kernel-mode PPPoE does not seem able to work with MPPE.

kernel-mode PPPoE does not seem able to work with MPPE.

[David Fernandez]

Hi there,

I've tried to run MPPE in a PPPoE connection to my LEDE linux server. The log is below.

Looking at wireshark traces, it seems to negotiate mschap-v2 and mppe fine, but then ppp seems not to accept encrypted payloads.

Although it should not be needed, if I use the option require-mppe, pppd complains of unrecognized option.

If I grep for mppe in the 2.4.7 sources downloaded by the LEDE build system, I see that it appears only in the pptp plugin, which is strange, as the mppe options are in the pppd manual page as generally available ones.

I've tried to load both plugins (rp-pppoe.so and pptp.so) in an attempt to have the mppe working with require-mppe, but the result seems the same (unrecognized option).

Anybody knows why it does not work as expected?

(started with pppoe-server -k -C myserver -S myservice -I eth1)


Feb  2 12:05:20 LEDE pppoe-server[1580]: Session 1 created for client 7c:d3:0a:15:22:49 (10.67.15.1) on eth1 using Service-Name 'myservice'
Feb  2 12:05:20 LEDE pppd[1580]: Plugin /etc/ppp/plugins/rp-pppoe.so loaded.
Feb  2 12:05:20 LEDE pppd[1580]: RP-PPPoE plugin version 3.8p compiled against pppd 2.4.7
Feb  2 12:05:20 LEDE modprobe: failed to find a module named netdev-10.0.0.1
Feb  2 12:05:20 LEDE modprobe: failed to find a module named netdev-10.0.0.1
Feb  2 12:05:20 LEDE pppd[1580]: pppd options in effect:
Feb  2 12:05:20 LEDE pppd[1580]: debug#011#011# (from /etc/ppp/pppoe-server-options)
Feb  2 12:05:20 LEDE pppd[1580]: nodetach#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: dump#011#011# (from /etc/ppp/pppoe-server-options)
Feb  2 12:05:20 LEDE pppd[1580]: plugin /etc/ppp/plugins/rp-pppoe.so#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: require-mschap-v2#011#011# (from /etc/ppp/pppoe-server-options)
Feb  2 12:05:20 LEDE pppd[1580]: name myserver#011#011# (from /etc/ppp/pppoe-server-options)
Feb  2 12:05:20 LEDE pppd[1580]: eth1#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_service myservice#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_sess 1:7c:d3:0a:15:22:49#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: eth1#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_service myservice#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_sess 1:7c:d3:0a:15:22:49#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: noaccomp#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: default-asyncmap#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: mru 1492#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: mtu 1492#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: nopcomp#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: lcp-echo-failure 2#011#011# (from /etc/ppp/pppoe-server-options)
Feb  2 12:05:20 LEDE pppd[1580]: lcp-echo-interval 10#011#011# (from /etc/ppp/pppoe-server-options)
Feb  2 12:05:20 LEDE pppd[1580]: noipdefault#011#011# (from /etc/ppp/pppoe-server-options)
Feb  2 12:05:20 LEDE pppd[1580]: nodefaultroute#011#011# (from /etc/ppp/pppoe-server-options)
Feb  2 12:05:20 LEDE pppd[1580]: netmask 255.0.0.0#011#011# (from /etc/ppp/pppoe-server-options)
Feb  2 12:05:20 LEDE pppd[1580]: 10.0.0.1:10.67.15.1#011#011# (from command line)
Feb  2 12:05:20 LEDE pppd[1580]: pppd 2.4.7 started by root, uid 0
Feb  2 12:05:20 LEDE pppd[1580]: Connected to 7c:d3:0a:15:22:49 via interface eth1
Feb  2 12:05:20 LEDE pppd[1580]: Using interface ppp0
Feb  2 12:05:20 LEDE pppd[1580]: Connect: ppp0 <--> eth1
Feb  2 12:05:22 LEDE pppd[1580]: peer from calling number 7C:D3:0A:15:22:49 authorized
Feb  2 12:05:22 LEDE pppd[1580]: MPPE 128-bit stateful compression enabled
Feb  2 12:05:22 LEDE pppd[1580]: local  IP address 10.0.0.1
Feb  2 12:05:22 LEDE pppd[1580]: remote IP address 10.67.15.1
Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0xc8c8 received
Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0x3d received
Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0x79 received
Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 'PPP Muxing' (0x59) received
Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0x2805 received
Feb  2 12:05:26 LEDE pppd[1580]: Unsupported protocol 0xf6a9 received
Feb  2 12:05:29 LEDE pppd[1580]: Unsupported protocol 0x2e59 received
...

