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    Subject[PATCH 5.15 24/66] netfilter: nf_tables: sanitize nft_set_desc_concat_parse()
    Date
    From: Pablo Neira Ayuso <pablo@netfilter.org>

    commit fecf31ee395b0295f2d7260aa29946b7605f7c85 upstream.

    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: f3a2181e16f1 ("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>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    net/netfilter/nf_tables_api.c | 17 +++++++++++++----
    1 file changed, 13 insertions(+), 4 deletions(-)

    --- a/net/netfilter/nf_tables_api.c
    +++ b/net/netfilter/nf_tables_api.c
    @@ -4151,6 +4151,9 @@ static int nft_set_desc_concat_parse(con
    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)
    @@ -4160,9 +4163,8 @@ static int nft_set_desc_concat_parse(con
    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;

    @@ -4173,7 +4175,8 @@ static int nft_set_desc_concat(struct nf
    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)
    @@ -4184,6 +4187,12 @@ static int nft_set_desc_concat(struct nf
    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;
    }


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