1 files changed, 28 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_d_path_check_rdonly_mem.c b/tools/testing/selftests/bpf/progs/test_d_path_check_rdonly_mem.c
new file mode 100644
index 000000000000..27c27cff6a3a
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_d_path_check_rdonly_mem.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Google */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+extern const int bpf_prog_active __ksym;
+
+SEC("fentry/security_inode_getattr")
+int BPF_PROG(d_path_check_rdonly_mem, struct path *path, struct kstat *stat,
+	     __u32 request_mask, unsigned int query_flags)
+{
+	void *active;
+	__u32 cpu;
+
+	cpu = bpf_get_smp_processor_id();
+	active = (void *)bpf_per_cpu_ptr(&bpf_prog_active, cpu);
+	if (active) {
+		/* FAIL here! 'active' points to readonly memory. bpf helpers
+		 * that update its arguments can not write into it.
+		 */
+		bpf_d_path(path, active, sizeof(int));
+	}
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";