From a26c1e49c8e97922edc8d7e23683384729d09f77 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 31 Mar 2020 23:02:59 +0200 Subject: netfilter: nf_tables: do not update stateful expressions if lookup is inverted Initialize set lookup matching element to NULL. Otherwise, the NFT_LOOKUP_F_INV flag reverses the matching logic and it leads to deference an uninitialized pointer to the matching element. Make sure element data area and stateful expression are accessed if there is a matching set element. This patch undoes 24791b9aa1ab ("netfilter: nft_set_bitmap: initialize set element extension in lookups") which is not required anymore. Fixes: 339706bc21c1 ("netfilter: nft_lookup: update element stateful expression") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_lookup.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'net/netfilter/nft_lookup.c') diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c index 1e70359d633c..f1363b8aabba 100644 --- a/net/netfilter/nft_lookup.c +++ b/net/netfilter/nft_lookup.c @@ -29,7 +29,7 @@ void nft_lookup_eval(const struct nft_expr *expr, { const struct nft_lookup *priv = nft_expr_priv(expr); const struct nft_set *set = priv->set; - const struct nft_set_ext *ext; + const struct nft_set_ext *ext = NULL; bool found; found = set->ops->lookup(nft_net(pkt), set, ®s->data[priv->sreg], @@ -39,11 +39,13 @@ void nft_lookup_eval(const struct nft_expr *expr, return; } - if (set->flags & NFT_SET_MAP) - nft_data_copy(®s->data[priv->dreg], - nft_set_ext_data(ext), set->dlen); + if (ext) { + if (set->flags & NFT_SET_MAP) + nft_data_copy(®s->data[priv->dreg], + nft_set_ext_data(ext), set->dlen); - nft_set_elem_update_expr(ext, regs, pkt); + nft_set_elem_update_expr(ext, regs, pkt); + } } static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = { -- cgit v1.2.3-59-g8ed1b