Added precert handling for SCT calculation

3 files changed, 58 insertions, 17 deletions

diff --git a/tools/certtools.py b/tools/certtools.py
index 1436863..cc423af 100644
--- a/tools/certtools.py
+++ b/tools/certtools.py
@@ -257,7 +257,7 @@ def create_sth_signature(tree_size, timestamp, root_hash, baseurl, key=None):
 
     return create_signature(baseurl, tree_head, key=key)
 
-def check_sct_signature(baseurl, leafcert, sct):
+def check_sct_signature(baseurl, signed_entry, sct, precert=False):
     publickey = base64.decodestring(publickeys[baseurl])
     calculated_logid = hashlib.sha256(publickey).digest()
     received_logid = base64.decodestring(sct["id"])
@@ -271,9 +271,12 @@ def check_sct_signature(baseurl, leafcert, sct):
     version = struct.pack(">b", sct["sct_version"])
     signature_type = struct.pack(">b", 0)
     timestamp = struct.pack(">Q", sct["timestamp"])
-    entry_type = struct.pack(">H", 0)
+    if precert:
+        entry_type = struct.pack(">H", 1)
+    else:
+        entry_type = struct.pack(">H", 0)
     signed_struct = version + signature_type + timestamp + \
-      entry_type + tls_array(leafcert, 3) + \
+      entry_type + signed_entry + \
       tls_array(base64.decodestring(sct["extensions"]), 2)
 
     check_signature(baseurl, signature, signed_struct)
@@ -292,15 +295,22 @@ def pack_mtl(timestamp, leafcert):
 def pack_mtl_precert(timestamp, cleanedcert, issuer_key_hash):
     entry_type = struct.pack(">H", 1)
     extensions = ""
-    assert len(issuer_key_hash) == 32
 
     timestamped_entry = struct.pack(">Q", timestamp) + entry_type + \
-      issuer_key_hash + tls_array(cleanedcert, 3) + tls_array(extensions, 2)
+      pack_precert(cleanedcert, issuer_key_hash) + tls_array(extensions, 2)
     version = struct.pack(">b", 0)
     leaf_type = struct.pack(">b", 0)
     merkle_tree_leaf = version + leaf_type + timestamped_entry
     return merkle_tree_leaf
 
+def pack_precert(cleanedcert, issuer_key_hash):
+    assert len(issuer_key_hash) == 32
+
+    return issuer_key_hash + tls_array(cleanedcert, 3)
+
+def pack_cert(cert):
+    return tls_array(cert, 3)
+
 def unpack_mtl(merkle_tree_leaf):
     version = merkle_tree_leaf[0:1]
     leaf_type = merkle_tree_leaf[1:2]
diff --git a/tools/submitcert.py b/tools/submitcert.py
index 1c79544..2e8cc33 100755
--- a/tools/submitcert.py
+++ b/tools/submitcert.py
@@ -13,6 +13,11 @@ import struct
 import hashlib
 import itertools
 from certtools import *
+from certtools import *
+try:
+    from precerttools import *
+except ImportError:
+    pass
 import os
 import signal
 import select
@@ -51,8 +56,20 @@ def submitcert((certfile, cert)):
 
     try:
         if precert:
+            if ext_key_usage_precert_signing_cert in get_ext_key_usage(certchain[0]):
+                issuer_key_hash = get_cert_key_hash(certchain[1])
+                issuer = certchain[1]
+            else:
+                issuer_key_hash = get_cert_key_hash(certchain[0])
+                issuer = None
+            cleanedcert = cleanprecert(precert, issuer=issuer)
+            signed_entry = pack_precert(cleanedcert, issuer_key_hash)
+            leafcert = cleanedcert
             result = add_prechain(baseurl, {"chain":map(base64.b64encode, [precert] + certchain)})
         else:
+            signed_entry = pack_cert(certchain[0])
+            leafcert = certchain[0]
+            issuer_key_hash = None
             result = add_chain(baseurl, {"chain":map(base64.b64encode, certchain)})
     except SystemExit:
         print "EXIT:", certfile
@@ -67,7 +84,7 @@ def submitcert((certfile, cert)):
 
     try:
         if args.check_sct:
-            check_sct_signature(baseurl, certchain[0], result)
+            check_sct_signature(baseurl, signed_entry, result, precert=precert)
             timing_point(timing, "checksig")
     except AssertionError, e:
         print "ERROR:", certfile, e
@@ -81,7 +98,7 @@ def submitcert((certfile, cert)):
 
     if lookup_in_log:
 
