From e582615ad33dbd39623084a02e95567b116e1eea Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 15 Jun 2016 06:24:00 -0700 Subject: gre: fix error handler MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Tom Herbert Cc: Maciej Żenczykowski Cc: Jiri Benc Signed-off-by: David S. Miller --- net/ipv4/gre_demux.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'net/ipv4/gre_demux.c') 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); -- cgit v1.2.3