crypto/crc32_generic.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2012 Xyratex Technology Limited
   4  */
   5
   6 /*
   7  * This is crypto api shash wrappers to crc32_le.
   8  */
   9
  10 #include <linux/unaligned.h>
  11 #include <linux/crc32.h>
  12 #include <crypto/internal/hash.h>
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15 #include <linux/string.h>
  16 #include <linux/kernel.h>
  17
  18 #define CHKSUM_BLOCK_SIZE       1
  19 #define CHKSUM_DIGEST_SIZE      4
  20
  21 /** No default init with ~0 */
  22 static int crc32_cra_init(struct crypto_tfm *tfm)
  23 {
  24         u32 *key = crypto_tfm_ctx(tfm);
  25
  26         *key = 0;
  27
  28         return 0;
  29 }
  30
  31 /*
  32  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  33  * If your algorithm starts with ~0, then XOR with ~0 before you set
  34  * the seed.
  35  */
  36 static int crc32_setkey(struct crypto_shash *hash, const u8 *key,
  37                         unsigned int keylen)
  38 {
  39         u32 *mctx = crypto_shash_ctx(hash);
  40
  41         if (keylen != sizeof(u32))
  42                 return -EINVAL;
  43         *mctx = get_unaligned_le32(key);
  44         return 0;
  45 }
  46
  47 static int crc32_init(struct shash_desc *desc)
  48 {
  49         u32 *mctx = crypto_shash_ctx(desc->tfm);
  50         u32 *crcp = shash_desc_ctx(desc);
  51
  52         *crcp = *mctx;
  53
  54         return 0;
  55 }
  56
  57 static int crc32_update(struct shash_desc *desc, const u8 *data,
  58                         unsigned int len)
  59 {
  60         u32 *crcp = shash_desc_ctx(desc);
  61
  62         *crcp = crc32_le_base(*crcp, data, len);
  63         return 0;
  64 }
  65
  66 static int crc32_update_arch(struct shash_desc *desc, const u8 *data,
  67                              unsigned int len)
  68 {
  69         u32 *crcp = shash_desc_ctx(desc);
  70
  71         *crcp = crc32_le(*crcp, data, len);
  72         return 0;
  73 }
  74
  75 /* No final XOR 0xFFFFFFFF, like crc32_le */
  76 static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len,
  77                          u8 *out)
  78 {
  79         put_unaligned_le32(crc32_le_base(*crcp, data, len), out);
  80         return 0;
  81 }
  82
  83 static int __crc32_finup_arch(u32 *crcp, const u8 *data, unsigned int len,
  84                               u8 *out)
  85 {
  86         put_unaligned_le32(crc32_le(*crcp, data, len), out);
  87         return 0;
  88 }
  89
  90 static int crc32_finup(struct shash_desc *desc, const u8 *data,
  91                        unsigned int len, u8 *out)
  92 {
  93         return __crc32_finup(shash_desc_ctx(desc), data, len, out);
  94 }
  95
  96 static int crc32_finup_arch(struct shash_desc *desc, const u8 *data,
  97                        unsigned int len, u8 *out)
  98 {
  99         return __crc32_finup_arch(shash_desc_ctx(desc), data, len, out);
 100 }
 101
 102 static int crc32_final(struct shash_desc *desc, u8 *out)
 103 {
 104         u32 *crcp = shash_desc_ctx(desc);
 105
 106         put_unaligned_le32(*crcp, out);
 107         return 0;
 108 }
 109
 110 static int crc32_digest(struct shash_desc *desc, const u8 *data,
 111                         unsigned int len, u8 *out)
 112 {
 113         return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, out);
 114 }
 115
 116 static int crc32_digest_arch(struct shash_desc *desc, const u8 *data,
 117                              unsigned int len, u8 *out)
 118 {
 119         return __crc32_finup_arch(crypto_shash_ctx(desc->tfm), data, len, out);
 120 }
 121
 122 static struct shash_alg algs[] = {{
 123         .setkey                 = crc32_setkey,
 124         .init                   = crc32_init,
 125         .update                 = crc32_update,
 126         .final                  = crc32_final,
 127         .finup                  = crc32_finup,
 128         .digest                 = crc32_digest,
 129         .descsize               = sizeof(u32),
 130         .digestsize             = CHKSUM_DIGEST_SIZE,
 131
 132         .base.cra_name          = "crc32",
 133         .base.cra_driver_name   = "crc32-generic",
 134         .base.cra_priority      = 100,
 135         .base.cra_flags         = CRYPTO_ALG_OPTIONAL_KEY,
 136         .base.cra_blocksize     = CHKSUM_BLOCK_SIZE,
 137         .base.cra_ctxsize       = sizeof(u32),
 138         .base.cra_module        = THIS_MODULE,
 139         .base.cra_init          = crc32_cra_init,
 140 }, {
 141         .setkey                 = crc32_setkey,
 142         .init                   = crc32_init,
 143         .update                 = crc32_update_arch,
 144         .final                  = crc32_final,
 145         .finup                  = crc32_finup_arch,
 146         .digest                 = crc32_digest_arch,
 147         .descsize               = sizeof(u32),
 148         .digestsize             = CHKSUM_DIGEST_SIZE,
 149
 150         .base.cra_name          = "crc32",
 151         .base.cra_driver_name   = "crc32-" __stringify(ARCH),
 152         .base.cra_priority      = 150,
 153         .base.cra_flags         = CRYPTO_ALG_OPTIONAL_KEY,
 154         .base.cra_blocksize     = CHKSUM_BLOCK_SIZE,
 155         .base.cra_ctxsize       = sizeof(u32),
 156         .base.cra_module        = THIS_MODULE,
 157         .base.cra_init          = crc32_cra_init,
 158 }};
 159
 160 static int __init crc32_mod_init(void)
 161 {
 162         /* register the arch flavor only if it differs from the generic one */
 163         return crypto_register_shashes(algs, 1 + (&crc32_le != &crc32_le_base));
 164 }
 165
 166 static void __exit crc32_mod_fini(void)
 167 {
 168         crypto_unregister_shashes(algs, 1 + (&crc32_le != &crc32_le_base));
 169 }
 170
 171 subsys_initcall(crc32_mod_init);
 172 module_exit(crc32_mod_fini);
 173
 174 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
 175 MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
 176 MODULE_LICENSE("GPL");
 177 MODULE_ALIAS_CRYPTO("crc32");
 178 MODULE_ALIAS_CRYPTO("crc32-generic");