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<a class="user-hover" rel="putmanb@shibboleth.net" id="email_putmanb@shibboleth.net" href="https://issues.shibboleth.net/jira/secure/ViewProfile.jspa?name=putmanb%40shibboleth.net" style="color:#326ca6;">Brent Putman</a>
created <img src="https://issues.shibboleth.net/jira/images/icons/issuetypes/bug.png" height="16" width="16" border="0" align="absmiddle" alt="Bug"> <a style='color:#326ca6;text-decoration:none;' href='https://issues.shibboleth.net/jira/browse/OSJ-108'>OSJ-108</a>
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<a style='color:#326ca6;text-decoration:none;' href='https://issues.shibboleth.net/jira/browse/OSJ-108'><strong>Generic parameterication of TrustEngines is too restrictive on components that evaluate an X509Credential</strong></a>
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<strong style="font-weight:normal;color:#505050;">Issue Type:</strong>
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<img src="https://issues.shibboleth.net/jira/images/icons/issuetypes/bug.png" height="16" width="16" border="0" align="absmiddle" alt="Bug"> Bug
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<strong style="font-weight:normal;color:#505050;">Affects Versions:</strong>
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3.0.0 </td>
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<strong style="font-weight:normal;color:#505050;">Assignee:</strong>
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<a class="user-hover" rel="putmanb@shibboleth.net" id="email_putmanb@shibboleth.net" href="https://issues.shibboleth.net/jira/secure/ViewProfile.jspa?name=putmanb%40shibboleth.net" style="color:#326ca6;">Brent Putman</a>
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<strong style="font-weight:normal;color:#505050;">Components:</strong>
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Security </td>
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<strong style="font-weight:normal;color:#505050;">Created:</strong>
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14/Feb/15 10:15 PM
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<strong style="font-weight:normal;color:#505050;">Description:</strong>
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<p style='margin-top:0;margin-bottom:10px;'>We have several components that are specified to take or return a TrustEngine<X509Credential>, b/c they are in some way involved with the eval of X509Credential tokens.</p>
<p style='margin-top:0;margin-bottom:10px;'>One ought to be able to use a TrustEngine<Credential> here, but this does not work, e.g.:</p>
<div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<pre class="code-java">
TrustEngine<Credential> engine = <span class="code-keyword">new</span> ExplicitKeyTrustEngine(...);
ClientTLSValidationParameters params = <span class="code-keyword">new</span> ClientTLSValidationParameters();
params.setX509TrustEngine(engine); <span class="code-comment">// This is not legal</span>
</pre>
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<p style='margin-top:0;margin-bottom:10px;'>The issue is incorrect use of generics. An <tt>X509Credential</tt> is a subtype of <tt>Credential</tt>. But: a <tt>TrustEngine<Credential></tt> is not a subtype of <tt>TrustEngine<X509Credential></tt>. So via the substitution principle, it can't be passed as the argument there.</p>
<p style='margin-top:0;margin-bottom:10px;'>(And for completeness, a <tt>TrustEngine<X509Credential></tt> is also not a subtype of <tt>TrustEngine<Credential)</tt>. Intuitively it seems like it would be, but generics just don't work that way.)</p>
<p style='margin-top:0;margin-bottom:10px;'>I <b>think</b> the solution here is that the things which take a trust engine for purposes of evaling an <tt>X509Credential</tt> should specify the trust engine as:</p>
<p style='margin-top:0;margin-bottom:10px;'><tt>TrustEngine<? super X509Credential></tt></p>
<p style='margin-top:0;margin-bottom:10px;'>Need to do some more investigation to confirm that there's not more to this. This whole has may have more general scope beyond just trust engines and credentials. </p>
<p style='margin-top:0;margin-bottom:10px;'>We have the same problem in v2. I think we've just avoided seeing issues with this b/c we use Spring, and hence reflection, and the generic stuff becomes less relevant. As long as the <tt>TrustEngine<Credential></tt> gets into the component, then at runtime it can eval an <tt>X509Credential</tt> just fine, since an <tt>X509Credential</tt> is a subtype of <tt>Credential</tt>. And since we generally wrap these in a chaining engine anyway, that's another layer of confusion. </p>
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<strong style="font-weight:normal;color:#505050;">Project:</strong>
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<a style="color:#326ca6;" href="https://issues.shibboleth.net/jira/browse/OSJ">OpenSAML - Java</a>
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<strong style="font-weight:normal;color:#505050;">Priority:</strong>
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<img src="https://issues.shibboleth.net/jira/images/icons/priorities/blocker.png" height="16" width="16" border="0" align="absmiddle" alt="Blocker"> Blocker
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<strong style="font-weight:normal;color:#505050;">Reporter:</strong>
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<a class="user-hover" rel="putmanb@shibboleth.net" id="email_putmanb@shibboleth.net" href="https://issues.shibboleth.net/jira/secure/ViewProfile.jspa?name=putmanb%40shibboleth.net" style="color:#326ca6;">Brent Putman</a>
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