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: c1894f2477ec ("netfilter: nf_tables: Support for sets with multiple ranged fields")
Reported-by: <zhangziming.zzm@antgroup.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index f4f1d0a2da43c0bbbacd8d8552be10b8c07faf87..dcefb5f36b3af9d53e5f99b7083222ad703734b7 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -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;
 }