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![Alexander Aring](/assets/img/avatar_default.png)
This patch checks if sk buffer is available to dererence ife header. If not then NULL will returned to signal an malformed ife packet. This avoids to crashing the kernel from outside. Signed-off-by: Alexander Aring <aring@mojatatu.com> Reviewed-by: Yotam Gigi <yotam.gi@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
176 lines
4.3 KiB
C
176 lines
4.3 KiB
C
/*
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* net/ife/ife.c - Inter-FE protocol based on ForCES WG InterFE LFB
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* Copyright (c) 2015 Jamal Hadi Salim <jhs@mojatatu.com>
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* Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
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*
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* Refer to: draft-ietf-forces-interfelfb-03 and netdev01 paper:
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* "Distributing Linux Traffic Control Classifier-Action Subsystem"
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* Authors: Jamal Hadi Salim and Damascene M. Joachimpillai
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/skbuff.h>
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#include <linux/rtnetlink.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <net/net_namespace.h>
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#include <net/netlink.h>
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#include <net/pkt_sched.h>
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#include <linux/etherdevice.h>
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#include <net/ife.h>
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struct ifeheadr {
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__be16 metalen;
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u8 tlv_data[];
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};
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void *ife_encode(struct sk_buff *skb, u16 metalen)
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{
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/* OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
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* where ORIGDATA = original ethernet header ...
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*/
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int hdrm = metalen + IFE_METAHDRLEN;
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int total_push = hdrm + skb->dev->hard_header_len;
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struct ifeheadr *ifehdr;
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struct ethhdr *iethh; /* inner ether header */
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int skboff = 0;
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int err;
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err = skb_cow_head(skb, total_push);
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if (unlikely(err))
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return NULL;
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iethh = (struct ethhdr *) skb->data;
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__skb_push(skb, total_push);
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memcpy(skb->data, iethh, skb->dev->hard_header_len);
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skb_reset_mac_header(skb);
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skboff += skb->dev->hard_header_len;
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/* total metadata length */
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ifehdr = (struct ifeheadr *) (skb->data + skboff);
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metalen += IFE_METAHDRLEN;
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ifehdr->metalen = htons(metalen);
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return ifehdr->tlv_data;
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}
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EXPORT_SYMBOL_GPL(ife_encode);
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void *ife_decode(struct sk_buff *skb, u16 *metalen)
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{
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struct ifeheadr *ifehdr;
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int total_pull;
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u16 ifehdrln;
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if (!pskb_may_pull(skb, skb->dev->hard_header_len + IFE_METAHDRLEN))
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return NULL;
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ifehdr = (struct ifeheadr *) (skb->data + skb->dev->hard_header_len);
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ifehdrln = ntohs(ifehdr->metalen);
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total_pull = skb->dev->hard_header_len + ifehdrln;
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if (unlikely(ifehdrln < 2))
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return NULL;
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if (unlikely(!pskb_may_pull(skb, total_pull)))
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return NULL;
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skb_set_mac_header(skb, total_pull);
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__skb_pull(skb, total_pull);
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*metalen = ifehdrln - IFE_METAHDRLEN;
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return &ifehdr->tlv_data;
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}
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EXPORT_SYMBOL_GPL(ife_decode);
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struct meta_tlvhdr {
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__be16 type;
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__be16 len;
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};
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static bool __ife_tlv_meta_valid(const unsigned char *skbdata,
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const unsigned char *ifehdr_end)
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{
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const struct meta_tlvhdr *tlv;
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u16 tlvlen;
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if (unlikely(skbdata + sizeof(*tlv) > ifehdr_end))
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return false;
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tlv = (const struct meta_tlvhdr *)skbdata;
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tlvlen = ntohs(tlv->len);
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/* tlv length field is inc header, check on minimum */
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if (tlvlen < NLA_HDRLEN)
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return false;
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/* overflow by NLA_ALIGN check */
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if (NLA_ALIGN(tlvlen) < tlvlen)
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return false;
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if (unlikely(skbdata + NLA_ALIGN(tlvlen) > ifehdr_end))
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return false;
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return true;
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}
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/* Caller takes care of presenting data in network order
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*/
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void *ife_tlv_meta_decode(void *skbdata, const void *ifehdr_end, u16 *attrtype,
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u16 *dlen, u16 *totlen)
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{
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struct meta_tlvhdr *tlv;
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if (!__ife_tlv_meta_valid(skbdata, ifehdr_end))
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return NULL;
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tlv = (struct meta_tlvhdr *)skbdata;
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*dlen = ntohs(tlv->len) - NLA_HDRLEN;
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*attrtype = ntohs(tlv->type);
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if (totlen)
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*totlen = nla_total_size(*dlen);
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return skbdata + sizeof(struct meta_tlvhdr);
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}
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EXPORT_SYMBOL_GPL(ife_tlv_meta_decode);
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void *ife_tlv_meta_next(void *skbdata)
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{
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struct meta_tlvhdr *tlv = (struct meta_tlvhdr *) skbdata;
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u16 tlvlen = ntohs(tlv->len);
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tlvlen = NLA_ALIGN(tlvlen);
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return skbdata + tlvlen;
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}
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EXPORT_SYMBOL_GPL(ife_tlv_meta_next);
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/* Caller takes care of presenting data in network order
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*/
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int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen, const void *dval)
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{
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__be32 *tlv = (__be32 *) (skbdata);
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u16 totlen = nla_total_size(dlen); /*alignment + hdr */
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char *dptr = (char *) tlv + NLA_HDRLEN;
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u32 htlv = attrtype << 16 | (dlen + NLA_HDRLEN);
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*tlv = htonl(htlv);
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memset(dptr, 0, totlen - NLA_HDRLEN);
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memcpy(dptr, dval, dlen);
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return totlen;
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}
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EXPORT_SYMBOL_GPL(ife_tlv_meta_encode);
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MODULE_AUTHOR("Jamal Hadi Salim <jhs@mojatatu.com>");
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MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
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MODULE_DESCRIPTION("Inter-FE LFB action");
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MODULE_LICENSE("GPL");
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