From e582615ad33dbd39623084a02e95567b116e1eea Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 15 Jun 2016 06:24:00 -0700 Subject: [PATCH] gre: fix error handler MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 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 --- 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 #include -#if IS_ENABLED(CONFIG_IPV6) -#include -#include -#include -#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; -- 2.39.5