[PATCH 5.19 0144/1157] netfilter: nf_tables: disallow jump to implicit chain from set element

From: Greg Kroah-Hartman
Date: Mon Aug 15 2022 - 18:30:09 EST


From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>

commit f323ef3a0d49e147365284bc1f02212e617b7f09 upstream.

Extend struct nft_data_desc to add a flag field that specifies
nft_data_init() is being called for set element data.

Use it to disallow jump to implicit chain from set element, only jump
to chain via immediate expression is allowed.

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/netfilter/nf_tables.h | 5 +++++
net/netfilter/nf_tables_api.c | 4 ++++
2 files changed, 9 insertions(+)

--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -206,10 +206,15 @@ struct nft_ctx {
bool report;
};

+enum nft_data_desc_flags {
+ NFT_DATA_DESC_SETELEM = (1 << 0),
+};
+
struct nft_data_desc {
enum nft_data_types type;
unsigned int size;
unsigned int len;
+ unsigned int flags;
};

int nft_data_init(const struct nft_ctx *ctx, struct nft_data *data,
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5226,6 +5226,7 @@ static int nft_setelem_parse_data(struct
desc->type = dtype;
desc->size = NFT_DATA_VALUE_MAXLEN;
desc->len = set->dlen;
+ desc->flags = NFT_DATA_DESC_SETELEM;

return nft_data_init(ctx, data, desc, attr);
}
@@ -9611,6 +9612,9 @@ static int nft_verdict_init(const struct
return PTR_ERR(chain);
if (nft_is_base_chain(chain))
return -EOPNOTSUPP;
+ if (desc->flags & NFT_DATA_DESC_SETELEM &&
+ chain->flags & NFT_CHAIN_BINDING)
+ return -EINVAL;

chain->use++;
data->verdict.chain = chain;