Mark untrusted certificates as such in Linux UI.

net/base/cert_database_nss.cc

Index: net/base/cert_database_nss.cc
diff --git a/net/base/cert_database_nss.cc b/net/base/cert_database_nss.cc
index 1e753dea7ac5358deaba7c97fa6f29f9ec6e8a5f..9d0f21986be20961b63eeafb0d3f9c3a5991b6d9 100644
--- a/net/base/cert_database_nss.cc
+++ b/net/base/cert_database_nss.cc
@@ -236,6 +236,19 @@ unsigned int CertDatabase::GetCertTrust(
   }
 }
 
+bool CertDatabase::IsUntrusted(const X509Certificate* cert) const {
+  CERTCertTrust nsstrust;
+  SECStatus rv = CERT_GetCertTrust(cert->os_cert_handle(), &nsstrust);
+  if (rv != SECSuccess) {
+    LOG(ERROR) << "CERT_GetCertTrust failed with error " << PORT_GetError();
+    return false;
+  }
+
+  return nsstrust.sslFlags == 0 &&
+         nsstrust.emailFlags == 0 &&
+         nsstrust.objectSigningFlags == 0;

[wtc, 2011/06/29 00:30:45]

I believe this is correct only for root certs.

(Note: the trusts for the IPS roots were removed in
https://bugzilla.mozilla.org/show_bug.cgi?id=530853.)

For non-root certs, I think we will need code similar to
the CERT_CheckLeafTrust function in Bob Relyea's patch
https://bug642503.bugzilla.mozilla.org/attachment.cgi?id=527127
in the NSS bug
https://bugzilla.mozilla.org/show_bug.cgi?id=642503

Specifically, we need to test if the
CERTDB_TERMINAL_RECORD bit (formerly named
CERTDB_VALID_PEER) is set.

nsstrust.sslFlags == 0 for a non-root cert actually means it
derives its trust from its CA.

Two important test cases for non-root certs are:
https://bugzilla.mozilla.org/show_bug.cgi?id=471715
https://bugzilla.mozilla.org/show_bug.cgi?id=642815

I will ask Bob Relyea (an NSS developer) about this.

[mattm, 2011/06/29 01:12:07]

Maybe we should only check the sslFlags?  If for some reason a cert is untrusted
for SSL but still trusted for other things we'd probably still want to display
the badge since we only use SSL trust, right?

+}
+
 bool CertDatabase::SetCertTrust(const X509Certificate* cert,
                                 CertType type,
                                 unsigned int trusted) {