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Support aokv3 in unpackarchive
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@mlschroe
mlschroe committed Jan 9, 2025
1 parent 1b1b5f4 commit c8854e6
Showing 1 changed file with 220 additions and 4 deletions.
224 changes: 220 additions & 4 deletions unpackarchive
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Original file line number Diff line number Diff line change
Expand Up @@ -244,6 +244,211 @@ sub tar_readhead {
}


#
# APKv3 handling
#

# schema definitions stripped to what we need
my $apkv3_acl_schema = [
[ 'i', 'mode' ],
];

my $apkv3_file_schema = [
[ 'b', 'name' ],
[ 'o', '', $apkv3_acl_schema ],
[ 'i', 'size' ],
[ 'i', 'mtime' ],
[ undef ],
[ 'b', 'target' ],
];

my $apkv3_dir_schema = [
[ 'b', 'name' ],
[ 'o', '', $apkv3_acl_schema ],
[ 'o*', 'files', $apkv3_file_schema ],
];

my $apkv3_scripts_schema = [
[ 'b', 'trigger' ],
[ 'b', 'preinstall' ],
[ 'b', 'postinstall' ],
[ 'b', 'preuninstall' ],
[ 'b', 'postuninstall' ],
[ 'b', 'preupgrade' ],
[ 'b', 'postupgrade' ],
];

my $apkv3_pkg_schema = [
[ undef ],
[ 'o*', 'dirs', $apkv3_dir_schema ],
[ 'o', '', $apkv3_scripts_schema ],
];

sub apkv3_walk {
#my ($adb, $data, $schema, $vals, $multi) = @_;
my @s = @{$_[2]};
my @vals = @{$_[3]};
my $multi = $_[4];
while (@vals && @s) {
my $s = shift @s;
my $v = shift @vals;
next if !defined($s) || !defined($s->[0]);
my $t = ($v >> 28) & 0x0f;
$v &= 0xfffffff;
next if $t == 0 && $v == 0; # NULL
my ($st, $name, $oschema, $cvt) = @$s;
next unless defined $st && defined $name;
if ($st =~ s/\*$// && !$multi) {
my $num = unpack("\@${v}V", $_[0]);
my @v = unpack("\@${v}V$num", $_[0]);
die unless @v && @v == $num;
shift @v;
apkv3_walk($_[0], $_[1], [ ($s) x ($num - 1) ], \@v, 1);
next;
}
if ($st eq 'b') {
die("wrong type for blob ($t)\n") if $t != 8 && $t != 9 && $t != 10;
my $l;
$l = unpack("\@${v}C", $_[0]) if $t == 8;
$l = unpack("\@${v}v", $_[0]) if $t == 9;
$l = unpack("\@${v}V", $_[0]) if $t == 10;
$v = substr($_[0], $v + $t - 7 + ($t == 10 ? 1 : 0), $l);
} elsif ($st eq 'i') {
die("wrong type for int ($t)\n") if $t != 1 && $t != 2 && $t != 3;
$v = unpack("\@${v}V", $_[0]) if $t == 2;
$v = unpack("\@${v}V", $_[0]) + (unpack("\@${v}VV", $_[0]))[1] * 65536 * 65536 if $t == 3;
} elsif ($st eq 'o') {
die("wrong type for obj ($t)\n") if $t != 14;
my $num = unpack("\@${v}V", $_[0]);
my @v = unpack("\@${v}V$num", $_[0]);
die unless @v && @v == $num;
shift @v;
$v = $name eq '' ? $_[1]: {};
apkv3_walk($_[0], $v, $s->[2], \@v);
next if $name eq '';
} else {
die("unsupported type $st in schema\n");
}
$v = $s->[3]->($v) if $cvt;
if ($multi) {
push @{$_[1]->{$name}}, $v;
} else {
$_[1]->{$name} = $v;
}
}
}

sub apkv3_walk_root {
my $data = {};
my $v = unpack('@4V', $_[0]);
apkv3_walk($_[0], $data, [[ 'o', '', $_[1]]], [ $v ]);
return $data;
}

sub apkv3_handle_decompression {
my ($prepend) = @_;
die unless length($prepend) == 16;
my ($alg, $level);
if (substr($prepend, 0, 4) eq 'ADBc') {
($alg, $level) = unpack('@4CC', $prepend);
substr($prepend, 0, 6, '');
} elsif (substr($prepend, 0, 4) eq 'ADBd') {
$alg = 1;
substr($prepend, 0, 4, '');
} elsif (substr($prepend, 0, 4) eq 'ADB.') {
$alg = 0;
} else {
die("not an apkv3 file\n");
}
die("unsupported compression $alg\n") if $alg > 2;
$prepend = "\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\x00$prepend" if $alg == 1;
die("zstd decompression error\n") if $alg == 2 && substr($prepend, 0, 3) ne "\x28\xb5\x2f";
handle_decompression($prepend, 1);
}

sub apkv3_read_blk_header {
my $type_size = unpack('V', readdata(4));
my ($type, $size) = ((($type_size >> 30) & 3), ($type_size & 0x3fffffff));
my $pad = $size & 7;;
if ($type == 3) {
$type = $size;
my @s = unpack('VVV', readdata(12));
$size = $s[1] + $s[2] * 65536 * 65536;
$pad = $s[1] & 7;
$size -= 12;
}
$size -= 4;
die("bad apkv3 block size\n") if $size < 0;
return ($type, $size, $pad ? 8 - $pad : 0);
}

sub apkv3_setup {
my ($prepend) = @_;
apkv3_handle_decompression($prepend);
# read file header
my $file_header = readdata(8);
die("not an apk package $file_header\n") unless $file_header eq "\x41\x44\x42\x2e\x70\x63\x6b\x67";

