check all keyslots for corruption */ for (i = 0 ; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS ; i++) { @@ -564,8 +517,9 @@ qcrypto_block_luks_check_header(const QCryptoBlockLUKS *luks, Error **errp) header_sectors, slot1->stripes); - if (slot1->stripes == 0) { - error_setg(errp, "Keyslot %zu is corrupted (stripes == 0)", i); + if (slot1->stripes != QCRYPTO_BLOCK_LUKS_STRIPES) { + error_setg(errp, "Keyslot %zu is corrupted (stripes %d != %d)", + i, slot1->stripes, QCRYPTO_BLOCK_LUKS_STRIPES); return -1; } @@ -576,6 +530,20 @@ qcrypto_block_luks_check_header(const QCryptoBlockLUKS *luks, Error **errp) return -1; } + if (slot1->active == QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED && + slot1->iterations == 0) { + error_setg(errp, "Keyslot %zu iteration count is zero", i); + return -1; + } + + if (start1 < DIV_ROUND_UP(QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET, + QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) { + error_setg(errp, + "Keyslot %zu is overlapping with the LUKS header", + i); + return -1; + } + if (start1 + len1 > luks->header.payload_offset_sector) { error_setg(errp, "Keyslot %zu is overlapping with the encrypted payload", @@ -624,7 +592,7 @@ qcrypto_block_luks_parse_header(QCryptoBlockLUKS *luks, Error **errp) */ ivgen_name = strchr(cipher_mode, '-'); if (!ivgen_name) { - error_setg(errp, "Unexpected cipher mode string format %s", + error_setg(errp, "Unexpected cipher mode string format '%s'", luks->header.cipher_mode); return -1; } |