Dr Josef Karthauser
2020-Feb-09 11:25 UTC
PAM modules; pthreads not reliably dispatching background threads :(.
Hi Folks, Has anyone got any experience with PAM and pthreads? We?re using a 2FA module (pam_yubico https://www.freebsd.org/cgi/man.cgi?query=pam_yubico&sektion=8 <https://www.freebsd.org/cgi/man.cgi?query=pam_yubico&sektion=8>). It?s proving unreliable. Digging deeper it uses libcurl to communication to an HTTP endpoint, and libcurl is using pthreads for to make asynchronous DNS lookup requests. It seems that the pthreads are not being handled reliably within the PAM runtime context - the background threads do not complete or dispatch. It?s very strange. The problem doesn?t happen if we use the same code running from a user land process. The pthreads are reliably in this context. Is there a known issue with PAM and pthreads? Hints are that there are (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214540 <https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214540>). But that problem was reported 3 years ago! HELP! If you know something I?d really appreciate a steer! Many thanks, Joe ? Dr Josef Karthauser Chief Technical Officer (01225) 300371 / (07703) 596893 www.truespeed.com <http://www.truespeed.com/>
Jan Bramkamp
2020-Feb-16 19:14 UTC
PAM modules; pthreads not reliably dispatching background threads :(.
On 09.02.20 12:25, Dr Josef Karthauser wrote:> Hi Folks, > > Has anyone got any experience with PAM and pthreads? > > We?re using a 2FA module (pam_yubico https://www.freebsd.org/cgi/man.cgi?query=pam_yubico&sektion=8 <https://www.freebsd.org/cgi/man.cgi?query=pam_yubico&sektion=8>). > > It?s proving unreliable. Digging deeper it uses libcurl to communication to an HTTP endpoint, and libcurl is using pthreads for to make asynchronous DNS lookup requests. > > It seems that the pthreads are not being handled reliably within the PAM runtime context - the background threads do not complete or dispatch. It?s very strange. > > The problem doesn?t happen if we use the same code running from a user land process. The pthreads are reliably in this context. > > Is there a known issue with PAM and pthreads? Hints are that there are (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214540 <https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214540>). But that problem was reported 3 years ago! > > HELP! > > If you know something I?d really appreciate a steer!Is the "host" process multithreaded or at least built with Pthread support?