Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932577Ab2F2QtY (ORCPT ); Fri, 29 Jun 2012 12:49:24 -0400 Received: from bhuna.collabora.co.uk ([93.93.135.160]:42796 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932238Ab2F2Qqa (ORCPT ); Fri, 29 Jun 2012 12:46:30 -0400 From: Vincent Sanders To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "David S. Miller" Cc: Javier Martinez Canillas , Alban Crequy Subject: [PATCH net-next 13/15] netfilter: nfdbus: Add D-bus message parsing Date: Fri, 29 Jun 2012 17:45:52 +0100 Message-Id: <1340988354-26981-14-git-send-email-vincent.sanders@collabora.co.uk> X-Mailer: git-send-email 1.7.10 In-Reply-To: <1340988354-26981-1-git-send-email-vincent.sanders@collabora.co.uk> References: <1340988354-26981-1-git-send-email-vincent.sanders@collabora.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8676 Lines: 300 From: Javier Martinez Canillas The netfilter D-Bus module needs to parse D-bus messages sent by applications to decide whether a peer can receive or not a D-Bus message. Add D-bus message parsing logic to be able to analyze. Signed-off-by: Javier Martinez Canillas Signed-off-by: Alban Crequy --- net/netfilter/nfdbus/message.c | 194 ++++++++++++++++++++++++++++++++++++++++ net/netfilter/nfdbus/message.h | 71 +++++++++++++++ 2 files changed, 265 insertions(+) create mode 100644 net/netfilter/nfdbus/message.c create mode 100644 net/netfilter/nfdbus/message.h diff --git a/net/netfilter/nfdbus/message.c b/net/netfilter/nfdbus/message.c new file mode 100644 index 0000000..93c409c --- /dev/null +++ b/net/netfilter/nfdbus/message.c @@ -0,0 +1,194 @@ +/* + * message.c Basic D-Bus message parsing + * + * Copyright (C) 2010-2012 Collabora Ltd + * Authors: Alban Crequy + * Copyright (C) 2002, 2003, 2004, 2005 Red Hat Inc. + * Copyright (C) 2002, 2003 CodeFactory AB + * + * 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 + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + */ + +#include + +#include "message.h" + +int dbus_message_type_from_string(const char *type_str) +{ + if (strcmp(type_str, "method_call") == 0) + return DBUS_MESSAGE_TYPE_METHOD_CALL; + if (strcmp(type_str, "method_return") == 0) + return DBUS_MESSAGE_TYPE_METHOD_RETURN; + else if (strcmp(type_str, "signal") == 0) + return DBUS_MESSAGE_TYPE_SIGNAL; + else if (strcmp(type_str, "error") == 0) + return DBUS_MESSAGE_TYPE_ERROR; + else + return DBUS_MESSAGE_TYPE_INVALID; +} + +int dbus_message_parse(unsigned char *message, size_t len, + struct dbus_message *dbus_message) +{ + unsigned char *cur; + int array_header_len; + + dbus_message->message = message; + + if (len < 4 + 4 + 4 + 4 || message[1] == 0 || message[1] > 4) + return -EINVAL; + + dbus_message->type = message[1]; + dbus_message->body_length = *((u32 *)(message + 4)); + cur = message + 12; + array_header_len = *(u32 *)cur; + dbus_message->len_offset = 12; + cur += 4; + while (cur < message + len + && cur < message + 12 + 4 + array_header_len) { + int header_code; + int signature_len; + unsigned char *signature; + int str_len; + unsigned char *str; + + /* D-Bus alignment craziness */ + if ((cur - message) % 8 != 0) + cur += 8 - (cur - message) % 8; + + header_code = *(char *)cur; + cur++; + signature_len = *(char *)cur; + /* All header fields of the current D-Bus spec have a simple + * type, either o, s, g, or u */ + if (signature_len != 1) + return -EINVAL; + cur++; + signature = cur; + cur += signature_len + 1; + if (signature[0] != 'o' && + signature[0] != 's' && + signature[0] != 'g' && + signature[0] != 'u') + return -EINVAL; + + if (signature[0] == 'u') { + cur += 4; + continue; + } + + if (signature[0] != 'g') { + str_len = *(u32 *)cur; + cur += 4; + } else { + str_len = *(char *)cur; + cur += 1; + } + + str = cur; + switch (header_code) { + case 1: + dbus_message->path = str; + break; + case 2: + dbus_message->interface = str; + break; + case 3: + dbus_message->member = str; + break; + case 6: + dbus_message->destination = str; + break; + case 7: + dbus_message->sender = str; + break; + case 8: + dbus_message->body_signature = str; + break; + } + cur += str_len + 1; + } + + dbus_message->padding_end = (8 - (cur - message) % 8) % 8; + + /* Jump to body D-Bus alignment craziness */ + if ((cur - message) % 8 != 0) + cur += 8 - (cur - message) % 8; + dbus_message->new_header_offset = cur - message; + + if (dbus_message->new_header_offset + + dbus_message->body_length != len) { + pr_warn("Message truncated? " \ + "Header %d + Body %d != Length %zd\n", + dbus_message->new_header_offset, + dbus_message->body_length, len); + return -EINVAL; + } + + if (dbus_message->body_signature && + dbus_message->body_signature[0] == 's') { + int str_len; + str_len = *(u32 *)cur; + cur += 4; + dbus_message->arg0 = cur; + cur += str_len + 1; + } + + if ((cur - message) % 4 != 0) + cur += 4 - (cur - message) % 4; + + if (dbus_message->body_signature && + dbus_message->body_signature[0] == 's' && + dbus_message->body_signature[1] == 's') { + int str_len; + str_len = *(u32 *)cur; + cur += 4; + dbus_message->arg1 = cur; + cur += str_len + 1; + } + + if ((cur - message) % 4 != 0) + cur += 4 - (cur - message) % 4; + + if (dbus_message->body_signature && + dbus_message->body_signature[0] == 's' && + dbus_message->body_signature[1] == 's' && + dbus_message->body_signature[2] == 's') { + int str_len; + str_len = *(u32 *)cur; + cur += 4; + dbus_message->arg2 = cur; + cur += str_len + 1; + } + + if ((cur - message) % 4 != 0) + cur += 4 - (cur - message) % 4; + + if (dbus_message->type == DBUS_MESSAGE_TYPE_SIGNAL && + dbus_message->sender && dbus_message->path && + dbus_message->interface && dbus_message->member && + dbus_message->arg0 && + strcmp(dbus_message->sender, "org.freedesktop.DBus") == 0 && + strcmp(dbus_message->interface, "org.freedesktop.DBus") == 0 && + strcmp(dbus_message->path, "/org/freedesktop/DBus") == 0) { + if (strcmp(dbus_message->member, "NameAcquired") == 0) + dbus_message->name_acquired = dbus_message->arg0; + else if (strcmp(dbus_message->member, "NameLost") == 0) + dbus_message->name_lost = dbus_message->arg0; + } + + return 0; +} diff --git a/net/netfilter/nfdbus/message.h b/net/netfilter/nfdbus/message.h new file mode 100644 index 0000000..e3ea4d3 --- /dev/null +++ b/net/netfilter/nfdbus/message.h @@ -0,0 +1,71 @@ +/* + * message.h Basic D-Bus message parsing + * + * Copyright (C) 2010 Collabora Ltd + * + * 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 + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + */ + +#ifndef DBUS_MESSAGE_H +#define DBUS_MESSAGE_H + +#include + +#define DBUS_MAXIMUM_MATCH_RULE_LENGTH 1024 + +/* Types of message */ + +#define DBUS_MESSAGE_TYPE_INVALID 0 +#define DBUS_MESSAGE_TYPE_METHOD_CALL 1 +#define DBUS_MESSAGE_TYPE_METHOD_RETURN 2 +#define DBUS_MESSAGE_TYPE_ERROR 3 +#define DBUS_MESSAGE_TYPE_SIGNAL 4 +#define DBUS_NUM_MESSAGE_TYPES 5 + +/* No need to implement a feature-complete parser. It only implement what is + * needed by the bus. */ +struct dbus_message { + char *message; + size_t len; + size_t new_len; + + /* direct pointers to the fields */ + int type; + char *path; + char *interface; + char *member; + char *destination; + char *sender; + char *body_signature; + int body_length; + char *arg0; + char *arg1; + char *arg2; + char *name_acquired; + char *name_lost; + + /* How to add the 'sender' field in the headers */ + int new_header_offset; + int len_offset; + int padding_end; +}; + +int dbus_message_type_from_string(const char *type_str); + +int dbus_message_parse(unsigned char *message, size_t len, + struct dbus_message *dbus_message); + +#endif /* DBUS_MESSAGE_H */ -- 1.7.10 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/