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Diffstat (limited to 'lib/avb/libavb/avb_slot_verify.h')
| -rw-r--r-- | lib/avb/libavb/avb_slot_verify.h | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/lib/avb/libavb/avb_slot_verify.h b/lib/avb/libavb/avb_slot_verify.h new file mode 100644 index 0000000..08b11fc --- /dev/null +++ b/lib/avb/libavb/avb_slot_verify.h @@ -0,0 +1,257 @@ +/* + * 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_SLOT_VERIFY_H_ +#define AVB_SLOT_VERIFY_H_ + +#include "avb_ops.h" +#include "avb_vbmeta_image.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/* Return codes used in avb_slot_verify(), see that function for + * documentation for each field. + * + * Use avb_slot_verify_result_to_string() to get a textual + * representation usable for error/debug output. + */ +typedef enum { + AVB_SLOT_VERIFY_RESULT_OK, + AVB_SLOT_VERIFY_RESULT_ERROR_OOM, + AVB_SLOT_VERIFY_RESULT_ERROR_IO, + AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, + AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX, + AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, + AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA, + AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION +} AvbSlotVerifyResult; + +/* Get a textual representation of |result|. */ +const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result); + +/* Maximum number of rollback index locations supported. */ +#define AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS 32 + +/* AvbPartitionData contains data loaded from partitions when using + * avb_slot_verify(). The |partition_name| field contains the name of + * the partition (without A/B suffix), |data| points to the loaded + * data which is |data_size| bytes long. + * + * Note that this is strictly less than the partition size - it's only + * the image stored there, not the entire partition nor any of the + * metadata. + */ +typedef struct { + char* partition_name; + uint8_t* data; + size_t data_size; +} AvbPartitionData; + +/* AvbVBMetaData contains a vbmeta struct loaded from a partition when + * using avb_slot_verify(). The |partition_name| field contains the + * name of the partition (without A/B suffix), |vbmeta_data| points to + * the loaded data which is |vbmeta_size| bytes long. + * + * The |verify_result| field contains the result of + * avb_vbmeta_image_verify() on the data. This is guaranteed to be + * AVB_VBMETA_VERIFY_RESULT_OK for all vbmeta images if + * avb_slot_verify() returns AVB_SLOT_VERIFY_RESULT_OK. + * + * You can use avb_descriptor_get_all(), avb_descriptor_foreach(), and + * avb_vbmeta_image_header_to_host_byte_order() with this data. + */ +typedef struct { + char* partition_name; + uint8_t* vbmeta_data; + size_t vbmeta_size; + AvbVBMetaVerifyResult verify_result; +} AvbVBMetaData; + +/* AvbSlotVerifyData contains data needed to boot a particular slot + * and is returned by avb_slot_verify() if partitions in a slot are + * successfully verified. + * + * All data pointed to by this struct - including data in each item in + * the |partitions| array - will be freed when the + * avb_slot_verify_data_free() function is called. + * + * The |ab_suffix| field is the copy of the of |ab_suffix| field + * passed to avb_slot_verify(). It is the A/B suffix of the slot. + * + * The VBMeta images that were checked are available in the + * |vbmeta_images| field. The field |num_vbmeta_images| contains the + * number of elements in this array. The first element - + * vbmeta_images[0] - is guaranteed to be from the partition with the + * top-level vbmeta struct. This is usually the "vbmeta" partition in + * the requested slot but if there is no "vbmeta" partition it can + * also be the "boot" partition. + * + * The partitions loaded and verified from from the slot are + * accessible in the |loaded_partitions| array. The field + * |num_loaded_partitions| contains the number of elements in this + * array. The order of partitions in this array may not necessarily be + * the same order as in the passed-in |requested_partitions| array. + * + * Rollback indexes for the verified slot are stored in the + * |rollback_indexes| field. Note that avb_slot_verify() will NEVER + * modify stored_rollback_index[n] locations e.g. it will never use + * the write_rollback_index() AvbOps operation. Instead it is the job + * of the caller of avb_slot_verify() to do this based on e.g. A/B + * policy and other factors. See libavb_ab/avb_ab_flow.c for an + * example of how to do this. + * + * The |cmdline| field is a NUL-terminated string in UTF-8 resulting + * from concatenating all |AvbKernelCmdlineDescriptor| and then + * performing proper substitution of the variables + * $(ANDROID_SYSTEM_PARTUUID), $(ANDROID_BOOT_PARTUUID), and + * $(ANDROID_VBMETA_PARTUUID) using the + * get_unique_guid_for_partition() operation in |AvbOps|. + * + * Additionally, the |cmdline| field will have the following kernel + * command-line options set: + * + * androidboot.vbmeta.device_state: set to "locked" or "unlocked" + * depending on the result of the result of AvbOps's + * read_is_unlocked() function. + * + * androidboot.vbmeta.