add --skip=chroot/mount and --skip=chroot/mount/dev, --skip=chroot/mount/proc, --skip=chroot/mount/sys

This commit is contained in:
Johannes Schauer Marin Rodrigues 2022-09-02 23:27:27 +02:00
parent e61e352f67
commit add9412a47
Signed by untrusted user: josch
GPG key ID: F2CBA5C78FBD83E1
3 changed files with 126 additions and 91 deletions

View file

@ -266,6 +266,9 @@ Test: remove-start-stop-daemon-and-policy-rc-d-in-hook
Test: skip-start-stop-daemon-policy-rc
Test: skip-mount
Modes: unshare
Test: compare-output-with-pre-seeded-var-cache-apt-archives
Needs-QEMU: true
Variants: any

View file

@ -1104,8 +1104,10 @@ sub run_chroot {
}
} elsif ($type == 3 or $type == 4) {
# character/block special
if ((any { $_ eq $options->{mode} } ('root', 'unshare'))
&& !$options->{canmount}) {
if (any { $_ =~ '^chroot/mount(?:/dev)?$' }
@{ $options->{skip} }) {
info "skipping chroot/mount/dev as requested";
} elsif (!$options->{canmount}) {
warning "skipping bind-mounting ./dev/$fname";
} elsif (!$options->{havemknod}) {
if (!-d "$options->{root}/dev") {
@ -1160,96 +1162,102 @@ sub run_chroot {
"$options->{root}/dev/$fname")
or error "mount ./dev/$fname failed: $?";
}
} elsif ($type == 5
&& (any { $_ eq $options->{mode} } ('root', 'unshare'))
&& !$options->{canmount}) {
warning "skipping bind-mounting ./dev/$fname";
} elsif ($type == 5) { # directory
if (!-d "$options->{root}/dev") {
warning(
"skipping creation of ./dev/$fname because the"
. " /dev directory is missing in the target");
next;
}
if (!-e "/dev/$fname" && $fname ne "pts/") {
warning("skipping creation of ./dev/$fname because"
. " /dev/$fname does not exist"
. " on the outside");
next;
}
if (!-d "/dev/$fname" && $fname ne "pts/") {
warning("skipping creation of ./dev/$fname because"
. " /dev/$fname on the outside is not a"
. " directory");
next;
}
if (!$options->{havemknod}) {
# If had mknod, then the directory to bind-mount into
# was already created in the run_setup function.
push @cleanup_tasks, sub {
rmdir "$options->{root}/dev/$fname"
or warning("cannot rmdir ./dev/$fname: $!");
};
if (-e "$options->{root}/dev/$fname") {
if (!-d "$options->{root}/dev/$fname") {
error "./dev/$fname already exists but is not"
. " a directory";
}
} else {
my $num_created
= make_path "$options->{root}/dev/$fname",
{ error => \my $err };
if ($err && @$err) {
error(
join "; ",
(
map {
"cannot create "
. (join ": ", %{$_})
} @$err
));
} elsif ($num_created == 0) {
error
"cannot create $options->{root}/dev/$fname";
}
}
chmod $mode, "$options->{root}/dev/$fname"
or error "cannot chmod ./dev/$fname: $!";
}
my @umountopts = ();
if ($options->{mode} eq 'unshare') {
push @umountopts, '--no-mtab';
}
push @cleanup_tasks, sub {
0 == system('umount', @umountopts,
"$options->{root}/dev/$fname")
or warning("umount ./dev/$fname failed: $?");
};
if ($fname eq "pts/") {
# We cannot just bind-mount /dev/pts from the host as
# doing so will make posix_openpt() fail. Instead, we
# need to mount a new devpts.
# We need ptmxmode=666 because /dev/ptmx is a symlink
# to /dev/pts/ptmx and without it posix_openpt() will
# fail if we are not the root user.
# See also:
# kernel.org/doc/Documentation/filesystems/devpts.txt
# salsa.debian.org/debian/schroot/-/merge_requests/2
# https://bugs.debian.org/856877
# https://bugs.debian.org/817236
0 == system(
'mount',
'-t',
'devpts',
'none',
"$options->{root}/dev/pts",
'-o',
'noexec,nosuid,uid=5,mode=620,ptmxmode=666'
) or error "mount /dev/pts failed";
} elsif ($type == 5) {
# directory
if (any { $_ =~ '^chroot/mount(?:/dev)?$' }
@{ $options->{skip} }) {
info "skipping chroot/mount/dev as requested";
} elsif (!$options->{canmount}) {
warning "skipping bind-mounting ./dev/$fname";
} else {
0 == system('mount', '-o', 'bind', "/dev/$fname",
"$options->{root}/dev/$fname")
or error "mount ./dev/$fname failed: $?";
if (!-d "$options->{root}/dev") {
warning(
"skipping creation of ./dev/$fname because the"
. " /dev directory is missing in the target"
);
next;
}
if (!-e "/dev/$fname" && $fname ne "pts/") {
warning("skipping creation of ./dev/$fname because"
. " /dev/$fname does not exist"
. " on the outside");
next;
}
if (!-d "/dev/$fname" && $fname ne "pts/") {
