From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9B969C47409 for ; Wed, 8 Jan 2020 23:17:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B1D3206DB for ; Wed, 8 Jan 2020 23:17:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727455AbgAHXRX (ORCPT ); Wed, 8 Jan 2020 18:17:23 -0500 Received: from correo.us.es ([193.147.175.20]:43146 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726721AbgAHXRX (ORCPT ); Wed, 8 Jan 2020 18:17:23 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 0586CFF9A3 for ; Thu, 9 Jan 2020 00:17:21 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id EBAE3DA715 for ; Thu, 9 Jan 2020 00:17:20 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id E11AFDA701; Thu, 9 Jan 2020 00:17:20 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id ACE9ADA701; Thu, 9 Jan 2020 00:17:18 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Thu, 09 Jan 2020 00:17:18 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from salvia.here (unknown [90.77.255.23]) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPA id 86526426CCB9; Thu, 9 Jan 2020 00:17:18 +0100 (CET) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org Subject: [PATCH 1/9] netfilter: arp_tables: init netns pointer in xt_tgchk_param struct Date: Thu, 9 Jan 2020 00:17:05 +0100 Message-Id: <20200108231713.100458-2-pablo@netfilter.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20200108231713.100458-1-pablo@netfilter.org> References: <20200108231713.100458-1-pablo@netfilter.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Florian Westphal We get crash when the targets checkentry function tries to make use of the network namespace pointer for arptables. When the net pointer got added back in 2010, only ip/ip6/ebtables were changed to initialize it, so arptables has this set to NULL. This isn't a problem for normal arptables because no existing arptables target has a checkentry function that makes use of par->net. However, direct users of the setsockopt interface can provide any target they want as long as its registered for ARP or UNPSEC protocols. syzkaller managed to send a semi-valid arptables rule for RATEEST target which is enough to trigger NULL deref: kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN RIP: xt_rateest_tg_checkentry+0x11d/0xb40 net/netfilter/xt_RATEEST.c:109 [..] xt_check_target+0x283/0x690 net/netfilter/x_tables.c:1019 check_target net/ipv4/netfilter/arp_tables.c:399 [inline] find_check_entry net/ipv4/netfilter/arp_tables.c:422 [inline] translate_table+0x1005/0x1d70 net/ipv4/netfilter/arp_tables.c:572 do_replace net/ipv4/netfilter/arp_tables.c:977 [inline] do_arpt_set_ctl+0x310/0x640 net/ipv4/netfilter/arp_tables.c:1456 Fixes: add67461240c1d ("netfilter: add struct net * to target parameters") Reported-by: syzbot+d7358a458d8a81aee898@syzkaller.appspotmail.com Signed-off-by: Florian Westphal Acked-by: Cong Wang Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/arp_tables.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 214154b47d56..069f72edb264 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -384,10 +384,11 @@ next: ; return 1; } -static inline int check_target(struct arpt_entry *e, const char *name) +static int check_target(struct arpt_entry *e, struct net *net, const char *name) { struct xt_entry_target *t = arpt_get_target(e); struct xt_tgchk_param par = { + .net = net, .table = name, .entryinfo = e, .target = t->u.kernel.target, @@ -399,8 +400,9 @@ static inline int check_target(struct arpt_entry *e, const char *name) return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); } -static inline int -find_check_entry(struct arpt_entry *e, const char *name, unsigned int size, +static int +find_check_entry(struct arpt_entry *e, struct net *net, const char *name, + unsigned int size, struct xt_percpu_counter_alloc_state *alloc_state) { struct xt_entry_target *t; @@ -419,7 +421,7 @@ find_check_entry(struct arpt_entry *e, const char *name, unsigned int size, } t->u.kernel.target = target; - ret = check_target(e, name); + ret = check_target(e, net, name); if (ret) goto err; return 0; @@ -512,7 +514,9 @@ static inline void cleanup_entry(struct arpt_entry *e) /* Checks and translates the user-supplied table segment (held in * newinfo). */ -static int translate_table(struct xt_table_info *newinfo, void *entry0, +static int translate_table(struct net *net, + struct xt_table_info *newinfo, + void *entry0, const struct arpt_replace *repl) { struct xt_percpu_counter_alloc_state alloc_state = { 0 }; @@ -569,7 +573,7 @@ static int translate_table(struct xt_table_info *newinfo, void *entry0, /* Finally, each sanity check must pass */ i = 0; xt_entry_foreach(iter, entry0, newinfo->size) { - ret = find_check_entry(iter, repl->name, repl->size, + ret = find_check_entry(iter, net, repl->name, repl->size, &alloc_state); if (ret != 0) break; @@ -974,7 +978,7 @@ static int do_replace(struct net *net, const void __user *user, goto free_newinfo; } - ret = translate_table(newinfo, loc_cpu_entry, &tmp); + ret = translate_table(net, newinfo, loc_cpu_entry, &tmp); if (ret != 0) goto free_newinfo; @@ -1149,7 +1153,8 @@ compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr, } } -static int translate_compat_table(struct xt_table_info **pinfo, +static int translate_compat_table(struct net *net, + struct xt_table_info **pinfo, void **pentry0, const struct compat_arpt_replace *compatr) { @@ -1217,7 +1222,7 @@ static int translate_compat_table(struct xt_table_info **pinfo, repl.num_counters = 0; repl.counters = NULL; repl.size = newinfo->size; - ret = translate_table(newinfo, entry1, &repl); + ret = translate_table(net, newinfo, entry1, &repl); if (ret) goto free_newinfo; @@ -1270,7 +1275,7 @@ static int compat_do_replace(struct net *net, void __user *user, goto free_newinfo; } - ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp); + ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp); if (ret != 0) goto free_newinfo; @@ -1546,7 +1551,7 @@ int arpt_register_table(struct net *net, loc_cpu_entry = newinfo->entries; memcpy(loc_cpu_entry, repl->entries, repl->size); - ret = translate_table(newinfo, loc_cpu_entry, repl); + ret = translate_table(net, newinfo, loc_cpu_entry, repl); if (ret != 0) goto out_free; -- 2.11.0