[PATCH 5.15 019/230] netfilter: nf_tables: stricter validation of element data

Greg Kroah-Hartman
2022-07-11T09:39:52Z

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

commit 7e6bc1f6cabcd30aba0b11219d8e01b952eacbb6 upstream.

Make sure element data type and length do not mismatch the one specified
by the set declaration.

Fixes: 7d7402642eaf ("netfilter: nf_tables: variable sized set element keys / data")
Reported-by: Hugues ANGUELKOV <hanguelkov@randorisec.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/netfilter/nf_tables_api.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5118,13 +5118,20 @@ static int nft_setelem_parse_data(struct
struct nft_data *data,
struct nlattr *attr)
{
+ u32 dtype;
int err;

err = nft_data_init(ctx, data, NFT_DATA_VALUE_MAXLEN, desc, attr);
if (err < 0)
return err;

- if (desc->type != NFT_DATA_VERDICT && desc->len != set->dlen) {
+ if (set->dtype == NFT_DATA_VERDICT)
+ dtype = NFT_DATA_VERDICT;
+ else
+ dtype = NFT_DATA_VALUE;
+
+ if (dtype != desc->type ||
+ set->dlen != desc->len) {
nft_data_release(data, desc->type);
return -EINVAL;
}