[dm-devel] [PATCH] Add dm-verity hash device detection to blkid.
Milan Broz
mbroz at redhat.com
Fri Jun 1 11:34:08 UTC 2012
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 at redhat.com>
---
libblkid/src/superblocks/lvm.c | 41 ++++++++++++++++++++++++++++++++
libblkid/src/superblocks/superblocks.c | 1 +
libblkid/src/superblocks/superblocks.h | 1 +
3 files changed, 43 insertions(+)
diff --git a/libblkid/src/superblocks/lvm.c b/libblkid/src/superblocks/lvm.c
index 3a9807c..57d2b6e 100644
--- 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 at vrfy.org>
* Copyright (C) 2008 Karel Zak <kzak at redhat.com>
+ * Copyright (C) 2012 Milan Broz <mbroz at 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 91f4f88..879a40f 100644
--- 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 c97e447..086a568 100644
--- 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;
--
1.7.10
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