libblkid: add dm-verity hash device detection

dm-verity can use separate device for hash verification,
in this case there is a superblock in the first sector.

See
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/device-mapper/verity.txt
for more info.

Signed-off-by: Milan Broz <mbroz@redhat.com>

diff --git a/libblkid/src/superblocks/lvm.c b/libblkid/src/superblocks/lvm.c
index 3a9807c8db540236040d5329f91bc3a8bcd9b444..57d2b6e10589b2614a51a4b8559529b948d82eef 100644 (file)
--- a/libblkid/src/superblocks/lvm.c
+++ b/libblkid/src/superblocks/lvm.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2001 by Andreas Dilger
  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
  * Copyright (C) 2008 Karel Zak <kzak@redhat.com>
+ * Copyright (C) 2012 Milan Broz <mbroz@redhat.com>
  *
  * This file may be redistributed under the terms of the
  * GNU Lesser General Public License.
@@ -142,6 +143,34 @@ static int probe_lvm1(blkid_probe pr, const struct blkid_idmag *mag)
        return 0;
 }
 
+#define MAX_SALT_SIZE 384
+struct verity_sb {
+       uint8_t signature[8];
+       uint8_t version;
+       uint8_t data_block_bits;
+       uint8_t hash_block_bits;
+       uint8_t pad1[1];
+       uint16_t salt_size;
+       uint8_t pad2[2];
+       uint32_t data_blocks_hi;
+       uint32_t data_blocks_lo;
+       uint8_t algorithm[16];
+       uint8_t salt[MAX_SALT_SIZE];
+       uint8_t pad3[88];
+} __attribute__((packed));
+
+static int probe_verity(blkid_probe pr, const struct blkid_idmag *mag)
+{
+       struct verity_sb *sb;
+
+       sb = blkid_probe_get_sb(pr, mag, struct verity_sb);
+       if (sb == NULL)
+               return -1;
+
+       blkid_probe_sprintf_version(pr, "%u", sb->version);
+       return 0;
+}
+
 /* NOTE: the original libblkid uses "lvm2pv" as a name */
 const struct blkid_idinfo lvm2_idinfo =
 {
@@ -180,3 +209,15 @@ const struct blkid_idinfo snapcow_idinfo =
                { NULL }
        }
 };
+
+const struct blkid_idinfo verity_hash_idinfo =
+{
+       .name           = "DM_verity_hash",
+       .usage          = BLKID_USAGE_CRYPTO,
+       .probefunc      = probe_verity,
+       .magics         =
+       {
+               { .magic = "verity\0\0", .len = 8 },
+               { NULL }
+       }
+};

diff --git a/libblkid/src/superblocks/superblocks.c b/libblkid/src/superblocks/superblocks.c
index 91f4f88371d9025e7ef0dfbcd4d4186150119083..879a40ff59506adc59459e204b0a8c9f8f149c8d 100644 (file)
--- a/libblkid/src/superblocks/superblocks.c
+++ b/libblkid/src/superblocks/superblocks.c
@@ -96,6 +96,7 @@ static const struct blkid_idinfo *idinfos[] =
        &lvm2_idinfo,
        &lvm1_idinfo,
        &snapcow_idinfo,
+       &verity_hash_idinfo,
        &luks_idinfo,
        &vmfs_volume_idinfo,
 

diff --git a/libblkid/src/superblocks/superblocks.h b/libblkid/src/superblocks/superblocks.h
index c97e4472457ce4f8079141403d21ab0aa34fb025..086a56861dc287671f0600e3825f5a32c570fd9f 100644 (file)
--- a/libblkid/src/superblocks/superblocks.h
+++ b/libblkid/src/superblocks/superblocks.h
@@ -50,6 +50,7 @@ extern const struct blkid_idinfo hpfs_idinfo;
 extern const struct blkid_idinfo lvm2_idinfo;
 extern const struct blkid_idinfo lvm1_idinfo;
 extern const struct blkid_idinfo snapcow_idinfo;
+extern const struct blkid_idinfo verity_hash_idinfo;
 extern const struct blkid_idinfo luks_idinfo;
 extern const struct blkid_idinfo highpoint37x_idinfo;
 extern const struct blkid_idinfo highpoint45x_idinfo;