Hello,

I tried using SFLphone with the SIPS port at ostel.me. While it works
flawlessly with "CSipSimple" on my Android device it is failing in SFLPhone.

Looking at the capture file of the failing attempt I can see that the
server immediately returns a handshake failure after the first TLSv1
client hello. So I compared the two TLS client hellos and can see a
differences in the different set of TLS extensions being used:

CSipSimple:
- server_name
- ec_point_formats
- elliptic_curves
- SessionTicket TLS

SFLphone:
- ec_point_formats
- elliptic_curves
- SessionTicket TLS
- heartbeat

The other difference and probably more important is the very limited
list of algorithms offered by SFLphone:
- TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (0xc014)
- TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (0xc00a)
- TLS_EMPTY_RENEGOTIATION_INFO_SCSV (0x00ff)

With CSipSimple the server choses TLS_RSA_WITH_AES_256_CBC_SHA (0x0035)
and continues without error.

References:
- http://tools.ietf.org/html/rfc5246#page-37
-
http://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xml


How do I extend the list of algorithms and/or limit the list of TLS
extensions? The extended TLS settings in SFLphone seem to offer
something in that way but I don't know what format this configuration
field expects. Or is my build somewhat limited (0.9.12-1build1) and it
really should support more methods?

Simon
_______________________________________________
SFLphone mailing list
[email protected]
http://lists.savoirfairelinux.net/mailman/listinfo/sflphone

Reply via email to