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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_hash_descriptor.h"
     26 #include "avb_util.h"
     27 
     28 bool avb_hash_descriptor_validate_and_byteswap(const AvbHashDescriptor* src,
     29                                                AvbHashDescriptor* dest) {
     30   uint64_t expected_size;
     31 
     32   avb_memcpy(dest, src, sizeof(AvbHashDescriptor));
     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_HASH) {
     39     avb_error("Invalid tag for hash descriptor.\n");
     40     return false;
     41   }
     42 
     43   dest->image_size = avb_be64toh(dest->image_size);
     44   dest->partition_name_len = avb_be32toh(dest->partition_name_len);
     45   dest->salt_len = avb_be32toh(dest->salt_len);
     46   dest->digest_len = avb_be32toh(dest->digest_len);
     47   dest->flags = avb_be32toh(dest->flags);
     48 
     49   /* Check that partition_name, salt, and digest are fully contained. */
     50   expected_size = sizeof(AvbHashDescriptor) - sizeof(AvbDescriptor);
     51   if (!avb_safe_add_to(&expected_size, dest->partition_name_len) ||
     52       !avb_safe_add_to(&expected_size, dest->salt_len) ||
     53       !avb_safe_add_to(&expected_size, dest->digest_len)) {
     54     avb_error("Overflow while adding up sizes.\n");
     55     return false;
     56   }
     57   if (expected_size > dest->parent_descriptor.num_bytes_following) {
     58     avb_error("Descriptor payload size overflow.\n");
     59     return false;
     60   }
     61   return true;
     62 }
     63