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- /* SPDX-License-Identifier: MIT */
- /*
- * Copyright (C) 2016 The Android Open Source Project
- */
- #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,
- AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT
- } AvbSlotVerifyResult;
- /* Various error handling modes for when verification fails using a
- * hashtree at runtime inside the HLOS.
- *
- * AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE means that the OS
- * will invalidate the current slot and restart.
- *
- * AVB_HASHTREE_ERROR_MODE_RESTART means that the OS will restart.
- *
- * AVB_HASHTREE_ERROR_MODE_EIO means that an EIO error will be
- * returned to applications.
- *
- * AVB_HASHTREE_ERROR_MODE_LOGGING means that errors will be logged
- * and corrupt data may be returned to applications. This mode should
- * be used ONLY for diagnostics and debugging. It cannot be used
- * unless AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is also
- * used.
- *
- * AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO means that either
- * AVB_HASHTREE_ERROR_MODE_RESTART or AVB_HASHTREE_ERROR_MODE_EIO is used
- * depending on state. This mode implements a state machine whereby
- * AVB_HASHTREE_ERROR_MODE_RESTART is used by default and when
- * AVB_SLOT_VERIFY_FLAGS_RESTART_CAUSED_BY_HASHTREE_CORRUPTION is passed the
- * mode transitions to AVB_HASHTREE_ERROR_MODE_EIO. When a new OS has been
- * detected the device transitions back to the AVB_HASHTREE_ERROR_MODE_RESTART
- * mode. To do this persistent storage is needed - specifically this means that
- * the passed in AvbOps will need to have the read_persistent_value() and
- * write_persistent_value() operations implemented. The name of the persistent
- * value used is "avb.managed_verity_mode" and 32 bytes of storage is needed.
- */
- typedef enum {
- AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE,
- AVB_HASHTREE_ERROR_MODE_RESTART,
- AVB_HASHTREE_ERROR_MODE_EIO,
- AVB_HASHTREE_ERROR_MODE_LOGGING,
- AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO
- } AvbHashtreeErrorMode;
- /* Flags that influence how avb_slot_verify() works.
- *
- * If AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is NOT set then
- * avb_slot_verify() 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 AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set
- * avb_slot_verify() 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, if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set the
- * contents loaded from |requested_partition| will be the contents of
- * the entire partition instead of just the size specified in the hash
- * descriptor.
- *
- * The AVB_SLOT_VERIFY_FLAGS_RESTART_CAUSED_BY_HASHTREE_CORRUPTION flag
- * should be set if using AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO
- * and the reason the boot loader is running is because the device
- * was restarted by the dm-verity driver.
- *
- * If the AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION flag is set then
- * data won't be loaded from the "vbmeta" partition and the
- * |validate_vbmeta_public_key| operation is never called. Instead, the
- * vbmeta structs in |requested_partitions| are loaded and processed and the
- * |validate_public_key_for_partition| operation is called for each of these
- * vbmeta structs. This flag is useful when booting into recovery on a device
- * not using A/B - see section "Booting into recovery" in README.md for
- * more information.
- */
- typedef enum {
- AVB_SLOT_VERIFY_FLAGS_NONE = 0,
- AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR = (1 << 0),
- AVB_SLOT_VERIFY_FLAGS_RESTART_CAUSED_BY_HASHTREE_CORRUPTION = (1 << 1),
- AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION = (1 << 2),
- } AvbSlotVerifyFlags;
- /* 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. If |preloaded| is set to true,
- * this structure dose not own |data|. The caller of |avb_slot_verify|
- * needs to make sure that the preloaded data outlives this
- * |AvbPartitionData| structure.
- *
- * 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;
- bool preloaded;
- } 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. This
- * value includes the leading underscore - typical values are "" (if
- * no slots are in use), "_a" (for the first slot), and "_b" (for the
- * second 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
- * $(ANDROID_VERITY_MODE) will be replaced with the proper dm-verity
- * option depending on the value of |hashtree_error_mode|.
- *
- * Additionally, the |cmdline| field will have the following kernel
- * command-line options set (unless verification is disabled, see
- * below):
- *
- * androidboot.veritymode: This is set to 'disabled' if the
- * AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED flag is set in top-level
- * vbmeta struct. Otherwise it is set to 'enforcing' if the
- * passed-in hashtree error mode is AVB_HASHTREE_ERROR_MODE_RESTART
- * or AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 'eio' if it's
- * set to AVB_HASHTREE_ERROR_MODE_EIO, and 'logging' if it's set to
- * AVB_HASHTREE_ERROR_MODE_LOGGING.
