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bk: фикс passkey по безопасности, без обратной совместимости #109

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216 changes: 213 additions & 3 deletions app/lib/Core/User/Passkey.pm
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,158 @@ use parent 'Core::Base';
use Core::Base;
use Core::Utils qw( now encode_json decode_json switch_user );

use MIME::Base64 qw(decode_base64url encode_base64url);
use MIME::Base64 qw(decode_base64url encode_base64url encode_base64 decode_base64);
use Digest::SHA qw(sha256);
use Crypt::PK::ECC;

sub _cbor_read_uint {
my ($data, $pos, $info) = @_;
if ( $info < 24 ) {
return ( $info, $$pos );
} elsif ( $info == 24 ) {
my $v = unpack( 'C', substr( $data, $$pos, 1 ) );
return ( $v, $$pos + 1 );
} elsif ( $info == 25 ) {
my $v = unpack( 'n', substr( $data, $$pos, 2 ) );
return ( $v, $$pos + 2 );
} elsif ( $info == 26 ) {
my $v = unpack( 'N', substr( $data, $$pos, 4 ) );
return ( $v, $$pos + 4 );
} elsif ( $info == 27 ) {
my ( $hi, $lo ) = unpack( 'NN', substr( $data, $$pos, 8 ) );
return ( $hi * 2**32 + $lo, $$pos + 8 );
}
die "CBOR: unsupported additional info $info";
}

sub _cbor_decode_item {
my ( $data, $pos ) = @_;

my $first = unpack( 'C', substr( $$data, $$pos, 1 ) );
$$pos++;
my $major = $first >> 5;
my $info = $first & 0x1f;

if ( $major == 0 ) { # unsigned int
my ( $v, $np ) = _cbor_read_uint( $$data, \$$pos, $info );
$$pos = $np;
return $v;
} elsif ( $major == 1 ) { # negative int
my ( $v, $np ) = _cbor_read_uint( $$data, \$$pos, $info );
$$pos = $np;
return -1 - $v;
} elsif ( $major == 2 ) { # byte string
my ( $len, $np ) = _cbor_read_uint( $$data, \$$pos, $info );
$$pos = $np;
my $v = substr( $$data, $$pos, $len );
$$pos += $len;
return $v;
} elsif ( $major == 3 ) { # text string
my ( $len, $np ) = _cbor_read_uint( $$data, \$$pos, $info );
$$pos = $np;
my $v = substr( $$data, $$pos, $len );
$$pos += $len;
return $v;
} elsif ( $major == 4 ) { # array
my ( $len, $np ) = _cbor_read_uint( $$data, \$$pos, $info );
$$pos = $np;
my @arr;
push @arr, _cbor_decode_item( $data, $pos ) for 1 .. $len;
return \@arr;
} elsif ( $major == 5 ) { # map
my ( $len, $np ) = _cbor_read_uint( $$data, \$$pos, $info );
$$pos = $np;
my %map;
for ( 1 .. $len ) {
my $k = _cbor_decode_item( $data, $pos );
my $v = _cbor_decode_item( $data, $pos );
$map{ $k } = $v;
}
return \%map;
} elsif ( $major == 7 ) { # simple/float/bool/null
if ( $info == 20 ) { return 0 }
if ( $info == 21 ) { return 1 }
if ( $info == 22 ) { return undef }
die "CBOR: unsupported simple value $info";
}
die "CBOR: unsupported major type $major";
}

sub _cbor_decode {
my $bytes = shift;
my $pos = 0;
return _cbor_decode_item( \$bytes, \$pos );
}

sub _parse_auth_data {
my $auth_data = shift;

return undef unless length( $auth_data ) >= 37;

my $rp_id_hash = substr( $auth_data, 0, 32 );
my $flags = unpack( 'C', substr( $auth_data, 32, 1 ) );
my $counter = unpack( 'N', substr( $auth_data, 33, 4 ) );

my %result = (
rp_id_hash => $rp_id_hash,
flags => $flags,
user_present => ( $flags & 0x01 ) ? 1 : 0,
user_verified => ( $flags & 0x04 ) ? 1 : 0,
counter => $counter,
);

my $pos = 37;
if ( $flags & 0x40 && length( $auth_data ) > $pos ) {
my $aaguid = substr( $auth_data, $pos, 16 ); $pos += 16;
my $cred_id_len = unpack( 'n', substr( $auth_data, $pos, 2 ) ); $pos += 2;
my $credential_id = substr( $auth_data, $pos, $cred_id_len ); $pos += $cred_id_len;

my $cose_key = _cbor_decode_item( \$auth_data, \$pos );

