[PATCH nft v2] evaluate: don't update cache for anonymous chains

[Florian Westphal <fw@strlen.de>]

Chain lookup needs a name, not a numerical id.
After patch, loading bogon gives following errors:

Error: No symbol type information a b index 1 10.1.26.a

v2: Don't return an error, just make it a no-op (Pablo Neira Ayuso)

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 src/evaluate.c                                            | 7 +++++++
 .../bogons/nft-f/null_deref_on_anon_chain_update_crash    | 8 ++++++++
 2 files changed, 15 insertions(+)
 create mode 100644 tests/shell/testcases/bogons/nft-f/null_deref_on_anon_chain_update_crash

diff --git a/src/evaluate.c b/src/evaluate.c
index a27961193da5..26aa0ef53241 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -5371,6 +5371,13 @@ static int rule_cache_update(struct eval_ctx *ctx, enum cmd_ops op)
 	if (!table)
 		return table_not_found(ctx);
 
+	/* chain is anonymous: no update needed, rules cannot be added
+	 * or removed from anon chains after the chain was committed to
+	 * kernel.
+	 */
+	if (!rule->handle.chain.name)
+		return 0;
+
 	chain = chain_cache_find(table, rule->handle.chain.name);
 	if (!chain)
 		return chain_not_found(ctx);
diff --git a/tests/shell/testcases/bogons/nft-f/null_deref_on_anon_chain_update_crash b/tests/shell/testcases/bogons/nft-f/null_deref_on_anon_chain_update_crash
new file mode 100644
index 000000000000..310486c59ee0
--- /dev/null
+++ b/tests/shell/testcases/bogons/nft-f/null_deref_on_anon_chain_update_crash
@@ -0,0 +1,8 @@
+table ip f {
+        chain c {
+                jump {
+                        accept
+                }
+        }
+}
+a b index 1 10.1.26.a
-- 
2.48.1