tests/tarfilter-idshift: use a fabricated tarball instead of real chroot

iputils-ping does not ship /bin/ping with xattrs anymore.
This commit is contained in:
Johannes Schauer Marin Rodrigues 2024-10-11 11:16:06 +02:00
parent 395ee60a7f
commit eca6cb314c
Signed by: josch
GPG key ID: F2CBA5C78FBD83E1

View file

@ -1,58 +1,111 @@
#!/bin/sh #!/bin/sh
set -eu set -eu
export LC_ALL=C.UTF-8 export LC_ALL=C.UTF-8
if [ ! -e /mmdebstrap-testenv ]; then
echo "this test modifies the system and should only be run inside a container" >&2 trap "rm -f /tmp/mkpaxtar.pl /tmp/orig.tar /tmp/file /tmp/expected /tmp/filtered.tar" EXIT INT TERM
exit 1
fi cat << 'END' > /tmp/mkpaxtar.pl
trap "rm -f /tmp/debian-chroot.tar /tmp/debian-chroot-shifted.tar /tmp/debian-chroot.txt /tmp/debian-chroot-shiftedback.tar /tmp/expected; rm -rf /tmp/debian-chroot" EXIT INT TERM #!/usr/bin/env perl
useradd --home-dir /home/user --create-home user
echo user:100000:65536 | cmp /etc/subuid - use strict;
echo user:100000:65536 | cmp /etc/subgid - use warnings;
# include iputils-ping so that we can verify that tarfilter does not remove
# extended attributes my @entries = (
# run through tarshift no-op to create a tarball that should be bit-by-bit # filename mode type content
# identical to a round trip through "tarfilter --idshift X" and "tarfilter --idshift -X" ['./PaxHeaders/file', oct(644), 'x', "57 SCHILY.xattr.security.capability=\x01\0\0\x02\0\x20\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x0a"],
runuser -u user -- {{ CMD }} --mode=unshare --variant=apt --include=iputils-ping {{ DIST }} - {{ MIRROR }} \ ['./file', oct(644), 0, 'test'],
| ./tarfilter --idshift 0 > /tmp/debian-chroot.tar );
my $num_entries = 0;
foreach my $file (@entries) {
my ($fname, $mode, $type, $content) = @{$file};
my $entry = pack(
'a100 a8 a8 a8 a12 a12 A8 a1 a100 a6 a2 a32 a32 a8 a8 a155 x12',
$fname,
sprintf('%07o', $mode),
sprintf('%07o', 0), # uid
sprintf('%07o', 0), # gid
sprintf('%011o', length $content), # size
sprintf('%011o', 0), # mtime
'', # checksum
$type,
'', # linkname
"ustar", # magic
"00", # version
'', # username
'', # groupname
'', # dev major
'', # dev minor
'', # prefix
);
# compute and insert checksum
substr($entry, 148, 7)
= sprintf("%06o\0", unpack("%16C*", $entry));
print $entry;
$num_entries += 1;
if (length $content) {
print(pack 'a512', $content);
$num_entries += 1;
}
}
# https://www.gnu.org/software/tar/manual/html_node/Standard.html
#
# Physically, an archive consists of a series of file entries terminated by an
# end-of-archive entry, which consists of two 512 blocks of zero bytes. At the
# end of the archive file there are two 512-byte blocks filled with binary
# zeros as an end-of-file marker.
print(pack 'a512', '');
print(pack 'a512', '');
$num_entries += 2;
# https://www.gnu.org/software/tar/manual/html_section/tar_76.html
#
# Some devices requires that all write operations be a multiple of a certain
# size, and so, tar pads the archive out to the next record boundary.
#
# The default blocking factor is 20. With a block size of 512 bytes, we get a
# record size of 10240.
for (my $i = $num_entries ; $i < 20 ; $i++) {
print(pack 'a512', '');
}
END
MMTARFILTER=
[ -x /usr/bin/mmtarfilter ] && MMTARFILTER=/usr/bin/mmtarfilter
[ -x ./tarfilter ] && MMTARFILTER=./tarfilter
perl /tmp/mkpaxtar.pl | "$MMTARFILTER" > /tmp/orig.tar
