fixed a problem in CryptoBox config reading

introduced "coding_guidelines.txt" for a consistent coding feeling :)
added CryptoBoxRootActions for future privilege separation

pythonrewrite/bin2/CryptoBox.py

@@ -82,8 +82,10 @@ class CryptoBox:
 				self.log.error("Could not find the specified configuration file (%s)" % config_file)
 				sys.exit(1)
 		try:
-			self.cbxPrefs = configobj.ConfigObj(conf_file)
+			self.cbxPrefs = configobj.ConfigObj(config_file)
 			self.log.debug("found config: %s" % self.cbxPrefs.items())
+		# TODO/RFC: more specific exception handling, please - or (if you want to have fun) just replace the line above with the following:
+		#	self.cbxPrefs = configobj.ConfigObj(obviouslyInvalidVariableName)
 		except:
 			self.log.error("Could not read configuration file. I give up.")
 			sys.exit(1)

pythonrewrite/bin2/CryptoBoxRootActions.py

@@ -0,0 +1,132 @@
+#!/usr/bin/env python
+"""module for executing the programs, that need root privileges
+
+Syntax:
+	- program
+	- device
+	- [action]
+	- [action args]
+"""
+
+# current problem: how to identify the "cryptobox" user - to check its permissions?
+
+import os
+import sys
+import subprocess
+import pwd
+import grp
+
+allowedProgs = {
+	"sfdisk":	"/sbin/sfdisk",
+	"cryptsetup":	"/sbin/cryptsetup",
+	}
+
+
+# check if this user has write-access to the device
+allowedUser	= "lars"
+# supply gids - otherwise the default groups of the above user are used
+#allowedGroups	= [6, 1000]
+
+
+def isWriteableBlock(device):
+	fstat = os.stat(device)
+	(dev_type, perm_u, perm_g, perm_o) = (
+		fstat.st_mode % 65536 / 4096,
+		fstat.st_mode % 512 / 64,
+		fstat.st_mode % 512 % 64 / 8,
+		fstat.st_mode % 512 % 64 % 8)
+	(owner_uid, owner_gid) = (fstat.st_uid, fstat.st_gid)
+	(trustUserName, trustUID, groupsOfTrustUser) = getUserInfo(allowedUser)
+	trustGIDs = []
+	try:
+		"if 'allowedGroups' are defined, then ignore the previously aquired groups"
+		"TODO: for now only group ids (no names) are allowed"
+		trustGIDs.extend(allowedGroups)
+	except NameError:
+		"'allowedGroups' was not defined - we use the default ones of the user"
+		trustGIDs.extend(groupsOfTrustUser)
+	except TypeError:
+		"if it fails, then 'allowedGroups' was really not well defined"
+		trustGIDs.append(allowedGID)
+	DEF_TYPES = { "pipe":1, "char":2, "dir":4, "block":6, "file":8, "link":10, "socket":12}
+	if dev_type != DEF_TYPES["block"]: return False
+	# replace this access check by "os.access"
+	"does the owner id match?"
+	if owner_uid == trustUID:
+		"is the write bit (2) set for the owner?"
+		return perm_u & 2
+	if owner_gid in trustGIDs:
+		return perm_g & 2
+	"we seem to be one of 'others' - so just check the bit"
+	return perm_o & 2
+
+
+def run_cryptsetup(device, args):
+	print "ok - you are free to call cryptsetup ..."
+	print "  not yet implemented ..."
+	return True
+
+
+def run_sfdisk(device, args):
+	print "ok - you are free to call sfdisk ..."
+	print "  not yet implemented ..."
+	return True
+
+
+def getUserInfo(user):
+	"""return information about the specified user
+
+	@user:		(uid or name)
+	@return:	tuple of (name, uid, (groups))
+	"""
+	if user is None: raise "KeyError", "no user supplied"
+	# first check, if 'user' contains an id - then check for a name
+	try:
+		userinfo = pwd.getpwuid(user)
+	except TypeError:
+		# if a KeyError is raised again, then the supplied user was invalid
+		userinfo = pwd.getpwnam(user)
+	u_groups =[one_group.gr_gid
+		for one_group in grp.getgrall()
+		if userinfo.pw_name in one_group.gr_mem]
+	if not userinfo.pw_gid in u_groups: u_groups.append(userinfo.pw_gid)
+	return (userinfo.pw_name, userinfo.pw_uid, u_groups)
+
+
+# **************** main **********************
+
+# prevent import
+if __name__ == "__main__":
+
+	# remove program name
+	sys.argv.remove(sys.argv[0])
+
+	if len(sys.argv) < 2:
+		sys.stderr.write("Not enough arguments supplied (%s)!\n" % " ".join(sys.argv))
+		sys.exit(1)
+
+	progRequest = sys.argv[0]
+	deviceRequest = sys.argv[1]
+	sys.argv.remove(progRequest)
+	sys.argv.remove(deviceRequest)
+
+	if not progRequest in allowedProgs.keys():
+		sys.stderr.write("Invalid program requested: %s\n" % progRequest)
+		sys.exit(2)
+
+	if not os.path.exists(deviceRequest):
+		sys.stderr.write("The specified device (%s) does not exist!\n" % deviceRequest)
+		sys.exit(3)
+
+	if not isWriteableBlock(deviceRequest):
+		sys.stderr.write("This device (%s) must be a writeable block device!\n" % deviceRequest)
+		sys.exit(4)
+
+	if progRequest == "cryptsetup":	runner = run_cryptsetup
+	elif progRequest == "sfdisk":	runner = run_sfdisk
+	else:
+		sys.stderr.write("The interface for this program (%s) is not yet implemented!\n" % progRequest)
+		sys.exit(1)
+
+	runner(deviceRequest, sys.argv)
+

pythonrewrite/bin2/coding_guidelines.txt

@@ -0,0 +1,14 @@
+Maybe we can add some notes here to get a consistent coding experience :)
+
+-------------------------------------------------------------------------------
+
+comments:
+	- should be usable for pydoc
+
+error handling:
+	- unspecific error handling is evil (try: "grep -r except: .")
+
+unit testing:
+	- commits with broken unit tests are evil (options: fix or disable)
+	- all classes should contain exhaustive unit tests prior to the first release
+