From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELtXry0WZwBgOkdyPGSvJSyYgrINXfNJQ7OJx1HS/6iQjXXFKczXL5lEchIJgKH0C7ObVfbD ARC-Seal: i=1; a=rsa-sha256; t=1520955155; cv=none; d=google.com; s=arc-20160816; b=lLRoxAbQ5JD5tpigzLJbdgBp7V9KRkuZRGTHQI1oIixC6lgarUIcwxOKuUfmAj4yQK KkpPC4ha36xEBbiewWe9OhiSkNK3Wr29zlVk39hmDOwNCIG+niQXQ4FDT9ltMJxNO2eU 42fCjRZjEMkCQmzvhns2hlmRGpuK2lzW0euJbEEsFJ5+NCgvOX0fvDqNtb8/zVJKcPX3 8stsWmP2X2T5xfry6jGIkti4LTwNZ0v/tPLkUBRe9FNBjPVxpIzOhZPrh4kah2sJDfK/ LLHjJfinPfmuKeN1yqQk9BgQrMVm80/4HTGruRgbeGix5+lTraqUWJnHwiL4FTBBSAh7 8tLw== 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=wrUxnTjaeC6p171pIaNuRcLqVA8GmhqktdvQjpevRWc=; b=nRteLWlonimkQK+g33HyimpjyuZpI3djAMft4SBgfT8a9ISX6H5f/VPivf8YH29SnK v/FlkVA8CGDAbdM/PpiX+vl8iNeXQhF8YRhhx0dyqc6jaKFAFtQ3gdhmbNe3y88n+CE6 bkQEGsTueFa1D3zSmIZI1sQ/N059tNtMem4dsRjjcH2HIpG3tvPJItyBfwfiaSsjzC4n GrM0kigUFhE7qPYrN1QIsb2MVMAIYXlJEpb2FW+gJFp+cx/eNUs3kkI4CIuBhHIIe/gS jwMQwYGDGeFMXqrYNqpuIY9C+YO6QKSl/vRGjJcIB0O2L/vHyf/vOjJEf7i+0nHYz7FL ZPpg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 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 90.92.71.90 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 4.15 108/146] netfilter: add back stackpointer size checks Date: Tue, 13 Mar 2018 16:24:35 +0100 Message-Id: <20180313152328.753314673@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180313152320.439085687@linuxfoundation.org> References: <20180313152320.439085687@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?1594837073339627575?= X-GMAIL-MSGID: =?utf-8?q?1594837073339627575?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-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 @@ -257,6 +257,10 @@ 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 @@ -335,8 +335,13 @@ 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 @@ -357,6 +357,10 @@ 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; }