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https://github.com/torvalds/linux
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bab2c80e5a
When pulling the NSH header in nsh_gso_segment, set the mac length
based on the encapsulated packet type.
skb_reset_mac_len computes an offset to the network header, which
here still points to the outer packet:
> skb_reset_network_header(skb);
> [...]
> __skb_pull(skb, nsh_len);
> skb_reset_mac_header(skb); // now mac hdr starts nsh_len == 8B after net hdr
> skb_reset_mac_len(skb); // mac len = net hdr - mac hdr == (u16) -8 == 65528
> [..]
> skb_mac_gso_segment(skb, ..)
Link: http://lkml.kernel.org/r/CAF=yD-KeAcTSOn4AxirAxL8m7QAS8GBBe1w09eziYwvPbbUeYA@mail.gmail.com
Reported-by: syzbot+7b9ed9872dab8c32305d@syzkaller.appspotmail.com
Fixes: c411ed8545 ("nsh: add GSO support")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
155 lines
3.4 KiB
C
155 lines
3.4 KiB
C
/*
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* Network Service Header
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*
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* Copyright (c) 2017 Red Hat, Inc. -- Jiri Benc <jbenc@redhat.com>
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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 version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <net/nsh.h>
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#include <net/tun_proto.h>
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int nsh_push(struct sk_buff *skb, const struct nshhdr *pushed_nh)
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{
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struct nshhdr *nh;
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size_t length = nsh_hdr_len(pushed_nh);
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u8 next_proto;
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if (skb->mac_len) {
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next_proto = TUN_P_ETHERNET;
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} else {
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next_proto = tun_p_from_eth_p(skb->protocol);
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if (!next_proto)
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return -EAFNOSUPPORT;
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}
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/* Add the NSH header */
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if (skb_cow_head(skb, length) < 0)
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return -ENOMEM;
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skb_push(skb, length);
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nh = (struct nshhdr *)(skb->data);
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memcpy(nh, pushed_nh, length);
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nh->np = next_proto;
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skb_postpush_rcsum(skb, nh, length);
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skb->protocol = htons(ETH_P_NSH);
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skb_reset_mac_header(skb);
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skb_reset_network_header(skb);
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skb_reset_mac_len(skb);
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return 0;
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}
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EXPORT_SYMBOL_GPL(nsh_push);
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int nsh_pop(struct sk_buff *skb)
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{
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struct nshhdr *nh;
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size_t length;
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__be16 inner_proto;
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if (!pskb_may_pull(skb, NSH_BASE_HDR_LEN))
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return -ENOMEM;
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nh = (struct nshhdr *)(skb->data);
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length = nsh_hdr_len(nh);
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if (length < NSH_BASE_HDR_LEN)
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return -EINVAL;
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inner_proto = tun_p_to_eth_p(nh->np);
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if (!pskb_may_pull(skb, length))
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return -ENOMEM;
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if (!inner_proto)
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return -EAFNOSUPPORT;
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skb_pull_rcsum(skb, length);
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skb_reset_mac_header(skb);
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skb_reset_network_header(skb);
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skb_reset_mac_len(skb);
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skb->protocol = inner_proto;
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return 0;
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}
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EXPORT_SYMBOL_GPL(nsh_pop);
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static struct sk_buff *nsh_gso_segment(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 nsh_len, mac_len;
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__be16 proto;
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int nhoff;
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skb_reset_network_header(skb);
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nhoff = skb->network_header - skb->mac_header;
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mac_len = skb->mac_len;
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if (unlikely(!pskb_may_pull(skb, NSH_BASE_HDR_LEN)))
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goto out;
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nsh_len = nsh_hdr_len(nsh_hdr(skb));
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if (nsh_len < NSH_BASE_HDR_LEN)
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goto out;
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if (unlikely(!pskb_may_pull(skb, nsh_len)))
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goto out;
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proto = tun_p_to_eth_p(nsh_hdr(skb)->np);
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if (!proto)
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goto out;
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__skb_pull(skb, nsh_len);
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skb_reset_mac_header(skb);
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skb->mac_len = proto == htons(ETH_P_TEB) ? ETH_HLEN : 0;
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skb->protocol = proto;
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features &= NETIF_F_SG;
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segs = skb_mac_gso_segment(skb, features);
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if (IS_ERR_OR_NULL(segs)) {
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skb_gso_error_unwind(skb, htons(ETH_P_NSH), nsh_len,
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skb->network_header - nhoff,
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mac_len);
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goto out;
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}
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for (skb = segs; skb; skb = skb->next) {
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skb->protocol = htons(ETH_P_NSH);
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__skb_push(skb, nsh_len);
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skb_set_mac_header(skb, -nhoff);
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skb->network_header = skb->mac_header + mac_len;
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skb->mac_len = mac_len;
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}
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out:
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return segs;
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}
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static struct packet_offload nsh_packet_offload __read_mostly = {
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.type = htons(ETH_P_NSH),
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.priority = 15,
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.callbacks = {
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.gso_segment = nsh_gso_segment,
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},
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};
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static int __init nsh_init_module(void)
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{
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dev_add_offload(&nsh_packet_offload);
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return 0;
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}
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static void __exit nsh_cleanup_module(void)
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{
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dev_remove_offload(&nsh_packet_offload);
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}
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module_init(nsh_init_module);
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module_exit(nsh_cleanup_module);
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MODULE_AUTHOR("Jiri Benc <jbenc@redhat.com>");
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MODULE_DESCRIPTION("NSH protocol");
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MODULE_LICENSE("GPL v2");
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