#read adb
my ($adbtype, $adbsize, $adbpad) = apkv3_read_blk_header();
die("bad adb block type\n") unless $adbtype == 0;
die("oversized adb block\n") if $adbsize > 0x10000000; # 256 MB
my $adb = readdata($adbsize);
readdata($adbpad) if $adbpad;
# read sig
my ($sigtype, $sigsize, $sigpad) = apkv3_read_blk_header();
die("bad sig block type $sigtype\n") unless $sigtype == 1;
die("oversized sig block\n") if $sigsize > 0x100000; # 1 MB
readdata($sigsize + $sigpad);

# parse adb
my $data = apkv3_walk_root($adb, $apkv3_pkg_schema);
my @ents;

# generate entries for the scripts
for my $script (qw{trigger preinstall postinstall preuninstall postuninstall preupgrade postupgrade}) {
my $scr = $data->{$script};
next unless defined $scr;
my $fn = ".$script";
$fn =~ s/(pre|post)/$1-/;
push @ents, { 'type' => 'f', 'name' => $fn, 'size' => length($scr), 'mode' => 0644, 'data' => $scr };
}

# generate entries for the file list
my $diridx = 0;
for my $d (@{$data->{'dirs'} || []}) {
push @ents, { 'type' => 'd', 'name' => (defined($d->{'name'}) ? $d->{'name'} : '.'), 'mode' => ($d->{'mode'} || 0755), 'diridx' => ++$diridx };
my $fileidx = 0;
for my $f (@{$d->{'files'} || []}) {
my $fn = defined($d->{'name'}) ? "$d->{'name'}/$f->{'name'}" : $f->{'name'};
my $ff = { 'type' => 'f', 'name' => $fn, 'size' => $f->{'size'}, 'mode' => ($f->{'mode'} || 0644), 'mtime' => $f->{'mtime'}, 'diridx' => $diridx, 'fileidx' => ++$fileidx };
my $target = $f->{'target'};
if (defined($target)) {
my $tmode = unpack('v', substr($target, 0, 2, ''));
next unless $tmode == 0xa000 || $tmode == 0x8000;
$ff->{'type'} = $tmode == 0xa000 ? 'l' : 'L';
$ff->{'linkname'} = $target;
}
push @ents, $ff;
}
}
return sub { apkv3_readhead(\@ents) };
}

sub apkv3_readhead {
my ($ents) = @_;
my $ent = shift @$ents;
return unless defined $ent;
return ($ent, 0, 0) unless $ent->{'type'} eq 'f' && $ent->{'size'} != 0 && !defined($ent->{'data'});
my ($datatype, $datasize, $datapad) = apkv3_read_blk_header();
die("bad data block type\n") unless $datatype == 2;
die("bad data block size\n") unless $datasize == 8 + $ent->{'size'};
my ($diridx, $fileidx) = unpack('VV', readdata(8));
die("mismatched data block\n") unless $diridx == $ent->{'diridx'} && $fileidx == $ent->{'fileidx'};
return ($ent, $ent->{'size'}, $datapad);
}


#
# Path resolving
#
Expand Down Expand Up @@ -320,8 +525,10 @@ sub detect_decompressor {
}

sub handle_decompression {
my $first16bytes = readdata(16);
my ($first16bytes, $force_pipe) = @_;
$first16bytes = readdata(16) unless defined $first16bytes;
my @decomp = detect_decompressor($first16bytes);
@decomp = ('cat') if $force_pipe && !@decomp;
return $first16bytes unless @decomp;
local *F;
open(F, "<&STDIN") || die("stdin dup: $!\n");
Expand All @@ -345,6 +552,7 @@ sub handle_decompression {
print G $d;
}
close(G) || die("pipe close: $!\n");
exit 0;
}
close(F);
return undef;
Expand All @@ -354,7 +562,7 @@ sub handle_decompression {
#
# Main
#
die("usage: unpackarchive --cpio|--tar [-C <root>]\n") unless @ARGV;
die("usage: unpackarchive --cpio|--tar|--apk [-C <root>]\n") unless @ARGV;
my $format = shift @ARGV;
my $root = '.';
while (@ARGV) {
Expand All @@ -365,19 +573,23 @@ while (@ARGV) {
} elsif ($ARGV[0] =~ /^-/) {
die("unpackarchive: unsupported option $ARGV[0]\n");
} else {
die("usage: unpackarchive --cpio|--tar [-C <root>]\n");
die("usage: unpackarchive --cpio|--tar|--apk [-C <root>]\n");
}
}

die("$root: No such file or directory\n") unless -d $root;
my $readhead;
$readhead = \&cpio_readhead if $format eq '--cpio';
$readhead = \&tar_readhead if $format eq '--tar';
$readhead = \&tar_readhead if $format eq '--apk';
die("unknown format option $format\n") unless $readhead;

umask(0); # do not mess with the modes

my $prepend = handle_decompression();

$readhead = apkv3_setup($prepend) if $format eq '--apk' && $prepend && substr($prepend, 0, 3) eq 'ADB';

while (1) {
my ($ent, $size, $pad) = $readhead->($prepend);
undef $prepend;
Expand Down Expand Up @@ -444,7 +656,11 @@ while (1) {
} elsif ($type eq 'f') {
my $fd;
sysopen($fd, "$root$name", O_WRONLY|O_CREAT|O_TRUNC, $ent->{'mode'} & 07777) || die("$root$name: $!\n");
copydata($fd, $size);
if (defined $ent->{'data'}) {
writedata($fd, $ent->{'data'});
} else {
copydata($fd, $size);
}
close($fd) || die("close $name: $!\n");
utime($ent->{'mtime'}, $ent->{'mtime'}, "$root$name");
skipdata($pad);
Expand Down

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