1 files changed, 52 insertions, 0 deletions
diff --git a/plat/common/tbbr/plat_tbbr.c b/plat/common/tbbr/plat_tbbr.c
new file mode 100644
index 0000000..12ab0a9
--- /dev/null
+++ b/plat/common/tbbr/plat_tbbr.c
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <string.h>
+
+#include <drivers/auth/auth_mod.h>
+#include <plat/common/platform.h>
+#if USE_TBBR_DEFS
+#include <tools_share/tbbr_oid.h>
+#else
+#include <platform_oid.h>
+#endif
+
+/*
+ * Store a new non-volatile counter value. This implementation
+ * only allows updating of the platform's Trusted NV counter when a
+ * certificate protected by the Trusted NV counter is signed with
+ * the ROT key. This avoids a compromised secondary certificate from
+ * updating the platform's Trusted NV counter, which could lead to the
+ * platform becoming unusable. The function is suitable for all TBBR
+ * compliant platforms.
+ *
+ * Return: 0 = success, Otherwise = error
+ */
+int plat_set_nv_ctr2(void *cookie, const auth_img_desc_t *img_desc,
+		unsigned int nv_ctr)
+{
+	int trusted_nv_ctr;
+
+	assert(cookie != NULL);
+	assert(img_desc != NULL);
+
+	trusted_nv_ctr = strcmp(cookie, TRUSTED_FW_NVCOUNTER_OID) == 0;
+
+	/*
+	 * Only update the Trusted NV Counter if the certificate
+	 * has been signed with the ROT key. Non Trusted NV counter
+	 * updates are unconditional.
+	 */
+	if (!trusted_nv_ctr || img_desc->parent == NULL)
+		return plat_set_nv_ctr(cookie, nv_ctr);
+
+	/*
+	 * Trusted certificates not signed with the ROT key are not
+	 * allowed to update the Trusted NV Counter.
+	 */
+	return 1;
+}