evaluate: remove table from cache on delete table

The following ruleset crashes nft if loaded twice, via nft -ef:

 add table inet filter
 delete table inet filter

 table inet filter {
        chain input {
                type filter hook input priority filter; policy drop;
                iifname { "eth0" } counter accept
        }
 }

If the table contains anonymous sets, such as __set0, then delete + add
table might result in nft reusing the existing stale __set0 in the cache.
The problem is that nft gets confused and it reuses the existing stale
__set0 instead of the new anonymous set __set0 with the same name.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/evaluate.c b/src/evaluate.c
index 26d73959..a84e9609 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -4172,6 +4172,18 @@ static int cmd_evaluate_add(struct eval_ctx *ctx, struct cmd *cmd)
 	}
 }
 
+static void table_del_cache(struct eval_ctx *ctx, struct cmd *cmd)
+{
+	struct table *table;
+
+	table = table_lookup(&cmd->handle, &ctx->nft->cache);
+	if (!table)
+		return;
+
+	list_del(&table->list);
+	table_free(table);
+}
+
 static int cmd_evaluate_delete(struct eval_ctx *ctx, struct cmd *cmd)
 {
 	switch (cmd->obj) {
@@ -4180,7 +4192,10 @@ static int cmd_evaluate_delete(struct eval_ctx *ctx, struct cmd *cmd)
 	case CMD_OBJ_SET:
 	case CMD_OBJ_RULE:
 	case CMD_OBJ_CHAIN:
+		return 0;
 	case CMD_OBJ_TABLE:
+		table_del_cache(ctx, cmd);
+		return 0;
 	case CMD_OBJ_FLOWTABLE:
 	case CMD_OBJ_COUNTER:
 	case CMD_OBJ_QUOTA: