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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Permission is hereby granted, free of charge, to any person
      5  * obtaining a copy of this software and associated documentation
      6  * files (the "Software"), to deal in the Software without
      7  * restriction, including without limitation the rights to use, copy,
      8  * modify, merge, publish, distribute, sublicense, and/or sell copies
      9  * of the Software, and to permit persons to whom the Software is
     10  * furnished to do so, subject to the following conditions:
     11  *
     12  * The above copyright notice and this permission notice shall be
     13  * included in all copies or substantial portions of the Software.
     14  *
     15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
     19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
     20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     22  * SOFTWARE.
     23  */
     24 
     25 #include "avb_chain_partition_descriptor.h"
     26 #include "avb_util.h"
     27 
     28 bool avb_chain_partition_descriptor_validate_and_byteswap(
     29     const AvbChainPartitionDescriptor* src, AvbChainPartitionDescriptor* dest) {
     30   uint64_t expected_size;
     31 
     32   avb_memcpy(dest, src, sizeof(AvbChainPartitionDescriptor));
     33 
     34   if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
     35                                             (AvbDescriptor*)dest))
     36     return false;
     37 
     38   if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_CHAIN_PARTITION) {
     39     avb_error("Invalid tag for chain partition descriptor.\n");
     40     return false;
     41   }
     42 
     43   dest->rollback_index_location = avb_be32toh(dest->rollback_index_location);
     44   dest->partition_name_len = avb_be32toh(dest->partition_name_len);
     45   dest->public_key_len = avb_be32toh(dest->public_key_len);
     46 
     47   if (dest->rollback_index_location < 1) {
     48     avb_error("Invalid rollback index location value.\n");
     49     return false;
     50   }
     51 
     52   /* Check that partition_name and public_key are fully contained. */
     53   expected_size = sizeof(AvbChainPartitionDescriptor) - sizeof(AvbDescriptor);
     54   if (!avb_safe_add_to(&expected_size, dest->partition_name_len) ||
     55       !avb_safe_add_to(&expected_size, dest->public_key_len)) {
     56     avb_error("Overflow while adding up sizes.\n");
     57     return false;
     58   }
     59   if (expected_size > dest->parent_descriptor.num_bytes_following) {
     60     avb_error("Descriptor payload size overflow.\n");
     61     return false;
     62   }
     63   return true;
     64 }
     65