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# ex:ts=8 sw=4:
# $OpenBSD: ArcCheck.pm,v 1.34 2016/05/14 21:12:40 espie Exp $
#
# Copyright (c) 2005-2006 Marc Espie <espie@openbsd.org>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
# Supplementary code to handle archives in the package context.
# Ustar allows about anything, but we want to forbid a lot of things.
# this code is used during creation and extraction
# specifically, during create time:
# - prevent a lot of weird objects from entering the archives
# - make sure all relevant users/modes are recorded in the PLIST item
# during extraction:
# - make sure complex objects have all their relevant properties recorded
# - disallow extraction of non-files/links.
# - guard against files much longer than they should be.
use strict;
use warnings;
use OpenBSD::Ustar;
package OpenBSD::Ustar::Object;
use POSIX;
sub is_allowed() { 0 }
# match archive header link name against actual link name
sub check_linkname
{
my ($self, $linkname) = @_;
my $c = $self->{linkname};
if ($self->isHardLink && defined $self->{cwd}) {
$c = $self->{cwd}.'/'.$c;
}
return $c eq $linkname;
}
sub validate_meta
{
my ($o, $item) = @_;
$o->{cwd} = $item->cwd;
if (defined $item->{symlink} || $o->isSymLink) {
unless (defined $item->{symlink} && $o->isSymLink) {
$o->errsay("bogus symlink #1", $item->name);
return 0;
}
if (!$o->check_linkname($item->{symlink})) {
$o->errsay("archive symlink does not match #1 != #2",
$o->{linkname}, $item->{symlink});
return 0;
}
} elsif (defined $item->{link} || $o->isHardLink) {
unless (defined $item->{link} && $o->isHardLink) {
$o->errsay("bogus hardlink #1", $item->name);
return 0;
}
if (!$o->check_linkname($item->{link})) {
$o->errsay("archive hardlink does not match #1 != #2",
$o->{linkname}, $item->{link});
return 0;
}
} elsif ($o->isFile) {
if (!defined $item->{size}) {
$o->errsay("Error: file #1 does not have recorded size",
$item->fullname);
return 0;
} elsif ($item->{size} != $o->{size}) {
$o->errsay("Error: size does not match for #1",
$item->fullname);
return 0;
}
} else {
$o->errsay("archive content for #1 should be file",
$item->name);
return 0;
}
return $o->verify_modes($item);
}
sub strip_modes
{
my ($o, $item) = @_;
my $result = $o->{mode};
# disallow writable files/dirs without explicit annotation
if (!defined $item->{mode}) {
# if there's an owner, we have to be explicit
if (defined $item->{owner}) {
$result &= ~(S_IWUSR|S_IWGRP|S_IWOTH);
} else {
$result &= ~(S_IWGRP|S_IWOTH);
}
# and make libraries non-executable
if ($item->is_a_library) {
$result &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
}
$result |= S_IROTH | S_IRGRP;
}
# if we're going to set the group or owner, sguid bits won't
# survive the extraction
if (defined $item->{group} || defined $item->{owner}) {
$result &= ~(S_ISUID|S_ISGID);
}
return $result;
}
sub printable_mode
{
my $o = shift;
return sprintf("%4o",
$o->{mode} & (S_IRWXU | S_IRWXG | S_IRWXO | S_ISUID | S_ISGID));
}
sub verify_modes
{
my ($o, $item) = @_;
my $result = 1;
if (!defined $item->{owner}) {
if ($o->{uname} ne 'root') {
$o->errsay("Error: no \@owner for #1 (#2)",
$item->fullname, $o->{uname});
$result = 0;
}
}
if (!defined $item->{group}) {
if ($o->{gname} ne 'bin' && $o->{gname} ne 'wheel') {
$o->errsay("Error: no \@group for #1 (#2)",
$item->fullname, $o->{gname});
$result = 0;
}
}
if ($o->{mode} != $o->strip_modes($o)) {
$o->errsay("Error: weird mode for #1: #2", $item->fullname,
$o->printable_mode);
$result = 0;
}
return $result;
}
package OpenBSD::Ustar::HardLink;
sub is_allowed() { 1 }
package OpenBSD::Ustar::SoftLink;
sub is_allowed() { 1 }
package OpenBSD::Ustar::File;
sub is_allowed() { 1 }
package OpenBSD::Ustar;
use POSIX;
# prepare item and introduce long names where needed.
sub prepare_long
{
my ($self, $item) = @_;
my $entry;
if (defined $item->{wtempname}) {
$entry = $self->prepare($item->{wtempname}, '');
} else {
$entry = $self->prepare($item->name);
}
if (defined $item->{owner}) {
$entry->{uname} = $item->{owner};
if (defined $item->{uid}) {
$entry->{uid} = $item->{uid};
} else {
delete $entry->{uid};
}
} else {
$entry->{uname} = "root";
delete $entry->{uid};
}
if (defined $item->{group}) {
$entry->{gname} = $item->{group};
if (defined $item->{gid}) {
$entry->{gid} = $item->{gid};
} else {
delete $entry->{gid};
}
} else {
$entry->{gname} = "bin";
delete $entry->{gid};
}
# likewise, we skip links on extractions, so hey, don't even care
# about modes and stuff.
if ($entry->isSymLink) {
$entry->{mode} = 0777;
$entry->{uname} = 'root';
$entry->{gname} = 'wheel';
delete $entry->{uid};
delete $entry->{gid};
}
$entry->recheck_owner;
if (!defined $entry->{uname}) {
$self->fatal("No user name for #1 (uid #2)",
$item->name, $entry->{uid});
}
if (!defined $entry->{gname}) {
$self->fatal("No group name for #1 (gid #2)",
$item->name, $entry->{gid});
}
$entry->{mode} = $entry->strip_modes($item);
if (defined $item->{ts}) {
delete $entry->{mtime};
}
$entry->set_name($item->name);
return $entry;
}
1;
|