Re: kernel-mode PPPoE does not seem able to work with MPPE.

[David Fernandez]

On 24/10/17 09:52, David Fernandez wrote:
> Hi there,
>
> I've tried to run MPPE in a PPPoE connection to my LEDE linux server. 
> The log is below.
>
> Looking at wireshark traces, it seems to negotiate mschap-v2 and mppe 
> fine, but then ppp seems not to accept encrypted payloads.
>

> Although it should not be needed, if I use the option require-mppe, 
> pppd complains of unrecognized option.
>
> If I grep for mppe in the 2.4.7 sources downloaded by the LEDE build 
> system, I see that it appears only in the pptp plugin, which is 
> strange, as the mppe options are in the pppd manual page as generally 
> available ones.
>
> I've tried to load both plugins (rp-pppoe.so and pptp.so) in an 
> attempt to have the mppe working with require-mppe, but the result 
> seems the same (unrecognized option).
>
On this bit, looking at the sources I found that the way it works is by 
making the option like:
mppe require
I guess that this should be updated in the manual...
With it I get this logging line:
Feb  3 09:09:16 LEDE pppd[3307]: mppe xxx # [don't know how to print 
value]#011#011# (from /etc/ppp/pppoe-server-options)
Everything else is the same.
So I guess this is some kind of bug in pppd/ccp.c?

> Anybody knows why it does not work as expected?
>
> (started with pppoe-server -k -C myserver -S myservice -I eth1)
>
>
> Feb  2 12:05:20 LEDE pppoe-server[1580]: Session 1 created for client 
> 7c:d3:0a:15:22:49 (10.67.15.1) on eth1 using Service-Name 'myservice'
> Feb  2 12:05:20 LEDE pppd[1580]: Plugin /etc/ppp/plugins/rp-pppoe.so 
> loaded.
> Feb  2 12:05:20 LEDE pppd[1580]: RP-PPPoE plugin version 3.8p compiled 
> against pppd 2.4.7
> Feb  2 12:05:20 LEDE modprobe: failed to find a module named 
> netdev-10.0.0.1
> Feb  2 12:05:20 LEDE modprobe: failed to find a module named 
> netdev-10.0.0.1
> Feb  2 12:05:20 LEDE pppd[1580]: pppd options in effect:
> Feb  2 12:05:20 LEDE pppd[1580]: debug#011#011# (from 
> /etc/ppp/pppoe-server-options)
> Feb  2 12:05:20 LEDE pppd[1580]: nodetach#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: dump#011#011# (from 
> /etc/ppp/pppoe-server-options)
> Feb  2 12:05:20 LEDE pppd[1580]: plugin 
> /etc/ppp/plugins/rp-pppoe.so#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: require-mschap-v2#011#011# (from 
> /etc/ppp/pppoe-server-options)
> Feb  2 12:05:20 LEDE pppd[1580]: name myserver#011#011# (from 
> /etc/ppp/pppoe-server-options)
> Feb  2 12:05:20 LEDE pppd[1580]: eth1#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_service myservice#011#011# 
> (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_sess 
> 1:7c:d3:0a:15:22:49#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: eth1#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_service myservice#011#011# 
> (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_sess 
> 1:7c:d3:0a:15:22:49#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: noaccomp#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: default-asyncmap#011#011# (from 
> command line)
> Feb  2 12:05:20 LEDE pppd[1580]: mru 1492#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: mtu 1492#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: nopcomp#011#011# (from command line)
> Feb  2 12:05:20 LEDE pppd[1580]: lcp-echo-failure 2#011#011# (from 
> /etc/ppp/pppoe-server-options)
> Feb  2 12:05:20 LEDE pppd[1580]: lcp-echo-interval 10#011#011# (from 
> /etc/ppp/pppoe-server-options)
> Feb  2 12:05:20 LEDE pppd[1580]: noipdefault#011#011# (from 
> /etc/ppp/pppoe-server-options)
> Feb  2 12:05:20 LEDE pppd[1580]: nodefaultroute#011#011# (from 
> /etc/ppp/pppoe-server-options)
> Feb  2 12:05:20 LEDE pppd[1580]: netmask 255.0.0.0#011#011# (from 
> /etc/ppp/pppoe-server-options)
> Feb  2 12:05:20 LEDE pppd[1580]: 10.0.0.1:10.67.15.1#011#011# (from 
> command line)
> Feb  2 12:05:20 LEDE pppd[1580]: pppd 2.4.7 started by root, uid 0
> Feb  2 12:05:20 LEDE pppd[1580]: Connected to 7c:d3:0a:15:22:49 via 
> interface eth1
> Feb  2 12:05:20 LEDE pppd[1580]: Using interface ppp0
> Feb  2 12:05:20 LEDE pppd[1580]: Connect: ppp0 <--> eth1
> Feb  2 12:05:22 LEDE pppd[1580]: peer from calling number 
> 7C:D3:0A:15:22:49 authorized
> Feb  2 12:05:22 LEDE pppd[1580]: MPPE 128-bit stateful compression 
> enabled
> Feb  2 12:05:22 LEDE pppd[1580]: local  IP address 10.0.0.1
> Feb  2 12:05:22 LEDE pppd[1580]: remote IP address 10.67.15.1
> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0xc8c8 received
> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0x3d received
> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0x79 received
> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 'PPP Muxing' 
> (0x59) received
> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0x2805 received
> Feb  2 12:05:26 LEDE pppd[1580]: Unsupported protocol 0xf6a9 received
> Feb  2 12:05:29 LEDE pppd[1580]: Unsupported protocol 0x2e59 received
> ...
>
>

