TLS fails on Android 7.0

[nekr0z]

Looks like syncthing-lite is suffering from what was recently discussed and fixed for syncthing-android. On Android 7.0 no connections to remote devices can be established; remote devices running Syncthing 1.0.1 show

INFO: Listen (BEP/tcp): TLS handshake: EOF
INFO: Listen (BEP/tcp): TLS handshake: remote error: tls: illegal parameter
INFO: Listen (BEP/tcp): TLS handshake: EOF
INFO: Listen (BEP/tcp): TLS handshake: remote error: tls: illegal parameter
INFO: Listen (BEP/tcp): TLS handshake: remote error: tls: illegal parameter

in their logs.

[l-jonas]

When looking at the linked merge request at https://github.com/syncthing/syncthing-android/pull/1281/files#diff-a6bf66b4cf404ae3f19b5148b0084e1dR118, I think that it's only related to the web UI and not to the block exchange protocol.

[nekr0z]

Could well be, I don't really speak Java to figure it out. Still, the problem exists. I'm currently testing the exactly same setup on Android 8 (no issues) and Android 7 (the problem described).

[l-jonas]

Does it work with Android 7 when the remote device uses an older syncthing version?

[nekr0z]

Will test, need to fire up a VM and deploy an old version for that.

[l-jonas]

I think a new system user with a user local installation would be enough.

[nekr0z]

0.14.51 - same behaviour.

[l-jonas]

Exactly the same behavior? The EOF's are expected, the illegal parameters should not occur. Otherwise it never worked at Android 7 (or the version you tested is too new or it is related to something like the ssl libraries of the OS of the non-android device).

[nekr0z]

Yes, exactly the same.
The version I'm testing is what's released in Google Play. And yes, it's as Android a device as one could get.
To be fair, from what I read in the abovementioned discussion, if st-lite relies on OS to provide TLS, it shouln't ever have worked on 7.0.

[Newar417]

For what it's worth I have the same issue on a stock Motorola G4plus, but not on a Asus Zenfone 2 with latest LineageOS. All the latest versions and Syncthing Lite is from FDroid on both.