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/* certwatch_db - Database schema
* Written by Rob Stradling
* Copyright (C) 2015-2016 COMODO CA Limited
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
CREATE OR REPLACE FUNCTION is_technically_constrained(
cert_data bytea
) RETURNS boolean
AS $$
DECLARE
t_count integer;
t_serverAuth boolean;
t_codeSigning boolean;
t_emailProtection boolean;
t_text text;
t_temp text;
t_offset1 integer;
t_index integer := 2;
t_line text[];
t_isPermitted boolean;
t_permittedDNS boolean := FALSE;
t_permittedIP boolean := FALSE;
t_permittedDirName boolean := FALSE;
t_permittedEmail boolean := FALSE;
t_excludedAllDNS boolean := FALSE;
t_excludedAllIPv4 boolean := FALSE;
t_excludedAllIPv6 boolean := FALSE;
BEGIN
-- "For a certificate to be considered technically constrained, the certificate MUST include an Extended Key Usage (EKU) extension"
SELECT count(*)
INTO t_count
FROM x509_extkeyusages(cert_data);
IF t_count = 0 THEN
RETURN FALSE;
END IF;
-- "The anyExtendedKeyUsage KeyPurposeId MUST NOT appear within this extension"
SELECT count(*)
INTO t_count
FROM x509_extkeyusages(cert_data)
WHERE x509_extkeyusages = '2.5.29.37.0';
IF t_count > 0 THEN
RETURN FALSE;
END IF;
t_serverAuth := x509_isEKUPermitted(cert_data, '1.3.6.1.5.5.7.3.1')
OR x509_isEKUPermitted(cert_data, '1.3.6.1.4.1.311.10.3.3') -- MS SGC.
OR x509_isEKUPermitted(cert_data, '2.16.840.1.113730.4.1'); -- NS Step-Up.
-- Don't consider Code Signing, because this is no longer of interest to Mozilla.
t_codeSigning := FALSE; -- x509_isEKUPermitted(cert_data, '1.3.6.1.5.5.7.3.3');
t_emailProtection := x509_isEKUPermitted(cert_data, '1.3.6.1.5.5.7.3.4');
IF t_serverAuth OR t_codeSigning OR t_emailProtection THEN
t_text := x509_print(cert_data);
t_temp := ' X509v3 Name Constraints:';
t_offset1 := position(t_temp in t_text);
IF t_offset1 = 0 THEN
RETURN FALSE;
END IF;
t_line := regexp_split_to_array(substring(t_text from (t_offset1 + length(t_temp))), E'\\n+');
LOOP
IF t_line[t_index] = ' Permitted:' THEN
t_isPermitted := TRUE;
ELSIF t_line[t_index] = ' Excluded:' THEN
t_isPermitted := FALSE;
ELSE
EXIT WHEN (t_line[t_index] IS NULL) OR (t_line[t_index] NOT LIKE ' %');
END IF;
EXIT WHEN t_isPermitted IS NULL;
IF t_isPermitted THEN
IF trim(t_line[t_index]) LIKE 'DNS:%' THEN
t_permittedDNS := TRUE;
ELSIF trim(t_line[t_index]) LIKE 'IP:%' THEN
t_permittedIP := TRUE;
ELSIF trim(t_line[t_index]) LIKE 'DirName:%' THEN
t_permittedDirName := TRUE;
ELSIF trim(t_line[t_index]) LIKE 'email:%' THEN
t_permittedEmail := TRUE;
END IF;
ELSE
IF trim(t_line[t_index]) = 'DNS:' THEN
t_excludedAllDNS := TRUE;
ELSIF trim(t_line[t_index]) = 'IP:0.0.0.0/0.0.0.0' THEN
t_excludedAllIPv4 := TRUE;
ELSIF trim(t_line[t_index]) = 'IP:0:0:0:0:0:0:0:0/0:0:0:0:0:0:0:0' THEN
t_excludedAllIPv6 := TRUE;
END IF;
END IF;
t_index := t_index + 1;
END LOOP;
IF t_serverAuth THEN
IF NOT t_permittedDirName THEN
RETURN FALSE;
ELSIF NOT (t_permittedDNS OR t_excludedAllDNS) THEN
RETURN FALSE;
ELSIF NOT (t_permittedIP OR (t_excludedAllIPv4 AND t_excludedAllIPv6)) THEN
RETURN FALSE;
END IF;
END IF;
IF t_codeSigning THEN
IF NOT t_permittedDirName THEN
RETURN FALSE;
END IF;
END IF;
IF t_emailProtection THEN
IF NOT t_permittedEmail THEN
RETURN FALSE;
END IF;
END IF;
END IF;
RETURN TRUE;
END;
$$ LANGUAGE plpgsql;
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