Bug 50620 - False positives in system diagnostics when http_proxy is used
Summary: False positives in system diagnostics when http_proxy is used
Status: CLOSED FIXED
Alias: None
Product: UCS
Classification: Unclassified
Component: UMC - System diagnostic
Version: UCS 4.4
Hardware: Other Linux
: P5 normal
Target Milestone: UCS 5.0-0-errata
Assignee: Christian Castens
QA Contact: Florian Best
URL:
Keywords:
Depends on:
Blocks: 53575
  Show dependency tree / graph
 
Reported: 2019-12-10 16:44 CET by Philipp Hahn
Modified: 2021-07-21 10:49 CEST (History)
11 users (show)

See Also:
What kind of report is it?: Bug Report
What type of bug is this?: 5: Major Usability: Impairs usability in key scenarios
Who will be affected by this bug?: 3: Will affect average number of installed domains
How will those affected feel about the bug?: 2: A Pain – users won’t like this once they notice it
User Pain: 0.171
Enterprise Customer affected?: Yes
School Customer affected?: Yes
ISV affected?:
Waiting Support:
Flags outvoted (downgraded) after PO Review:
Ticket number: 2020011421000538, 2020072421000508, 2020070321000299, 2020080321000564, 2020082521000273, 2020122821000214
Bug group (optional): External feedback, Regression
Customer ID: 02149, 05017, 07317, 10568, 27658, 44145
Max CVSS v3 score:

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Description Philipp Hahn univentionstaff 2019-12-10 16:44:43 CET 
Situation: Internal DNS does not resolve external addresses. Access to internet only works through http-proxy.

Running the diagnostic checks fails:

univention-run-diagnostic-checks --username Administrator --bindpwdfile <(echo -n univention) -t 11_nameserver
  timeout resolving 'www.univention.de' with NS X.X.X.X

univention-run-diagnostic-checks --username Administrator --bindpwdfile <(echo -n univention) -t 12_proxy
  Failed writing body (0 != 8088) (code=23)

univention-run-diagnostic-checks --username Administrator --bindpwdfile <(echo -n univention) -t 23_check_update_sites
  {updates,appcenter}.software-univention.de are not resolvable
  The PROXY server does that, the host itself does not need to be able to resolve the host
Comment 1 Philipp Hahn univentionstaff 2019-12-10 16:45:11 CET 
TT: 2019-12-09/10
Comment 2 Christina Scheinig univentionstaff 2020-01-14 14:54:55 CET 
(In reply to Philipp Hahn from comment #0)
> Situation: Internal DNS does not resolve external addresses. Access to
> internet only works through http-proxy.
> 
> Running the diagnostic checks fails:

> univention-run-diagnostic-checks --username Administrator --bindpwdfile
> <(echo -n univention) -t 12_proxy
>   Failed writing body (0 != 8088) (code=23)
> 


A customer has this issue in two environments, after an update to 4.4-3 e413
Comment 3 Philipp Hahn univentionstaff 2020-06-19 17:10:04 CEST 
TT: 2020-06-18/19
TT: 2020-05-14/15
TT: 2020-04-23/24
Comment 5 Dirk Schnick univentionstaff 2020-08-04 07:38:04 CEST 
Added affected customers and ticket numbers I had to spend time on this issue (was not the main problem of the ticket, but had to explain the critical alert)
Comment 6 Christian Völker univentionstaff 2020-08-04 10:33:59 CEST 
Same again... adding ticket.
Comment 7 Frank Greif 2020-08-24 20:16:38 CEST 
Seems to me that 12_proxy.py does never succeed as soon as a proxy is set. I got used to tell my customers they only have to allow www.univention.de (http and https) in their proxy, but this never cured the problem.

You always get the write error (23) no matter if the proxy allows access.

I'd suspect the culprit to be line 53:

buf = io.StringIO()

which was changed from StringIO.StringIO() somewhere along the lines of Python3 preparation.

According to the docs http://pycurl.io/docs/latest/callbacks.html#writefunction the write function only accepts bytes strings, while io.StringIO requires unicode.

Changing line 53 to read

buf = io.BytesIO()

made it work.
Comment 8 Philipp Hahn univentionstaff 2020-08-26 18:38:59 CEST 
Another major customer is affected by this.
Comment 9 Philipp Hahn univentionstaff 2020-11-18 17:18:25 CET 
TT: 2020-11-19/20

diff --git a/management/univention-management-console-module-diagnostic/umc/python/diagnostic/plugins/12_proxy.py b/management/univention-management-console-module-diagnostic/umc/python/diagnostic/plugins/12_proxy.py
index f9e823c8d2..77d4b7ba45 100644
--- a/management/univention-management-console-module-diagnostic/umc/python/diagnostic/plugins/12_proxy.py
+++ b/management/univention-management-console-module-diagnostic/umc/python/diagnostic/plugins/12_proxy.py
@@ -50,7 +50,7 @@ def run(_umc_instance, url='http://www.univention.de/', connecttimeout=30, timeo
        curl.setopt(pycurl.URL, url)
        # curl.setopt(pycurl.VERBOSE, bVerbose)
 
-       buf = io.StringIO()
+       buf = io.BytesIO()
        curl.setopt(pycurl.WRITEFUNCTION, buf.write)
        MODULE.process(''.join("Trying to connect to %s via HTTP proxy %s" % (url, proxy)))
Comment 11 Dirk Ahrnke univentionstaff 2021-02-19 16:47:45 CET 
TT: 2021-02-18/19
Comment 12 Christian Castens univentionstaff 2021-07-13 17:03:01 CEST 
The patch from one of the previous comments has been applied.


5.0-0:
3936c2a2a47cd20a7f9f9d028e844943dedb053a (changes)
ab309682fd0c7ee244e492e008e6ac1475e42bfb (yaml)

Package: univention-management-console-module-diagnostic
Version: 6.0.0-13A~5.0.0.202107131648
Branch: ucs_5.0-0
Scope: errata5.0-0
Comment 13 Florian Best univentionstaff 2021-07-15 11:59:30 CEST 
OK: fix
OK: code review
OK: YAML