1 /* SPDX-License-Identifier: MIT */
3 * Copyright (C) 2016 The Android Open Source Project
6 #if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
7 #error "Never include this file directly, include libavb.h instead."
10 #ifndef AVB_SLOT_VERIFY_H_
11 #define AVB_SLOT_VERIFY_H_
14 #include "avb_vbmeta_image.h"
20 /* Return codes used in avb_slot_verify(), see that function for
21 * documentation for each field.
23 * Use avb_slot_verify_result_to_string() to get a textual
24 * representation usable for error/debug output.
27 AVB_SLOT_VERIFY_RESULT_OK,
28 AVB_SLOT_VERIFY_RESULT_ERROR_OOM,
29 AVB_SLOT_VERIFY_RESULT_ERROR_IO,
30 AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION,
31 AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX,
32 AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED,
33 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA,
34 AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION,
35 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT
36 } AvbSlotVerifyResult;
38 /* Various error handling modes for when verification fails using a
39 * hashtree at runtime inside the HLOS.
41 * AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE means that the OS
42 * will invalidate the current slot and restart.
44 * AVB_HASHTREE_ERROR_MODE_RESTART means that the OS will restart.
46 * AVB_HASHTREE_ERROR_MODE_EIO means that an EIO error will be
47 * returned to applications.
49 * AVB_HASHTREE_ERROR_MODE_LOGGING means that errors will be logged
50 * and corrupt data may be returned to applications. This mode should
51 * be used ONLY for diagnostics and debugging. It cannot be used
52 * unless AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is also
56 AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE,
57 AVB_HASHTREE_ERROR_MODE_RESTART,
58 AVB_HASHTREE_ERROR_MODE_EIO,
59 AVB_HASHTREE_ERROR_MODE_LOGGING
60 } AvbHashtreeErrorMode;
62 /* Flags that influence how avb_slot_verify() works.
64 * If AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is NOT set then
65 * avb_slot_verify() will bail out as soon as an error is encountered
66 * and |out_data| is set only if AVB_SLOT_VERIFY_RESULT_OK is
69 * Otherwise if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set
70 * avb_slot_verify() will continue verification efforts and |out_data|
71 * is also set if AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED,
72 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, or
73 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned. It is
74 * undefined which error is returned if more than one distinct error
75 * is encountered. It is guaranteed that AVB_SLOT_VERIFY_RESULT_OK is
76 * returned if, and only if, there are no errors. This mode is needed
77 * to boot valid but unverified slots when the device is unlocked.
79 * Also, if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set the
80 * contents loaded from |requested_partition| will be the contents of
81 * the entire partition instead of just the size specified in the hash
85 AVB_SLOT_VERIFY_FLAGS_NONE = 0,
86 AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR = (1 << 0)
89 /* Get a textual representation of |result|. */
90 const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result);
92 /* Maximum number of rollback index locations supported. */
93 #define AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS 32
95 /* AvbPartitionData contains data loaded from partitions when using
96 * avb_slot_verify(). The |partition_name| field contains the name of
97 * the partition (without A/B suffix), |data| points to the loaded
98 * data which is |data_size| bytes long. If |preloaded| is set to true,
99 * this structure dose not own |data|. The caller of |avb_slot_verify|
100 * needs to make sure that the preloaded data outlives this
101 * |AvbPartitionData| structure.
103 * Note that this is strictly less than the partition size - it's only
104 * the image stored there, not the entire partition nor any of the
108 char* partition_name;
114 /* AvbVBMetaData contains a vbmeta struct loaded from a partition when
115 * using avb_slot_verify(). The |partition_name| field contains the
116 * name of the partition (without A/B suffix), |vbmeta_data| points to
117 * the loaded data which is |vbmeta_size| bytes long.
119 * The |verify_result| field contains the result of
120 * avb_vbmeta_image_verify() on the data. This is guaranteed to be
121 * AVB_VBMETA_VERIFY_RESULT_OK for all vbmeta images if
122 * avb_slot_verify() returns AVB_SLOT_VERIFY_RESULT_OK.
124 * You can use avb_descriptor_get_all(), avb_descriptor_foreach(), and
125 * avb_vbmeta_image_header_to_host_byte_order() with this data.
128 char* partition_name;
129 uint8_t* vbmeta_data;
131 AvbVBMetaVerifyResult verify_result;
134 /* AvbSlotVerifyData contains data needed to boot a particular slot
135 * and is returned by avb_slot_verify() if partitions in a slot are
136 * successfully verified.
