libgnutls30 3.4.10 segfaults with knot-resolver 2.3

[Ondrej Vasko]

Activating DNS over TLS in knot-resolver 2.3.0-1 with Ubuntu 16.04 (Xenial) and libgnutls 3.4.10 results in segmentation fault (double free).

Upstream bug in Knot-resolver is filled here (https://gitlab.labs.nic.cz/knot/knot-resolver/issues/365). Discussion with developers lead us to bug in gnutls, which was patched in version 3.5.5 (https://gitlab.com/gnutls/gnutls/blob/gnutls_3_6_2/NEWS#L413).

Test with same configuration on Ubuntu 18 (Bionic), where version of libgnutls30:amd64 is 3.5.18-1ubuntu1 works good.

Please consider update to newer minor version of GNUTLS.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Nikos Mavrogiannopoulos (nmavrogiannopoulos)]

That also affected ocserv:
https://gitlab.com/ocserv/ocserv/issues/152

[Nikos Mavrogiannopoulos (nmavrogiannopoulos)]

Related commits:
https://gitlab.com/gnutls/gnutls/commit/af09650c5b48ff0bce41007e588c2838d8e2a0be
https://gitlab.com/gnutls/gnutls/commit/c59df1554b55748ea95ad1a89a6bcb6ab91963d2

test:
https://gitlab.com/gnutls/gnutls/commit/365804d56a0241260b1a12a32f7abbc32b504f30