[tor-relays] Tor 2.6.10 fails to generate fresh DH Keys

[cyb3rwr3ck]

Hi there,

after a unsuspected reboot of wr3ck3d0ni0n01 I decided to refresh all the keys.
I took the chance to upgrade to 2.6.10 (Debian) and recognized that the
relay wont start afterwards. It looks like it is unable to generate the
new krypto:

Aug 01 11:56:01.000 [notice] Tor 0.2.6.10 (git-71459b2fe953a1c0) opening log file.
Aug 01 11:56:01.000 [notice] Generating fresh dynamic DH modulus. This might take a while...
Aug 01 11:56:01.000 [err] tor_assertion_failed_(): Bug: ../src/common/crypto.c:1788: crypto_generate_dynamic_dh_modulus: Assertion r == 0 failed; aborting.
Aug 01 11:56:01.000 [err] Bug: Assertion r == 0 failed in crypto_generate_dynamic_dh_modulus at ../src/common/crypto.c:1788. Stack trace:
Aug 01 11:56:01.000 [err] Bug:     /usr/bin/tor(log_backtrace+0x41) [0x7f892b3b3601]
Aug 01 11:56:01.000 [err] Bug:     /usr/bin/tor(tor_assertion_failed_+0x9f) [0x7f892b3c0def]
Aug 01 11:56:01.000 [err] Bug:     /usr/bin/tor(crypto_set_tls_dh_prime+0x7db) [0x7f892b3cfb1b]
Aug 01 11:56:01.000 [err] Bug:     /usr/bin/tor(set_options+0x1ce5) [0x7f892b35ee25]
Aug 01 11:56:01.000 [err] Bug:     /usr/bin/tor(options_init_from_string+0x2d3) [0x7f892b35f503]
Aug 01 11:56:01.000 [err] Bug:     /usr/bin/tor(options_init_from_torrc+0x1ca) [0x7f892b35f81a]
Aug 01 11:56:01.000 [err] Bug:     /usr/bin/tor(tor_init+0x2e2) [0x7f892b2d1202]
Aug 01 11:56:01.000 [err] Bug:     /usr/bin/tor(tor_main+0x55) [0x7f892b2d23a5]
Aug 01 11:56:01.000 [err] Bug:     /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xfd) [0x7f8929bc2ead]
Aug 01 11:56:01.000 [err] Bug:     /usr/bin/tor(+0x362ad) [0x7f892b2cd2ad]

I wasn’t able to find any known bugs regarding this behaviour. Anyone
out there who has seen this before?
Best regards!
Felix