1 files changed, 45 insertions, 0 deletions
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
new file mode 100644
index 000000000..8723ae70e
--- /dev/null
+++ b/kernel/module_signing.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Module signature checker
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/module_signature.h>
+#include <linux/string.h>
+#include <linux/verification.h>
+#include <crypto/public_key.h>
+#include "module-internal.h"
+
+/*
+ * Verify the signature on a module.
+ */
+int mod_verify_sig(const void *mod, struct load_info *info)
+{
+	struct module_signature ms;
+	size_t sig_len, modlen = info->len;
+	int ret;
+
+	pr_devel("==>%s(,%zu)\n", __func__, modlen);
+
+	if (modlen <= sizeof(ms))
+		return -EBADMSG;
+
+	memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
+
+	ret = mod_check_sig(&ms, modlen, "module");
+	if (ret)
+		return ret;
+
+	sig_len = be32_to_cpu(ms.sig_len);
+	modlen -= sig_len + sizeof(ms);
+	info->len = modlen;
+
+	return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
+				      VERIFY_USE_SECONDARY_KEYRING,
+				      VERIFYING_MODULE_SIGNATURE,
+				      NULL, NULL);
+}