1 files changed, 48 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_fsverity.c b/tools/testing/selftests/bpf/progs/test_fsverity.c
new file mode 100644
index 000000000000..9e0f73e8189c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_fsverity.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_kfuncs.h"
+
+char _license[] SEC("license") = "GPL";
+
+#ifndef SHA256_DIGEST_SIZE
+#define SHA256_DIGEST_SIZE      32
+#endif
+
+#define SIZEOF_STRUCT_FSVERITY_DIGEST 4  /* sizeof(struct fsverity_digest) */
+
+char expected_digest[SIZEOF_STRUCT_FSVERITY_DIGEST + SHA256_DIGEST_SIZE];
+char digest[SIZEOF_STRUCT_FSVERITY_DIGEST + SHA256_DIGEST_SIZE];
+__u32 monitored_pid;
+__u32 got_fsverity;
+__u32 digest_matches;
+
+SEC("lsm.s/file_open")
+int BPF_PROG(test_file_open, struct file *f)
+{
+	struct bpf_dynptr digest_ptr;
+	__u32 pid;
+	int ret;
+	int i;
+
+	pid = bpf_get_current_pid_tgid() >> 32;
+	if (pid != monitored_pid)
+		return 0;
+
+	bpf_dynptr_from_mem(digest, sizeof(digest), 0, &digest_ptr);
+	ret = bpf_get_fsverity_digest(f, &digest_ptr);
+	if (ret < 0)
+		return 0;
+	got_fsverity = 1;
+
+	for (i = 0; i < (int)sizeof(digest); i++) {
+		if (digest[i] != expected_digest[i])
+			return 0;
+	}
+
+	digest_matches = 1;
+	return 0;
+}