diff options
Diffstat (limited to 'src/lib/Bcfg2/Client/Tools/POSIX/base.py')
-rw-r--r-- | src/lib/Bcfg2/Client/Tools/POSIX/base.py | 639 |
1 files changed, 639 insertions, 0 deletions
diff --git a/src/lib/Bcfg2/Client/Tools/POSIX/base.py b/src/lib/Bcfg2/Client/Tools/POSIX/base.py new file mode 100644 index 000000000..1ec1d36d5 --- /dev/null +++ b/src/lib/Bcfg2/Client/Tools/POSIX/base.py @@ -0,0 +1,639 @@ +import os +import sys +import pwd +import grp +import stat +import shutil +import Bcfg2.Client.Tools +import Bcfg2.Client.XML + +try: + import selinux + has_selinux = True +except ImportError: + has_selinux = False + +try: + import posix1e + has_acls = True +except ImportError: + has_acls = False + +# map between dev_type attribute and stat constants +device_map = dict(block=stat.S_IFBLK, + char=stat.S_IFCHR, + fifo=stat.S_IFIFO) + +# map between permissions characters and numeric ACL constants +acl_map = dict(r=posix1e.ACL_READ, + w=posix1e.ACL_WRITE, + x=posix1e.ACL_EXECUTE) + +class POSIXTool(Bcfg2.Client.Tools.Tool): + def fully_specified(self, entry): + # checking is done by __req__ + return True + + def verify(self, entry, modlist): + if not self._verify_metadata(entry): + return False + if entry.get('recursive', 'false').lower() == 'true': + # verify ownership information recursively + for root, dirs, files in os.walk(entry.get('name')): + for p in dirs + files: + if not self._verify_metadata(entry, + path=os.path.join(root, p)): + return False + return True + + def install(self, entry): + plist = [entry.get('name')] + rv = True + rv &= self._set_perms(entry) + if entry.get('recursive', 'false').lower() == 'true': + # set metadata recursively + for root, dirs, files in os.walk(entry.get('name')): + for path in dirs + files: + rv &= self._set_perms(entry, path=os.path.join(root, path)) + return rv + + def _exists(self, entry, remove=False): + try: + # check for existing paths and optionally remove them + ondisk = os.lstat(entry.get('name')) + if remove: + if os.path.isdir(entry.get('name')): + rm = shutil.rmtree + else: + rm = os.unlink + try: + rm(entry.get('name')) + return False + except OSError: + err = sys.exc_info()[1] + self.logger.warning('POSIX: Failed to unlink %s: %s' % + (entry.get('name'), err)) + return ondisk # probably still exists + else: + return ondisk + except OSError: + return False + + def _set_perms(self, entry, path=None): + if path is None: + path = entry.get("name") + + rv = True + if entry.get("owner") and entry.get("group"): + try: + self.logger.debug("POSIX: Setting ownership of %s to %s:%s" % + (path, + self._norm_entry_uid(entry), + self._norm_entry_gid(entry))) + os.chown(path, self._norm_entry_uid(entry), + self._norm_entry_gid(entry)) + except KeyError: + self.logger.error('POSIX: Failed to change ownership of %s' % + path) + rv = False + os.chown(path, 0, 0) + except OSError: + self.logger.error('POSIX: Failed to change ownership of %s' % + path) + rv = False + + if entry.get("perms"): + configPerms = int(entry.get('perms'), 8) + if entry.get('dev_type'): + configPerms |= device_map[entry.get('dev_type')] + try: + self.logger.debug("POSIX: Setting permissions on %s to %s" % + (path, oct(configPerms))) + os.chmod(path, configPerms) + except (OSError, KeyError): + self.logger.error('POSIX: Failed to change permissions on %s' % + path) + rv = False + + if entry.get('mtime'): + try: + os.utime(entry.get('name'), (int(entry.get('mtime')), + int(entry.get('mtime')))) + except OSError: + self.logger.error("POSIX: Failed to set mtime of %s" % path) + rv = False + + rv &= self._set_secontext(entry, path=path) + rv &= self._set_acls(entry, path=path) + return rv + + + def _set_acls(self, entry, path=None): + """ set POSIX ACLs on