[PATCH 5.10 42/86] netfilter: nf_tables: disallow jump to implicit chain from set element

Greg Kroah-Hartman
2022-08-29T11:11:21Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit f323ef3a0d49e147365284bc1f02212e617b7f09 ]

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@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/net/netfilter/nf_tables.h | 5 +++++
net/netfilter/nf_tables_api.c | 4 ++++
2 files changed, 9 insertions(+)

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 6c062b2509b9b..e66fee99ed3ea 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -176,10 +176,15 @@ 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,
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index df79ea6004a59..b36728cfc5d81 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4865,6 +4865,7 @@ static int nft_setelem_parse_data(struct nft_ctx *ctx, struct nft_set *set,
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);
}
@@ -8677,6 +8678,9 @@ static int nft_verdict_init(const struct nft_ctx *ctx, struct nft_data *data,
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;
--
2.35.1