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gre: do not pull header in ICMP error processing

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[ Upstream commit b7f8fe251e4609e2a437bd2c2dea01e61db6849c ]

iptunnel_pull_header expects that IP header was already pulled; with this
expectation, it pulls the tunnel header. This is not true in gre_err.
Furthermore, ipv4_update_pmtu and ipv4_redirect expect that skb->data points
to the IP header.

We cannot pull the tunnel header in this path. It's just a matter of not
calling iptunnel_pull_header - we don't need any of its effects.

Fixes: bda7bb463436 ("gre: Allow multiple protocol listener for gre protocol.")
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Benc 2016-04-29 23:31:32 +02:00 committed by Greg Kroah-Hartman
parent 390d4b3e0d
commit c985780791
1 changed files with 8 additions and 3 deletions
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11
net/ipv4/ip_gre.c
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@ -180,6 +180,7 @@ static __be16 tnl_flags_to_gre_flags(__be16 tflags)
return flags;
}
/* Fills in tpi and returns header length to be pulled. */
static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
bool *csum_err)
{
@ -239,7 +240,7 @@ static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
return -EINVAL;
}
}
return iptunnel_pull_header(skb, hdr_len, tpi->proto);
return hdr_len;
}
static void ipgre_err(struct sk_buff *skb, u32 info,
@ -342,7 +343,7 @@ static void gre_err(struct sk_buff *skb, u32 info)
struct tnl_ptk_info tpi;
bool csum_err = false;
if (parse_gre_header(skb, &tpi, &csum_err)) {
if (parse_gre_header(skb, &tpi, &csum_err) < 0) {
if (!csum_err) /* ignore csum errors. */
return;
}
@ -420,6 +421,7 @@ static int gre_rcv(struct sk_buff *skb)
{
struct tnl_ptk_info tpi;
bool csum_err = false;
int hdr_len;
#ifdef CONFIG_NET_IPGRE_BROADCAST
if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {
@ -429,7 +431,10 @@ static int gre_rcv(struct sk_buff *skb)
}
#endif
if (parse_gre_header(skb, &tpi, &csum_err) < 0)
hdr_len = parse_gre_header(skb, &tpi, &csum_err);
if (hdr_len < 0)
goto drop;
if (iptunnel_pull_header(skb, hdr_len, tpi.proto) < 0)
goto drop;
if (ipgre_rcv(skb, &tpi) == PACKET_RCVD)