[PATCH RFC v2 3/4] selftests/bpf: Add negative test for sockmap update from non-sockmap iter

[Michal Luczaj <mhal@rbox.co>]

Iterator-context sockmap updates are now restricted to iter/sockmap. Add a
test that attempts an update from iter/unix and expects it to fail.

Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 .../testing/selftests/bpf/progs/verifier_sockmap_mutate.c  | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/verifier_sockmap_mutate.c b/tools/testing/selftests/bpf/progs/verifier_sockmap_mutate.c
index 20332a731d4e..1516fe1524bb 100644
--- a/tools/testing/selftests/bpf/progs/verifier_sockmap_mutate.c
+++ b/tools/testing/selftests/bpf/progs/verifier_sockmap_mutate.c
@@ -19,6 +19,12 @@ struct bpf_iter__sockmap {
 	};
 } __attribute__((preserve_access_index));
 
+struct bpf_iter__unix {
+	union {
+		struct sock *unix_sk;
+	};
+} __attribute__((preserve_access_index));
+
 struct {
 	__uint(type, BPF_MAP_TYPE_SOCKHASH);
 	__uint(max_entries, 1);
@@ -113,6 +119,14 @@ int test_trace_iter(struct bpf_iter__sockmap *ctx)
 	return 0;
 }
 
+SEC("iter/unix")
+__failure __msg("cannot update sockmap in this context")
+int test_trace_iter_unix(struct bpf_iter__unix *ctx)
+{
+	test_sockmap_mutate(ctx->unix_sk);
+	return 0;
+}
+
 SEC("raw_tp/kfree")
 __failure __msg("cannot update sockmap in this context")
 int test_raw_tp_delete(const void *ctx __always_unused)

-- 
2.56.0