From: Jorge Boncompte Date: Thu, 3 May 2007 01:14:27 +0000 (+0200) Subject: [PATCH] {ip, nf}_nat_proto_gre: do not modify/corrupt GREv0 packets through NAT X-Git-Tag: v2.6.20.14~28 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=26bba2674d09ceccc41bc34c4831fdaaa2ba5f66;p=karo-tx-linux.git [PATCH] {ip, nf}_nat_proto_gre: do not modify/corrupt GREv0 packets through NAT While porting some changes of the 2.6.21-rc7 pptp/proto_gre conntrack and nat modules to a 2.4.32 kernel I noticed that the gre_key function returns a wrong pointer to the GRE key of a version 0 packet thus corrupting the packet payload. The intended behaviour for GREv0 packets is to act like nf_conntrack_proto_generic/nf_nat_proto_unknown so I have ripped the offending functions (not used anymore) and modified the nf_nat_proto_gre modules to not touch version 0 (non PPTP) packets. Signed-off-by: Jorge Boncompte Signed-off-by: Patrick McHardy Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- diff --git a/include/linux/netfilter/nf_conntrack_proto_gre.h b/include/linux/netfilter/nf_conntrack_proto_gre.h index 4e6bbce04ff8..535e4219d2bb 100644 --- a/include/linux/netfilter/nf_conntrack_proto_gre.h +++ b/include/linux/netfilter/nf_conntrack_proto_gre.h @@ -87,24 +87,6 @@ int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir, /* delete keymap entries */ void nf_ct_gre_keymap_destroy(struct nf_conn *ct); -/* get pointer to gre key, if present */ -static inline __be32 *gre_key(struct gre_hdr *greh) -{ - if (!greh->key) - return NULL; - if (greh->csum || greh->routing) - return (__be32 *)(greh+sizeof(*greh)+4); - return (__be32 *)(greh+sizeof(*greh)); -} - -/* get pointer ot gre csum, if present */ -static inline __sum16 *gre_csum(struct gre_hdr *greh) -{ - if (!greh->csum) - return NULL; - return (__sum16 *)(greh+sizeof(*greh)); -} - extern void nf_ct_gre_keymap_flush(void); extern void nf_nat_need_gre(void); diff --git a/include/linux/netfilter_ipv4/ip_conntrack_proto_gre.h b/include/linux/netfilter_ipv4/ip_conntrack_proto_gre.h index e371e0fc1672..d0f36f5022c3 100644 --- a/include/linux/netfilter_ipv4/ip_conntrack_proto_gre.h +++ b/include/linux/netfilter_ipv4/ip_conntrack_proto_gre.h @@ -90,25 +90,6 @@ int ip_ct_gre_keymap_add(struct ip_conntrack *ct, /* delete keymap entries */ void ip_ct_gre_keymap_destroy(struct ip_conntrack *ct); - -/* get pointer to gre key, if present */ -static inline __be32 *gre_key(struct gre_hdr *greh) -{ - if (!greh->key) - return NULL; - if (greh->csum || greh->routing) - return (__be32 *) (greh+sizeof(*greh)+4); - return (__be32 *) (greh+sizeof(*greh)); -} - -/* get pointer ot gre csum, if present */ -static inline __sum16 *gre_csum(struct gre_hdr *greh) -{ - if (!greh->csum) - return NULL; - return (__sum16 *) (greh+sizeof(*greh)); -} - #endif /* __KERNEL__ */ #endif /* _CONNTRACK_PROTO_GRE_H */ diff --git a/net/ipv4/netfilter/ip_nat_proto_gre.c b/net/ipv4/netfilter/ip_nat_proto_gre.c index 95810202d849..e3146a356f46 100644 --- a/net/ipv4/netfilter/ip_nat_proto_gre.c +++ b/net/ipv4/netfilter/ip_nat_proto_gre.c @@ -70,6 +70,11 @@ gre_unique_tuple(struct ip_conntrack_tuple *tuple, __be16 *keyptr; unsigned int min, i, range_size; + /* If there is no master conntrack we are not PPTP, + do not change tuples */ + if (!conntrack->master) + return 0; + if (maniptype == IP_NAT_MANIP_SRC) keyptr = &tuple->src.u.gre.key; else @@ -122,18 +127,9 @@ gre_manip_pkt(struct sk_buff **pskb, if (maniptype == IP_NAT_MANIP_DST) { /* key manipulation is always dest */ switch (greh->version) { - case 0: - if (!greh->key) { - DEBUGP("can't nat GRE w/o key\n"); - break; - } - if (greh->csum) { - /* FIXME: Never tested this code... */ - nf_proto_csum_replace4(gre_csum(greh), *pskb, - *(gre_key(greh)), - tuple->dst.u.gre.key, 0); - } - *(gre_key(greh)) = tuple->dst.u.gre.key; + case GRE_VERSION_1701: + /* We do not currently NAT any GREv0 packets. + * Try to behave like "ip_nat_proto_unknown" */ break; case GRE_VERSION_PPTP: DEBUGP("call_id -> 0x%04x\n", diff --git a/net/ipv4/netfilter/nf_nat_proto_gre.c b/net/ipv4/netfilter/nf_nat_proto_gre.c index e5a34c17d927..ca3ff8480f5e 100644 --- a/net/ipv4/netfilter/nf_nat_proto_gre.c +++ b/net/ipv4/netfilter/nf_nat_proto_gre.c @@ -72,6 +72,11 @@ gre_unique_tuple(struct nf_conntrack_tuple *tuple, __be16 *keyptr; unsigned int min, i, range_size; + /* If there is no master conntrack we are not PPTP, + do not change tuples */ + if (!conntrack->master) + return 0; + if (maniptype == IP_NAT_MANIP_SRC) keyptr = &tuple->src.u.gre.key; else @@ -122,18 +127,9 @@ gre_manip_pkt(struct sk_buff **pskb, unsigned int iphdroff, if (maniptype != IP_NAT_MANIP_DST) return 1; switch (greh->version) { - case 0: - if (!greh->key) { - DEBUGP("can't nat GRE w/o key\n"); - break; - } - if (greh->csum) { - /* FIXME: Never tested this code... */ - nf_proto_csum_replace4(gre_csum(greh), *pskb, - *(gre_key(greh)), - tuple->dst.u.gre.key, 0); - } - *(gre_key(greh)) = tuple->dst.u.gre.key; + case GRE_VERSION_1701: + /* We do not currently NAT any GREv0 packets. + * Try to behave like "nf_nat_proto_unknown" */ break; case GRE_VERSION_PPTP: DEBUGP("call_id -> 0x%04x\n", ntohs(tuple->dst.u.gre.key));