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import sqlite3
import gflags
from ct.client.db import cert_db
from ct.client.db import cert_desc
FLAGS = gflags.FLAGS
gflags.DEFINE_bool("cert_db_sqlite_synchronous_write", True, "If set to true, "
"sqlite will use synchronous write.")
class SQLiteCertDB(cert_db.CertDB):
def __init__(self, connection_manager):
"""Initialize the database and tables.
Args:
connection: an SQLiteConnectionManager object."""
self.__mgr = connection_manager
cert_repeated_field_tables = [
("issuer", [("type", "TEXT"), ("name", "TEXT"),]),
("subject", [("type", "TEXT"), ("name", "TEXT"),]),
("subject_alternative_names", [("type", "TEXT"),
("name", "TEXT"),]),
# subject common names and dnsnames for easy lookup of given
# domain name
("subject_names", [("name", "TEXT")]),
("root_issuer", [("type", "TEXT"), ("name", "TEXT")])]
cert_single_field_tables = [("version", "INTEGER"),
("serial_number", "TEXT")]
with self.__mgr.get_connection() as conn:
# the |cert| BLOB is also unique but we don't force this as it would
# create a superfluous index.
conn.execute("CREATE TABLE IF NOT EXISTS certs("
"log INTEGER,"
"id INTEGER,"
"sha256_hash BLOB UNIQUE,"
"cert BLOB," +
', '.join(['%s %s' % (column, type_) for column, type_
in cert_single_field_tables]) +
", PRIMARY KEY(log, id))")
for entry in cert_repeated_field_tables:
self.__create_table_for_field(conn, *entry)
conn.execute("CREATE INDEX IF NOT EXISTS certs_by_subject "
"on subject_names(name)")
self.__tables = (["logs", "certs"] +
[column for column, _ in cert_repeated_field_tables])
@staticmethod
def __create_table_for_field(conn, table_name, fields):
"""Helper method that creates table for given certificate field. Each
row in that table refers to some certificate in certs table.
Args:
table_name: name of the table
fields: iterable of (column_name, type) tuples"""
conn.execute("CREATE TABLE IF NOT EXISTS {table_name}("
"log INTEGER, cert_id INTEGER,"
"{fields},"
"FOREIGN KEY(log, cert_id) REFERENCES certs(log, id))"
.format(table_name=table_name,
fields=','.join(
["%s %s" % field for field in fields])))
def __repr__(self):
return "%r(db: %r)" % (self.__class__.__name__, self.__db)
def __str__(self):
return "%s(db: %s, tables: %s): " % (self.__class__.__name__, self.__db,
self.__tables)
@staticmethod
def __compare_processed_names(prefix, name):
return prefix == name[:len(prefix)]
def __store_cert(self, cert, index, log_key, cursor):
if not FLAGS.cert_db_sqlite_synchronous_write:
cursor.execute("PRAGMA synchronous = OFF")
try:
cursor.execute("INSERT INTO certs(log, id, sha256_hash, cert, "
"version, serial_number) VALUES(?, ?, ?, ?, ?, ?) ",
(log_key, index,
sqlite3.Binary(cert.sha256_hash),
sqlite3.Binary(cert.der),
cert.version,
cert.serial_number,))
except sqlite3.IntegrityError:
# cert already exists
return
for sub in cert.subject:
cursor.execute("INSERT INTO subject(log, cert_id, type, name)"
"VALUES(?, ?, ?, ?)",
(log_key, index, sub.type, sub.value))
if sub.type == "CN":
cursor.execute("INSERT INTO subject_names(log, cert_id, name)"
"VALUES(?, ?, ?)",
(log_key, index, sub.value))
for alt in cert.subject_alternative_names:
cursor.execute("INSERT INTO subject_alternative_names(log, cert_id,"
"type, name) VALUES(?, ?, ?, ?)",
(log_key, index, alt.type, alt.value))
if alt.type == "dNSName":
cursor.execute("INSERT INTO subject_names(log, cert_id, name)"
"VALUES(?, ?, ?)",
(log_key, index, alt.value))
for iss in cert.issuer:
cursor.execute("INSERT INTO issuer(log, cert_id, type, name)"
"VALUES(?, ?, ?, ?)",
(log_key, index, iss.type, iss.value))
for iss in cert.root_issuer:
cursor.execute("INSERT INTO root_issuer(log, cert_id, type, name)"
"VALUES(?, ?, ?, ?)",
(log_key, index, iss.type, iss.value))
def store_certs_desc(self, certs, log_key):
"""Store certificates using their descriptions.
Args:
certs: iterable of (CertificateDescription, index) tuples
log_key: log id in LogDB"""
with self.__mgr.get_connection() as conn:
cursor = conn.cursor()
for cert in certs:
self.__store_cert(cert[0], cert[1], log_key, cursor)
def store_cert_desc(self, cert, index, log_key):
"""Store a certificate using its description.
Args:
cert: CertificateDescription
index: position in log
log_key: log id in LogDB"""
self.store_certs_desc([(cert, index)], log_key)
def get_cert_by_sha256_hash(self, cert_sha256_hash):
"""Fetch a certificate with a matching SHA256 hash
Args:
cert_sha256_hash: the SHA256 hash of the certificate
Returns:
A DER-encoded certificate, or None if the cert is not found."""
with self.__mgr.get_connection() as conn:
res = conn.execute("SELECT cert FROM certs WHERE sha256_hash == ?",
(sqlite3.Binary(cert_sha256_hash),))
try:
return str(res.next()["cert"])
except StopIteration:
pass
def scan_certs(self, limit=0):
"""Scan all certificates.
Args:
limit: maximum number of entries to yield. Default is no limit.
Yields:
DER-encoded certificates."""
sql_limit = -1 if not limit else limit
with self.__mgr.get_connection() as conn:
for row in conn.execute(
"SELECT cert FROM certs LIMIT ?", (sql_limit,)):
yield str(row["cert"])
# RFC 2818 (HTTP over TLS) states that "names may contain the wildcard
# character * which is considered to match any single domain name
# component or component fragment."
#
# So theoretically a cert for www.*.com or www.e*.com is valid for
# www.example.com (although common browsers reject overly broad certs).
# This makes wildcard matching in index scans difficult.
#
# The subject index scan thus does not match wildcards: it is not intended
# for fetching all certificates that may be deemed valid for a given domain.
# Applications should define their own rules for detecting wildcard certs
# and anything else of interest.
def scan_certs_by_subject(self, subject_name, limit=0):
"""Scan certificates matching a subject name.
Args:
subject_name: a subject name, usually a domain. A scan for
example.com returns certificates for www.example.com,
*.example.com, test.mail.example.com, etc. Similarly
'com' can be used to look for all .com certificates.
Wildcards are treated as literal characters: a search
for *.example.com returns certificates for
*.example.com but not for mail.example.com and vice
versa.
Name may also be a common name rather than a DNS name,
e.g., "Trustworthy Certificate Authority".
limit: maximum number of entries to yield. Default is no
limit.
Yields:
DER-encoded certificates."""
sql_limit = -1 if not limit else limit
prefix = cert_desc.process_name(subject_name)
with self.__mgr.get_connection() as conn:
for row in conn.execute(
"SELECT certs.cert as cert, subject_names.name as name "
"FROM certs, subject_names WHERE name >= ? AND certs.id == "
"subject_names.cert_id ORDER BY name ASC LIMIT ?",
(".".join(prefix), sql_limit)):
name = cert_desc.process_name(row["name"], reverse=False)
if self.__compare_processed_names(prefix, name):
yield str(row["cert"])
else:
break
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