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0e033e04c2
Commit 1e2bd517c1 ("udp6: Fix udp
fragmentation for tunnel traffic.") changed the calculation if
there is enough space to include a fragment header in the skb from a
skb->mac_header dervived one to skb_headroom. Because we already peeled
off the skb to transport_header this is wrong. Change this back to check
if we have enough room before the mac_header.
This fixes a panic Saran Neti reported. He used the tbf scheduler which
skb_gso_segments the skb. The offsets get negative and we panic in memcpy
because the skb was erroneously not expanded at the head.
Reported-by: Saran Neti <Saran.Neti@telus.com>
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/*
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* IPV6 GSO/GRO offload support
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* Linux INET6 implementation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* UDPv6 GSO support
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*/
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#include <linux/skbuff.h>
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#include <net/protocol.h>
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#include <net/ipv6.h>
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#include <net/udp.h>
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#include <net/ip6_checksum.h>
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#include "ip6_offload.h"
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static int udp6_ufo_send_check(struct sk_buff *skb)
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{
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const struct ipv6hdr *ipv6h;
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struct udphdr *uh;
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if (!pskb_may_pull(skb, sizeof(*uh)))
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return -EINVAL;
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if (likely(!skb->encapsulation)) {
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ipv6h = ipv6_hdr(skb);
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uh = udp_hdr(skb);
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uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
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IPPROTO_UDP, 0);
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = offsetof(struct udphdr, check);
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skb->ip_summed = CHECKSUM_PARTIAL;
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}
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return 0;
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}
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static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
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netdev_features_t features)
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{
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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unsigned int mss;
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unsigned int unfrag_ip6hlen, unfrag_len;
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struct frag_hdr *fptr;
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u8 *packet_start, *prevhdr;
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u8 nexthdr;
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u8 frag_hdr_sz = sizeof(struct frag_hdr);
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int offset;
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__wsum csum;
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int tnl_hlen;
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mss = skb_shinfo(skb)->gso_size;
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if (unlikely(skb->len <= mss))
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goto out;
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if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
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/* Packet is from an untrusted source, reset gso_segs. */
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int type = skb_shinfo(skb)->gso_type;
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if (unlikely(type & ~(SKB_GSO_UDP |
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SKB_GSO_DODGY |
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SKB_GSO_UDP_TUNNEL |
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SKB_GSO_GRE |
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SKB_GSO_IPIP |
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SKB_GSO_SIT |
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SKB_GSO_MPLS) ||
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!(type & (SKB_GSO_UDP))))
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goto out;
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skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
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segs = NULL;
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goto out;
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}
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if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
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segs = skb_udp_tunnel_segment(skb, features);
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else {
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/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
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* do checksum of UDP packets sent as multiple IP fragments.
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*/
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offset = skb_checksum_start_offset(skb);
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csum = skb_checksum(skb, offset, skb->len - offset, 0);
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offset += skb->csum_offset;
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*(__sum16 *)(skb->data + offset) = csum_fold(csum);
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skb->ip_summed = CHECKSUM_NONE;
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/* Check if there is enough headroom to insert fragment header. */
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tnl_hlen = skb_tnl_header_len(skb);
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if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
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if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
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goto out;
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}
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/* Find the unfragmentable header and shift it left by frag_hdr_sz
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* bytes to insert fragment header.
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*/
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unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
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nexthdr = *prevhdr;
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*prevhdr = NEXTHDR_FRAGMENT;
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unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
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unfrag_ip6hlen + tnl_hlen;
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packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
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memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);
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SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
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skb->mac_header -= frag_hdr_sz;
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skb->network_header -= frag_hdr_sz;
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fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
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fptr->nexthdr = nexthdr;
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fptr->reserved = 0;
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ipv6_select_ident(fptr, (struct rt6_info *)skb_dst(skb));
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/* Fragment the skb. ipv6 header and the remaining fields of the
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* fragment header are updated in ipv6_gso_segment()
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*/
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segs = skb_segment(skb, features);
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}
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out:
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return segs;
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}
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static const struct net_offload udpv6_offload = {
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.callbacks = {
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.gso_send_check = udp6_ufo_send_check,
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.gso_segment = udp6_ufo_fragment,
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},
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};
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int __init udp_offload_init(void)
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{
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return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
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}
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