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Created attachment 925060 [details] backport of TCP timeout patch to krb5-1.11/f20. Description of problem: When performing OTP authentication with `kinit', an aggressive timeout causes, with >50% likelihood (in my environment, YMMV), a second transmission of the AS_REQ request. When using HOTP authentication, if a response to the second request (which necessarily fails) is received and processed ahead of the response to the first request, `kinit' fails (and the ticket in the successful response is discarded). Version-Release number of selected component (if applicable): krb5-workstation-1.11.5-10 How reproducible: In my setup, resent occurs >50% of time, and failure occurs in the majority of these cases. Steps to Reproduce: 1. Use `kinit' to perform a preauthenticated ticket request, using krb5-1.11.5. (I have mainly be using the FreeIPA web UI, since it take care of getting the armor cache). 2. Observe that, with high probability, multiple requests are received by KDC, and one of these fails when HOTP is used. Example /var/log/krb5kdc.log: Aug 08 00:12:38 ipa-2.ipa.local krb5kdc[28303](info): AS_REQ (6 etypes {18 17 16 23 25 26}) 192.168.122.141: NEEDED_PREAUTH: HTTP/ipa-2.ipa.local@IPA.LOCAL for krbtgt/IPA.LOCAL@IPA.LOCAL, Additional pre-authentication required Aug 08 00:12:39 ipa-2.ipa.local krb5kdc[28302](info): AS_REQ (6 etypes {18 17 16 23 25 26}) 192.168.122.141: ISSUE: authtime 1407471159, etypes {rep=18 tkt=18 ses=18}, HTTP/ipa-2.ipa.local@IPA.LOCAL for krbtgt/IPA.LOCAL@IPA.LOCAL Aug 08 00:12:39 ipa-2.ipa.local krb5kdc[28303](info): AS_REQ (6 etypes {18 17 16 23 25 26}) 192.168.122.141: ISSUE: authtime 1407471159, etypes {rep=18 tkt=18 ses=18}, HTTP/ipa-2.ipa.local@IPA.LOCAL for krbtgt/IPA.LOCAL@IPA.LOCAL Aug 08 00:12:39 ipa-2.ipa.local krb5kdc[28302](info): AS_REQ (6 etypes {18 17 16 23 25 26}) 192.168.122.141: NEEDED_PREAUTH: bresc@IPA.LOCAL for krbtgt/IPA.LOCAL@IPA.LOCAL, Additional pre-authentication required Aug 08 00:12:39 ipa-2.ipa.local krb5kdc[28303](info): closing down fd 13 Aug 08 00:12:40 ipa-2.ipa.local krb5kdc[28303](info): preauth (otp) verify failure: Generic preauthentication failure Aug 08 00:12:40 ipa-2.ipa.local krb5kdc[28303](info): AS_REQ (6 etypes {18 17 16 23 25 26}) 192.168.122.141: PREAUTH_FAILED: bresc@IPA.LOCAL for krbtgt/IPA.LOCAL@IPA.LOCAL, Preauthentication failed Aug 08 00:12:41 ipa-2.ipa.local krb5kdc[28302](info): AS_REQ (6 etypes {18 17 16 23 25 26}) 192.168.122.141: ISSUE: authtime 1407471159, etypes {rep=18 tkt=18 ses=18}, bresc@IPA.LOCAL for krbtgt/IPA.LOCAL@IPA.LOCAL Aug 08 00:12:41 ipa-2.ipa.local krb5kdc[28303](info): closing down fd 13 Actual results: Multiple preauthenticated AS_REQ requests from kinit to KDC, one of which fails due to HOTP token counter increment, causing authentication failure. Occurs with high probability. Expected results: A single preauthenticated AS_REQ request from kinit to KDC (or more specifically, a reasonable timeout prior to retry). Assuming correct credentials, client receives ticket. Additional info: Backport of krb5 commit f423c28 (Dynamically expand timeout when TCP connects) was undertaken, but did not resolve issue; the Fedora package patch that was used is attached. Recent comment by Greg Hudson on the original upstream ticket may be relevant: http://krbdev.mit.edu/rt/Ticket/Display.html?id=7604 This problem does not occur in krb5-1.12 on f21.
Do you have the client trace log (obtained by running the client with KRB5_TRACE set to /dev/stderr in its environment)?
Is your test server configured to not listen for UDP clients? That's the only way I can get the suggested behavior with 1.12 when I'm running kinit on the server itself (granted, using enc-timestamp rather than otp).
Created attachment 925299 [details] proposed patch for 1.11
The proposed patch does not work for me - either on its own or in conjunction with my initial backport patch - I still get the two requests in quick succession. My server listens on UDP and TCP. If I force it to listen on TCP only** everything works fine, even without any of these patches. ** actually, I couldn't work out how to do this, so I instead force it to listen to a nonstandard UDP port, resulting in the client connecting via TCP.
(In reply to Fraser Tweedale from comment #4) > The proposed patch does not work for me - either on its own or in > conjunction with my initial backport patch - I still get the two requests in > quick succession. > > My server listens on UDP and TCP. If I force it to listen on TCP only** > everything works fine, even without any of these patches. I'm rather surprised that 1.12 behaves any differently, then. Can you run your test under strace so that we can double-check the timeout values that are being passed to poll()? It's a quirk of how the configuration parsing is done, but you can set the port number to 0 to turn off UDP at the server.
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.
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