#!/usr/bin/env python
# Utility functions
-# Copyright (C) 2000, 2001, 2002 James Troup <james@nocrew.org>
-# $Id: utils.py,v 1.54 2002-12-08 17:25:17 troup Exp $
+# Copyright (C) 2000, 2001, 2002, 2003 James Troup <james@nocrew.org>
+# $Id: utils.py,v 1.55 2003-02-07 14:53:42 troup Exp $
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
################################################################################
-import commands, os, pwd, re, socket, shutil, string, sys, tempfile, traceback;
+import commands, os, pwd, re, select, socket, shutil, string, sys, tempfile, traceback;
import apt_pkg;
import db_access;
################################################################################
+def Dict(**dict): return dict
+
+########################################
+
+# Our very own version of commands.getouputstatus(), hacked to support
+# gpgv's status fd.
+def gpgv_get_status_output(cmd, status_read, status_write):
+ cmd = ['/bin/sh', '-c', cmd];
+ p2cread, p2cwrite = os.pipe();
+ c2pread, c2pwrite = os.pipe();
+ errout, errin = os.pipe();
+ pid = os.fork();
+ if pid == 0:
+ # Child
+ os.close(0);
+ os.close(1);
+ os.dup(p2cread);
+ os.dup(c2pwrite);
+ os.close(2);
+ os.dup(errin);
+ for i in range(3, 256):
+ if i != status_write:
+ try:
+ os.close(i);
+ except:
+ pass;
+ try:
+ os.execvp(cmd[0], cmd);
+ finally:
+ os._exit(1);
+
+ # parent
+ os.close(p2cread)
+ os.dup2(c2pread, c2pwrite);
+ os.dup2(errout, errin);
+
+ output = status = "";
+ while 1:
+ i, o, e = select.select([c2pwrite, errin, status_read], [], []);
+ more_data = [];
+ for fd in i:
+ r = os.read(fd, 8196);
+ if len(r) > 0:
+ more_data.append(fd);
+ if fd == c2pwrite or fd == errin:
+ output += r;
+ elif fd == status_read:
+ status += r;
+ else:
+ fubar("Unexpected file descriptor [%s] returned from select\n" % (fd));
+ if not more_data:
+ pid, exit_status = os.waitpid(pid, 0)
+ try:
+ os.close(status_write);
+ os.close(status_read);
+ os.close(c2pread);
+ os.close(c2pwrite);
+ os.close(p2cwrite);
+ os.close(errin);
+ os.close(errout);
+ except:
+ pass;
+ break;
+
+ return output, status, exit_status;
+
+############################################################
+
+
+def check_signature (filename, reject):
+ """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
+reject function and is called when an error is found. The reject()
+function must allow for two arguments: the first is the error message,
+the second is an optional prefix string. It is possible that reject()
+is called more than once during an invocation of check_signature()."""
+
+ # Ensure the filename contains no shell meta-characters or other badness
+ if not re_taint_free.match(os.path.basename(filename)):
+ reject("!!WARNING!! tainted filename: '%s'." % (filename));
+ return 0;
+
+ # Invoke gpgv on the file
+ status_read, status_write = os.pipe();
+ cmd = "gpgv --status-fd %s --keyring %s --keyring %s %s" \
+ % (status_write, Cnf["Dinstall::PGPKeyring"], Cnf["Dinstall::GPGKeyring"], filename);
+ (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;
+
+ # If we failed to parse the status-fd output, let's just whine and bail now
+ if internal_error:
+ reject("internal error while performing signature check on %s." % (filename));
+ reject(internal_error, "");
+ reject("Please report the above errors to the Archive maintainers by replying to this mail.", "");
+ return None;
+
+ # Now check for obviously bad things in the processed output
+ if keywords.has_key("SIGEXPIRED"):
+ reject("key used to sign %s has expired." % (filename));
+ bad = 1;
+ if keywords.has_key("KEYREVOKED"):
+ reject("key used to sign %s has been revoked." % (filename));
+ bad = 1;
+ if keywords.has_key("BADSIG"):
+ reject("bad signature on %s." % (filename));
+ bad = 1;
+ if keywords.has_key("ERRSIG") and not keywords.has_key("NO_PUBKEY"):
+ reject("failed to check signature on %s." % (filename));
+ bad = 1;
+ if keywords.has_key("NO_PUBKEY"):
+ reject("key used to sign %s not found in keyring." % (filename));
+ bad = 1;
+ if keywords.has_key("BADARMOR"):
+ reject("ascii armour of signature was corrupt in %s." % (filename));
+ bad = 1;
+ if keywords.has_key("NODATA"):
+ reject("no signature found in %s." % (filename));
+ bad = 1;
+
+ if bad:
+ return None;
+
+ # Next check gpgv exited with a zero return code
+ if exit_status:
+ reject("gpgv failed while checking %s." % (filename));
+ if status.strip():
+ reject(prefix_multi_line_string(status, " [GPG status-fd output:] "), "");
+ else:
+ reject(prefix_multi_line_string(output, " [GPG output:] "), "");
+ return None;
+
+ # Sanity check the good stuff we expect
+ if not keywords.has_key("VALIDSIG"):
+ reject("signature on %s does not appear to be valid [No VALIDSIG]." % (filename));
+ bad = 1;
+ else:
+ args = keywords["VALIDSIG"];
+ if len(args) < 1:
+ reject("internal error while checking signature on %s." % (filename));
+ bad = 1;
+ else:
+ fingerprint = args[0];
+ if not keywords.has_key("GOODSIG"):
+ reject("signature on %s does not appear to be valid [No GOODSIG]." % (filename));
+ bad = 1;
+ if not keywords.has_key("SIG_ID"):
+ reject("signature on %s does not appear to be valid [No SIG_ID]." % (filename));
+ bad = 1;
+
+ # Finally ensure there's not something we don't recognise
+ known_keywords = Dict(VALIDSIG="",SIG_ID="",GOODSIG="",BADSIG="",ERRSIG="",
+ SIGEXPIRED="",KEYREVOKED="",NO_PUBKEY="",BADARMOR="",
+ NODATA="");
+
+ for keyword in keywords.keys():
+ if not known_keywords.has_key(keyword):
+ reject("found unknown status token '%s' from gpgv with args '%r' in %s." % (keyword, keywords[keyword], filename));
+ bad = 1;
+
+ if bad:
+ return None;
+ else:
+ return fingerprint;
+
+################################################################################
+
apt_pkg.init()
Cnf = apt_pkg.newConfiguration();
projects / dak.git / blobdiff