-        merkle_tree_leaf = pack_mtl(result["timestamp"], certchain[0])
+        merkle_tree_leaf = pack_mtl(result["timestamp"], leafcert)
 
         leaf_hash = get_leaf_hash(merkle_tree_leaf)
 
@@ -119,7 +136,7 @@ def submitcert((certfile, cert)):
             print "and submitted chain has length", len(submittedcertchain)
 
     timing_point(timing, "lookup")
-    return ((certchain[0], result), timing["deltatimes"])
+    return ((leafcert, issuer_key_hash, result), timing["deltatimes"])
 
 def get_ncerts(certfiles):
     n = 0
@@ -142,9 +159,12 @@ def get_all_certificates(certfiles):
         else:
             yield (certfile, open(certfile).read())
 
-def save_sct(sct, sth):
+def save_sct(sct, sth, leafcert, issuer_key_hash):
     sctlog = open(args.sct_file, "a")
-    json.dump({"leafcert": base64.b64encode(leafcert), "sct": sct, "sth": sth}, sctlog)
+    sctentry = {"leafcert": base64.b64encode(leafcert), "sct": sct, "sth": sth}
+    if issuer_key_hash:
+        sctentry["issuer_key_hash"] = base64.b64encode(issuer_key_hash)
+    json.dump(sctentry, sctlog)
     sctlog.write("\n")
     sctlog.close()
 
@@ -163,8 +183,8 @@ certs = get_all_certificates(certfiles)
 (result, timing) = submitcert(certs.next())
 if result != None:
     nsubmitted += 1
-    (leafcert, sct) = result
-    save_sct(sct, sth)
+    (leafcert, issuer_key_hash, sct) = result
+    save_sct(sct, sth, leafcert, issuer_key_hash)
 
 if args.pre_warm:
     select.select([], [], [], 3.0)
@@ -181,8 +201,8 @@ try:
             sys.exit(1)
         if result != None:
             nsubmitted += 1
-            (leafcert, sct) = result
-            save_sct(sct, sth)
+            (leafcert, issuer_key_hash, sct) = result
+            save_sct(sct, sth, leafcert, issuer_key_hash)
         deltatime = datetime.datetime.now() - starttime
         deltatime_f = deltatime.seconds + deltatime.microseconds / 1000000.0
         rate = nsubmitted / deltatime_f
diff --git a/tools/verifysct.py b/tools/verifysct.py
index 699a0ad..27ab4c9 100755
--- a/tools/verifysct.py
+++ b/tools/verifysct.py
@@ -34,8 +34,16 @@ def verifysct(sctentry):
     timing = timing_point()
 
     leafcert = base64.b64decode(sctentry["leafcert"])
+    if "issuer_key_hash" in sctentry:
+        issuer_key_hash = base64.b64decode(sctentry["issuer_key_hash"])
+    else:
+        issuer_key_hash = None
     try:
-        check_sct_signature(baseurl, leafcert, sctentry["sct"])
+        if issuer_key_hash:
+            signed_entry = pack_precert(leafcert, issuer_key_hash)
+        else:
+            signed_entry = pack_cert(leafcert)
+        check_sct_signature(baseurl, signed_entry, sctentry["sct"], precert=issuer_key_hash)
         timing_point(timing, "checksig")
     except AssertionError, e:
         print "ERROR:", e
@@ -47,7 +55,10 @@ def verifysct(sctentry):
         print "ERROR: bad signature"
         return (None, None)
 
-    merkle_tree_leaf = pack_mtl(sctentry["sct"]["timestamp"], leafcert)
+    if issuer_key_hash:
+        merkle_tree_leaf = pack_mtl_precert(sctentry["sct"]["timestamp"], leafcert, issuer_key_hash)
+    else:
+        merkle_tree_leaf = pack_mtl(sctentry["sct"]["timestamp"], leafcert)
 
     leaf_hash = get_leaf_hash(merkle_tree_leaf)
 
@@ -76,7 +87,7 @@ def verifysct(sctentry):
 p = Pool(args.parallel, lambda: signal.signal(signal.SIGINT, signal.SIG_IGN))
 
 sctfile = open(args.sct_file)
-scts = [json.loads(row) for row in sctfile]
+scts = (json.loads(row) for row in sctfile)
 
 nverified = 0
 lastprinted = 0