1 files changed, 113 insertions, 0 deletions
diff --git a/lib/libavb/avb_descriptor.h b/lib/libavb/avb_descriptor.h
new file mode 100644
index 0000000000..13a3efde27
--- /dev/null
+++ b/lib/libavb/avb_descriptor.h
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_DESCRIPTOR_H_
+#define AVB_DESCRIPTOR_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Well-known descriptor tags.
+ *
+ * AVB_DESCRIPTOR_TAG_PROPERTY: see |AvbPropertyDescriptor| struct.
+ * AVB_DESCRIPTOR_TAG_HASHTREE: see |AvbHashtreeDescriptor| struct.
+ * AVB_DESCRIPTOR_TAG_HASH: see |AvbHashDescriptor| struct.
+ * AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE: see |AvbKernelCmdlineDescriptor| struct.
+ * AVB_DESCRIPTOR_TAG_CHAIN_PARTITION: see |AvbChainPartitionDescriptor| struct.
+ */
+typedef enum {
+  AVB_DESCRIPTOR_TAG_PROPERTY,
+  AVB_DESCRIPTOR_TAG_HASHTREE,
+  AVB_DESCRIPTOR_TAG_HASH,
+  AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE,
+  AVB_DESCRIPTOR_TAG_CHAIN_PARTITION,
+} AvbDescriptorTag;
+
+/* The header for a serialized descriptor.
+ *
+ * A descriptor always have two fields, a |tag| (denoting its type,
+ * see the |AvbDescriptorTag| enumeration) and the size of the bytes
+ * following, |num_bytes_following|.
+ *
+ * For padding, |num_bytes_following| is always a multiple of 8.
+ */
+typedef struct AvbDescriptor {
+  uint64_t tag;
+  uint64_t num_bytes_following;
+} AVB_ATTR_PACKED AvbDescriptor;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ *
+ * Data following the struct is not validated nor copied.
+ */
+bool avb_descriptor_validate_and_byteswap(
+    const AvbDescriptor* src, AvbDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Signature for callback function used in avb_descriptor_foreach().
+ * The passed in descriptor is given by |descriptor| and the
+ * |user_data| passed to avb_descriptor_foreach() function is in
+ * |user_data|. Return true to continue iterating, false to stop
+ * iterating.
+ *
+ * Note that |descriptor| points into the image passed to
+ * avb_descriptor_foreach() - all fields need to be byteswapped!
+ */
+typedef bool AvbDescriptorForeachFunc(const AvbDescriptor* descriptor,
+                                      void* user_data);
+
+/* Convenience function to iterate over all descriptors in an vbmeta
+ * image.
+ *
+ * The function given by |foreach_func| will be called for each
+ * descriptor. The given function should return true to continue
+ * iterating, false to stop.
+ *
+ * The |user_data| parameter will be passed to |foreach_func|.
+ *
+ * Returns false if the iteration was short-circuited, that is if
+ * an invocation of |foreach_func| returned false.
+ *
+ * Before using this function, you MUST verify |image_data| with
+ * avb_vbmeta_image_verify() and reject it unless it's signed by a known
+ * good public key. Additionally, |image_data| must be word-aligned.
+ */
+bool avb_descriptor_foreach(const uint8_t* image_data,
+                            size_t image_size,
+                            AvbDescriptorForeachFunc foreach_func,
+                            void* user_data);
+
+/* Gets all descriptors in a vbmeta image.
+ *
+ * The return value is a NULL-pointer terminated array of
+ * AvbDescriptor pointers. Free with avb_free() when you are done with
+ * it. If |out_num_descriptors| is non-NULL, the number of descriptors
+ * will be returned there.
+ *
+ * Note that each AvbDescriptor pointer in the array points into
+ * |image_data| - all fields need to be byteswapped!
+ *
+ * Before using this function, you MUST verify |image_data| with
+ * avb_vbmeta_image_verify() and reject it unless it's signed by a known
+ * good public key. Additionally, |image_data| must be word-aligned.
+ */
+const AvbDescriptor** avb_descriptor_get_all(const uint8_t* image_data,
+                                             size_t image_size,
+                                             size_t* out_num_descriptors)
+    AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_DESCRIPTOR_H_ */