From 3e385281f6302cdbe57858bf9157e84bff063d29 Mon Sep 17 00:00:00 2001 From: James Troup Date: Sun, 21 May 2006 19:07:27 -0500 Subject: [PATCH] Add (not enabled by default) support for auto-fetching keys from a keyserver. Originally written for the debian-women DAK install. --- ChangeLog | 14 ++++++ daklib/utils.py | 110 +++++++++++++++++++++++++++++++++++---------- docs/README.config | 9 ++++ 3 files changed, 109 insertions(+), 24 deletions(-) diff --git a/ChangeLog b/ChangeLog index 556e156b..23566093 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,17 @@ +2006-05-21 James Troup + + * daklib/utils.py (process_gpgv_output): new function, split out + of check_signature(). + (check_signature): adapt accordingly. + (retrieve_key): new function that will try to retrieve the key + that signed a given file from a keyserver. + (check_signature): add 'autofetch' argument that if not set + defaults to the value of Dinstall::KeyAutoFetch (if that exists). + If 'autofetch' is true, invoke retrieve_key(). + + * docs/README.config: document Dinstall::KeyAutoFetch and + Dinstall:KeyServer. + 2006-05-20 James Troup * dak/find_null_maintainers.py (main): diff --git a/daklib/utils.py b/daklib/utils.py index c4c13669..47978228 100644 --- a/daklib/utils.py +++ b/daklib/utils.py @@ -865,10 +865,80 @@ def gpgv_get_status_output(cmd, status_read, status_write): return output, status, exit_status -############################################################ +################################################################################ +def process_gpgv_output(status): + # Process the status-fd output + keywords = {} + internal_error = "" + for line in status.split('\n'): + line = line.strip() + if line == "": + continue + split = line.split() + if len(split) < 2: + internal_error += "gpgv status line is malformed (< 2 atoms) ['%s'].\n" % (line) + continue + (gnupg, keyword) = split[:2] + if gnupg != "[GNUPG:]": + internal_error += "gpgv status line is malformed (incorrect prefix '%s').\n" % (gnupg) + continue + args = split[2:] + if keywords.has_key(keyword) and (keyword != "NODATA" and keyword != "SIGEXPIRED"): + internal_error += "found duplicate status token ('%s').\n" % (keyword) + continue + else: + keywords[keyword] = args + + return (keywords, internal_error) + +################################################################################ + +def retrieve_key (filename, keyserver=None, keyring=None): + """Retrieve the key that signed 'filename' from 'keyserver' and +add it to 'keyring'. Returns nothing on success, or an error message +on error.""" + + # Defaults for keyserver and keyring + if not keyserver: + keyserver = Cnf["Dinstall::KeyServer"] + if not keyring: + keyring = Cnf["Dinstall::GPGKeyring"] + + # Ensure the filename contains no shell meta-characters or other badness + if not re_taint_free.match(filename): + return "%s: tainted filename" % (filename) + + # Invoke gpgv on the file + status_read, status_write = os.pipe(); + cmd = "gpgv --status-fd %s --keyring /dev/null %s" % (status_write, filename) + (_, status, _) = gpgv_get_status_output(cmd, status_read, status_write) -def check_signature (sig_filename, reject, data_filename="", keyrings=None): + # Process the status-fd output + (keywords, internal_error) = process_gpgv_output(status) + if internal_error: + return internal_error + + if not keywords.has_key("NO_PUBKEY"): + return "didn't find expected NO_PUBKEY in gpgv status-fd output" + + fingerprint = keywords["NO_PUBKEY"][0] + # XXX - gpg sucks. You can't use --secret-keyring=/dev/null as + # it'll try to create a lockfile in /dev. A better solution might + # be a tempfile or something. + cmd = "gpg --no-default-keyring --secret-keyring=%s --no-options" \ + % (Cnf["Dinstall::SigningKeyring"]) + cmd += " --keyring %s --keyserver %s --recv-key %s" \ + % (keyring, keyserver, fingerprint) + (result, output) = commands.getstatusoutput(cmd) + if (result != 0): + return "'%s' failed with exit code %s" % (cmd, result) + + return "" + +################################################################################ + +def check_signature (sig_filename, reject, data_filename="", keyrings=None, autofetch=None): """Check the signature of a file and return the fingerprint if the signature is valid or 'None' if it's not. The first argument is the filename whose signature should be checked. The second argument is a @@ -878,8 +948,9 @@ the second is an optional prefix string. It's possible for reject() to be called more than once during an invocation of check_signature(). The third argument is optional and is the name of the files the detached signature applies to. The fourth argument is optional and is -a *list* of keyrings to use. -""" +a *list* of keyrings to use. 'autofetch' can either be None, True or +False. If None, the default behaviour specified in the config will be +used.""" # Ensure the filename contains no shell meta-characters or other badness if not re_taint_free.match(sig_filename): @@ -893,6 +964,15 @@ a *list* of keyrings to use. if not keyrings: keyrings = (Cnf["Dinstall::PGPKeyring"], Cnf["Dinstall::GPGKeyring"]) + # Autofetch the signing key if that's enabled + if autofetch == None: + autofetch = Cnf.get("Dinstall::KeyAutoFetch") + if autofetch: + error_msg = retrieve_key(sig_filename) + if error_msg: + reject(error_msg) + return None + # Build the command line status_read, status_write = os.pipe(); cmd = "gpgv --status-fd %s" % (status_write) @@ -903,26 +983,7 @@ a *list* of keyrings to use. (output, status, exit_status) = gpgv_get_status_output(cmd, status_read, status_write) # Process the status-fd output - keywords = {} - bad = internal_error = "" - for line in status.split('\n'): - line = line.strip() - if line == "": - continue - split = line.split() - if len(split) < 2: - internal_error += "gpgv status line is malformed (< 2 atoms) ['%s'].\n" % (line) - continue - (gnupg, keyword) = split[:2] - if gnupg != "[GNUPG:]": - internal_error += "gpgv status line is malformed (incorrect prefix '%s').\n" % (gnupg) - continue - args = split[2:] - if keywords.has_key(keyword) and (keyword != "NODATA" and keyword != "SIGEXPIRED"): - internal_error += "found duplicate status token ('%s').\n" % (keyword) - continue - else: - keywords[keyword] = args + (keywords, internal_error) = process_gpgv_output(status) # If we failed to parse the status-fd output, let's just whine and bail now if internal_error: @@ -931,6 +992,7 @@ a *list* of keyrings to use. reject("Please report the above errors to the Archive maintainers by replying to this mail.", "") return None + bad = "" # Now check for obviously bad things in the processed output if keywords.has_key("SIGEXPIRED"): reject("The key used to sign %s has expired." % (sig_filename)) diff --git a/docs/README.config b/docs/README.config index 645c22ad..52588bdc 100644 --- a/docs/README.config +++ b/docs/README.config @@ -291,6 +291,15 @@ SkipTime (required): an integer value which is the number of seconds that a file must be older than (via it's last modified timestamp) before dak process-unchecked will REJECT rather than SKIP the package. +KeyAutoFetch (optional): boolean (default: false), which if set (and +not overriden by explicit argument to check_signature()) will enable +auto key retrieval. Requires KeyServer and SigningKeyIds variables be +set. NB: you should only enable this variable on production systems +if you have strict control of your upload queue. + +KeyServer (optional): keyserver used for key auto-retrieval +(c.f. KeyAutoFetch). + ================================================================================ Archive -- 2.39.2