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To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>,
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Subject: Re: [pve-devel] [PATCH v2 container] fix #4192: revamp check for
systemd version
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Am 12/09/2022 um 14:41 schrieb Fabian Gr=C3=BCnbichler:
>> Instead of iterating through several folders, it might just be easier =
to
>> check the ldd output of /sbin/init and getting the version from there.=
>> Furthermore, the regex for checking the version has been adapted so th=
at
>> it's more precise.
> ldd is not suited for this purpose for security reasons, since /sbin/in=
it=20
> is a user/attacker-controlled binary in this case and we are only in a =
> chroot while doing the setup, not really containerized. given a crafted=
=20
> container template/backup archive/.. this could execute arbitrary code.=
>=20
> it's manpage suggests using
>=20
> objdump -p /path/to/binary
>=20
> and looking at the lines with "NEEDED", which seems to me should be fin=
e=20
> for what we want to achieve here =F0=9F=98=84
>=20
tbf, I suggested using something like ldd here, but I mostly meant if we =
actually
need to further extend this than simply checking three instead of two pat=
hs.
But I actually like the much shorter code, so from that POV it could be a=
nicer
option, but it makes us dependent on actually executing code from the CT =
archive,
which also assumes the availability of something like ldd or objdump, whi=
ch may
not be the case in all templates?
Two small nits w.r.t. to the v2 still inline.
Am 12/09/2022 um 14:25 schrieb Leo Nunner:
> + my $version =3D undef;
> + PVE::Tools::run_command(
> + [
> + 'ldd',
> + '/sbin/init'
> + ],
you can put the array ref in one line, e.g., with Fabian relayed manpage
suggestion it'd be fine to do:
[ 'objdump', '-p', '/sbin/init' ],
> + outfunc =3D> sub {
> + my $line =3D shift;
> + if ($line =3D~ /^\s*libsystemd-shared-(\d+)(?:\.[a-zA-Z0-9]*)?\.s=
o/) {
> + $version =3D $1;
> + }},
> + errmsg =3D> "ldd on /sbin/init failed"
above is missing a trailing comma, which would ensure that any possible a=
ddition of an
option in the future won't need to touch an unrelated line.
> + );
> +
> + return $version;
> }