diff options
Diffstat (limited to 'libblkid/src/superblocks/luks.c')
| -rw-r--r-- | libblkid/src/superblocks/luks.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/libblkid/src/superblocks/luks.c b/libblkid/src/superblocks/luks.c new file mode 100644 index 0000000..0230b34 --- /dev/null +++ b/libblkid/src/superblocks/luks.c @@ -0,0 +1,134 @@ +/* + * Copyright (C) 2008 Karel Zak <kzak@redhat.com> + * Copyright (C) 2018 Milan Broz <gmazyland@gmail.com> + * + * Inspired by libvolume_id by + * Kay Sievers <kay.sievers@vrfy.org> + * + * This file may be redistributed under the terms of the + * GNU Lesser General Public License. + */ +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <errno.h> +#include <ctype.h> +#include <stdint.h> + +#include "superblocks.h" + +#define LUKS_CIPHERNAME_L 32 +#define LUKS_CIPHERMODE_L 32 +#define LUKS_HASHSPEC_L 32 +#define LUKS_DIGESTSIZE 20 +#define LUKS_SALTSIZE 32 +#define LUKS_MAGIC_L 6 +#define UUID_STRING_L 40 +#define LUKS2_LABEL_L 48 +#define LUKS2_SALT_L 64 +#define LUKS2_CHECKSUM_ALG_L 32 +#define LUKS2_CHECKSUM_L 64 + +#define LUKS_MAGIC "LUKS\xba\xbe" +#define LUKS_MAGIC_2 "SKUL\xba\xbe" + +/* Offsets for secondary header (for scan if primary header is corrupted). */ +#define LUKS2_HDR2_OFFSETS { 0x04000, 0x008000, 0x010000, 0x020000, \ + 0x40000, 0x080000, 0x100000, 0x200000, 0x400000 } + +static const uint64_t secondary_offsets[] = LUKS2_HDR2_OFFSETS; + +struct luks_phdr { + uint8_t magic[LUKS_MAGIC_L]; + uint16_t version; + uint8_t cipherName[LUKS_CIPHERNAME_L]; + uint8_t cipherMode[LUKS_CIPHERMODE_L]; + uint8_t hashSpec[LUKS_HASHSPEC_L]; + uint32_t payloadOffset; + uint32_t keyBytes; + uint8_t mkDigest[LUKS_DIGESTSIZE]; + uint8_t mkDigestSalt[LUKS_SALTSIZE]; + uint32_t mkDigestIterations; + uint8_t uuid[UUID_STRING_L]; +} __attribute__((packed)); + +struct luks2_phdr { + char magic[LUKS_MAGIC_L]; + uint16_t version; + uint64_t hdr_size; /* in bytes, including JSON area */ + uint64_t seqid; /* increased on every update */ + char label[LUKS2_LABEL_L]; + char checksum_alg[LUKS2_CHECKSUM_ALG_L]; + uint8_t salt[LUKS2_SALT_L]; /* unique for every header/offset */ + char uuid[UUID_STRING_L]; + char subsystem[LUKS2_LABEL_L]; /* owner subsystem label */ + uint64_t hdr_offset; /* offset from device start in bytes */ + char _padding[184]; + uint8_t csum[LUKS2_CHECKSUM_L]; + /* Padding to 4k, then JSON area */ +} __attribute__ ((packed)); + +static int luks_attributes(blkid_probe pr, struct luks2_phdr *header, uint64_t offset) +{ + int version; + struct luks_phdr *header_v1; + + if (blkid_probe_set_magic(pr, offset, LUKS_MAGIC_L, (unsigned char *) &header->magic)) + return BLKID_PROBE_NONE; + + version = be16_to_cpu(header->version); + blkid_probe_sprintf_version(pr, "%u", version); + + if (version == 1) { + header_v1 = (struct luks_phdr *)header; + blkid_probe_strncpy_uuid(pr, + (unsigned char *) header_v1->uuid, UUID_STRING_L); + } else if (version == 2) { + blkid_probe_strncpy_uuid(pr, + (unsigned char *) header->uuid, UUID_STRING_L); + blkid_probe_set_label(pr, + (unsigned char *) header->label, LUKS2_LABEL_L); + blkid_probe_set_id_label(pr, "SUBSYSTEM", + (unsigned char *) header->subsystem, LUKS2_LABEL_L); + } + + return BLKID_PROBE_OK; +} + +static int probe_luks(blkid_probe pr, const struct blkid_idmag *mag __attribute__((__unused__))) +{ + struct luks2_phdr *header; + size_t i; + + header = (struct luks2_phdr *) blkid_probe_get_buffer(pr, 0, sizeof(struct luks2_phdr)); + if (!header) + return errno ? -errno : BLKID_PROBE_NONE; + + if (!memcmp(header->magic, LUKS_MAGIC, LUKS_MAGIC_L)) { + /* LUKS primary header was found. */ + return luks_attributes(pr, header, 0); + } + + /* No primary header, scan for known offsets of LUKS2 secondary header. */ + for (i = 0; i < ARRAY_SIZE(secondary_offsets); i++) { + header = (struct luks2_phdr *) blkid_probe_get_buffer(pr, + secondary_offsets[i], sizeof(struct luks2_phdr)); + + if (!header) + return errno ? -errno : BLKID_PROBE_NONE; + + if (!memcmp(header->magic, LUKS_MAGIC_2, LUKS_MAGIC_L)) + return luks_attributes(pr, header, secondary_offsets[i]); + } + + return BLKID_PROBE_NONE; +} + +const struct blkid_idinfo luks_idinfo = +{ + .name = "crypto_LUKS", + .usage = BLKID_USAGE_CRYPTO, + .probefunc = probe_luks, + .magics = BLKID_NONE_MAGIC +}; |