$result{aaguid} = $aaguid;
$result{credential_id} = $credential_id;
$result{cose_key} = $cose_key;
}

return \%result;
}

sub _cose_key_to_stored_format {
my $cose_key = shift;

return undef unless ref $cose_key eq 'HASH';

my $kty = $cose_key->{1};
my $alg = $cose_key->{3};
my $crv = $cose_key->{-1};
my $x = $cose_key->{-2};
my $y = $cose_key->{-3};

return undef unless $kty && $kty == 2 && $crv && $crv == 1 && $x && $y;

return {
kty => 2,
alg => $alg,
crv => 1,
x => unpack( 'H*', $x ),
y => unpack( 'H*', $y ),
};
}

sub _stored_key_to_pk {
my $stored = shift;

return undef unless ref $stored eq 'HASH' && $stored->{x} && $stored->{y};

my $raw = pack( 'C', 0x04 ) . pack( 'H*', $stored->{x} ) . pack( 'H*', $stored->{y} );

my $pk = eval {
my $k = Crypt::PK::ECC->new();
$k->import_key_raw( $raw, 'secp256r1' );
$k;
};
return $pk;
}

sub table { return 'users' };

Expand Down Expand Up @@ -202,9 +353,34 @@ sub api_register_complete {
return undef;
}

my $attestation_object = decode_base64url($args{response}->{attestationObject} || '');
my $attestation = eval { _cbor_decode($attestation_object) };
unless ($attestation && ref $attestation eq 'HASH' && $attestation->{authData}) {
$report->add_error('INVALID_ATTESTATION');
return undef;
}

my $auth_data = eval { _parse_auth_data($attestation->{authData}) };
unless ($auth_data && $auth_data->{cose_key}) {
$report->add_error('INVALID_ATTESTATION');
return undef;
}

my $expected_rp_id_hash = sha256($self->get_rp_id());
unless ($auth_data->{rp_id_hash} eq $expected_rp_id_hash) {
$report->add_error('RP_ID_MISMATCH');
return undef;
}

my $stored_key = _cose_key_to_stored_format($auth_data->{cose_key});
unless ($stored_key) {
$report->add_error('UNSUPPORTED_KEY_ALGORITHM');
return undef;
}

$self->add_credential($user,
id => $args{credential_id},
public_key => $args{response}->{attestationObject},
public_key => $stored_key,
name => $args{name},
);

Expand Down Expand Up @@ -347,11 +523,45 @@ sub api_auth_public {
return undef;
}

unless ($self->find_credential($user, $args{credential_id})) {
my $credential = $self->find_credential($user, $args{credential_id});
unless ($credential) {
$report->add_error('UNKNOWN_CREDENTIAL');
return undef;
}

my $pk = _stored_key_to_pk($credential->{public_key});
unless ($pk) {
# Легаси/повреждённая запись без корректного публичного ключа - доверять нельзя
$report->add_error('CREDENTIAL_REQUIRES_REREGISTRATION');
return undef;
}

my $auth_data_raw = decode_base64url($args{response}->{authenticatorData} || '');
my $signature = decode_base64url($args{response}->{signature} || '');
unless ($auth_data_raw && $signature) {
$report->add_error('INVALID_PASSKEY_RESPONSE');
return undef;
}

my $auth_data = _parse_auth_data($auth_data_raw);
unless ($auth_data && $auth_data->{user_present}) {
$report->add_error('INVALID_AUTHENTICATOR_DATA');
return undef;
}

unless ($auth_data->{rp_id_hash} eq sha256($self->get_rp_id())) {
$report->add_error('RP_ID_MISMATCH');
return undef;
}

my $client_data_json = decode_base64url($args{response}->{clientDataJSON} || '');
my $signed_data = $auth_data_raw . sha256($client_data_json);

unless (eval { $pk->verify_message($signature, $signed_data, 'SHA256') }) {
$report->add_error('INVALID_SIGNATURE');
return undef;
}

switch_user($user_id);
$self->set_settings($user, verified_at => now());

Expand Down