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-rw-r--r--libblkid/src/superblocks/luks.c134
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
+};