Use of payload expression to match against IPv6 nexthdr field does not
work if extension headers are present. A simple example for that is
matching for fragmented icmpv6 traffic. Instead, generate a 'meta
l4proto' expression which works even if extension headers are present.
For consistency, apply the same change to iptables-nft as well.
No adjustment to reverse path required as the needed bits were added by
commit 6ea7579e6fe24 ("nft: decode meta l4proto") already.
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
iptables/nft-ipv4.c | 3 +--
iptables/nft-ipv6.c | 3 +--
iptables/nft-shared.c | 6 ++++++
iptables/nft-shared.h | 1 +
4 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/iptables/nft-ipv4.c b/iptables/nft-ipv4.c
index 105b1341549fa..2d1bd10e30aaa 100644
--- a/iptables/nft-ipv4.c
+++ b/iptables/nft-ipv4.c
@@ -45,8 +45,7 @@ static int nft_ipv4_add(struct nftnl_rule *r, void *data)
if (cs->fw.ip.proto != 0) {
op = nft_invflags2cmp(cs->fw.ip.invflags, XT_INV_PROTO);
- add_proto(r, offsetof(struct iphdr, protocol), 1,
- cs->fw.ip.proto, op);
+ add_l4proto(r, cs->fw.ip.proto, op);
}
if (cs->fw.ip.src.s_addr != 0) {
diff --git a/iptables/nft-ipv6.c b/iptables/nft-ipv6.c
index dd23557c7e6c0..48a7cefe023bc 100644
--- a/iptables/nft-ipv6.c
+++ b/iptables/nft-ipv6.c
@@ -44,8 +44,7 @@ static int nft_ipv6_add(struct nftnl_rule *r, void *data)
if (cs->fw6.ipv6.proto != 0) {
op = nft_invflags2cmp(cs->fw6.ipv6.invflags, XT_INV_PROTO);
- add_proto(r, offsetof(struct ip6_hdr, ip6_nxt), 1,
- cs->fw6.ipv6.proto, op);
+ add_l4proto(r, cs->fw6.ipv6.proto, op);
}
if (!IN6_IS_ADDR_UNSPECIFIED(&cs->fw6.ipv6.src)) {
diff --git a/iptables/nft-shared.c b/iptables/nft-shared.c
index b31234ee8dfa4..62a57dd5f02b4 100644
--- a/iptables/nft-shared.c
+++ b/iptables/nft-shared.c
@@ -188,6 +188,12 @@ void add_proto(struct nftnl_rule *r, int offset, size_t len,
add_cmp_u8(r, proto, op);
}
+void add_l4proto(struct nftnl_rule *r, uint8_t proto, uint32_t op)
+{
+ add_meta(r, NFT_META_L4PROTO);
+ add_cmp_u8(r, proto, op);
+}
+
bool is_same_interfaces(const char *a_iniface, const char *a_outiface,
unsigned const char *a_iniface_mask,
unsigned const char *a_outiface_mask,
diff --git a/iptables/nft-shared.h b/iptables/nft-shared.h
index 807507845fbaf..59e1062a725bf 100644
--- a/iptables/nft-shared.h
+++ b/iptables/nft-shared.h
@@ -122,6 +122,7 @@ void add_addr(struct nftnl_rule *r, int offset,
void *data, void *mask, size_t len, uint32_t op);
void add_proto(struct nftnl_rule *r, int offset, size_t len,
uint8_t proto, uint32_t op);
+void add_l4proto(struct nftnl_rule *r, uint8_t proto, uint32_t op);
void add_compat(struct nftnl_rule *r, uint32_t proto, bool inv);
bool is_same_interfaces(const char *a_iniface, const char *a_outiface,
--
2.18.0
