From patchwork Thu Jul 12 10:34:13 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Fernando F. Mancera" X-Patchwork-Id: 942898 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netfilter-devel-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=riseup.net Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=riseup.net header.i=@riseup.net header.b="p9VUAmg6"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 41RC3n0PY4z9ryt for ; Thu, 12 Jul 2018 20:34:28 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726492AbeGLKnY (ORCPT ); Thu, 12 Jul 2018 06:43:24 -0400 Received: from mx1.riseup.net ([198.252.153.129]:40505 "EHLO mx1.riseup.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726453AbeGLKnY (ORCPT ); Thu, 12 Jul 2018 06:43:24 -0400 Received: from piha.riseup.net (piha-pn.riseup.net [10.0.1.163]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client CN "*.riseup.net", Issuer "COMODO RSA Domain Validation Secure Server CA" (verified OK)) by mx1.riseup.net (Postfix) with ESMTPS id 4E8901A04E0 for ; Thu, 12 Jul 2018 03:34:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=riseup.net; s=squak; t=1531391666; bh=akN9k794hQDyV4FTZsj7rNH8X7aHRHu3Vku/LH+yXuw=; h=From:To:Cc:Subject:Date:From; b=p9VUAmg6iS9QaWAEtBhRwf71r8vlS/Mue6AemsOYQXZWRaAHmFZxx/vCueFcag6tn rQVZZ8natjKaTUNG3X0FVv+CGJJoEK2QIkECaQntdkCVIpCie524TdiimeiC/2o8N/ OHIe9FgqmFxJ03qLQlbcHOlVNYFqJ+FJGF7ppHtM= X-Riseup-User-ID: B8D43E0A5940A04AEACD0437BD3295AEC18A4E60DCF1D0E02879BD35A80FC503 Received: from [127.0.0.1] (localhost [127.0.0.1]) by piha.riseup.net with ESMTPSA id 3ECDE2E1C0; Thu, 12 Jul 2018 03:34:25 -0700 (PDT) From: Fernando Fernandez Mancera To: netfilter-devel@vger.kernel.org Cc: Fernando Fernandez Mancera Subject: [PATCH 1/2 WIP nf-next] netfilter: implement Passive OS fingerprint module in nft_osf Date: Thu, 12 Jul 2018 12:34:13 +0200 Message-Id: <20180712103414.2501-1-ffmancera@riseup.net> Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Add basic module functions into nft_osf.[ch] in order to start the implementation of OSF module in nf_tables. Signed-off-by: Fernando Fernandez Mancera --- include/uapi/linux/netfilter/nf_osf.h | 7 ++ include/uapi/linux/netfilter/xt_osf.h | 6 +- net/netfilter/Kconfig | 7 ++ net/netfilter/Makefile | 1 + net/netfilter/nft_osf.c | 108 ++++++++++++++++++++++++++ 5 files changed, 128 insertions(+), 1 deletion(-) create mode 100644 net/netfilter/nft_osf.c diff --git a/include/uapi/linux/netfilter/nf_osf.h b/include/uapi/linux/netfilter/nf_osf.h index 8f2f2f403183..79882b2f7f8e 100644 --- a/include/uapi/linux/netfilter/nf_osf.h +++ b/include/uapi/linux/netfilter/nf_osf.h @@ -16,9 +16,16 @@ #define NF_OSF_TTL_TRUE 0 /* True ip and fingerprint TTL comparison */ +/* Check if ip TTL is less than fingerprint one */ +#define NF_OSF_TTL_LESS 1 + /* Do not compare ip and fingerprint TTL at all */ #define NF_OSF_TTL_NOCHECK 2 +#define NF_OSF_FLAGMASK (NF_OSF_GENRE | \ + NF_OSF_TTL | \ + NF_OSF_LOG | \ + NF_OSF_INVERT) /* Wildcard MSS (kind of). * It is used to implement a state machine for the different wildcard values * of the MSS and window sizes. diff --git a/include/uapi/linux/netfilter/xt_osf.h b/include/uapi/linux/netfilter/xt_osf.h index 72956eceeb09..2f5d4e6d0434 100644 --- a/include/uapi/linux/netfilter/xt_osf.h +++ b/include/uapi/linux/netfilter/xt_osf.h @@ -37,8 +37,12 @@ #define XT_OSF_TTL_TRUE NF_OSF_TTL_TRUE #define XT_OSF_TTL_NOCHECK NF_OSF_TTL_NOCHECK +#define XT_OSF_TTL_LESS NF_OSF_TTL_LESS -#define XT_OSF_TTL_LESS 1 /* Check if ip TTL is less than fingerprint one */ +#define XT_OSF_FLAGMASK (XT_OSF_GENRE | \ + XT_OSF_TTL | \ + XT_OSF_LOG | \ + XT_OSF_INVERT) #define xt_osf_wc nf_osf_wc #define xt_osf_opt nf_osf_opt diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index