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Diffstat (limited to 'lib/avb/libavb/avb_descriptor.h')
-rw-r--r-- | lib/avb/libavb/avb_descriptor.h | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/lib/avb/libavb/avb_descriptor.h b/lib/avb/libavb/avb_descriptor.h new file mode 100644 index 0000000..5d0f0c6 --- /dev/null +++ b/lib/avb/libavb/avb_descriptor.h @@ -0,0 +1,131 @@ +/* + * Copyright (C) 2016 The Android Open Source Project + * + * Permission is hereby granted, free of charge, to any person + * obtaining a copy of this software and associated documentation + * files (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, copy, + * modify, merge, publish, distribute, sublicense, and/or sell copies + * of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#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_ */ |