@@ -8362,6 +8362,7 @@ static int nf_tables_commit_chain_prepare(struct net *net, struct nft_chain *cha
void *data, *data_boundary;
struct nft_rule_dp *prule;
struct nft_rule *rule;
+ bool reduce;
/* already handled or inactive chain? */
if (chain->blob_next || !nft_is_active_next(net, chain))
@@ -8398,13 +8399,16 @@ static int nf_tables_commit_chain_prepare(struct net *net, struct nft_chain *cha
size = 0;
track.last = nft_expr_last(rule);
+ reduce = true;
nft_rule_for_each_expr(expr, last, rule) {
track.cur = expr;
- if (nft_expr_reduce(&track, expr)) {
+ if (nft_expr_reduce(&track, expr) && reduce) {
+ reduce = false;
expr = track.cur;
continue;
}
+ reduce = false;
if (WARN_ON_ONCE(data + expr->ops->size > data_boundary))
return -ENOMEM;
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 guaranteed to be evaluated always, therefore, keep tracking registers and restrict reduction to first expression. Fixes: b2d306542ff9 ("netfilter: nf_tables: do not reduce read-only expressions") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> --- v2: simplify logic, proposed by Phil Sutter. net/netfilter/nf_tables_api.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)