/*
* 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_OPS_H_
#define AVB_OPS_H_
#include "avb_sysdeps.h"
#ifdef __cplusplus
extern "C" {
#endif
/* Well-known names of named persistent values. */
#define AVB_NPV_PERSISTENT_DIGEST_PREFIX "avb.persistent_digest."
/* Return codes used for I/O operations.
*
* AVB_IO_RESULT_OK is returned if the requested operation was
* successful.
*
* AVB_IO_RESULT_ERROR_IO is returned if the underlying hardware (disk
* or other subsystem) encountered an I/O error.
*
* AVB_IO_RESULT_ERROR_OOM is returned if unable to allocate memory.
*
* AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION is returned if the requested
* partition does not exist.
*
* AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION is returned if the
* range of bytes requested to be read or written is outside the range
* of the partition.
*
* AVB_IO_RESULT_ERROR_NO_SUCH_VALUE is returned if a named persistent value
* does not exist.
*
* AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE is returned if a named persistent
* value size is not supported or does not match the expected size.
*
* AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE is returned if a buffer is too small
* for the requested operation.
*/
typedef enum {
AVB_IO_RESULT_OK,
AVB_IO_RESULT_ERROR_OOM,
AVB_IO_RESULT_ERROR_IO,
AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION,
AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION,
AVB_IO_RESULT_ERROR_NO_SUCH_VALUE,
AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE,
AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE,
} AvbIOResult;
struct AvbOps;
typedef struct AvbOps AvbOps;
/* Forward-declaration of operations in libavb_ab. */
struct AvbABOps;
/* Forward-declaration of operations in libavb_atx. */
struct AvbAtxOps;
/* High-level operations/functions/methods that are platform
* dependent.
*
* Operations may be added in the future so when implementing it
* always make sure to zero out sizeof(AvbOps) bytes of the struct to
* ensure that unimplemented operations are set to NULL.
*/
struct AvbOps {
/* This pointer can be used by the application/bootloader using
* libavb and is typically used in each operation to get a pointer
* to platform-specific resources. It cannot be used by libraries.
*/
void* user_data;
/* If libavb_ab is used, this should point to the
* AvbABOps. Otherwise it must be set to NULL.
*/
struct AvbABOps* ab_ops;
/* If libavb_atx is used, this should point to the
* AvbAtxOps. Otherwise it must be set to NULL.
*/
struct AvbAtxOps* atx_ops;
/* Reads |num_bytes| from offset |offset| from partition with name
* |partition| (NUL-terminated UTF-8 string). If |offset| is
* negative, its absolute value should be interpreted as the number
* of bytes from the end of the partition.
*
* This function returns AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION if
* there is no partition with the given name,
* AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION if the requested
* |offset| is outside the partition, and AVB_IO_RESULT_ERROR_IO if
* there was an I/O error from the underlying I/O subsystem. If the
* operation succeeds as requested AVB_IO_RESULT_OK is returned and
* the data is available in |buffer|.
*
* The only time partial I/O may occur is if reading beyond the end
* of the partition. In this case the value returned in
* |out_num_read| may be smaller than |num_bytes|.
*/
AvbIOResult (*read_from_partition)(AvbOps* ops,
const char* partition,
int64_t offset,
size_t num_bytes,
void* buffer,
size_t* out_num_read);
/* Gets the starting pointer of a partition that is pre-loaded in memory, and
* save it to |out_pointer|. The preloaded partition is expected to be
* |num_bytes|, where the actual preloaded byte count is returned in
* |out_num_bytes_preloaded|. |out_num_bytes_preloaded| must be no larger than
* |num_bytes|.
*
* This provides an alternative way to access a partition that is preloaded
* into memory without a full memory copy. When this function pointer is not
* set (has value NULL), or when the |out_pointer| is set to NULL as a result,
* |read_from_partition| will be used as the fallback. This function is mainly
* used for accessing the entire partition content to calculate its hash.
*
* Preloaded partition data must outlive the lifespan of the
* |AvbSlotVerifyData| structure that |avb_slot_verify| outputs.
*/
AvbIOResult (*get_preloaded_partition)(AvbOps* ops,
const char* partition,
size_t num_bytes,
uint8_t** out_pointer,
size_t* out_num_bytes_preloaded);
/* Writes |num_bytes| from |bffer| at offset |offset| to partition
* with name |partition| (NUL-terminated UTF-8 string). If |offset|
* is negative, its absolute value should be interpreted as the
* number of bytes from the end of the partition.
*
* This function returns AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION if
* there is no partition with the given name,
* AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION if the requested
* byterange goes outside the partition, and AVB_IO_RESULT_ERROR_IO
* if there was an I/O error from the underlying I/O subsystem. If
* the operation succeeds as requested AVB_IO_RESULT_OK is
* returned.
*
* This function never does any partial I/O, it either transfers all
* of the requested bytes or returns an error.
*/
AvbIOResult (*write_to_partition)(AvbOps* ops,
const char* partition,
int64_t offset,
size_t num_bytes,
const void* buffer);
/* Checks if the given public key used to sign the 'vbmeta'
* partition is trusted. Boot loaders typically compare this with
* embedded key material generated with 'avbtool
* extract_public_key'.