Re: kernel-mode PPPoE does not seem able to work with MPPE.

[Christoph Schulz]

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Hello!

David Fernandez <david.fernandez.work@googlemail.com> schrieb am Di 24  
Okt 2017 10:52:46 CEST:

> Hi there,
>
> I've tried to run MPPE in a PPPoE connection to my LEDE linux  
> server. The log is below.
> [...]
> Although it should not be needed, if I use the option require-mppe,  
> pppd complains of unrecognized option.

As the sources only define (and understand) the "require-mppe" option  
iff the preprocessor symbol MPPE has been defined during compilation,  
I suspect that your (i.e. LEDE's) pppd has been compiled without MPPE  
support. You should check this first.


Regards,

Christoph Schulz


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Re: kernel-mode PPPoE does not seem able to work with MPPE.

[David Fernandez]

On 24/10/17 15:17, Christoph Schulz wrote:
> Hello!
>
> David Fernandez <david.fernandez.work@googlemail.com> schrieb am Di 24 
> Okt 2017 10:52:46 CEST:
>
>> Hi there,
>>
>> I've tried to run MPPE in a PPPoE connection to my LEDE linux server. 
>> The log is below.
>> [...]
>> Although it should not be needed, if I use the option require-mppe, 
>> pppd complains of unrecognized option.
>
> As the sources only define (and understand) the "require-mppe" option 
> iff the preprocessor symbol MPPE has been defined during compilation, 
> I suspect that your (i.e. LEDE's) pppd has been compiled without MPPE 
> support. You should check this first.
>
Hi Christoph,

The MPPE is defined, as I see code conditionally compiled with #ifdef 
MPPE putting things in the log, like:
Feb  2 12:05:22 LEDE pppd[1580]: MPPE 128-bit stateful compression enabled

AFAICS the downloaded 2.4.7 sources in pppd/ccp.c define and understand 
the option mppe or +mppe with special arguments 
no40,no56,no128,stateless,required comma separated, as per int 
setmppe(char **argv) function... unless I am getting something wrong, 
obviously.

