Matthias Andree wrote:
On Thu, 21 Aug 2008, Alberto Gonzalez Iniesta wrote:
It seems that tightening the security on OpenVPN brought some surprises
[1] to users and broke some features [2].
As for [1], I included a note in the Debian NEWS file on the new
--script-security option. But those updating a VPN using the very same
VPN (and without previous knowledge of this option) may find themselves
without access to the remote system (if the VPN/system is restarted, and
a script is to be executed). Also, those using NetworkManager [3] aren't
able to specify the '--script-security' option, and since NetworkManager
may/will call external scripts, this new security feature will break
their VPNs. The option is really useful, but 2 would be a more sensible
default IMHO.
One might argue that NetworkManager doesn't support all *RC versions of
OpenVPN's. At the end of the day, it will be a NetworkManager issue.
Interfaces change...
Regarding [2] an strace shows that calls to external commands with
arguments include the arguments as part of the command filename:
For:
--up "/tmp/foo up"
The call is:
[pid 3519] execve("/tmp/foo up", ["/tmp/foo up", "tun0", "1500", "1542",
"10.XXX.XXX.X", "10.XXX.XXX.X", "init"], [/* 30 vars */]) = -1 ENOENT
(No such file or directory)
Apparently argument splitting - as documented in the --up section of the
manpage - no longer works; it was probably formerly done by the implicit
/bin/sh -c that is now gone with the switch to exec*().
(I didn't check, and didn't check the two Debian BTS reports either.)
So either the code needs argument splitting or you need a two-line shell
wrapper similar to:
#! /bin/sh -e
exec /tmp/foo up "$@"
Not my call to make.
I agree that argument splitting in --up "/tmp/foo up" should be
supported, as it doesn't detract from the sought-after security goals in
migrating from system() to execve(), and preserves backward compatibility.
James
