From 9e539c5b6d9c5b996e45105921ee9dd955c0f535 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 18 May 2022 14:51:34 +0200 Subject: netfilter: nf_tables: disable expression reduction infra Either userspace or kernelspace need to pre-fetch keys inconditionally before comparisons for this to work. Otherwise, register tracking data is misleading and it might result in reducing expressions which are not yet registers. First expression is also guaranteed to be evaluated always, however, certain expressions break before writing data to registers, before comparing the data, leaving the register in undetermined state. This patch disables this infrastructure by now. Fixes: b2d306542ff9 ("netfilter: nf_tables: do not reduce read-only expressions") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_api.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 16c3a39689f4..a096b9fbbbdf 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -8342,16 +8342,7 @@ EXPORT_SYMBOL_GPL(nf_tables_trans_destroy_flush_work); static bool nft_expr_reduce(struct nft_regs_track *track, const struct nft_expr *expr) { - if (!expr->ops->reduce) { - pr_warn_once("missing reduce for expression %s ", - expr->ops->type->name); - return false; - } - - if (nft_reduce_is_readonly(expr)) - return false; - - return expr->ops->reduce(track, expr); + return false; } static int nf_tables_commit_chain_prepare(struct net *net, struct nft_chain *chain) -- cgit