These are the options defined in ccp.c:
#ifdef MPPE
     { "mppc", o_bool, &ccp_wantoptions[0].mppc,
       "request MPPC compression", 1, &ccp_allowoptions[0].mppc },
     { "+mppc", o_bool, &ccp_wantoptions[0].mppc,
       "request MPPC compression", 1, &ccp_allowoptions[0].mppc, 
OPT_ALIAS },
     { "nomppc", o_bool, &ccp_wantoptions[0].mppc,
       "don't allow MPPC compression", OPT_PRIOSUB | OPT_A2CLR,
       &ccp_allowoptions[0].mppc },
     { "-mppc", o_bool, &ccp_wantoptions[0].mppc,
       "don't allow MPPC compression", OPT_ALIAS | OPT_PRIOSUB | OPT_A2CLR,
       &ccp_allowoptions[0].mppc },
     { "mppe", o_special, (void *)setmppe,
       "request MPPE encryption" },
     { "+mppe", o_special, (void *)setmppe,
       "request MPPE encryption" },
     { "nomppe", o_special_noarg, (void *)setnomppe,
       "don't allow MPPE encryption" },
     { "-mppe", o_special_noarg, (void *)setnomppe,
       "don't allow MPPE encryption" },
#endif /* MPPE */

These are the download definitions:
PKG_NAME:=ppp
PKG_VERSION:=2.4.7
PKG_RELEASE:\x10

PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
PKG_SOURCE_URL:=https://download.samba.org/pub/ppp/
PKG_HASH:\x02e0a3dd3e4799e33103f70ec7df75348c8540966ee7c948e4ed8a42bbccfb30


>
> Regards,
>
> Christoph Schulz
>
Regards

David

Re: kernel-mode PPPoE does not seem able to work with MPPE.

[Christoph Schulz]

[-- Attachment #1: Type: text/plain, Size: 574 bytes --]

Hello!

David Fernandez <david.fernandez.work@googlemail.com> schrieb am Di 24  
Okt 2017 17:13:32 CEST:

> Hi Christoph,
>
> The MPPE is defined, as I see code conditionally compiled with  
> #ifdef MPPE putting things in the log, like:
> Feb  2 12:05:22 LEDE pppd[1580]: MPPE 128-bit stateful compression enabled

Yes, you are right. I looked a bit around and found that LEDE uses  
201-mppe_mppc_1.1.patch (which I didn't know about) from OpenWRT which  
changes the way MPPE is configured for pppd. Sorry for the noise.


Regards,

Christoph Schulz


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Re: kernel-mode PPPoE does not seem able to work with MPPE.

[David Fernandez]

