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ipvs: Fix panic due to non-linear skb
Receiving a ICMP response to an IPIP packet in a non-linear skb could
cause a kernel panic in __skb_pull.
The problem was introduced in
commit f2edb9f770
("ipvs: implement
passive PMTUD for IPIP packets").
Signed-off-by: Peter Christensen <pch@ordbogen.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
This commit is contained in:
parent
3b084e99a3
commit
f44a5f45f5
@ -1392,15 +1392,19 @@ ip_vs_in_icmp(struct sk_buff *skb, int *related, unsigned int hooknum)
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if (ipip) {
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__be32 info = ic->un.gateway;
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__u8 type = ic->type;
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__u8 code = ic->code;
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/* Update the MTU */
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if (ic->type == ICMP_DEST_UNREACH &&
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ic->code == ICMP_FRAG_NEEDED) {
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struct ip_vs_dest *dest = cp->dest;
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u32 mtu = ntohs(ic->un.frag.mtu);
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__be16 frag_off = cih->frag_off;
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/* Strip outer IP and ICMP, go to IPIP header */
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__skb_pull(skb, ihl + sizeof(_icmph));
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if (pskb_pull(skb, ihl + sizeof(_icmph)) == NULL)
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goto ignore_ipip;
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offset2 -= ihl + sizeof(_icmph);
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skb_reset_network_header(skb);
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IP_VS_DBG(12, "ICMP for IPIP %pI4->%pI4: mtu=%u\n",
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@ -1408,7 +1412,7 @@ ip_vs_in_icmp(struct sk_buff *skb, int *related, unsigned int hooknum)
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ipv4_update_pmtu(skb, dev_net(skb->dev),
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mtu, 0, 0, 0, 0);
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/* Client uses PMTUD? */
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if (!(cih->frag_off & htons(IP_DF)))
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if (!(frag_off & htons(IP_DF)))
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goto ignore_ipip;
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/* Prefer the resulting PMTU */
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if (dest) {
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@ -1427,12 +1431,13 @@ ip_vs_in_icmp(struct sk_buff *skb, int *related, unsigned int hooknum)
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/* Strip outer IP, ICMP and IPIP, go to IP header of
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* original request.
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*/
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__skb_pull(skb, offset2);
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if (pskb_pull(skb, offset2) == NULL)
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goto ignore_ipip;
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skb_reset_network_header(skb);
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IP_VS_DBG(12, "Sending ICMP for %pI4->%pI4: t=%u, c=%u, i=%u\n",
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&ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
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ic->type, ic->code, ntohl(info));
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icmp_send(skb, ic->type, ic->code, info);
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type, code, ntohl(info));
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icmp_send(skb, type, code, info);
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/* ICMP can be shorter but anyways, account it */
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ip_vs_out_stats(cp, skb);
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