This also adds NF_CT_LABELS_MAX_SIZE so it can be re-used
as BUILD_BUG_ON in nft_ct.
At this time, nft doesn't yet support writing to the label area;
when this changes the label->words handling needs to be moved
out of xt_connlabel.c into nf_conntrack_labels.c.
Also removes a useless run-time check: words cannot grow beyond
4 (32 bit) or 2 (64bit) since xt_connlabel enforces a maximum of
128 labels.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
Changes since v1:
- treat 'no label extension area' like 'no labels set [ this
is also what xt_connlabel match does ]
- replace run-time check on label->words length with BUILD_BUG_ON()
include/net/netfilter/nf_conntrack_labels.h | 4 +++-
include/uapi/linux/netfilter/nf_tables.h | 1 +
net/netfilter/nf_conntrack_netlink.c | 5 ++---
net/netfilter/nft_ct.c | 24 ++++++++++++++++++++++++
4 files changed, 30 insertions(+), 4 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack_labels.h b/include/net/netfilter/nf_conntrack_labels.h
index c985695..dec6336 100644
--- a/include/net/netfilter/nf_conntrack_labels.h
+++ b/include/net/netfilter/nf_conntrack_labels.h
@@ -7,6 +7,8 @@
#include <uapi/linux/netfilter/xt_connlabel.h>
+#define NF_CT_LABELS_MAX_SIZE ((XT_CONNLABEL_MAXBIT + 1) / BITS_PER_BYTE)
+
struct nf_conn_labels {
u8 words;
unsigned long bits[];
@@ -29,7 +31,7 @@ static inline struct nf_conn_labels *nf_ct_labels_ext_add(struct nf_conn *ct)
u8 words;
words = ACCESS_ONCE(net->ct.label_words);
- if (words == 0 || WARN_ON_ONCE(words > 8))
+ if (words == 0)
return NULL;
cl_ext = nf_ct_ext_add_length(ct, NF_CT_EXT_LABELS,
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 83c985a..c84c452 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -601,6 +601,7 @@ enum nft_ct_keys {
NFT_CT_PROTOCOL,
NFT_CT_PROTO_SRC,
NFT_CT_PROTO_DST,
+ NFT_CT_LABELS,
};
/**
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index bb322d0..47e9369 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -966,7 +966,6 @@ ctnetlink_parse_help(const struct nlattr *attr, char **helper_name,
return 0;
}
-#define __CTA_LABELS_MAX_LENGTH ((XT_CONNLABEL_MAXBIT + 1) / BITS_PER_BYTE)
static const struct nla_policy ct_nla_policy[CTA_MAX+1] = {
[CTA_TUPLE_ORIG] = { .type = NLA_NESTED },
[CTA_TUPLE_REPLY] = { .type = NLA_NESTED },
@@ -984,9 +983,9 @@ static const struct nla_policy ct_nla_policy[CTA_MAX+1] = {
[CTA_ZONE] = { .type = NLA_U16 },
[CTA_MARK_MASK] = { .type = NLA_U32 },
[CTA_LABELS] = { .type = NLA_BINARY,
- .len = __CTA_LABELS_MAX_LENGTH },
+ .len = NF_CT_LABELS_MAX_SIZE },
[CTA_LABELS_MASK] = { .type = NLA_BINARY,
- .len = __CTA_LABELS_MAX_LENGTH },
+ .len = NF_CT_LABELS_MAX_SIZE },
};
static int
diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 917052e..4ac733f 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -19,6 +19,7 @@
#include <net/netfilter/nf_conntrack_tuple.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_ecache.h>
+#include <net/netfilter/nf_conntrack_labels.h>
struct nft_ct {
enum nft_ct_keys key:8;
@@ -97,6 +98,26 @@ static void nft_ct_get_eval(const struct nft_expr *expr,
goto err;
strncpy((char *)dest->data, helper->name, sizeof(dest->data));
return;
+#ifdef CONFIG_NF_CONNTRACK_LABELS
+ case NFT_CT_LABELS: {
+ struct nf_conn_labels *labels = nf_ct_labels_find(ct);
+ unsigned int size;
+
+ if (!labels) {
+ memset(dest->data, 0, sizeof(dest->data));
+ return;
+ }
+
+ BUILD_BUG_ON(NF_CT_LABELS_MAX_SIZE > sizeof(dest->data));
+ size = labels->words * sizeof(long);
+
+ memcpy(dest->data, labels->bits, size);
+ if (size < sizeof(dest->data))
+ memset(((char *) dest->data) + size, 0,
+ sizeof(dest->data) - size);
+ return;
+ }
+#endif
}
tuple = &ct->tuplehash[priv->dir].tuple;
@@ -221,6 +242,9 @@ static int nft_ct_init_validate_get(const struct nft_expr *expr,
#ifdef CONFIG_NF_CONNTRACK_SECMARK
case NFT_CT_SECMARK:
#endif
+#ifdef CONFIG_NF_CONNTRACK_LABELS
+ case NFT_CT_LABELS:
+#endif
case NFT_CT_EXPIRATION:
case NFT_CT_HELPER:
if (tb[NFTA_CT_DIRECTION] != NULL)
--
1.8.1.5
--
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