Hello,

You should not write to this list for those questions. but to "shr-devel" <
[email protected]>,

I hope someone will be able to answer to your interesting questions.

Regards

Sylvain Paré



Le 23 mars 2012 16:16, Matthias Apitz <[email protected]> a écrit :

>
> Hello,
>
> In GSM the BS can force the mobile to run the call in unencrypted mode;
> this feature is used, for example, to sniff GSM calls with IMSI
> catchers; for more details see
>
> http://en.wikipedia.org/wiki/IMSI-catcher
>
> I was investigating this a bit in the log file fsogsmd.log and have some
> kind of surprise and some questions:
>
> A 'grep CPRI fsogsmd.log' after a fresh reboot shows that %CPRI=1 is
> enabled, i.e. during a phone call the device will show if or if not
> encryption takes place:
>
> fsogsmd.log:2012-03-23T14:46:00.026356Z [INFO]  libfsotransport <0710:3>:
> SRC: "%CPRI=1" -> [ "OK" ]
> fsogsmd.log:2012-03-23T14:46:55.872445Z [INFO]  libfsotransport <0710:3>:
> URC: [ "%CPRI: 1,2" ]
>
> the meaning of "%CPRI: 1,2", is that: '1' is for GSM (ciphering enabled)
> and the '2' for GPRS (ciphering state not applicable)
>
> now I did some phone call (in/out) and always ciphering was shown and
> enabled:
>
> fsogsmd.log:2012-03-23T14:47:03.324784Z [INFO]  libfsotransport <0710:3>:
> URC: [ "%CPRI: 1,2" ]
> fsogsmd.log:2012-03-23T14:48:33.408969Z [INFO]  libfsotransport <0710:3>:
> URC: [ "%CPRI: 1,2" ]
> fsogsmd.log:2012-03-23T14:50:24.799359Z [INFO]  libfsotransport <0710:3>:
> URC: [ "%CPRI: 1,2" ]
>
> now I let the FR suspending and waked it up again; and during the
> re-init of the modem it is set to "do not show encryption" on call, i.e.
> is is switched of with "%CPRI=0":
>
> fsogsmd.log:2012-03-23T14:52:13.633599Z [INFO]  libfsotransport <0710:3>:
> SRC: "%CPRI=0" -> [ "OK" ]
> fsogsmd.log:2012-03-23T14:54:09.952246Z [INFO]  libfsotransport <0710:3>:
> SRC: "%CPRI=0" -> [ "OK" ]
>
> Why is this?
>
> Another question is, when I try from userland to switch cipher
> notification on again, it seems that this chat(1) does not work:
>
> root@om-gta02:~# chat -vs < /dev/ttySAC0 > /dev/ttySAC0 '' 'AT%CPRI=1'
>
> What I'm doing wrong here with chat(1)?
>
> I'm attaching as well an older thread from the comunity list from last
> year;
>
> In general I think that
>
> a) SHR should switch cipher notification to on
> b) SHR should show during the call if the call is encrypted or not on
> the screen (and not only in the log files);
>
> any comments on this?
>
> Thanks
>
>        matthias
>
>
> ----- Forwarded message from Matthias Apitz <[email protected]> -----
>
> Date: Tue, 5 Jul 2011 07:57:24 +0200
> From: Matthias Apitz <[email protected]>
> To: Timo Juhani Lindfors <[email protected]>
> Cc: List for Openmoko community discussion <[email protected]>
> Subject: Re: FR && non encrypted calls
>
> El día Monday, July 04, 2011 a las 09:35:24AM +0300, Timo Juhani Lindfors
> escribió:
>
> > Matthias Apitz <[email protected]> writes:
> > > Is the FR capable to show that the call runs in non encrypted mode
> > > because the BS forced the ME to this mode? The question is for Om2008.9
> > > but as well valid for any other distribution running on the FR.
> >
> > I think the GSM part (Calypso) delivers this information in the AT%CPRI
> > message. With ogsmd (part of the python version of fso-frameworkd) I
> > have lines like
> >
> > Jul  3 11:57:43 ginger org.freesmartphone.GSM.Network.CypherStatus:
> enabled: unknown
> >
> > in /var/log/syslog.
> >
> > om2008.9 does not use ogsmd afaik but gsmd.
>
> I did some tests sending down AT-cmds with the 'chat' command
> and watching the AT chatting in /var/log/messages:
>
> Per default it is set to off:
>
> root@om-gta02:~# chat -vs < /dev/ttySAC0 > /dev/ttySAC0 '' 'AT%CPRI?'
>
> Jul  5 07:39:50 om-gta02 local2.info chat[1556]: send (AT%CPRI?^M)
> Jul  5 07:39:50 om-gta02 user.notice root: AtChat :  ? : "%CPRI: 0"
> Jul  5 07:39:50 om-gta02 user.notice root: AtChat :  ? : "OK"
>
> Then I switched it on with:
>
> root@om-gta02:~# chat -vs < /dev/ttySAC0 > /dev/ttySAC0 '' 'AT%CPRI=1'
>
> which gives in the /var/log/messages:
>
> Jul  5 07:41:37 om-gta02 local2.info chat[1557]: send (AT%CPRI=1^M)
> Jul  5 07:41:37 om-gta02 user.notice root: AtChat :  ? : "OK"
>
> then I dialed a number:
>
> Jul  5 07:43:49 om-gta02 user.notice root: AtChat :  T : "ATD089xxxxxxxx;"
> Jul  5 07:43:51 om-gta02 user.notice root: AtChat :  N : "+CSSI: 1"
> Jul  5 07:44:17 om-gta02 user.notice root: AtChat :  F : "OK"
> Jul  5 07:44:17 om-gta02 user.notice root: Modem :
> QModemCall::dialRequestDone()
> Jul  5 07:44:17 om-gta02 user.notice root: AtChat :  T : "AT+CLCC"
> Jul  5 07:44:17 om-gta02 user.notice root: AtChat :  F : "%CPRI: 1,2"
> Jul  5 07:44:17 om-gta02 user.notice root: AtChat :  F : "OK"
> Jul  5 07:44:17 om-gta02 user.notice root: Modem :  dialing was ok, we are
> connected
> Jul  5 07:44:23 om-gta02 user.notice root: Modem :  QModemCall::hangup()
> Jul  5 07:44:23 om-gta02 user.notice root: AtChat :  T : "AT+CHLD=1"
> Jul  5 07:44:23 om-gta02 user.notice root: Modem :  hangup groups
> Jul  5 07:44:23 om-gta02 user.notice root: AtChat :  F : "OK"
>
> as you see, one of the result code of the TE is "%CPRI: 1,2", where the
> '1' is for GSM (ciphering enabled) and the '2' for GPRS (ciphering state
> not applicable), see also page 167 for the values in
>
> http://www.cartft.com/support_db/support_files/CTFPND-3_AT_Command_Reference.pdf
>
> with a bit of tweaking, at least this information is visible in the log
> files if the connection is ciphered or not.
>
> HIH
>
>        matthias
> --
> Matthias Apitz
> t +49-89-61308 351 - f +49-89-61308 399 - m +49-170-4527211
> e <[email protected]> - w http://www.unixarea.de/
>
> _______________________________________________
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>
> ----- End forwarded message -----
>
> --
> Matthias Apitz
> e <[email protected]> - w http://www.unixarea.de/
> UNIX since V7 on PDP-11, UNIX on mainframe since ESER 1055 (IBM /370)
> UNIX on x86 since SVR4.2 UnixWare 2.1.2, FreeBSD since 2.2.5
> _______________________________________________
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>
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