138 * All data pointed to by this struct - including data in each item in
139 * the |partitions| array - will be freed when the
140 * avb_slot_verify_data_free() function is called.
142 * The |ab_suffix| field is the copy of the of |ab_suffix| field
143 * passed to avb_slot_verify(). It is the A/B suffix of the slot. This
144 * value includes the leading underscore - typical values are "" (if
145 * no slots are in use), "_a" (for the first slot), and "_b" (for the
148 * The VBMeta images that were checked are available in the
149 * |vbmeta_images| field. The field |num_vbmeta_images| contains the
150 * number of elements in this array. The first element -
151 * vbmeta_images[0] - is guaranteed to be from the partition with the
152 * top-level vbmeta struct. This is usually the "vbmeta" partition in
153 * the requested slot but if there is no "vbmeta" partition it can
154 * also be the "boot" partition.
156 * The partitions loaded and verified from from the slot are
157 * accessible in the |loaded_partitions| array. The field
158 * |num_loaded_partitions| contains the number of elements in this
159 * array. The order of partitions in this array may not necessarily be
160 * the same order as in the passed-in |requested_partitions| array.
162 * Rollback indexes for the verified slot are stored in the
163 * |rollback_indexes| field. Note that avb_slot_verify() will NEVER
164 * modify stored_rollback_index[n] locations e.g. it will never use
165 * the write_rollback_index() AvbOps operation. Instead it is the job
166 * of the caller of avb_slot_verify() to do this based on e.g. A/B
167 * policy and other factors. See libavb_ab/avb_ab_flow.c for an
168 * example of how to do this.
170 * The |cmdline| field is a NUL-terminated string in UTF-8 resulting
171 * from concatenating all |AvbKernelCmdlineDescriptor| and then
172 * performing proper substitution of the variables
173 * $(ANDROID_SYSTEM_PARTUUID), $(ANDROID_BOOT_PARTUUID), and
174 * $(ANDROID_VBMETA_PARTUUID) using the
175 * get_unique_guid_for_partition() operation in |AvbOps|. Additionally
176 * $(ANDROID_VERITY_MODE) will be replaced with the proper dm-verity
177 * option depending on the value of |hashtree_error_mode|.
179 * Additionally, the |cmdline| field will have the following kernel
180 * command-line options set (unless verification is disabled, see
183 * androidboot.veritymode: This is set to 'disabled' if the
184 * AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED flag is set in top-level
185 * vbmeta struct. Otherwise it is set to 'enforcing' if the
186 * passed-in hashtree error mode is AVB_HASHTREE_ERROR_MODE_RESTART
187 * or AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 'eio' if it's
188 * set to AVB_HASHTREE_ERROR_MODE_EIO, and 'logging' if it's set to
189 * AVB_HASHTREE_ERROR_MODE_LOGGING.
191 * androidboot.vbmeta.invalidate_on_error: This is set to 'yes' only
192 * if hashtree validation isn't disabled and the passed-in hashtree
193 * error mode is AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE.
195 * androidboot.vbmeta.device_state: set to "locked" or "unlocked"
196 * depending on the result of the result of AvbOps's
197 * read_is_unlocked() function.
199 * androidboot.vbmeta.{hash_alg, size, digest}: Will be set to
200 * the digest of all images in |vbmeta_images|.
202 * androidboot.vbmeta.device: This is set to the value
203 * PARTUUID=$(ANDROID_VBMETA_PARTUUID) before substitution so it
204 * will end up pointing to the vbmeta partition for the verified
205 * slot. If there is no vbmeta partition it will point to the boot
206 * partition of the verified slot.
208 * androidboot.vbmeta.avb_version: This is set to the decimal value
209 * of AVB_VERSION_MAJOR followed by a dot followed by the decimal
210 * value of AVB_VERSION_MINOR, for example "1.0" or "1.4". This
211 * version number represents the vbmeta file format version
212 * supported by libavb copy used in the boot loader. This is not
213 * necessarily the same version number of the on-disk metadata for
214 * the slot that was verified.
216 * Note that androidboot.slot_suffix is not set in the |cmdline| field
217 * in |AvbSlotVerifyData| - you will have to set this yourself.
