add initial WIP

[chaz/p5-File-KDBX] / lib / File / KDBX / Loader / V3.pm

diff --git a/lib/File/KDBX/Loader/V3.pm b/lib/File/KDBX/Loader/V3.pm
new file mode 100644 (file)
index 0000000..68d7f9c
--- /dev/null
+++ b/lib/File/KDBX/Loader/V3.pm
@@ -0,0 +1,164 @@
+package File::KDBX::Loader::V3;
+# ABSTRACT: Load KDBX3 files
+
+# magic
+# headers
+# body
+#   CRYPT(
+#     start bytes
+#     HASH(
+#       COMPRESS(
+#         xml
+#       )
+#     )
+#   )
+
+use warnings;
+use strict;
+
+use Crypt::Digest qw(digest_data);
+use Encode qw(decode);
+use File::KDBX::Constants qw(:header :compression :kdf);
+use File::KDBX::Error;
+use File::KDBX::Util qw(:io assert_64bit erase_scoped);
+use PerlIO::via::File::KDBX::Crypt;
+use PerlIO::via::File::KDBX::HashBlock;
+use namespace::clean;
+
+use parent 'File::KDBX::Loader';
+
+our $VERSION = '999.999'; # VERSION
+
+sub _read_header {
+    my $self = shift;
+    my $fh = shift;
+
+    read_all $fh, my $buf, 3 or throw 'Malformed header field, expected header type and size';
+    my ($type, $size) = unpack('C S<', $buf);
+
+    my $val;
+    if (0 < $size) {
+        read_all $fh, $val, $size or throw 'Expected header value', type => $type, size => $size;
+        $buf .= $val;
+    }
+
+    $type = KDBX_HEADER($type);
+    if ($type == HEADER_END) {
+        # done
+    }
+    elsif ($type == HEADER_COMMENT) {
+        $val = decode('UTF-8', $val);
+    }
+    elsif ($type == HEADER_CIPHER_ID) {
+        $size == 16 or throw 'Invalid cipher UUID length', got => $size, expected => $size;
+    }
+    elsif ($type == HEADER_COMPRESSION_FLAGS) {
+        $val = unpack('L<', $val);
+    }
+    elsif ($type == HEADER_MASTER_SEED) {
+        $size == 32 or throw 'Invalid master seed length', got => $size, expected => $size;
+    }
+    elsif ($type == HEADER_TRANSFORM_SEED) {
+        # nothing
+    }
+    elsif ($type == HEADER_TRANSFORM_ROUNDS) {
+        assert_64bit;
+        $val = unpack('Q<', $val);
+    }
+    elsif ($type == HEADER_ENCRYPTION_IV) {
+        # nothing
+    }
+    elsif ($type == HEADER_INNER_RANDOM_STREAM_KEY) {
+        # nothing
+    }
+    elsif ($type == HEADER_STREAM_START_BYTES) {
+        # nothing
+    }
+    elsif ($type == HEADER_INNER_RANDOM_STREAM_ID) {
+        $val = unpack('L<', $val);
+    }
+    elsif ($type == HEADER_KDF_PARAMETERS ||
+           $type == HEADER_PUBLIC_CUSTOM_DATA) {
+        throw "Unexpected KDBX4 header: $type", type => $type;
+    }
+    else {
+        alert "Unknown header: $type", type => $type;
+    }
+
+    return wantarray ? ($type => $val, $buf) : $buf;
+}
+
+sub _read_body {
+    my $self = shift;
+    my $fh   = shift;
+    my $key  = shift;
+    my $header_data = shift;
+    my $kdbx = $self->kdbx;
+
+    # assert all required headers present
+    for my $field (
+        HEADER_CIPHER_ID,
+        HEADER_ENCRYPTION_IV,
+        HEADER_MASTER_SEED,
+        HEADER_INNER_RANDOM_STREAM_KEY,
+        HEADER_STREAM_START_BYTES,
+    ) {
+        defined $kdbx->headers->{$field} or throw "Missing $field";
+    }
+
+    $kdbx->kdf_parameters({
+        KDF_PARAM_UUID()        => KDF_UUID_AES,
+        KDF_PARAM_AES_ROUNDS()  => delete $kdbx->headers->{+HEADER_TRANSFORM_ROUNDS},
+        KDF_PARAM_AES_SEED()    => delete $kdbx->headers->{+HEADER_TRANSFORM_SEED},
+    });
+
+    my $master_seed = $kdbx->headers->{+HEADER_MASTER_SEED};
+
+    my @cleanup;
+    $key = $kdbx->composite_key($key);
+
+    my $response = $key->challenge($master_seed);
+    push @cleanup, erase_scoped $response;
+
+    my $transformed_key = $kdbx->kdf->transform($key);
+    push @cleanup, erase_scoped $transformed_key;
+
+    my $final_key = digest_data('SHA256', $master_seed, $response, $transformed_key);
+    push @cleanup, erase_scoped $final_key;
+
+    my $cipher = $kdbx->cipher(key => $final_key);
+    PerlIO::via::File::KDBX::Crypt->push($fh, $cipher);
+
+    read_all $fh, my $start_bytes, 32 or throw 'Failed to read starting bytes';
+
+    my $expected_start_bytes = $kdbx->headers->{stream_start_bytes};
+    $start_bytes eq $expected_start_bytes
+        or throw "Invalid credentials or data is corrupt (wrong starting bytes)\n",
+            got => $start_bytes, expected => $expected_start_bytes, headers => $kdbx->headers;
+
+    $kdbx->key($key);
+
+    PerlIO::via::File::KDBX::HashBlock->push($fh);
+
+    my $compress = $kdbx->headers->{+HEADER_COMPRESSION_FLAGS};
+    if ($compress == COMPRESSION_GZIP) {
+        require PerlIO::via::File::KDBX::Compression;
+        PerlIO::via::File::KDBX::Compression->push($fh);
+    }
+    elsif ($compress != COMPRESSION_NONE) {
+        throw "Unsupported compression ($compress)\n", compression_flags => $compress;
+    }
+
+    $self->_read_inner_body($fh);
+
+    binmode($fh, ':pop') if $compress;
+    binmode($fh, ':pop:pop');
+
+    if (my $header_hash = $kdbx->meta->{header_hash}) {
+        my $got_header_hash = digest_data('SHA256', $header_data);
+        $header_hash eq $got_header_hash
+            or throw 'Header hash does not match', got => $got_header_hash, expected => $header_hash;
+    }
+}
+
+1;