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Logging $ssl_session_id can crash Nginx 1.5.9 worker

January 22, 2014 02:02PM
I run the nginx.org mainline packages on Ubuntu 12.04, 32- and 64-bit. I use a wacky custom log format, and after 1.5.9 was released today, I enabled logging the $ssl_session_id variable. I later ran an SSL Labs SSL Server Test, [0] which makes numerous HTTPS requests of various sorts, and lo and behold, one of my worker processes core dumped. I fooled around with my configuration and determined that the problem was logging $ssl_session_id. If I don't log it, it's fine. If I enable a log that contains $ssl_session_id -- even only $ssl_session_id -- it crashes.

Normal HTTPS requests -- well, I just tried curl and Firefox -- work fine. I notice that curl does log a session ID, but for Firefox that field is just a "-". I have no idea if that's an(other) Nginx bug or just a difference between the two clients, but it smells funny to me. I briefly enabled $ssl_session_id logging on 2013-12-17 with 1.5.7 or 1.5.8 and whatever Firefox version was current at the time and it did log he session data. (I never tried curl or SSL Labs then.)

nginx.conf: https://mn9.us/tmp/nginx.conf (my logging nonsense is at the end)

Good and bad log snippets at https://mn9.us/tmp/nginx.log and pasted below.

Bad:

==> /var/log/nginx/access13.log <==
173.203.79.216 36823 "www.mn9.us" 192.155.93.101 443 "mn9.us" 586 1 on TLSv1.2 - "-" [2014-01-22T18:05:54+00:00] "GET / HTTP/1.0" 200 975 612 - "-" "SSL Labs (https://www.ssllabs.com/about/assessment.html)" "-" "ECDHE-RSA-AES128-SHA" "-"
173.203.79.216 36876 "-" 192.155.93.101 443 "mn9.us" 594 1 on TLSv1 - "-" [2014-01-22T18:06:06+00:00] "HEAD /?SSL_Labs_Renegotiation_Test=User_Agent_May_Not_Show HTTP/1.0" 400 0 0 - "-" "SSL Labs (https://www.ssllabs.com/about/assessment.html)" "-" "DHE-RSA-AES128-SHA" "-"

==> /var/log/nginx/error.log <==
2014/01/22 18:06:06 [notice] 24848#0: *595 SSL renegotiation disabled while reading client request headers, client: 173.203.79.216, server: mn9.us, request: "HEAD /?SSL_Labs_Renegotiation_Test=User_Agent_May_Not_Show HTTP/1.0"
2014/01/22 18:06:07 [notice] 24681#0: signal 17 (SIGCHLD) received
2014/01/22 18:06:07 [alert] 24681#0: worker process 24848 exited on signal 11 (core dumped)
2014/01/22 18:06:07 [notice] 24681#0: start worker process 26865
2014/01/22 18:06:07 [notice] 24681#0: signal 29 (SIGIO) received

Good:

==> /var/log/nginx/access11.log <==
173.203.79.216 60618 "www.mn9.us" 192.155.93.101 443 "mn9.us" 1003 1 on TLSv1.2 - "-" [2014-01-22T18:27:09+00:00] "GET / HTTP/1.0" 200 975 612 - "-" "SSL Labs (https://www.ssllabs.com/about/assessment.html)" "-" "ECDHE-RSA-AES128-SHA"
173.203.79.216 60701 "-" 192.155.93.101 443 "mn9.us" 1008 1 on TLSv1 - "-" [2014-01-22T18:27:22+00:00] "HEAD /?SSL_Labs_Renegotiation_Test=User_Agent_May_Not_Show HTTP/1.0" 400 0 0 - "-" "SSL Labs (https://www.ssllabs.com/about/assessment.html)" "-" "DHE-RSA-AES128-SHA"

==> /var/log/nginx/error.log <==
2014/01/22 18:27:22 [notice] 27156#0: *1009 SSL renegotiation disabled while reading client request headers, client: 173.203.79.216, server: mn9.us, request: "HEAD /?SSL_Labs_Renegotiation_Test=User_Agent_May_Not_Show HTTP/1.0"

==> /var/log/nginx/access11.log <==
173.203.79.216 60948 "-" 192.155.93.101 443 "mn9.us" 1009 1 on TLSv1.2 - "-" [2014-01-22T18:27:22+00:00] "HEAD /?SSL_Labs_Renegotiation_Test=User_Agent_May_Not_Show HTTP/1.0" 400 0 0 - "-" "SSL Labs (https://www.ssllabs.com/about/assessment.html)" "-" "(NONE)"

[0] https://www.ssllabs.com/ssltest/index.html

Cheers
--

--
Matt Nordhoff
Subject Author Posted

Logging $ssl_session_id can crash Nginx 1.5.9 worker

mnordhoff January 22, 2014 02:02PM

Re: Logging $ssl_session_id can crash Nginx 1.5.9 worker

Ruslan Ermilov January 22, 2014 03:08PM

Re: Logging $ssl_session_id can crash Nginx 1.5.9 worker

Maxim Dounin January 22, 2014 04:50PM

Re: Logging $ssl_session_id can crash Nginx 1.5.9 worker

Ruslan Ermilov January 23, 2014 05:56AM

Re: Logging $ssl_session_id can crash Nginx 1.5.9 worker

Maxim Dounin January 22, 2014 04:36PM



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