# make sure that xattrs are set in the original tarball # make sure that xattrs are set in the original tarball
mkdir /tmp/debian-chroot tar --xattrs --xattrs-include='*' --directory /tmp/ -xf /tmp/orig.tar ./file
tar --xattrs --xattrs-include='*' --directory /tmp/debian-chroot -xf /tmp/debian-chroot.tar ./usr/bin/ping echo "/tmp/file cap_net_raw=ep" > /tmp/expected
echo "/tmp/debian-chroot/usr/bin/ping cap_net_raw=ep" > /tmp/expected getcap /tmp/file | diff -u /tmp/expected - >&2
getcap /tmp/debian-chroot/usr/bin/ping | diff -u /tmp/expected - >&2 # make sure that the file content is as expected
rm /tmp/debian-chroot/usr/bin/ping printf test | diff -u /tmp/file - >&2
rmdir /tmp/debian-chroot/usr/bin # make sure that uid/gid are as expected in the original tarball
rmdir /tmp/debian-chroot/usr echo "0 0 644" > /tmp/expected
rmdir /tmp/debian-chroot stat --format="%u %g %a" /tmp/file | diff -u /tmp/expected - >&2
# shift the uid/gid forward by 100000 and backward by 100000 rm /tmp/file
./tarfilter --idshift 100000 < /tmp/debian-chroot.tar > /tmp/debian-chroot-shifted.tar # tarball must be bit by-bit-identical after round-trip
./tarfilter --idshift -100000 < /tmp/debian-chroot-shifted.tar > /tmp/debian-chroot-shiftedback.tar "$MMTARFILTER" --idshift 0 < /tmp/orig.tar > /tmp/filtered.tar
# the tarball before and after the roundtrip through tarfilter should be bit cmp /tmp/orig.tar /tmp/filtered.tar
# by bit identical
cmp /tmp/debian-chroot.tar /tmp/debian-chroot-shiftedback.tar # now shift uid/gid
# manually adjust uid/gid and compare "tar -t" output "$MMTARFILTER" --idshift 100000 < /tmp/orig.tar > /tmp/filtered.tar
tar --numeric-owner -tvf /tmp/debian-chroot.tar \ # make sure that uid/gid are as expected in the filtered tarball
| sed 's# 42/0 # 100042/100000 #' \ tar --xattrs --xattrs-include='*' --directory /tmp/ -xf /tmp/filtered.tar ./file
| sed 's# 0/0 # 100000/100000 #' \ echo "100000 100000 644" > /tmp/expected
| sed 's# 0/5 # 100000/100005 #' \ stat --format="%u %g %a" /tmp/file | diff -u /tmp/expected - >&2
| sed 's# 0/8 # 100000/100008 #' \ rm /tmp/file
| sed 's# 0/42 # 100000/100042 #' \
| sed 's# 0/43 # 100000/100043 #' \ # now shift uid/gid back to create a round-trip
| sed 's# 0/50 # 100000/100050 #' \ "$MMTARFILTER" --idshift -100000 < /tmp/filtered.tar > /tmp/filtered2.tar
| sed 's/ \+/ /g' \
> /tmp/debian-chroot.txt # the result must be identical to the original and will thus also include the
tar --numeric-owner -tvf /tmp/debian-chroot-shifted.tar \ # correct xattr information
| sed 's/ \+/ /g' \ cmp /tmp/orig.tar /tmp/filtered2.tar
| diff -u /tmp/debian-chroot.txt - >&2
mkdir /tmp/debian-chroot
tar --xattrs --xattrs-include='*' --directory /tmp/debian-chroot -xf /tmp/debian-chroot-shifted.tar
echo "100000 100000" > /tmp/expected
stat --format="%u %g" /tmp/debian-chroot/usr/bin/ping | diff -u /tmp/expected - >&2
echo "/tmp/debian-chroot/usr/bin/ping cap_net_raw=ep" > /tmp/expected
getcap /tmp/debian-chroot/usr/bin/ping | diff -u /tmp/expected - >&2
echo "0 0" > /tmp/expected
runuser -u user -- {{ CMD }} --unshare-helper /usr/sbin/chroot /tmp/debian-chroot stat --format="%u %g" /usr/bin/ping \
| diff -u /tmp/expected - >&2
echo "/usr/bin/ping cap_net_raw=ep" > /tmp/expected
runuser -u user -- {{ CMD }} --unshare-helper /usr/sbin/chroot /tmp/debian-chroot getcap /usr/bin/ping \
| diff -u /tmp/expected - >&2