From e5e16bd47f36e0c735d24cdc677191617a533aa7 Mon Sep 17 00:00:00 2001
From: Trammell Hudson <hudson@trmm.net>
Date: Fri, 5 Aug 2016 23:17:41 -0400
Subject: [PATCH] convert veritysetup into a dmsetup table

---
 verity-sign | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100755 verity-sign

diff --git a/verity-sign b/verity-sign
new file mode 100755
index 00000000..1f1e202e
--- /dev/null
+++ b/verity-sign
@@ -0,0 +1,92 @@
+#!/usr/bin/perl
+# Generate dm-verity hashes and sign the root hash
+#
+# Output looks like
+#
+# VERITY header information for hdd.img
+# UUID:               73532888-a3e9-4f16-a50a-1d03a265b94f
+# Hash type:          1
+# Data blocks:        7680
+# Data block size:    4096
+# Hash block size:    4096
+# Hash algorithm:     sha256
+# Salt:               3d0cd593d29715005794c4e1cd5164c14ba6456c3dbd2c6d8a26007c01ca9937
+# Root hash:          91beda90d7fa1ab92463344966eb56ec9706f4f26063933a86d701a02a961a10
+#
+my $usage = <<"";
+Usage:
+size=32
+dd if=/dev/zero of=hdd.img bs=1M count=$size
+mkfs.ext4 -b 4096 ./hdd.img
+mkdir /tmp/loop
+sudo mount -o loop hdd.img /tmp/loop
+(populate /tmp/loop)
+sudo umount /tmp/loop
+veritysetup \
+	--hash-offset $[$size*1024*1024] \
+	--data-blocks $[$size*1024*1024/4096] \
+	format hdd.img hdd.img \
+| ./verity-sign /dev/sda1 \
+| tee hdd.table
+
+
+use warnings;
+use strict;
+
+my $dev = shift;
+
+local $_ = <STDIN>;
+chomp;
+
+my ($orig_device) = /^VERITY header information for (.*)/
+	or die "Missing VERITY header\n";
+
+my %params;
+
+$dev ||= $orig_device;
+
+while(<>)
+{
+	chomp;
+	my ($key,$value) = split /:\s+/;
+	$params{$key} = $value;
+}
+
+my @missing;
+
+
+# All the necessary parameters were in the header, generate
+# the command to mount the filesystem
+my $data_blocks = $params{'Data blocks'}
+	or push @missing, 'Data blocks';
+my $data_block_size = $params{'Data block size'}
+	or push @missing, 'Data block size';
+my $hash_block_size = $params{'Hash block size'}
+	or push @missing, 'Hash block size';
+my $salt = $params{'Salt'}
+	or push @missing, 'Salt';
+my $root_hash = $params{'Root hash'}
+	or push @missing, 'Root hash';
+my $hash_type = $params{'Hash type'}
+	or push @missing, 'Hash type';
+my $hash_algorithm = $params{'Hash algorithm'}
+	or push @missing, 'Hash algorithm';
+
+# Check for any missing parameters
+die "Missing parameter: ", join(', ', @missing), "\n"
+	if @missing;
+
+my $data_size = $data_blocks * $data_block_size;
+my $data_size_512b = $data_size / 512;
+my $first_hash_block = $data_blocks + 1;
+
+print <<"";
+0 $data_size_512b verity $hash_type
+$dev $dev
+$data_block_size $hash_block_size
+$data_blocks $first_hash_block
+$hash_algorithm
+$root_hash
+$salt
+
+__END__