the file on disk according to the config """ + if not has_acls: + if entry.findall("ACL"): + self.logger.debug("POSIX: ACLs listed for %s but no pylibacl " + "library installed" % entry.get('name')) + return True + + if path is None: + path = entry.get("name") + + try: + acl = posix1e.ACL(file=path) + except IOError: + err = sys.exc_info()[1] + if err.errno == 95: + # fs is mounted noacl + self.logger.error("POSIX: Cannot set ACLs on filesystem " + "mounted without ACL support: %s" % path) + else: + self.logger.error("POSIX: Error getting current ACLS on %s: %s" + % (path, err)) + return False + # clear ACLs out so we start fresh -- way easier than trying + # to add/remove/modify ACLs + for aclentry in acl: + if aclentry.tag_type in [posix1e.ACL_USER, posix1e.ACL_GROUP]: + acl.delete_entry(aclentry) + if os.path.isdir(path): + defacl = posix1e.ACL(filedef=path) + if not defacl.valid(): + # when a default ACL is queried on a directory that + # has no default ACL entries at all, you get an empty + # ACL, which is not valid. in this circumstance, we + # just copy the access ACL to get a base valid ACL + # that we can add things to. + defacl = posix1e.ACL(acl=acl) + else: + for aclentry in defacl: + if aclentry.tag_type in [posix1e.ACL_USER, + posix1e.ACL_GROUP]: + defacl.delete_entry(aclentry) + else: + defacl = None + + for aclkey, perms in self._list_entry_acls(entry).items(): + atype, scope, qualifier = aclkey + if atype == "default": + if defacl is None: + self.logger.warning("POSIX: Cannot set default ACLs on " + "non-directory %s" % path) + continue + entry = posix1e.Entry(defacl) + else: + entry = posix1e.Entry(acl) + for perm in acl_map.values(): + if perm & perms: + entry.permset.add(perm) + entry.tag_type = scope + try: + if scope == posix1e.ACL_USER: + scopename = "user" + entry.qualifier = self._norm_uid(qualifier) + elif scope == posix1e.ACL_GROUP: + scopename = "group" + entry.qualifier = self._norm_gid(qualifier) + except (OSError, KeyError): + err = sys.exc_info()[1] + self.logger.error("POSIX: Could not resolve %s %s: %s" % + (scopename, qualifier, err)) + continue + acl.calc_mask() + + def _apply_acl(acl, path, atype=posix1e.ACL_TYPE_ACCESS): + if atype == posix1e.ACL_TYPE_ACCESS: + atype_str = "access" + else: + atype_str = "default" + if acl.valid(): + self.logger.debug("POSIX: Applying %s ACL to %s:" % (atype_str, + path)) + for line in str(acl).splitlines(): + self.logger.debug(" " + line) + try: + acl.applyto(path, atype) + return True + except: + err = sys.exc_info()[1] + self.logger.error("POSIX: Failed to set ACLs on %s: %s" % + (path, err)) + return False + else: + self.logger.warning("POSIX: %s ACL created for %s was invalid:" + % (atype_str.title(), path)) + for line in str(acl).splitlines(): + self.logger.warning(" " + line) + return False + + rv = _apply_acl(acl, path) + if defacl: + defacl.calc_mask() + rv &= _apply_acl(defacl, path, posix1e.ACL_TYPE_DEFAULT) + return rv + + def _set_secontext(self, entry, path=None): + """ set the SELinux context of the file on disk according to the + config""" + if not has_selinux: + return True + + if path is None: + path = entry.get("name") + context = entry.get("secontext") + if context is None: + # no context listed + return True + + if context == '__default__': + try: + selinux.restorecon(path) + rv = True + except: + err = sys.exc_info()[1] + self.logger.error("POSIX: Failed to restore SELinux context " + "for %s: %s" % (path, err)) + rv = False + else: + try: + rv = selinux.lsetfilecon(path, context) == 0 + except: + err = sys.exc_info()[1] + self.logger.error("POSIX: Failed to restore SELinux context " + "for %s: %s" % (path, err)) + rv = False + return rv + + def _norm_gid(self, gid): + """ This takes a group name or gid and returns the + corresponding gid. """ + try: + return int(gid) + except ValueError: + return int(grp.getgrnam(gid)[2]) + + def _norm_entry_gid(self, entry): + try: + return self._norm_gid(entry.get('group')) + except (OSError, KeyError): + err = sys.exc_info()[1] + self.logger.error('POSIX: GID normalization failed for %s on %s: %s' + % (entry.get('group'), entry.get('name'), err)) + return 0 + + def _norm_uid(self, uid): + """ This takes a username or uid and returns the + corresponding uid. """ + try: + return int(uid) + except ValueError: + return int(pwd.getpwnam(uid)[2]) + + def _norm_entry_uid(self, entry): + try: + return self._norm_uid(entry.get("owner")) + except (OSError, KeyError): + err = sys.exc_info()[1] + self.logger.error('POSIX: UID normalization failed for %s on %s: %s' + % (entry.get('owner'), entry.get('name'), err)) + return 0 + + def _norm_acl_perms(self, perms): + """ takes a representation of an ACL permset and returns a digit + representing the permissions entailed by it. representations can + either be a single octal digit, a string of up to three 'r', + 'w', 'x', or '-' characters, or a posix1e.Permset object""" + if hasattr(perms, 'test'): + # Permset object + return sum([p for p in acl_map.values() + if perms.test(p)]) + + try: + # single octal digit + rv = int(perms) + if rv > 0 and rv < 8: + return rv + else: + self.logger.error("POSIX: Permissions digit out of range in " + "ACL: %s" % perms) + return 0 + except ValueError: + # couldn't be converted to an int; process as a string + if len(perms) > 3: + self.logger.error("POSIX: Permissions string too long in ACL: " + "%s" % perms) + return 0 + rv = 0 + for char in perms: + if char == '-': + continue + elif char not in acl_map: + self.logger.warning("POSIX: Unknown permissions character " + "in ACL: %s" % char) + elif rv & acl_map[char]: + self.logger.warning("POSIX: Duplicate permissions " + "character in ACL: %s" % perms) + else: + rv |= acl_map[char] + return rv + + def _acl2string(self, aclkey, perms): + atype, scope, qualifier = aclkey + acl_str = [] + if atype == 'default': + acl_str.append(atype) + if scope == posix1e.ACL_USER: + acl_str.append("user") + elif scope == posix1e.ACL_GROUP: + acl_str.append("group") + acl_str.append(qualifier) + acl_str.append(self._acl_perm2string(perms)) + return ":".join(acl_str) + + def _acl_perm2string(self, perm): + rv = [] + for char in 'rwx': + if acl_map[char] & perm: + rv.append(char) + else: + rv.append('-') + return ''.join(rv) + + def _gather_data(self, path): + try: + ondisk = os.stat(path) + except OSError: + self.logger.debug("POSIX: %s does not exist" % path) + return (False, None, None, None, None, None) + + try: + owner = str(ondisk[stat.ST_UID]) + except OSError: + err = sys.exc_info()[1] + self.logger.debug("POSIX: Could not get current owner of %s: %s" % + (path, err)) + owner = None + except KeyError: + self.logger.error('POSIX: User resolution failed for %s' % path) + owner = None + + try: + group = str(ondisk[stat.ST_GID]) + except (OSError, KeyError): + err = sys.exc_info()[1] + self.logger.debug("POSIX: Could not get current group of %s: %s" % + (path, err)) + group = None + except KeyError: + self.logger.error('POSIX: Group resolution failed for %s' % path) + group = None + + try: + perms = oct(ondisk[stat.ST_MODE])[-4:] + except (OSError, KeyError, TypeError): + err = sys.exc_info()[1] + self.logger.debug("POSIX: Could not get current permissions of %s: " + "%s" % (path, err)) + perms = None + + if has_selinux: + try: + secontext = selinux.getfilecon(path)[1].split(":")[2] + except (OSError, KeyError): + err = sys.exc_info()[1] + self.logger.debug("POSIX: Could not get current SELinux " + "context of %s: %s" % (path, err)) + secontext = None + else: + secontext = None + + if has_acls: + acls = self._list_file_acls(path) + else: + acls = None + return (ondisk, owner, group, perms, secontext, acls) + + def _verify_metadata(self, entry, path=None): + """ generic method to verify perms, owner, group, secontext, acls, + and mtime """ + # allow setting an alternate path for recursive permissions checking + if path is None: + path = entry.get('name') + attrib = dict() + ondisk, attrib['current_owner'], attrib['current_group'], \ + attrib['current_perms'], attrib['current_secontext'], acls = \ + self._gather_data(path) + + if not ondisk: + entry.set('current_exists', 'false') + return False + + # we conditionally verify every bit of metadata only if it's + # specified on the entry. consequently, canVerify() and + # fully_specified() are preconditions of _verify_metadata(), + # since they will ensure that everything that needs to be + # specified actually is. this lets us gracefully handle + # symlink and hardlink entries, which have SELinux contexts + # but not other permissions, optional secontext and mtime + # attrs, and so on. + configOwner, configGroup, configPerms, mtime = None, None, None, -1 + if entry.get('mtime', '-1') != '-1': + mtime = str(ondisk[stat.ST_MTIME]) + if entry.get("owner"): + configOwner = str(self._norm_entry_uid(entry)) + if entry.get("group"): + configGroup = str(self._norm_entry_gid(entry)) + if entry.get("perms"): + while len(entry.get('perms', '')) < 4: + entry.set('perms', '0' + entry.get('perms', '')) + configPerms = int(entry.get('perms'), 8) + + errors = [] + if configOwner and attrib['current_owner'] != configOwner: + errors.append("Owner for path %s is incorrect. " + "Current owner is %s but should be %s" % + (path, attrib['current_owner'], entry.get('owner'))) + + if configGroup and attrib['current_group'] != configGroup: + errors.append("Group for path %s is incorrect. " + "Current group is %s but should be %s" % + (path, attrib['current_group'], entry.get('group'))) + + if (configPerms and + oct(int(attrib['current_perms'], 8)) != oct(configPerms)): + errors.append("Permissions for path %s are incorrect. " + "Current permissions are %s but should be %s" % + (path, attrib['current_perms'], entry.get('perms'))) + + if entry.get('mtime'): + attrib['current_mtime'] = mtime + if mtime != entry.get('mtime', '-1'): + errors.append("mtime for path %s is incorrect. " + "Current mtime is %s but should be %s" % + (path, mtime, entry.get('mtime'))) + + if has_selinux and entry.get("secontext"): + if entry.get("secontext") == "__default__": + configContext = selinux.matchpathcon(path, 0)[1].split(":")[2] + else: + configContext = entry.get("secontext") + if attrib['current_secontext'] != configContext: + errors.append("SELinux context for path %s is incorrect. " + "Current context is %s but should be %s" % + (path, attrib['current_secontext'], + configContext)) + + if errors: + for error in errors: + self.logger.debug("POSIX: " + error) + entry.set('qtext', "\n".join([entry.get('qtext', '')] + errors)) + if path == entry.get("name"): + for attr, val in attrib.items(): + entry.set(attr, val) + + aclVerifies = self._verify_acls(entry, path=path) + return aclVerifies and len(errors) == 0 + + def _list_entry_acls(self, entry): + wanted = dict() + for acl in entry.findall("ACL"): + if acl.get("scope") == "user": + scope = posix1e.ACL_USER + elif acl.get("scope") == "group": + scope = posix1e.ACL_GROUP + else: + self.logger.error("POSIX: Unknown ACL scope %s" % + acl.get("scope")) + continue + wanted[(acl.get("type"), scope, acl.get(acl.get("scope")))] = \ + self._norm_acl_perms(acl.get('perms')) + return wanted + + def _list_file_acls(self, path): + def _process_acl(acl, atype): + try: + if acl.tag_type == posix1e.ACL_USER: + qual = pwd.getpwuid(acl.qualifier)[0] + elif acl.tag_type == posix1e.ACL_GROUP: + qual = grp.getgrgid(acl.qualifier)[0] + else: + return + except (OSError, KeyError): + err = sys.exc_info()[1] + self.logger.error("POSIX: Lookup of %s %s failed: %s" % + (scope, acl.qualifier, err)) + qual = acl.qualifier + existing[(atype, acl.tag_type, qual)] = \ + self._norm_acl_perms(acl.permset) + + existing = dict() + try: + for acl in posix1e.ACL(file=path): + _process_acl(acl, "access") + except IOError: + err = sys.exc_info()[1] + if err.errno == 95: + # fs is mounted noacl + self.logger.debug("POSIX: Filesystem mounted without ACL " + "support: %s" % path) + else: + self.logger.error("POSIX: Error getting current ACLS on %s: %s" + % (path, err)) + return existing + + if os.path.isdir(path): + for acl in posix1e.ACL(filedef=path): + _process_acl(acl, "default") + return existing + + def _verify_acls(self, entry, path=None): + if not has_acls: + if entry.findall("ACL"): + self.logger.debug("POSIX: ACLs listed for %s but no pylibacl " + "library installed" % entry.get('name')) + return True + + if path is None: + path = entry.get("name") + + # create lists of normalized representations of the ACLs we want + # and the ACLs we have. this will make them easier to compare + # than trying to mine that data out of the ACL objects and XML + # objects and compare it at the same time. + wanted = self._list_entry_acls(entry) + existing = self._list_file_acls(path) + + missing = [] + extra = [] + wrong = [] + for aclkey, perms in wanted.items(): + if aclkey not in existing: + missing.append(self._acl2string(aclkey, perms)) + elif existing[aclkey] != perms: + wrong.append((self._acl2string(aclkey, perms), + self._acl2string(aclkey, existing[aclkey]))) + if path == entry.get("name"): + atype, scope, qual = aclkey + aclentry = Bcfg2.Client.XML.Element("ACL", type=atype, + perms=str(perms)) + if scope == posix1e.ACL_USER: + aclentry.set("scope", "user") + elif scope == posix1e.ACL_GROUP: + aclentry.set("scope", "group") + else: + self.logger.debug("POSIX: Unknown ACL scope %s on %s" % + (scope, path)) + continue + aclentry.set(aclentry.get("scope"), qual) + entry.append(aclentry) + + for aclkey, perms in existing.items(): + if aclkey not in wanted: + extra.append(self._acl2string(aclkey, perms)) + + msg = [] + if missing: + msg.append("%s ACLs are missing: %s" % (len(missing), + ", ".join(missing))) + if wrong: + msg.append("%s ACLs are wrong: %s" % + (len(wrong), + "; ".join(["%s should be %s" % (e, w) + for w, e in wrong]))) + if extra: + msg.append("%s extra ACLs: %s" % (len(extra), ", ".join(extra))) + + if msg: + msg.insert(0, "POSIX: ACLs for %s are incorrect." % path) + self.logger.debug(msg[0]) + for line in msg[1:]: + self.logger.debug(" " + line) + entry.set('qtext', "\n".join([entry.get("qtext", '')] + msg)) + return False + return True + + def _makedirs(self, entry, path=None): + """ os.makedirs helpfully creates all parent directories for + us, but it sets permissions according to umask, which is + probably wrong. we need to find out which directories were + created and set permissions on those + (http://trac.mcs.anl.gov/projects/bcfg2/ticket/1125) """ + created = [] + if path is None: + path = entry.get("name") + cur = path + while cur != '/': + if not os.path.exists(cur): + created.append(cur) + cur = os.path.dirname(cur) + rv = True + try: + os.makedirs(path) + except OSError: + err = sys.exc_info()[1] + self.logger.error('POSIX: Failed to create directory %s: %s' % + (path, err)) + rv = False + for cpath in created: + rv &= self._set_perms(entry, path=cpath) + return rv |