On 24/10/17 13:09, David Fernandez wrote:
> On 24/10/17 09:52, David Fernandez wrote:
>> Hi there,
>>
>> I've tried to run MPPE in a PPPoE connection to my LEDE linux server. 
>> The log is below.
>>
>> Looking at wireshark traces, it seems to negotiate mschap-v2 and mppe 
>> fine, but then ppp seems not to accept encrypted payloads.
>>
>
>> Although it should not be needed, if I use the option require-mppe, 
>> pppd complains of unrecognized option.
>>
>> If I grep for mppe in the 2.4.7 sources downloaded by the LEDE build 
>> system, I see that it appears only in the pptp plugin, which is 
>> strange, as the mppe options are in the pppd manual page as generally 
>> available ones.
>>
>> I've tried to load both plugins (rp-pppoe.so and pptp.so) in an 
>> attempt to have the mppe working with require-mppe, but the result 
>> seems the same (unrecognized option).
>>
> On this bit, looking at the sources I found that the way it works is 
> by making the option like:
> mppe require
> I guess that this should be updated in the manual...
> With it I get this logging line:
> Feb  3 09:09:16 LEDE pppd[3307]: mppe xxx # [don't know how to print 
> value]#011#011# (from /etc/ppp/pppoe-server-options)
> Everything else is the same.
> So I guess this is some kind of bug in pppd/ccp.c?
>
>> Anybody knows why it does not work as expected?
>>
>> (started with pppoe-server -k -C myserver -S myservice -I eth1)
>>
>>
>> Feb  2 12:05:20 LEDE pppoe-server[1580]: Session 1 created for client 
>> 7c:d3:0a:15:22:49 (10.67.15.1) on eth1 using Service-Name 'myservice'
>> Feb  2 12:05:20 LEDE pppd[1580]: Plugin /etc/ppp/plugins/rp-pppoe.so 
>> loaded.
>> Feb  2 12:05:20 LEDE pppd[1580]: RP-PPPoE plugin version 3.8p 
>> compiled against pppd 2.4.7
>> Feb  2 12:05:20 LEDE modprobe: failed to find a module named 
>> netdev-10.0.0.1
>> Feb  2 12:05:20 LEDE modprobe: failed to find a module named 
>> netdev-10.0.0.1
>> Feb  2 12:05:20 LEDE pppd[1580]: pppd options in effect:
>> Feb  2 12:05:20 LEDE pppd[1580]: debug#011#011# (from 
>> /etc/ppp/pppoe-server-options)
>> Feb  2 12:05:20 LEDE pppd[1580]: nodetach#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: dump#011#011# (from 
>> /etc/ppp/pppoe-server-options)
>> Feb  2 12:05:20 LEDE pppd[1580]: plugin 
>> /etc/ppp/plugins/rp-pppoe.so#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: require-mschap-v2#011#011# (from 
>> /etc/ppp/pppoe-server-options)
>> Feb  2 12:05:20 LEDE pppd[1580]: name myserver#011#011# (from 
>> /etc/ppp/pppoe-server-options)
>> Feb  2 12:05:20 LEDE pppd[1580]: eth1#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_service myservice#011#011# 
>> (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_sess 
>> 1:7c:d3:0a:15:22:49#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: eth1#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_service myservice#011#011# 
>> (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: rp_pppoe_sess 
>> 1:7c:d3:0a:15:22:49#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: noaccomp#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: default-asyncmap#011#011# (from 
>> command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: mru 1492#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: mtu 1492#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: nopcomp#011#011# (from command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: lcp-echo-failure 2#011#011# (from 
>> /etc/ppp/pppoe-server-options)
>> Feb  2 12:05:20 LEDE pppd[1580]: lcp-echo-interval 10#011#011# (from 
>> /etc/ppp/pppoe-server-options)
>> Feb  2 12:05:20 LEDE pppd[1580]: noipdefault#011#011# (from 
>> /etc/ppp/pppoe-server-options)
>> Feb  2 12:05:20 LEDE pppd[1580]: nodefaultroute#011#011# (from 
>> /etc/ppp/pppoe-server-options)
>> Feb  2 12:05:20 LEDE pppd[1580]: netmask 255.0.0.0#011#011# (from 
>> /etc/ppp/pppoe-server-options)
>> Feb  2 12:05:20 LEDE pppd[1580]: 10.0.0.1:10.67.15.1#011#011# (from 
>> command line)
>> Feb  2 12:05:20 LEDE pppd[1580]: pppd 2.4.7 started by root, uid 0
>> Feb  2 12:05:20 LEDE pppd[1580]: Connected to 7c:d3:0a:15:22:49 via 
>> interface eth1
>> Feb  2 12:05:20 LEDE pppd[1580]: Using interface ppp0
>> Feb  2 12:05:20 LEDE pppd[1580]: Connect: ppp0 <--> eth1
>> Feb  2 12:05:22 LEDE pppd[1580]: peer from calling number 
>> 7C:D3:0A:15:22:49 authorized
>> Feb  2 12:05:22 LEDE pppd[1580]: MPPE 128-bit stateful compression 
>> enabled
>> Feb  2 12:05:22 LEDE pppd[1580]: local  IP address 10.0.0.1
>> Feb  2 12:05:22 LEDE pppd[1580]: remote IP address 10.67.15.1
>> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0xc8c8 received
>> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0x3d received
>> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0x79 received
>> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 'PPP Muxing' 
>> (0x59) received
>> Feb  2 12:05:22 LEDE pppd[1580]: Unsupported protocol 0x2805 received
>> Feb  2 12:05:26 LEDE pppd[1580]: Unsupported protocol 0xf6a9 received
>> Feb  2 12:05:29 LEDE pppd[1580]: Unsupported protocol 0x2e59 received
>> ...
>>
>
Seems that this problem was kind of reported here as this:

I Found it originally here: 
https://www.spinics.net/lists/linux-ppp/msg01106.html

It is indeed in the list here: 
https://marc.info/?l=linux-ppp&m\x129753728204109&w=2

Seems that it does solve two problems, but not all of them... Anyway, it 
seems that it is an olde kernel version problem, as I'm using kernel 4.4 
and this might be fixed entirely in modern kernels...

I'll check what the latest kernel ppp_mppe.c looks like.