warning("skipping creation of ./dev/$fname because"
. " /dev/$fname on the outside is not a"
. " directory");
next;
}
if (!$options->{havemknod}) {
# If had mknod, then the directory to bind-mount into
# was already created in the run_setup function.
push @cleanup_tasks, sub {
rmdir "$options->{root}/dev/$fname"
or warning("cannot rmdir ./dev/$fname: $!");
};
if (-e "$options->{root}/dev/$fname") {
if (!-d "$options->{root}/dev/$fname") {
error
"./dev/$fname already exists but is not"
. " a directory";
}
} else {
my $num_created
= make_path "$options->{root}/dev/$fname",
{ error => \my $err };
if ($err && @$err) {
error(
join "; ",
(
map {
"cannot create "
. (join ": ", %{$_})
} @$err
));
} elsif ($num_created == 0) {
error( "cannot create $options->{root}"
. "/dev/$fname");
}
}
chmod $mode, "$options->{root}/dev/$fname"
or error "cannot chmod ./dev/$fname: $!";
}
my @umountopts = ();
if ($options->{mode} eq 'unshare') {
push @umountopts, '--no-mtab';
}
push @cleanup_tasks, sub {
0 == system('umount', @umountopts,
"$options->{root}/dev/$fname")
or warning("umount ./dev/$fname failed: $?");
};
if ($fname eq "pts/") {
# We cannot just bind-mount /dev/pts from the host as
# doing so will make posix_openpt() fail. Instead, we
# need to mount a new devpts.
# We need ptmxmode=666 because /dev/ptmx is a symlink
# to /dev/pts/ptmx and without it posix_openpt() will
# fail if we are not the root user.
# See also:
# kernel.org/doc/Documentation/filesystems/devpts.txt
# salsa.debian.org/debian/schroot/-/merge_requests/2
# https://bugs.debian.org/856877
# https://bugs.debian.org/817236
0 == system(
'mount',
'-t',
'devpts',
'none',
"$options->{root}/dev/pts",
'-o',
'noexec,nosuid,uid=5,mode=620,ptmxmode=666'
) or error "mount /dev/pts failed";
} else {
0 == system('mount', '-o', 'bind', "/dev/$fname",
"$options->{root}/dev/$fname")
or error "mount ./dev/$fname failed: $?";
}
}
} else {
error "unsupported type: $type";
@ -1269,6 +1277,9 @@ sub run_chroot {
# set because if we mount it before, then base-files will not be able
# to extract those
if ((any { $_ eq $options->{mode} } ('root', 'unshare'))
&& (any { $_ =~ '^chroot/mount(?:/sys)?$' } @{ $options->{skip} })) {
info "skipping chroot/mount/sys as requested";
} elsif ((any { $_ eq $options->{mode} } ('root', 'unshare'))
&& !$options->{canmount}) {
warning "skipping mount sysfs";
} elsif ((any { $_ eq $options->{mode} } ('root', 'unshare'))
@ -1344,6 +1355,9 @@ sub run_chroot {
error "unknown mode: $options->{mode}";
}
if ((any { $_ eq $options->{mode} } ('root', 'unshare'))
&& (any { $_ =~ '^chroot/mount(?:/proc)?$' } @{ $options->{skip} })) {
info "skipping chroot/mount/proc as requested";
} elsif ((any { $_ eq $options->{mode} } ('root', 'unshare'))
&& !$options->{canmount}) {
warning "skipping mount proc";
} elsif ((any { $_ eq $options->{mode} } ('root', 'unshare'))
@ -6783,6 +6797,12 @@ out in B<extract> mode.
Run B<--customize-hook> options and all F<customize*> scripts in B<--hook-dir>.
This step is not carried out in B<extract> mode.
Whenever B<mmdebstrap> does a chroot call in B<root> or B<unshare> modes, it
will mount relevant device nodes, F</proc> and F</sys> into the chroot and
unmount them afterwards. This can be disabled using B<--skip=chroot/mount> or
specifically by B<--skip=chroot/mount/dev>, B<--skip=chroot/mount/proc> and
B<--skip=chroot/mount/sys>, respectively.
For each command that is run inside the chroot, B<mmdebstrap> will disable
running services by temporarily moving F</usr/sbin/policy-rc.d> and
F</sbin/start-stop-daemon> if they exist. This can be disabled with

12
tests/skip-mount Normal file
View file

@ -0,0 +1,12 @@
#!/bin/sh
set -eu
export LC_ALL=C.UTF-8
[ "{{ MODE }}" = "unshare" ]
trap "rm -f /tmp/debian-chroot.tar" EXIT INT TERM
{{ CMD }} --mode=unshare --variant=apt \
--skip=chroot/mount/proc,chroot/mount/sys \
--customize-hook='mountpoint "$1"/dev/null' \
--customize-hook='if mountpoint "$1"/sys; then exit 1; fi' \
--customize-hook='if mountpoint "$1"/proc; then exit 1; fi' \
{{ DIST }} /tmp/debian-chroot.tar {{ MIRROR }}
tar -tf /tmp/debian-chroot.tar | sort | diff -u tar1.txt -