*
* The public key is in the array pointed to by |public_key_data|
* and is of |public_key_length| bytes.
*
* If there is no public key metadata (set with the avbtool option
* --public_key_metadata) then |public_key_metadata| will be set to
* NULL. Otherwise this field points to the data which is
* |public_key_metadata_length| bytes long.
*
* If AVB_IO_RESULT_OK is returned then |out_is_trusted| is set -
* true if trusted or false if untrusted.
*/
AvbIOResult (*validate_vbmeta_public_key)(AvbOps* ops,
const uint8_t* public_key_data,
size_t public_key_length,
const uint8_t* public_key_metadata,
size_t public_key_metadata_length,
bool* out_is_trusted);
/* Gets the rollback index corresponding to the location given by
* |rollback_index_location|. The value is returned in
* |out_rollback_index|. Returns AVB_IO_RESULT_OK if the rollback
* index was retrieved, otherwise an error code.
*
* A device may have a limited amount of rollback index locations (say,
* one or four) so may error out if |rollback_index_location| exceeds
* this number.
*/
AvbIOResult (*read_rollback_index)(AvbOps* ops,
size_t rollback_index_location,
uint64_t* out_rollback_index);
/* Sets the rollback index corresponding to the location given by
* |rollback_index_location| to |rollback_index|. Returns
* AVB_IO_RESULT_OK if the rollback index was set, otherwise an
* error code.
*
* A device may have a limited amount of rollback index locations (say,
* one or four) so may error out if |rollback_index_location| exceeds
* this number.
*/
AvbIOResult (*write_rollback_index)(AvbOps* ops,
size_t rollback_index_location,
uint64_t rollback_index);
/* Gets whether the device is unlocked. The value is returned in
* |out_is_unlocked| (true if unlocked, false otherwise). Returns
* AVB_IO_RESULT_OK if the state was retrieved, otherwise an error
* code.
*/
AvbIOResult (*read_is_device_unlocked)(AvbOps* ops, bool* out_is_unlocked);
/* Gets the unique partition GUID for a partition with name in
* |partition| (NUL-terminated UTF-8 string). The GUID is copied as
* a string into |guid_buf| of size |guid_buf_size| and will be NUL
* terminated. The string must be lower-case and properly
* hyphenated. For example:
*
* 527c1c6d-6361-4593-8842-3c78fcd39219
*
* Returns AVB_IO_RESULT_OK on success, otherwise an error code.
*/
AvbIOResult (*get_unique_guid_for_partition)(AvbOps* ops,
const char* partition,
char* guid_buf,
size_t guid_buf_size);
/* Gets the size of a partition with the name in |partition|
* (NUL-terminated UTF-8 string). Returns the value in
* |out_size_num_bytes|.
*
* Returns AVB_IO_RESULT_OK on success, otherwise an error code.
*/
AvbIOResult (*get_size_of_partition)(AvbOps* ops,
const char* partition,
uint64_t* out_size_num_bytes);
/* Reads a persistent value corresponding to the given |name|. The value is
* returned in |out_buffer| which must point to |buffer_size| bytes. On
* success |out_num_bytes_read| contains the number of bytes read into
* |out_buffer|. If AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE is returned,
* |out_num_bytes_read| contains the number of bytes that would have been read
* which can be used to allocate a buffer.
*
* The |buffer_size| may be zero and the |out_buffer| may be NULL, but if
* |out_buffer| is NULL then |buffer_size| *must* be zero.
*
* Returns AVB_IO_RESULT_OK on success, otherwise an error code.
*
* If the value does not exist, is not supported, or is not populated, returns
* AVB_IO_RESULT_ERROR_NO_SUCH_VALUE. If |buffer_size| is smaller than the
* size of the stored value, returns AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE.
*
* This operation is currently only used to support persistent digests. If a
* device does not use persistent digests this function pointer can be set to
* NULL.
*/
AvbIOResult (*read_persistent_value)(AvbOps* ops,
const char* name,
size_t buffer_size,
uint8_t* out_buffer,
size_t* out_num_bytes_read);
/* Writes a persistent value corresponding to the given |name|. The value is
* supplied in |value| which must point to |value_size| bytes. Any existing
* value with the same name is overwritten. If |value_size| is zero, future
* calls to |read_persistent_value| will return
* AVB_IO_RESULT_ERROR_NO_SUCH_VALUE.
*
* Returns AVB_IO_RESULT_OK on success, otherwise an error code.
*
* If the value |name| is not supported, returns
* AVB_IO_RESULT_ERROR_NO_SUCH_VALUE. If the |value_size| is not supported,
* returns AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE.
*
* This operation is currently only used to support persistent digests. If a
* device does not use persistent digests this function pointer can be set to
* NULL.
*/
AvbIOResult (*write_persistent_value)(AvbOps* ops,
const char* name,
size_t value_size,
const uint8_t* value);
};
#ifdef __cplusplus
}
#endif
#endif /* AVB_OPS_H_ */