Bug #7215: Remaining messages on OpenSSL error queue after Certificate#verify

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-linux]

[larskanis1 (Lars Kanis)]

While investigating a ruby-pg issue [1], we noticed that a SSL connection with PostgreSQL can fail, after a call to OpenSSL::X509::Certificate#verify with result 'false'. Root cause is the thread local error queue of OpenSSL, that is used to transmit textual error messages to the application after a failed crypto operation. A failure in Certificate#verify leaves some messages on the error queue, which can lead to errors in a SSL communication of other parts of the application.

According to the comment on OpenSSL.errors [2], remaining messages on the error queue are probably due to a bug. So the queue should become somehow cleared. I currently see these variants:

• Return the OpenSSL error list in Certificate#verify instead of true/false - This will change the API in an incompatible way, so it will probably be no real option.
• Drop the error list at the end of Certificate#verify - So there will be no way to get the particular error text. Maybe add another method in the way as 1.
• Add a note in the documentation that suggest the user should call OpenSSL.errors after a failed call to Certificate#verify.

A patch for the postgresql side of the issue is already inserted into the patch list for the next commit fest [3].

[1] https://bitbucket.org/ged/ruby-pg/issue/142/async_exec-over-ssl-connection-can-fail-on
[2] https://github.com/ruby/ruby/blob/trunk/ext/openssl/ossl.c#L349
[3] https://commitfest.postgresql.org/action/patch_view?id=961

[MartinBosslet (Martin Bosslet)]

• Status changed from Open to Assigned
• Assignee set to MartinBosslet (Martin Bosslet)

[deafbybeheading (Maciek Sakrejda)]

Hi,

Any progress on this? Postgres has rejected the patch that was submitted on the grounds that this is an OpenSSL client issue and libpq has no business clearing the error queue.

It seems like clearing the error queue but giving some side channel to access the errors from the last Certifivate#verify call would still make the errors available for interested clients, without forcing a byzantine API requiring a separate step to clear the error queue (something that would likely be missed by many clients).

Thanks!

[kritik (Vladimir Krylov)]

Any changes here? Can confirm that problem persists in newer versions of ruby (i.e. 2.1.0p0 (2013-12-25 revision 44422) [x86_64-linux] and 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]).

[nyku.rn (Nicolae Rotaru)]

the only solution at the moment is running :

OpenSSL.errors.clear

after certificate verifying. This clears OpenSSL errors array and keeps database connection alive.

[zzak (zzak _)]

• Assignee changed from MartinBosslet (Martin Bosslet) to 7150

• Status changed from Assigned to Closed

Applied in changeset r55051.

---

openssl: clear OpenSSL error queue before return to Ruby

• ext/openssl/ossl_x509cert.c (ossl_x509_verify): X509_verify()
  family may put errors on 0 return (0 means verification failure).
  Clear OpenSSL error queue before return to Ruby. Since the queue is
  thread global, remaining errors in the queue can cause an unexpected
  error in the next OpenSSL operation. [ruby-core:48284] [Bug #7215]

• ext/openssl/ossl_x509crl.c (ossl_x509crl_verify): ditto.

• ext/openssl/ossl_x509req.c (ossl_x509req_verify): ditto.

• ext/openssl/ossl_x509store.c (ossl_x509stctx_verify): ditto.

• ext/openssl/ossl_pkey_dh.c (dh_generate): clear the OpenSSL error
  queue before re-raising exception.

• ext/openssl/ossl_pkey_dsa.c (dsa_generate): ditto.

• ext/openssl/ossl_pkey_rsa.c (rsa_generate): ditto.

• ext/openssl/ossl_ssl.c (ossl_start_ssl): ditto.

• test/openssl: check that OpenSSL.errors is empty every time after
  running a test case.

[larskanis (Lars Kanis)]

Thanks for fixing this issue! It has been resolved on the PostgreSQL side as well: https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=a3c17b2af89cd46b47df3483bb693312d7521795