commit 68bb0d6621ddb4806285ccaab298d2fa166050a6 Author: Damian Johnson <atagar@torproject.org> Date: Sun Mar 18 15:49:33 2012 -0700 Parsing descriptor signature blocks --- stem/descriptor/server_descriptor.py | 57 +++++++++++++++++++++++++++++---- 1 files changed, 50 insertions(+), 7 deletions(-) diff --git a/stem/descriptor/server_descriptor.py b/stem/descriptor/server_descriptor.py index 4ec4586..3d416dd 100644 --- a/stem/descriptor/server_descriptor.py +++ b/stem/descriptor/server_descriptor.py @@ -22,8 +22,8 @@ ENTRY_END = "router-signature" KEYWORD_CHAR = "[a-zA-Z0-9-]" WHITESPACE = "[ \t]" KEYWORD_LINE = re.compile("^(%s+)%s*(%s*)$" % (KEYWORD_CHAR, WHITESPACE, KEYWORD_CHAR)) -SIGNATURE_START = re.compile("^-----BEGIN %s+ PUBLIC KEY-----$" % KEYWORD_CHAR) -SIGNATURE_END = re.compile("^-----END %s+ PUBLIC KEY-----$" % KEYWORD_CHAR) +SIGNATURE_START = re.compile("^-----BEGIN (%s+) PUBLIC KEY-----$" % KEYWORD_CHAR) +SIGNATURE_END = "-----END %s PUBLIC KEY-----" # entries must have exactly one of the following REQUIRED_FIELDS = ( @@ -53,6 +53,43 @@ def parse_server_descriptors_v2(path, descriptor_file): pass +def _get_sig_block(remaining_contents): + """ + Checks if given contents begins with a signature block and, if so, pops it + off and provides it back to the caller. + + Arguments: + remaining_contents (list) - lines to be checked for a signature block + + Returns: + String with the signature block, or None if it doesn't exist + + Raises: + ValueError if the contents starts with a signature block but it's malformed + (for instance, if it lacks an ending line) + """ + + if not remaining_contents: + return None # nothing left + + sig_match = SIGNATURE_START.match(remaining_contents[0]) + + if sig_match: + sig_type = sig_match.groups()[0] + sig_lines = [] + + while True: + if not remaining_contents: + raise ValueError("Unterminated signature block") + + line = remaining_contents.pop(0) + sig_lines.append(line) + + if line == SIGNATURE_END $ sig_type: + return "\n".join(sig_lines) + else: + return None + class ServerDescriptorV2(Descriptor): """ Version 2 server descriptor, as specified in... @@ -82,6 +119,7 @@ class ServerDescriptorV2(Descriptor): platform = tor_version = published = fingerprint = None uptime = None hibernating = False + unrecognized_entries = [] def __init__(self, contents): Descriptor.__init__(self, contents) @@ -97,7 +135,10 @@ class ServerDescriptorV2(Descriptor): entries = {} exit_policy_lines = [] - for line in contents.split("\n"): + remaining_contents = contents.split("\n") + while remaining_contents: + line = remaining_contents.pop(0) + # Some lines have an 'opt ' for backward compatability. They should be # ignored. This prefix is being removed in... # https://trac.torproject.org/projects/tor/ticket/5419 @@ -110,13 +151,14 @@ class ServerDescriptorV2(Descriptor): raise ValueError("Line contains invalid characters: %s" % line) keyword, value = line_match.groups() + sig_block = _get_sig_block(remaining_contents) if keyword in ("accept", "reject"): exit_policy_lines.append("%s %s" % (keyword, value)) elif keyword in entries: - entries[keyword].append(value) + entries[keyword].append((value, sig_block)) else: - entries[keyword] = [value] + entries[keyword] = [(value, sig_block)] # validates restrictions about the entries @@ -131,7 +173,7 @@ class ServerDescriptorV2(Descriptor): # parse all the entries into our attributes for keyword, values in entres.items(): - value = values[0] # most just work with the first (and only) value + value, sig_block = values[0] # most just work with the first (and only) value line = "%s %s" % (keyword, value) # original line if keyword == "router": @@ -222,5 +264,6 @@ class ServerDescriptorV2(Descriptor): raise TypeError("Uptime line must have an integer value: %s" % value) self.uptime = int(value) - + else: + unrecognized_entries.append(line)