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227 lines
6.2 KiB
227 lines
6.2 KiB
/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*
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* Misc functions which need access to vb2_context but are not public APIs
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*/
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#include "2sysincludes.h"
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#include "2api.h"
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#include "2misc.h"
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#include "2nvstorage.h"
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#include "2secdata.h"
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#include "2sha.h"
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#include "2rsa.h"
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#include "vb2_common.h"
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int vb2_load_fw_keyblock(struct vb2_context *ctx)
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{
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struct vb2_shared_data *sd = vb2_get_sd(ctx);
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struct vb2_workbuf wb;
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uint8_t *key_data;
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uint32_t key_size;
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struct vb2_packed_key *packed_key;
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struct vb2_public_key root_key;
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struct vb2_keyblock *kb;
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uint32_t block_size;
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int rv;
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vb2_workbuf_from_ctx(ctx, &wb);
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/* Read the root key */
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key_size = sd->gbb_rootkey_size;
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key_data = vb2_workbuf_alloc(&wb, key_size);
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if (!key_data)
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return VB2_ERROR_FW_KEYBLOCK_WORKBUF_ROOT_KEY;
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rv = vb2ex_read_resource(ctx, VB2_RES_GBB, sd->gbb_rootkey_offset,
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key_data, key_size);
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if (rv)
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return rv;
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/* Unpack the root key */
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rv = vb2_unpack_key(&root_key, key_data, key_size);
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if (rv)
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return rv;
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/* Load the firmware keyblock header after the root key */
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kb = vb2_workbuf_alloc(&wb, sizeof(*kb));
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if (!kb)
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return VB2_ERROR_FW_KEYBLOCK_WORKBUF_HEADER;
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rv = vb2ex_read_resource(ctx, VB2_RES_FW_VBLOCK, 0, kb, sizeof(*kb));
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if (rv)
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return rv;
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block_size = kb->keyblock_size;
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/*
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* Load the entire keyblock, now that we know how big it is. Note that
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* we're loading the entire keyblock instead of just the piece after
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* the header. That means we re-read the header. But that's a tiny
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* amount of data, and it makes the code much more straightforward.
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*/
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kb = vb2_workbuf_realloc(&wb, sizeof(*kb), block_size);
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if (!kb)
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return VB2_ERROR_FW_KEYBLOCK_WORKBUF;
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rv = vb2ex_read_resource(ctx, VB2_RES_FW_VBLOCK, 0, kb, block_size);
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if (rv)
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return rv;
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/* Verify the keyblock */
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rv = vb2_verify_keyblock(kb, block_size, &root_key, &wb);
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if (rv) {
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vb2_fail(ctx, VB2_RECOVERY_FW_KEYBLOCK, rv);
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return rv;
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}
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/* Key version is the upper 16 bits of the composite firmware version */
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if (kb->data_key.key_version > 0xffff)
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rv = VB2_ERROR_FW_KEYBLOCK_VERSION_RANGE;
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if (!rv && kb->data_key.key_version < (sd->fw_version_secdata >> 16))
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rv = VB2_ERROR_FW_KEYBLOCK_VERSION_ROLLBACK;
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if (rv) {
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vb2_fail(ctx, VB2_RECOVERY_FW_KEY_ROLLBACK, rv);
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return rv;
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}
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sd->fw_version = kb->data_key.key_version << 16;
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/*
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* Save the data key in the work buffer. This overwrites the root key
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* we read above. That's ok, because now that we have the data key we
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* no longer need the root key.
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*/
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packed_key = (struct vb2_packed_key *)key_data;
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packed_key->algorithm = kb->data_key.algorithm;
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packed_key->key_version = kb->data_key.key_version;
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packed_key->key_size = kb->data_key.key_size;
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/*
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* Use memmove() instead of memcpy(). In theory, the destination will
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* never overlap because with the source because the root key is likely
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* to be at least as large as the data key, but there's no harm here in
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* being paranoid.
