Verify config file signature

Read log key from config file in more places.
Check STH signature in storagegc.py

6 files changed, 71 insertions, 14 deletions

diff --git a/tools/compileconfig.py b/tools/compileconfig.py
index 0ee3fab..b5e5053 100755
--- a/tools/compileconfig.py
+++ b/tools/compileconfig.py
@@ -5,7 +5,7 @@
 
 import argparse
 import sys
-import yaml
+import readconfig
 import re
 import base64
 
@@ -405,7 +405,6 @@ def gen_testmakefile(config, testmakefile, machines, shellvars=False):
 
     configfile.close()
 
-
 def main():
     parser = argparse.ArgumentParser(description="")
     parser.add_argument('--config', help="System configuration", required=True)
@@ -415,13 +414,16 @@ def main():
     parser.add_argument("--machines", type=int, metavar="n", help="Number of machines")
     args = parser.parse_args()
 
-    config = yaml.load(open(args.config))
     if args.testmakefile and args.machines:
+        config = readconfig.read_config(args.config)
         gen_testmakefile(config, args.testmakefile, args.machines)
     elif args.testshellvars and args.machines:
+        config = readconfig.read_config(args.config)
         gen_testmakefile(config, args.testshellvars, args.machines, shellvars=True)
     elif args.localconfig:
-        localconfig = yaml.load(open(args.localconfig))
+        localconfig = readconfig.read_config(args.localconfig)
+        config = readconfig.verify_and_read_config(args.config, localconfig["logadminkey"])
+
         localnodes = localconfig["localnodes"]
         for localnode in localnodes:
             gen_config(localnode, config, localconfig)
diff --git a/tools/loginfo.py b/tools/loginfo.py
index c61ad1b..1537c5e 100755
--- a/tools/loginfo.py
+++ b/tools/loginfo.py
@@ -6,7 +6,7 @@
 
 import sys
 import argparse
-import yaml
+import readconfig
 from certtools import create_ssl_context, get_sth
 
 def main():
@@ -26,8 +26,7 @@ def main():
                         required=True)
     parser.add_argument('baseurl', help="Log base URL")
     args = parser.parse_args()
-    #config = yaml.load(open(args.config))
-    localconfig = yaml.load(open(args.localconfig))
+    localconfig = readconfig.read_config(args.localconfig)
     paths = localconfig["paths"]
 
     create_ssl_context(cafile=paths["https_cacertfile"])
diff --git a/tools/merge_sth.py b/tools/merge_sth.py
index 6b1bb60..2bc19dd 100755
--- a/tools/merge_sth.py
+++ b/tools/merge_sth.py
@@ -12,6 +12,7 @@ import json
 import urllib2
 import time
 import requests
+import base64
 from base64 import b64encode
 from mergetools import parse_args, get_nfetched, hexencode, hexdecode, \
      get_logorder, get_sth
@@ -31,7 +32,7 @@ def merge_sth(args, config, localconfig):
     sthfile = mergedb + "/sth"
     logorderfile = mergedb + "/logorder"
     currentsizefile = mergedb + "/fetched"
-    logpublickey = get_public_key_from_file(paths["logpublickey"])
+    logpublickey = base64.decodestring(config["logpublickey"])
     backupquorum = config.get("backup-quorum-size", 0)
     assert backupquorum <= len(mergenodes) - 1
     create_ssl_context(cafile=paths["https_cacertfile"])
diff --git a/tools/mergetools.py b/tools/mergetools.py
index f49e789..0afec24 100644
--- a/tools/mergetools.py
+++ b/tools/mergetools.py
@@ -7,7 +7,7 @@ import hashlib
 import sys
 import struct
 import json
-import yaml
+import readconfig
 import argparse
 import requests
 try:
@@ -430,8 +430,8 @@ def parse_args():
                         help="Print timing information")
     args = parser.parse_args()
 
-    config = yaml.load(open(args.config))
-    localconfig = yaml.load(open(args.localconfig))
+    localconfig = readconfig.read_config(args.localconfig)
+    config = readconfig.verify_and_read_config(args.config, localconfig["logadminkey"])
 
     set_api_keys(config)
 
diff --git a/tools/readconfig.py b/tools/readconfig.py
new file mode 100644
index 0000000..5079691
--- /dev/null
+++ b/tools/readconfig.py
@@ -0,0 +1,54 @@
+import io
+import ecdsa
+import hashlib
+import yaml
+import base64
+import sys
+
+class ErrorHandlingDict(dict):
+    def __init__(self, filename, path):
+        self._filename = filename
+        self._path = path
+        dict.__init__({})
+    def __missing__(self, key):
+        if self._path:
+            path = ", ".join(self._path)
+        else:
+            path = "the top level"
+        print >>sys.stderr, "error: could not find configuration key '%s' at %s in %s" % (key, path, self._filename)
+        sys.exit(1)
+
+def errorhandlify(term, filename, path=[]):
+    if isinstance(term, basestring):
+        return term
+    elif isinstance(term, int):
+        return term
+    elif isinstance(term, dict):
+        result = ErrorHandlingDict(filename, path)
+        for k, v in term.items():
+            result[k] = errorhandlify(v, filename, path + [k])
+        return result
+    elif isinstance(term, list):
+        return [errorhandlify(e, filename, path + ["item %d" % i]) for i, e in enumerate(term, start=1)]
+    else:
+        print "unknown type", type(term)
+        sys.exit(1)
+
+def verify_and_read_config(filename, publickey_base64):
+    rawconfig = open(filename).read()
+    signature = open(filename + ".sig").read()
+
+    publickey = base64.decodestring(publickey_base64)
+
+    try:
+        vk = ecdsa.VerifyingKey.from_der(publickey)
+        vk.verify(signature, rawconfig, hashfunc=hashlib.sha256,
+                sigdecode=ecdsa.util.sigdecode_der)
+    except ecdsa.keys.BadSignatureError:
+        print >>sys.stderr, "error: configuration file %s did not have a correct signature" % (filename,)
+        sys.exit(1)
+
+    return errorhandlify(yaml.load(io.BytesIO(rawconfig), yaml.SafeLoader), filename)
+
+def read_config(filename):
+    return errorhandlify(yaml.load(open(filename), yaml.SafeLoader), filename)
diff --git a/tools/storagegc.py b/tools/storagegc.py
index 38b5379..6360495 100755
--- a/tools/storagegc.py
+++ b/tools/storagegc.py
@@ -9,7 +9,7 @@ import urllib
 import json
 import base64
 import sys
-import yaml
+import readconfig
 from certtools import *
 
 parser = argparse.ArgumentParser(description='')
@@ -17,8 +17,8 @@ parser.add_argument('--config', help="System configuration", required=True)
 parser.add_argument('--localconfig', help="Local configuration", required=True)
 args = parser.parse_args()
 
-config = yaml.load(open(args.config))
-localconfig = yaml.load(open(args.localconfig))
+localconfig = readconfig.read_config(args.localconfig)
+config = readconfig.verify_and_read_config(args.config, localconfig["logadminkey"])
 
 paths = localconfig["paths"]
 db_path = paths["db"]
@@ -27,6 +27,7 @@ create_ssl_context(cafile=paths.get("public_cacertfile", None))
 baseurl = config["baseurl"]
 
 sth = get_sth(baseurl)
+check_sth_signature(baseurl, sth, base64.decodestring(config["logpublickey"]))
 
 def verifyleafhash(leaf_hash):
     try: