livefiles_cs_plugin/lf_cs_checksum.c

   1 //
   2 // Copyright (c) 2009-2019 Apple Inc. All rights reserved.
   3 //
   4 // lf_cs_checksum.h - Implements checksum handling for livefiles
   5 //                    Apple_CoreStorage plugin.
   6 //
   7 // This implementation is copied from CoreStorage project.
   8 //
   9
  10 #include "lf_cs_checksum.h"
  11
  12 //
  13 // CRC32-C using polynomial 0x1EDC6F41
  14 //
  15 static const uint32_t crc32_table[256] = {
  16         0x00000000, 0xf26b8303, 0xe13b70f7, 0x1350f3f4,
  17         0xc79a971f, 0x35f1141c, 0x26a1e7e8, 0xd4ca64eb,
  18         0x8ad958cf, 0x78b2dbcc, 0x6be22838, 0x9989ab3b,
  19         0x4d43cfd0, 0xbf284cd3, 0xac78bf27, 0x5e133c24,
  20         0x105ec76f, 0xe235446c, 0xf165b798, 0x030e349b,
  21         0xd7c45070, 0x25afd373, 0x36ff2087, 0xc494a384,
  22         0x9a879fa0, 0x68ec1ca3, 0x7bbcef57, 0x89d76c54,
  23         0x5d1d08bf, 0xaf768bbc, 0xbc267848, 0x4e4dfb4b,
  24         0x20bd8ede, 0xd2d60ddd, 0xc186fe29, 0x33ed7d2a,
  25         0xe72719c1, 0x154c9ac2, 0x061c6936, 0xf477ea35,
  26         0xaa64d611, 0x580f5512, 0x4b5fa6e6, 0xb93425e5,
  27         0x6dfe410e, 0x9f95c20d, 0x8cc531f9, 0x7eaeb2fa,
  28         0x30e349b1, 0xc288cab2, 0xd1d83946, 0x23b3ba45,
  29         0xf779deae, 0x05125dad, 0x1642ae59, 0xe4292d5a,
  30         0xba3a117e, 0x4851927d, 0x5b016189, 0xa96ae28a,
  31         0x7da08661, 0x8fcb0562, 0x9c9bf696, 0x6ef07595,
  32         0x417b1dbc, 0xb3109ebf, 0xa0406d4b, 0x522bee48,
  33         0x86e18aa3, 0x748a09a0, 0x67dafa54, 0x95b17957,
  34         0xcba24573, 0x39c9c670, 0x2a993584, 0xd8f2b687,
  35         0x0c38d26c, 0xfe53516f, 0xed03a29b, 0x1f682198,
  36         0x5125dad3, 0xa34e59d0, 0xb01eaa24, 0x42752927,
  37         0x96bf4dcc, 0x64d4cecf, 0x77843d3b, 0x85efbe38,
  38         0xdbfc821c, 0x2997011f, 0x3ac7f2eb, 0xc8ac71e8,
  39         0x1c661503, 0xee0d9600, 0xfd5d65f4, 0x0f36e6f7,
  40         0x61c69362, 0x93ad1061, 0x80fde395, 0x72966096,
  41         0xa65c047d, 0x5437877e, 0x4767748a, 0xb50cf789,
  42         0xeb1fcbad, 0x197448ae, 0x0a24bb5a, 0xf84f3859,
  43         0x2c855cb2, 0xdeeedfb1, 0xcdbe2c45, 0x3fd5af46,
  44         0x7198540d, 0x83f3d70e, 0x90a324fa, 0x62c8a7f9,
  45         0xb602c312, 0x44694011, 0x5739b3e5, 0xa55230e6,
  46         0xfb410cc2, 0x092a8fc1, 0x1a7a7c35, 0xe811ff36,
  47         0x3cdb9bdd, 0xceb018de, 0xdde0eb2a, 0x2f8b6829,
  48         0x82f63b78, 0x709db87b, 0x63cd4b8f, 0x91a6c88c,
  49         0x456cac67, 0xb7072f64, 0xa457dc90, 0x563c5f93,
  50         0x082f63b7, 0xfa44e0b4, 0xe9141340, 0x1b7f9043,
  51         0xcfb5f4a8, 0x3dde77ab, 0x2e8e845f, 0xdce5075c,
  52         0x92a8fc17, 0x60c37f14, 0x73938ce0, 0x81f80fe3,
  53         0x55326b08, 0xa759e80b, 0xb4091bff, 0x466298fc,
  54         0x1871a4d8, 0xea1a27db, 0xf94ad42f, 0x0b21572c,
  55         0xdfeb33c7, 0x2d80b0c4, 0x3ed04330, 0xccbbc033,
  56         0xa24bb5a6, 0x502036a5, 0x4370c551, 0xb11b4652,
  57         0x65d122b9, 0x97baa1ba, 0x84ea524e, 0x7681d14d,