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*/
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memmove(key_data + packed_key->key_offset,
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(uint8_t*)&kb->data_key + kb->data_key.key_offset,
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packed_key->key_size);
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/* Save the packed key offset and size */
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sd->workbuf_data_key_offset = vb2_offset_of(ctx->workbuf, key_data);
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sd->workbuf_data_key_size =
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packed_key->key_offset + packed_key->key_size;
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/* Preamble follows the keyblock in the vblock */
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sd->vblock_preamble_offset = kb->keyblock_size;
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/* Data key will persist in the workbuf after we return */
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ctx->workbuf_used = sd->workbuf_data_key_offset +
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sd->workbuf_data_key_size;
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return VB2_SUCCESS;
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}
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int vb2_load_fw_preamble(struct vb2_context *ctx)
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{
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struct vb2_shared_data *sd = vb2_get_sd(ctx);
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struct vb2_workbuf wb;
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uint8_t *key_data = ctx->workbuf + sd->workbuf_data_key_offset;
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uint32_t key_size = sd->workbuf_data_key_size;
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struct vb2_public_key data_key;
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/* Preamble goes in the next unused chunk of work buffer */
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struct vb2_fw_preamble *pre;
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uint32_t pre_size;
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int rv;
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vb2_workbuf_from_ctx(ctx, &wb);
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/* Unpack the firmware data key */
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if (!sd->workbuf_data_key_size)
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return VB2_ERROR_FW_PREAMBLE2_DATA_KEY;
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rv = vb2_unpack_key(&data_key, key_data, key_size);
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if (rv)
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return rv;
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/* Load the firmware preamble header */
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pre = vb2_workbuf_alloc(&wb, sizeof(*pre));
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if (!pre)
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return VB2_ERROR_FW_PREAMBLE2_WORKBUF_HEADER;
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rv = vb2ex_read_resource(ctx, VB2_RES_FW_VBLOCK,
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sd->vblock_preamble_offset,
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pre, sizeof(*pre));
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if (rv)
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return rv;
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pre_size = pre->preamble_size;
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/* Load the entire firmware preamble, now that we know how big it is */
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pre = vb2_workbuf_realloc(&wb, sizeof(*pre), pre_size);
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if (!pre)
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return VB2_ERROR_FW_PREAMBLE2_WORKBUF;
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rv = vb2ex_read_resource(ctx, VB2_RES_FW_VBLOCK,
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sd->vblock_preamble_offset,
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pre, pre_size);
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if (rv)
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return rv;
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/* Work buffer now contains the data subkey data and the preamble */
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/* Verify the preamble */
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rv = vb2_verify_fw_preamble(pre, pre_size, &data_key, &wb);
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if (rv) {
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vb2_fail(ctx, VB2_RECOVERY_FW_PREAMBLE, rv);
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return rv;
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}
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/*
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* Firmware version is the lower 16 bits of the composite firmware
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* version.
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*/
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if (pre->firmware_version > 0xffff)
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rv = VB2_ERROR_FW_PREAMBLE_VERSION_RANGE;
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/* Combine with the key version from vb2_load_fw_keyblock() */
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sd->fw_version |= pre->firmware_version;
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if (!rv && sd->fw_version < sd->fw_version_secdata)
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rv = VB2_ERROR_FW_PREAMBLE_VERSION_ROLLBACK;
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if (rv) {
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vb2_fail(ctx, VB2_RECOVERY_FW_ROLLBACK, rv);
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return rv;
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}
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/*
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* If this is a newer version than in secure storage, and we
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* successfully booted the same slot last boot, roll forward the
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* version in secure storage.
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*/
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if (sd->fw_version > sd->fw_version_secdata &&
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sd->last_fw_slot == sd->fw_slot &&
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sd->last_fw_result == VB2_FW_RESULT_SUCCESS) {
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sd->fw_version_secdata = sd->fw_version;
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rv = vb2_secdata_set(ctx, VB2_SECDATA_VERSIONS, sd->fw_version);
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if (rv)
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return rv;
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}
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/* Keep track of where we put the preamble */
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sd->workbuf_preamble_offset = vb2_offset_of(ctx->workbuf, pre);
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sd->workbuf_preamble_size = pre_size;
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/* Preamble will persist in work buffer after we return */
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ctx->workbuf_used = sd->workbuf_preamble_offset + pre_size;
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return VB2_SUCCESS;
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}
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