From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:54522 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934337AbeD0OJF (ORCPT ); Fri, 27 Apr 2018 10:09:05 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Aring , Yotam Gigi , Jamal Hadi Salim , "David S. Miller" Subject: [PATCH 4.14 34/80] net: sched: ife: handle malformed tlv length Date: Fri, 27 Apr 2018 15:58:27 +0200 Message-Id: <20180427135734.704177687@linuxfoundation.org> In-Reply-To: <20180427135732.928644313@linuxfoundation.org> References: <20180427135732.928644313@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Aring [ Upstream commit cc74eddd0ff325d57373cea99f642b787d7f76f5 ] There is currently no handling to check on a invalid tlv length. This patch adds such handling to avoid killing the kernel with a malformed ife packet. Signed-off-by: Alexander Aring Reviewed-by: Yotam Gigi Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/net/ife.h | 3 ++- net/ife/ife.c | 35 +++++++++++++++++++++++++++++++++-- net/sched/act_ife.c | 7 ++++++- 3 files changed, 41 insertions(+), 4 deletions(-) --- a/include/net/ife.h +++ b/include/net/ife.h @@ -12,7 +12,8 @@ void *ife_encode(struct sk_buff *skb, u16 metalen); void *ife_decode(struct sk_buff *skb, u16 *metalen); -void *ife_tlv_meta_decode(void *skbdata, u16 *attrtype, u16 *dlen, u16 *totlen); +void *ife_tlv_meta_decode(void *skbdata, const void *ifehdr_end, u16 *attrtype, + u16 *dlen, u16 *totlen); int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen, const void *dval); --- a/net/ife/ife.c +++ b/net/ife/ife.c @@ -92,12 +92,43 @@ struct meta_tlvhdr { __be16 len; }; +static bool __ife_tlv_meta_valid(const unsigned char *skbdata, + const unsigned char *ifehdr_end) +{ + const struct meta_tlvhdr *tlv; + u16 tlvlen; + + if (unlikely(skbdata + sizeof(*tlv) > ifehdr_end)) + return false; + + tlv = (const struct meta_tlvhdr *)skbdata; + tlvlen = ntohs(tlv->len); + + /* tlv length field is inc header, check on minimum */ + if (tlvlen < NLA_HDRLEN) + return false; + + /* overflow by NLA_ALIGN check */ + if (NLA_ALIGN(tlvlen) < tlvlen) + return false; + + if (unlikely(skbdata + NLA_ALIGN(tlvlen) > ifehdr_end)) + return false; + + return true; +} + /* Caller takes care of presenting data in network order */ -void *ife_tlv_meta_decode(void *skbdata, u16 *attrtype, u16 *dlen, u16 *totlen) +void *ife_tlv_meta_decode(void *skbdata, const void *ifehdr_end, u16 *attrtype, + u16 *dlen, u16 *totlen) { - struct meta_tlvhdr *tlv = (struct meta_tlvhdr *) skbdata; + struct meta_tlvhdr *tlv; + + if (!__ife_tlv_meta_valid(skbdata, ifehdr_end)) + return NULL; + tlv = (struct meta_tlvhdr *)skbdata; *dlen = ntohs(tlv->len) - NLA_HDRLEN; *attrtype = ntohs(tlv->type); --- a/net/sched/act_ife.c +++ b/net/sched/act_ife.c @@ -639,7 +639,12 @@ static int tcf_ife_decode(struct sk_buff u16 mtype; u16 dlen; - curr_data = ife_tlv_meta_decode(tlv_data, &mtype, &dlen, NULL); + curr_data = ife_tlv_meta_decode(tlv_data, ifehdr_end, &mtype, + &dlen, NULL); + if (!curr_data) { + qstats_drop_inc(this_cpu_ptr(ife->common.cpu_qstats)); + return TC_ACT_SHOT; + } if (find_decode_metaid(skb, ife, mtype, dlen, curr_data)) { /* abuse overlimits to count when we receive metadata