From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 66174882B for ; Fri, 10 Mar 2023 15:12:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC473C4339B; Fri, 10 Mar 2023 15:12:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678461149; bh=g+WRA40AXCzQ/MUswcjb2SxNS/EahIusfV1GfShmCZ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TCZsEQ57AWWISg+TyJmu28z//bt2W/4Hjpv/4MjdkfWql02o+fpLVoyWXU0v6uN+J UUNJxGjg6mzdRsxsoTf2qlLbw5BgpI5cbiy5xadzON6/giRI2CWiNZNkLDQDZ650UJ bT5tVtTFbPZEnNBfSlp9iMVa6v9J1j2/nchBPvmU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+f61594de72d6705aea03@syzkaller.appspotmail.com, Florian Westphal , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 5.15 042/136] netfilter: ebtables: fix table blob use-after-free Date: Fri, 10 Mar 2023 14:42:44 +0100 Message-Id: <20230310133708.348313249@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230310133706.811226272@linuxfoundation.org> References: <20230310133706.811226272@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Florian Westphal [ Upstream commit e58a171d35e32e6e8c37cfe0e8a94406732a331f ] We are not allowed to return an error at this point. Looking at the code it looks like ret is always 0 at this point, but its not. t = find_table_lock(net, repl->name, &ret, &ebt_mutex); ... this can return a valid table, with ret != 0. This bug causes update of table->private with the new blob, but then frees the blob right away in the caller. Syzbot report: BUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 Read of size 4 at addr ffffc90005425000 by task kworker/u4:4/74 Workqueue: netns cleanup_net Call Trace: kasan_report+0xbf/0x1f0 mm/kasan/report.c:517 __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613 ... ip(6)tables appears to be ok (ret should be 0 at this point) but make this more obvious. Fixes: c58dd2dd443c ("netfilter: Can't fail and free after table replacement") Reported-by: syzbot+f61594de72d6705aea03@syzkaller.appspotmail.com Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/bridge/netfilter/ebtables.c | 2 +- net/ipv4/netfilter/ip_tables.c | 3 +-- net/ipv6/netfilter/ip6_tables.c | 3 +-- 3 files changed, 3 insertions(+), 5 deletions(-) diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 16774559c52cb..a09b2fc11c80e 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1090,7 +1090,7 @@ static int do_replace_finish(struct net *net, struct ebt_replace *repl, audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries, AUDIT_XT_OP_REPLACE, GFP_KERNEL); - return ret; + return 0; free_unlock: mutex_unlock(&ebt_mutex); diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 13acb687c19ab..91301dc3924a2 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1044,7 +1044,6 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks, struct xt_counters *counters; struct ipt_entry *iter; - ret = 0; counters = xt_counters_alloc(num_counters); if (!counters) { ret = -ENOMEM; @@ -1090,7 +1089,7 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks, net_warn_ratelimited("iptables: counters copy to user failed while replacing table\n"); } vfree(counters); - return ret; + return 0; put_module: module_put(t->me); diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index a579ea14a69b6..7ba68388d2e1f 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -1062,7 +1062,6 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks, struct xt_counters *counters; struct ip6t_entry *iter; - ret = 0; counters = xt_counters_alloc(num_counters); if (!counters) { ret = -ENOMEM; @@ -1108,7 +1107,7 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks, net_warn_ratelimited("ip6tables: counters copy to user failed while replacing table\n"); } vfree(counters); - return ret; + return 0; put_module: module_put(t->me); -- 2.39.2