Commit fecf31ee authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso
Browse files

netfilter: nf_tables: sanitize nft_set_desc_concat_parse() 



Add several sanity checks for nft_set_desc_concat_parse():

- validate desc->field_count not larger than desc->field_len array.
- field length cannot be larger than desc->field_len (ie. U8_MAX)
- total length of the concatenation cannot be larger than register array.

Joint work with Florian Westphal.

Fixes: f3a2181e ("netfilter: nf_tables: Support for sets with multiple ranged fields")
Reported-by: default avatar <zhangziming.zzm@antgroup.com>
Reviewed-by: default avatarStefano Brivio <sbrivio@redhat.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 09e545f7

net/netfilter/nf_tables_api.c

+13 −4
Original line number Diff line number Diff line
@@ -4246,6 +4246,9 @@ static int nft_set_desc_concat_parse(const struct nlattr *attr, 
	u32 len;

	int err;



	if (desc->field_count >= ARRAY_SIZE(desc->field_len))

		return -E2BIG;



	err = nla_parse_nested_deprecated(tb, NFTA_SET_FIELD_MAX, attr,

					  nft_concat_policy, NULL);

	if (err < 0)
@@ -4255,9 +4258,8 @@ static int nft_set_desc_concat_parse(const struct nlattr *attr, 
		return -EINVAL;



	len = ntohl(nla_get_be32(tb[NFTA_SET_FIELD_LEN]));



	if (len * BITS_PER_BYTE / 32 > NFT_REG32_COUNT)

		return -E2BIG;

	if (!len || len > U8_MAX)

		return -EINVAL;



	desc->field_len[desc->field_count++] = len;
@@ -4268,7 +4270,8 @@ static int nft_set_desc_concat(struct nft_set_desc *desc, 
			       const struct nlattr *nla)

{

	struct nlattr *attr;

	int rem, err;

	u32 num_regs = 0;

	int rem, err, i;



	nla_for_each_nested(attr, nla, rem) {

		if (nla_type(attr) != NFTA_LIST_ELEM)
@@ -4279,6 +4282,12 @@ static int nft_set_desc_concat(struct nft_set_desc *desc, 
			return err;

	}



	for (i = 0; i < desc->field_count; i++)

		num_regs += DIV_ROUND_UP(desc->field_len[i], sizeof(u32));



	if (num_regs > NFT_REG32_COUNT)

		return -E2BIG;



	return 0;

}