{hash_alg, size, digest}: Will be set to + * the digest of all images in |vbmeta_images|. + * + * androidboot.vbmeta.device: This is set to the value + * PARTUUID=$(ANDROID_VBMETA_PARTUUID) before substitution so it + * will end up pointing to the vbmeta partition for the verified + * slot. If there is no vbmeta partition it will point to the boot + * partition of the verified slot. + * + * androidboot.vbmeta.avb_version: This is set to the decimal value + * of AVB_VERSION_MAJOR followed by a dot followed by the decimal + * value of AVB_VERSION_MINOR, for example "1.0" or "1.4". This + * version number represents the vbmeta file format version + * supported by libavb copy used in the boot loader. This is not + * necessarily the same version number of the on-disk metadata for + * the slot that was verified. + * + * Note that androidboot.slot_suffix is not set in |cmdline| - you + * will have to pass this command-line option yourself. + * + * This struct may grow in the future without it being considered an + * ABI break. + */ +typedef struct { + char* ab_suffix; + AvbVBMetaData* vbmeta_images; + size_t num_vbmeta_images; + AvbPartitionData* loaded_partitions; + size_t num_loaded_partitions; + char* cmdline; + uint64_t rollback_indexes[AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS]; +} AvbSlotVerifyData; + +/* Frees a |AvbSlotVerifyData| including all data it points to. */ +void avb_slot_verify_data_free(AvbSlotVerifyData* data); + +/* Performs a full verification of the slot identified by |ab_suffix| + * and load the contents of the partitions whose name is in the + * NULL-terminated string array |requested_partitions| (each partition + * must use hash verification). If not using A/B, pass an empty string + * (e.g. "", not NULL) for |ab_suffix|. + * + * Typically the |requested_partitions| array only contains a single + * item for the boot partition, 'boot'. + * + * Verification includes loading data from the 'vbmeta', all hash + * partitions, and possibly other partitions (with |ab_suffix| + * appended), inspecting rollback indexes, and checking if the public + * key used to sign the data is acceptable. The functions in |ops| + * will be used to do this. + * + * If |out_data| is not NULL, it will be set to a newly allocated + * |AvbSlotVerifyData| struct containing all the data needed to + * actually boot the slot. This data structure should be freed with + * avb_slot_verify_data_free() when you are done with it. See below + * for when this is returned. + * + * If |allow_verification_error| is false this function will bail out + * as soon as an error is encountered and |out_data| is set only if + * AVB_SLOT_VERIFY_RESULT_OK is returned. + * + * Otherwise if |allow_verification_error| is true the function will + * continue verification efforts and |out_data| is also set if + * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, + * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, or + * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned. It is + * undefined which error is returned if more than one distinct error + * is encountered. It is guaranteed that AVB_SLOT_VERIFY_RESULT_OK is + * returned if, and only if, there are no errors. This mode is needed + * to boot valid but unverified slots when the device is unlocked. + * + * Also note that |out_data| is never set if + * AVB_SLOT_VERIFY_RESULT_ERROR_OOM, AVB_SLOT_VERIFY_RESULT_ERROR_IO, + * or AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned. + * + * AVB_SLOT_VERIFY_RESULT_OK is returned if everything is verified + * correctly and all public keys are accepted. + * + * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED is returned if + * everything is verified correctly out but one or more public keys + * are not accepted. This includes the case where integrity data is + * not signed. + * + * AVB_SLOT_VERIFY_RESULT_ERROR_OOM is returned if unable to + * allocate memory. + * + * AVB_SLOT_VERIFY_RESULT_ERROR_IO is returned if an I/O error + * occurred while trying to load data or get a rollback index. + * + * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION is returned if the data + * did not verify, e.g. the digest didn't match or signature checks + * failed. + * + * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned if a + * rollback index was less than its stored value. + * + * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned if some + * of the metadata is invalid or inconsistent. + * + * AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION is returned if + * some of the metadata requires a newer version of libavb than what + * is in use. + */ +AvbSlotVerifyResult avb_slot_verify(AvbOps* ops, + const char* const* requested_partitions, + const char* ab_suffix, + bool allow_verification_error, + AvbSlotVerifyData** out_data); + +#ifdef __cplusplus +} +#endif + +#endif /* AVB_SLOT_VERIFY_H_ */ |