From: Eric Dumazet <eduma...@google.com>
1) gre_parse_header() can be called from gre_err()
At this point transport header points to ICMP header, not the inner
header.
2) We can not really change transport header as ipgre_err() will later
assume transport header still points to ICMP header (using icmp_hdr())
3) pskb_may_pull() logic in gre_parse_header() really works
if we are interested at zone pointed by skb->data
4) As Jiri explained in commit b7f8fe251e46 ("gre: do not pull header in
ICMP error processing") we should not pull headers in error handler.
So this fix :
A) changes gre_parse_header() to use skb->data instead of
skb_transport_header()
B) Adds a nhs parameter to gre_parse_header() so that we can skip the
not pulled IP header from error path.
This offset is 0 for normal receive path.
C) remove obsolete IPV6 includes
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Tom Herbert <t...@herbertland.com>
Cc: Maciej Żenczykowski <m...@google.com>
Cc: Jiri Benc <jb...@redhat.com>
---
include/net/gre.h | 2 +-
net/ipv4/gre_demux.c | 10 +++++-----
net/ipv4/ip_gre.c | 12 ++++--------
net/ipv6/ip6_gre.c | 2 +-
4 files changed, 11 insertions(+), 15 deletions(-)
diff --git a/include/net/gre.h b/include/net/gre.h
index 5dce30a6abe3..7a54a31d1d4c 100644
--- a/include/net/gre.h
+++ b/include/net/gre.h
@@ -26,7 +26,7 @@ int gre_del_protocol(const struct gre_protocol *proto, u8
version);
struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
u8 name_assign_type);
int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
- bool *csum_err, __be16 proto);
+ bool *csum_err, __be16 proto, int nhs);
static inline int gre_calc_hlen(__be16 o_flags)
{
diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
index 4c39f4fd332a..de1d119a4497 100644
--- a/net/ipv4/gre_demux.c
+++ b/net/ipv4/gre_demux.c
@@ -62,26 +62,26 @@ EXPORT_SYMBOL_GPL(gre_del_protocol);
/* Fills in tpi and returns header length to be pulled. */
int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
- bool *csum_err, __be16 proto)
+ bool *csum_err, __be16 proto, int nhs)
{
const struct gre_base_hdr *greh;
__be32 *options;
int hdr_len;
- if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
+ if (unlikely(!pskb_may_pull(skb, nhs + sizeof(struct gre_base_hdr))))
return -EINVAL;
- greh = (struct gre_base_hdr *)skb_transport_header(skb);
+ greh = (struct gre_base_hdr *)(skb->data + nhs);
if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
return -EINVAL;
tpi->flags = gre_flags_to_tnl_flags(greh->flags);
hdr_len = gre_calc_hlen(tpi->flags);
- if (!pskb_may_pull(skb, hdr_len))
+ if (!pskb_may_pull(skb, nhs + hdr_len))
return -EINVAL;
- greh = (struct gre_base_hdr *)skb_transport_header(skb);
+ greh = (struct gre_base_hdr *)(skb->data + nhs);
tpi->proto = greh->protocol;
options = (__be32 *)(greh + 1);
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 07c5cf1838d8..1d000af7f561 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -49,12 +49,6 @@
#include <net/gre.h>
#include <net/dst_metadata.h>
-#if IS_ENABLED(CONFIG_IPV6)
-#include <net/ipv6.h>
-#include <net/ip6_fib.h>
-#include <net/ip6_route.h>
-#endif
-
/*
Problems & solutions
--------------------
@@ -217,12 +211,14 @@ static void gre_err(struct sk_buff *skb, u32 info)
* by themselves???
*/
+ const struct iphdr *iph = (struct iphdr *)skb->data;
const int type = icmp_hdr(skb)->type;
const int code = icmp_hdr(skb)->code;
struct tnl_ptk_info tpi;
bool csum_err = false;
- if (gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP)) < 0) {
+ if (gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP),
+ iph->ihl * 4) < 0) {
if (!csum_err) /* ignore csum errors. */
return;
}
@@ -338,7 +334,7 @@ static int gre_rcv(struct sk_buff *skb)
}
#endif
- hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP));
+ hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP), 0);
if (hdr_len < 0)
goto drop;
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index fdc9de276ab1..776d145113e1 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -468,7 +468,7 @@ static int gre_rcv(struct sk_buff *skb)
bool csum_err = false;
int hdr_len;
- hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IPV6));
+ hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IPV6), 0);
if (hdr_len < 0)
goto drop;
