summaryrefslogtreecommitdiffstats
path: root/iptables/nft.c
diff options
context:
space:
mode:
authorPhil Sutter <phil@nwl.cc>2019-11-15 10:47:25 +0100
committerPhil Sutter <phil@nwl.cc>2019-11-15 15:45:18 +0100
commit7a373f6683afb799c8387bdec1da6a07e9e55b33 (patch)
tree9ed419fb1b03a4014a9e80402b22399232801f31 /iptables/nft.c
parent7084d0b6c95b11f03b3ae979fe30b6918cb26542 (diff)
nft: Fix -Z for rules with NFTA_RULE_COMPAT
The special nested attribute NFTA_RULE_COMPAT holds information about any present l4proto match (given via '-p' parameter) in input. The match is contained as meta expression as well, but some xtables extensions explicitly check it's value (see e.g. xt_TPROXY). This nested attribute is input only, the information is lost after parsing (and initialization of compat extensions). So in order to feed a rule back to kernel with zeroed counters, the attribute has to be reconstructed based on the rule's expressions. Other code paths are not affected since rule_to_cs() callback will populate respective fields in struct iptables_command_state and 'add' callback (which is the inverse to rule_to_cs()) calls add_compat() in any case. Signed-off-by: Phil Sutter <phil@nwl.cc> Reviewed-by: Florian Westphal <fw@strlen.de> Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'iptables/nft.c')
-rw-r--r--iptables/nft.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/iptables/nft.c b/iptables/nft.c
index 83cf5fb7..599c2f7e 100644
--- a/iptables/nft.c
+++ b/iptables/nft.c
@@ -2897,6 +2897,44 @@ const char *nft_strerror(int err)
return strerror(err);
}
+static int recover_rule_compat(struct nftnl_rule *r)
+{
+ struct nftnl_expr_iter *iter;
+ struct nftnl_expr *e;
+ uint32_t reg;
+ int ret = -1;
+
+ iter = nftnl_expr_iter_create(r);
+ if (!iter)
+ return -1;
+
+next_expr:
+ e = nftnl_expr_iter_next(iter);
+ if (!e)
+ goto out;
+
+ if (strcmp("meta", nftnl_expr_get_str(e, NFTNL_EXPR_NAME)) ||
+ nftnl_expr_get_u32(e, NFTNL_EXPR_META_KEY) != NFT_META_L4PROTO)
+ goto next_expr;
+
+ reg = nftnl_expr_get_u32(e, NFTNL_EXPR_META_DREG);
+
+ e = nftnl_expr_iter_next(iter);
+ if (!e)
+ goto out;
+
+ if (strcmp("cmp", nftnl_expr_get_str(e, NFTNL_EXPR_NAME)) ||
+ reg != nftnl_expr_get_u32(e, NFTNL_EXPR_CMP_SREG))
+ goto next_expr;
+
+ add_compat(r, nftnl_expr_get_u8(e, NFTNL_EXPR_CMP_DATA),
+ nftnl_expr_get_u32(e, NFTNL_EXPR_CMP_OP) == NFT_CMP_NEQ);
+ ret = 0;
+out:
+ nftnl_expr_iter_destroy(iter);
+ return ret;
+}
+
struct chain_zero_data {
struct nft_handle *handle;
bool verbose;
@@ -2961,6 +2999,7 @@ static int __nft_chain_zero_counters(struct nftnl_chain *c, void *data)
* Unset RULE_POSITION for older kernels, we want to replace
* rule based on its handle only.
*/
+ recover_rule_compat(r);
nftnl_rule_unset(r, NFTNL_RULE_POSITION);
if (!batch_rule_add(h, NFT_COMPAT_RULE_REPLACE, r)) {
nftnl_rule_iter_destroy(iter);