  58         0x2892ed69, 0xdaf96e6a, 0xc9a99d9e, 0x3bc21e9d,
  59         0xef087a76, 0x1d63f975, 0x0e330a81, 0xfc588982,
  60         0xb21572c9, 0x407ef1ca, 0x532e023e, 0xa145813d,
  61         0x758fe5d6, 0x87e466d5, 0x94b49521, 0x66df1622,
  62         0x38cc2a06, 0xcaa7a905, 0xd9f75af1, 0x2b9cd9f2,
  63         0xff56bd19, 0x0d3d3e1a, 0x1e6dcdee, 0xec064eed,
  64         0xc38d26c4, 0x31e6a5c7, 0x22b65633, 0xd0ddd530,
  65         0x0417b1db, 0xf67c32d8, 0xe52cc12c, 0x1747422f,
  66         0x49547e0b, 0xbb3ffd08, 0xa86f0efc, 0x5a048dff,
  67         0x8ecee914, 0x7ca56a17, 0x6ff599e3, 0x9d9e1ae0,
  68         0xd3d3e1ab, 0x21b862a8, 0x32e8915c, 0xc083125f,
  69         0x144976b4, 0xe622f5b7, 0xf5720643, 0x07198540,
  70         0x590ab964, 0xab613a67, 0xb831c993, 0x4a5a4a90,
  71         0x9e902e7b, 0x6cfbad78, 0x7fab5e8c, 0x8dc0dd8f,
  72         0xe330a81a, 0x115b2b19, 0x020bd8ed, 0xf0605bee,
  73         0x24aa3f05, 0xd6c1bc06, 0xc5914ff2, 0x37faccf1,
  74         0x69e9f0d5, 0x9b8273d6, 0x88d28022, 0x7ab90321,
  75         0xae7367ca, 0x5c18e4c9, 0x4f48173d, 0xbd23943e,
  76         0xf36e6f75, 0x0105ec76, 0x12551f82, 0xe03e9c81,
  77         0x34f4f86a, 0xc69f7b69, 0xd5cf889d, 0x27a40b9e,
  78         0x79b737ba, 0x8bdcb4b9, 0x988c474d, 0x6ae7c44e,
  79         0xbe2da0a5, 0x4c4623a6, 0x5f16d052, 0xad7d5351
  80 };
  81
  82 //
  83 // Initialize 'cksum' buffer for the cksum function for a given
  84 // algorithm 'alg'.  Doubles as alg verification for probe/boot.
  85 //
  86 bool
  87 cksum_init(cksum_alg_t alg, uint8_t cksum[MAX_CKSUM_NBYTES])
  88 {
  89         switch (alg) {
  90
  91         case CKSUM_NONE:
  92                 memset(cksum, 0, MAX_CKSUM_NBYTES);
  93                 break;
  94
  95         case CKSUM_ALG_CRC_32:
  96                 memset(cksum, ~0, MAX_CKSUM_NBYTES);
  97                 break;
  98
  99         default:
 100                 return false;
 101
 102         }
 103
 104         return true;
 105 }
 106
 107 //
 108 // cksum - Apply passed checksum algorithm.
 109 //
 110 // Apply checksum algorithm 'alg' to data block 'p' for 'len' bytes and insert
 111 // the result (to max MAX_CKSUM_NBYTES) into 'cksum'.  To support incremental
 112 // cksum calculation the caller is responsible for first initialising the
 113 // 'cksum' buffer (using cksum_init).
 114 //
 115 void
 116 cksum(cksum_alg_t alg, const void *p, size_t len,
 117       uint8_t cksum[MAX_CKSUM_NBYTES])
 118 {
 119         const uint8_t *data = (const uint8_t *)p;
 120         uint32_t c32;
 121
 122         switch (alg) {
 123
 124         case CKSUM_NONE:
 125                 break;
 126
 127         case CKSUM_ALG_CRC_32:
 128
 129                 c32 = *(uint32_t *)cksum;
 130
 131                 while (len-- > 0) {
 132                         c32 = crc32_table[(c32 ^ *data++) & 0xff] ^
 133                                 (c32 >> 8);
 134                 }
 135
 136                 *(uint32_t *)cksum = c32;
 137                 break;
 138         }
 139 }