219 * If the |AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED| flag is set
220 * in the top-level vbmeta struct then only the top-level vbmeta
221 * struct is verified and descriptors will not processed. The return
222 * value will be set accordingly (if this flag is set via 'avbctl
223 * disable-verification' then the return value will be
224 * |AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION|) and
225 * |AvbSlotVerifyData| is returned. Additionally all partitions in the
226 * |requested_partitions| are loaded and the |cmdline| field is set to
227 * "root=PARTUUID=$(ANDROID_SYSTEM_PARTUUID)" and the GUID for the
228 * appropriate system partition is substituted in. Note that none of
229 * the androidboot.* options mentioned above will be set.
231 * This struct may grow in the future without it being considered an
236 AvbVBMetaData* vbmeta_images;
237 size_t num_vbmeta_images;
238 AvbPartitionData* loaded_partitions;
239 size_t num_loaded_partitions;
241 uint64_t rollback_indexes[AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS];
244 /* Calculates a digest of all vbmeta images in |data| using
245 * the digest indicated by |digest_type|. Stores the result
246 * in |out_digest| which must be large enough to hold a digest
247 * of the requested type.
249 void avb_slot_verify_data_calculate_vbmeta_digest(AvbSlotVerifyData* data,
250 AvbDigestType digest_type,
251 uint8_t* out_digest);
253 /* Frees a |AvbSlotVerifyData| including all data it points to. */
254 void avb_slot_verify_data_free(AvbSlotVerifyData* data);
256 /* Performs a full verification of the slot identified by |ab_suffix|
257 * and load and verify the contents of the partitions whose name is in
258 * the NULL-terminated string array |requested_partitions| (each
259 * partition must use hash verification). If not using A/B, pass an
260 * empty string (e.g. "", not NULL) for |ab_suffix|. This parameter
261 * must include the leading underscore, for example "_a" should be
262 * used to refer to the first slot.
264 * Typically the |requested_partitions| array only contains a single
265 * item for the boot partition, 'boot'.
267 * Verification includes loading and verifying data from the 'vbmeta',
268 * the requested hash partitions, and possibly other partitions (with
269 * |ab_suffix| appended), inspecting rollback indexes, and checking if
270 * the public key used to sign the data is acceptable. The functions
271 * in |ops| will be used to do this.
273 * If |out_data| is not NULL, it will be set to a newly allocated
274 * |AvbSlotVerifyData| struct containing all the data needed to
275 * actually boot the slot. This data structure should be freed with
276 * avb_slot_verify_data_free() when you are done with it. See below
277 * for when this is returned.
279 * The |flags| parameter is used to influence the semantics of
280 * avb_slot_verify() - for example the
281 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR flag can be used to
282 * ignore verification errors which is something needed in the
283 * UNLOCKED state. See the AvbSlotVerifyFlags enumeration for details.
285 * The |hashtree_error_mode| parameter should be set to the desired
286 * error handling mode when hashtree validation fails inside the
287 * HLOS. This value isn't used by libavb per se - it is forwarded to
288 * the HLOS through the androidboot.veritymode and
289 * androidboot.vbmeta.invalidate_on_error cmdline parameters. See the
290 * AvbHashtreeErrorMode enumeration for details.
292 * Also note that |out_data| is never set if
293 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM, AVB_SLOT_VERIFY_RESULT_ERROR_IO,
294 * or AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned.
296 * AVB_SLOT_VERIFY_RESULT_OK is returned if everything is verified
297 * correctly and all public keys are accepted.
299 * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED is returned if
300 * everything is verified correctly out but one or more public keys
301 * are not accepted. This includes the case where integrity data is
304 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM is returned if unable to
307 * AVB_SLOT_VERIFY_RESULT_ERROR_IO is returned if an I/O error
308 * occurred while trying to load data or get a rollback index.
310 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION is returned if the data
311 * did not verify, e.g. the digest didn't match or signature checks
314 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned if a
315 * rollback index was less than its stored value.
317 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned if some
318 * of the metadata is invalid or inconsistent.
320 * AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION is returned if
321 * some of the metadata requires a newer version of libavb than what
324 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT is returned if the
325 * caller passed invalid parameters, for example trying to use
326 * AVB_HASHTREE_ERROR_MODE_LOGGING without
327 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR.
329 AvbSlotVerifyResult avb_slot_verify(AvbOps* ops,
330 const char* const* requested_partitions,
331 const char* ab_suffix,
332 AvbSlotVerifyFlags flags,
333 AvbHashtreeErrorMode hashtree_error_mode,
334 AvbSlotVerifyData** out_data);
340 #endif /* AVB_SLOT_VERIFY_H_ */