dbd7d1fad277..e630aac8a081 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -631,6 +631,13 @@ config NFT_SOCKET This option allows matching for the presence or absence of a corresponding socket and its attributes. +config NFT_OSF + tristate "Netfilter nf_tables passive OS fingerprinting support" + depends on NETFILTER_ADVANCED && NETFILTER_NETLINK + select NF_OSF + help + This option allows matching packets from an specific OS. + if NF_TABLES_NETDEV config NF_DUP_NETDEV diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 44449389e527..d15bd858ecef 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -104,6 +104,7 @@ obj-$(CONFIG_NFT_FIB_INET) += nft_fib_inet.o obj-$(CONFIG_NFT_FIB_NETDEV) += nft_fib_netdev.o obj-$(CONFIG_NF_OSF) += nf_osf.o obj-$(CONFIG_NFT_SOCKET) += nft_socket.o +obj-$(CONFIG_NFT_OSF) += nft_osf.o # nf_tables netdev obj-$(CONFIG_NFT_DUP_NETDEV) += nft_dup_netdev.o diff --git a/net/netfilter/nft_osf.c b/net/netfilter/nft_osf.c new file mode 100644 index 000000000000..30c503f2bf53 --- /dev/null +++ b/net/netfilter/nft_osf.c @@ -0,0 +1,108 @@ +#include +#include + +#define OSF_GENRE_SIZE 32 + +struct nft_osf { + char genre[OSF_GENRE_SIZE]; + __u32 flags; + __u32 loglevel; + __u32 ttl; + __u32 len; +}; + +/* placeholder function WIP */ +static inline bool match_packet(struct nft_osf *priv, struct sk_buff *skb) +{ + return 1; +} + +static const struct nla_policy nft_osf_policy[NFTA_OSF_MAX + 1] = { + [NFTA_OSF_GENRE] = { .type = NLA_STRING, .len = OSF_GENRE_SIZE }, + [NFTA_OSF_FLAGS] = { .type = NLA_U32 }, + [NFTA_OSF_LOGLEVEL] = { .type = NLA_U32 }, + [NFTA_OSF_TTL] = { .type = NLA_U32 }, +}; + +static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + struct nft_osf *priv = nft_expr_priv(expr); + struct sk_buff *skb = pkt->skb; + + if (!match_packet(priv, skb)) + regs->verdict.code = NFT_BREAK; +} + +static int nft_osf_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_osf *priv = nft_expr_priv(expr); + + if (tb[NFTA_OSF_GENRE] == NULL) + return -EINVAL; + nla_strlcpy(priv->genre, tb[NFTA_OSF_GENRE], OSF_GENRE_SIZE); + if (ntohl(nla_get_be32(tb[NFTA_OSF_FLAGS])) & ~NF_OSF_FLAGMASK) + return -EINVAL; + priv->flags = ntohl(nla_get_be32(tb[NFTA_OSF_FLAGS])); + if (ntohl(nla_get_be32(tb[NFTA_OSF_LOGLEVEL])) >= + NF_OSF_LOGLEVEL_ALL_KNOWN) + return -EINVAL; + priv->loglevel = ntohl(nla_get_be32(tb[NFTA_OSF_LOGLEVEL])); + if (ntohl(nla_get_be32(tb[NFTA_OSF_TTL])) >= NF_OSF_TTL_NOCHECK) + return -EINVAL; + priv->ttl = ntohl(nla_get_be32(tb[NFTA_OSF_TTL])); + priv->len = strlen(priv->genre); + return 0; +} + +static int nft_osf_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct nft_osf *priv = nft_expr_priv(expr); + + if (nla_put_string(skb, NFTA_OSF_GENRE, priv->genre) || + nla_put_be32(skb, NFTA_OSF_FLAGS, htonl(priv->flags)) || + nla_put_be32(skb, NFTA_OSF_LOGLEVEL, htonl(priv->loglevel)) || + nla_put_be32(skb, NFTA_OSF_TTL, htonl(priv->ttl))) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + +static struct nft_expr_type nft_osf_type; + +static const struct nft_expr_ops nft_osf_op = { + .eval = nft_osf_eval, + .size = NFT_EXPR_SIZE(sizeof(struct nft_osf)), + .init = nft_osf_init, + .dump = nft_osf_dump, + .type = &nft_osf_type, +}; + +static struct nft_expr_type nft_osf_type __read_mostly = { + .ops = &nft_osf_op, + .name = "osf", + .owner = THIS_MODULE, + .policy = nft_osf_policy, + .maxattr = NFTA_OSF_MAX, +}; + +static int __init nft_osf_module_init(void) +{ + return nft_register_expr(&nft_osf_type); +} + +static void __exit nft_osf_module_exit(void) +{ + return nft_unregister_expr(&nft_osf_type); +} + +module_init(nft_osf_module_init); +module_exit(nft_osf_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Fernando Fernandez "); +MODULE_ALIAS_NFT_EXPR("osf");