- *
- * androidboot.veritymode.managed: This is set to 'yes' only
- * if hashtree validation isn't disabled and the passed-in hashtree
- * error mode is AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO.
- *
- * androidboot.vbmeta.invalidate_on_error: This is set to 'yes' only
- * if hashtree validation isn't disabled and the passed-in hashtree
- * error mode is AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE.
- *
- * androidboot.vbmeta.device_state: set to "locked" or "unlocked"
- * depending on the result of the result of AvbOps's
- * read_is_unlocked() function.
- *
- * androidboot.vbmeta.{hash_alg, size, digest}: Will be set to
- * the digest of all images in |vbmeta_images|.
- *
- * androidboot.vbmeta.device: This is set to the value
- * PARTUUID=$(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. If the flag
- * AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION is used, this is not
- * set.
- *
- * 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 the |cmdline| field
- * in |AvbSlotVerifyData| - you will have to set this yourself.
- *
- * If the |AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED| flag is set
- * in the top-level vbmeta struct then only the top-level vbmeta
- * struct is verified and descriptors will not processed. The return
- * value will be set accordingly (if this flag is set via 'avbctl
- * disable-verification' then the return value will be
- * |AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION|) and
- * |AvbSlotVerifyData| is returned. Additionally all partitions in the
- * |requested_partitions| are loaded and the |cmdline| field is set to
- * "root=PARTUUID=$(ANDROID_SYSTEM_PARTUUID)" and the GUID for the
- * appropriate system partition is substituted in. Note that none of
- * the androidboot.* options mentioned above will be set.
- *
- * The |resolved_hashtree_error_mode| is the the value of the passed
- * avb_slot_verify()'s |hashtree_error_mode| parameter except that it never has
- * the value AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO. If this value was
- * passed in, then the restart/eio state machine is used resulting in
- * |resolved_hashtree_error_mode| being set to either
- * AVB_HASHTREE_ERROR_MODE_RESTART or AVB_HASHTREE_ERROR_MODE_EIO. If set to
- * AVB_HASHTREE_ERROR_MODE_EIO the boot loader should present a RED warning
- * screen for the user to click through before continuing to boot.
- *
- * 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];
- AvbHashtreeErrorMode resolved_hashtree_error_mode;
- } AvbSlotVerifyData;
- /* Calculates a digest of all vbmeta images in |data| using
- * the digest indicated by |digest_type|. Stores the result
- * in |out_digest| which must be large enough to hold a digest
- * of the requested type.
- */
- void avb_slot_verify_data_calculate_vbmeta_digest(AvbSlotVerifyData* data,
- AvbDigestType digest_type,
- uint8_t* out_digest);
- /* 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 and verify 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|. This parameter
- * must include the leading underscore, for example "_a" should be
- * used to refer to the first slot.
- *
- * Typically the |requested_partitions| array only contains a single
- * item for the boot partition, 'boot'.
- *
- * Verification includes loading and verifying data from the 'vbmeta',
- * the requested 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.
- *
- * The |flags| parameter is used to influence the semantics of
- * avb_slot_verify() - for example the
- * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR flag can be used to
- * ignore verification errors which is something needed in the
- * UNLOCKED state. See the AvbSlotVerifyFlags enumeration for details.
- *
- * The |hashtree_error_mode| parameter should be set to the desired error
- * handling mode. See the AvbHashtreeErrorMode enumeration for details.
- *
- * 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.
- *
- * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT is returned if the
- * caller passed invalid parameters, for example trying to use
- * AVB_HASHTREE_ERROR_MODE_LOGGING without
- * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR.
- */
- AvbSlotVerifyResult avb_slot_verify(AvbOps* ops,
- const char* const* requested_partitions,
- const char* ab_suffix,
- AvbSlotVerifyFlags flags,
- AvbHashtreeErrorMode hashtree_error_mode,
- AvbSlotVerifyData** out_data);
- #ifdef __cplusplus
- }
- #endif
- #endif /* AVB_SLOT_VERIFY_H_ */
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