From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELsmxu2JTNu4d2yJyF/qCkqiwEW4r9JPP9UiYWozPS/9SwQTxuZkEamIjclSVWPf4KZl/9H9 ARC-Seal: i=1; a=rsa-sha256; t=1521214322; cv=none; d=google.com; s=arc-20160816; b=SzEyQr15kkJe+EAbV5X/WHjjQ01VTUzSsJphMLyE7DuFfdZZKwYRRrXXXKmmpsRSqh wVX1Z7GY4831yUjT5b6XBrkAEx6Bo2tPLCOI/W++rCGJ1/SQrRuvurOxvJbS1HailAhE lBQYKE2XLJLC1IbMIBrisIJx5yKvRTAZtkYHyeFcs+4xu/wlUEJRYKXN4w5+SDgvc5BJ kCQErRkZtcaA9UPRY7ODJv3ZX9/fiO4pXtHHDkTuw68quWfAPjS9s4OKxj/Ga417JdD3 PC3YAbZvp4P+DVi1BAXX3iQNW33odepkslvMvzF0uBahNO24xOJO3BnLhuBhYnyLc/r8 velg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=NpGzpDTXNIxdGl//Qb4u5bO0DLsWsFoB2yUasPMWf5s=; b=nYZ3yx5/zS/ZOgjwonAVJp0hlp6kaTZnGTNI7HSgJ/b3wX6FymswJaqCf5bCuAePlj FZwJh2ZevmxZ7uzpJbpJRCjEaaWIZRqdH1Buyq42cSskpSvFNZP/rTc13fkXld20Fa22 cucD1UkB/cLPQVpToEMyi2dS17GvbKY79XJluQbTcvQqwx0eGOLPbwU30dingUiGLbEY IdfDiR661M2IuZxVDPPNrskGZzy7zOL/66xN/pTyrZQr95gzKvVSQ5XcYU4em8x73eg2 yho9b2FV6kVQv1m/gKV2z1WL8YSkKDLts/LeUcO+nMtBhJArTD5LhNAQC5EQ9WANtCFj xkVA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+e783f671527912cd9403@syzkaller.appspotmail.com, Florian Westphal , Pablo Neira Ayuso Subject: [PATCH 4.9 54/86] netfilter: add back stackpointer size checks Date: Fri, 16 Mar 2018 16:23:17 +0100 Message-Id: <20180316152321.040192570@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180316152317.167709497@linuxfoundation.org> References: <20180316152317.167709497@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1595108579155830036?= X-GMAIL-MSGID: =?utf-8?q?1595108829226032368?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal commit 57ebd808a97d7c5b1e1afb937c2db22beba3c1f8 upstream. The rationale for removing the check is only correct for rulesets generated by ip(6)tables. In iptables, a jump can only occur to a user-defined chain, i.e. because we size the stack based on number of user-defined chains we cannot exceed stack size. However, the underlying binary format has no such restriction, and the validation step only ensures that the jump target is a valid rule start point. IOW, its possible to build a rule blob that has no user-defined chains but does contain a jump. If this happens, no jump stack gets allocated and crash occurs because no jumpstack was allocated. Fixes: 7814b6ec6d0d6 ("netfilter: xtables: don't save/restore jumpstack offset") Reported-by: syzbot+e783f671527912cd9403@syzkaller.appspotmail.com Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/ipv4/netfilter/arp_tables.c | 4 ++++ net/ipv4/netfilter/ip_tables.c | 7 ++++++- net/ipv6/netfilter/ip6_tables.c | 4 ++++ 3 files changed, 14 insertions(+), 1 deletion(-) --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -261,6 +261,10 @@ unsigned int arpt_do_table(struct sk_buf } if (table_base + v != arpt_next_entry(e)) { + if (unlikely(stackidx >= private->stacksize)) { + verdict = NF_DROP; + break; + } jumpstack[stackidx++] = e; } --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -345,8 +345,13 @@ ipt_do_table(struct sk_buff *skb, continue; } if (table_base + v != ipt_next_entry(e) && - !(e->ip.flags & IPT_F_GOTO)) + !(e->ip.flags & IPT_F_GOTO)) { + if (unlikely(stackidx >= private->stacksize)) { + verdict = NF_DROP; + break; + } jumpstack[stackidx++] = e; + } e = get_entry(table_base, v); continue; --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -376,6 +376,10 @@ ip6t_do_table(struct sk_buff *skb, } if (table_base + v != ip6t_next_entry(e) && !(e->ipv6.flags & IP6T_F_GOTO)) { + if (unlikely(stackidx >= private->stacksize)) { + verdict = NF_DROP; + break; + } jumpstack[stackidx++] = e; }