dirmngr: prevent crash

[RJVB (René Bertin)]

I've been seeing regular dirmngr crashes when I open a signed message in kmail.

It seems this was due to calling a function from port:pth without proper initialisation (which appears to be done implicitly). Pth allows for multiple calls to pth_init, so a call to that function before the code leading to the crash seems to have solved the issue.

[ryandesign (Ryan Carsten Schmidt)]

Is this problem already known to the developers of dirmngr? i.e. can you give us the bug report URL?

[RJVB (René Bertin)]

No, and checking just now I see that this particular issue isn't patched by Debian/Ubuntu either.

Really, my patch is probably just a workaround for an underlying issue I'm not really interested to hunt down. If you look at dirmngr.c:667,

  /* Libgcrypt requires us to register the threading model first.
     Note that this will also do the pth_init. */

  /* Init Libgcrypt. */
  rc = gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_pth);

that would suggest that gcry_control doesn't call pth_init() properly. Or some other later call undoes that, for whatever reason. An extra pth_init() that is redundant (does nothing) in the cases where the crash did not occur protects against such events.

As I said, I'm not interested in hunting this down properly if this workaround is enough to prevent a crash report window from popping up for certain messages. I thought initially that that crash might be OS X specific, but it seems I don't get them on my Linux rig because kmail doesn't attempt certificate verification (despite being configured to do so).

[tanner@…]

this is old upstream bug ​https://bugs.g10code.com/gnupg/issue1590 (patch included) but upstream seems to have forgotten to release a new version.

[RJVB (René Bertin)]

So, should we use that patch, or just use mine (which in essence does the same thing) and wait for an upstream new version?

[kurthindenburg (Kurt Hindenburg)]

Cc Me!

[kurthindenburg (Kurt Hindenburg)]

thanks I used the bug report patch r147633