the-tree/crypto/crc32_generic.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright 2012 Xyratex Technology Limited
0004  */
0005
0006 /*
0007  * This is crypto api shash wrappers to crc32_le.
0008  */
0009
0010 #include <asm/unaligned.h>
0011 #include <linux/crc32.h>
0012 #include <crypto/internal/hash.h>
0013 #include <linux/init.h>
0014 #include <linux/module.h>
0015 #include <linux/string.h>
0016 #include <linux/kernel.h>
0017
0018 #define CHKSUM_BLOCK_SIZE   1
0019 #define CHKSUM_DIGEST_SIZE  4
0020
0021 /** No default init with ~0 */
0022 static int crc32_cra_init(struct crypto_tfm *tfm)
0023 {
0024     u32 *key = crypto_tfm_ctx(tfm);
0025
0026     *key = 0;
0027
0028     return 0;
0029 }
0030
0031 /*
0032  * Setting the seed allows arbitrary accumulators and flexible XOR policy
0033  * If your algorithm starts with ~0, then XOR with ~0 before you set
0034  * the seed.
0035  */
0036 static int crc32_setkey(struct crypto_shash *hash, const u8 *key,
0037             unsigned int keylen)
0038 {
0039     u32 *mctx = crypto_shash_ctx(hash);
0040
0041     if (keylen != sizeof(u32))
0042         return -EINVAL;
0043     *mctx = get_unaligned_le32(key);
0044     return 0;
0045 }
0046
0047 static int crc32_init(struct shash_desc *desc)
0048 {
0049     u32 *mctx = crypto_shash_ctx(desc->tfm);
0050     u32 *crcp = shash_desc_ctx(desc);
0051
0052     *crcp = *mctx;
0053
0054     return 0;
0055 }
0056
0057 static int crc32_update(struct shash_desc *desc, const u8 *data,
0058             unsigned int len)
0059 {
0060     u32 *crcp = shash_desc_ctx(desc);
0061
0062     *crcp = crc32_le(*crcp, data, len);
0063     return 0;
0064 }
0065
0066 /* No final XOR 0xFFFFFFFF, like crc32_le */
0067 static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len,
0068              u8 *out)
0069 {
0070     put_unaligned_le32(crc32_le(*crcp, data, len), out);
0071     return 0;
0072 }
0073
0074 static int crc32_finup(struct shash_desc *desc, const u8 *data,
0075                unsigned int len, u8 *out)
0076 {
0077     return __crc32_finup(shash_desc_ctx(desc), data, len, out);
0078 }
0079
0080 static int crc32_final(struct shash_desc *desc, u8 *out)
0081 {
0082     u32 *crcp = shash_desc_ctx(desc);
0083
0084     put_unaligned_le32(*crcp, out);
0085     return 0;
0086 }
0087
0088 static int crc32_digest(struct shash_desc *desc, const u8 *data,
0089             unsigned int len, u8 *out)
0090 {
0091     return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len,
0092                  out);
0093 }
0094 static struct shash_alg alg = {
0095     .setkey     = crc32_setkey,
0096     .init       = crc32_init,
0097     .update     = crc32_update,
0098     .final      = crc32_final,
0099     .finup      = crc32_finup,
0100     .digest     = crc32_digest,
0101     .descsize   = sizeof(u32),
0102     .digestsize = CHKSUM_DIGEST_SIZE,
0103     .base       = {
0104         .cra_name       = "crc32",
0105         .cra_driver_name    = "crc32-generic",
0106         .cra_priority       = 100,
0107         .cra_flags      = CRYPTO_ALG_OPTIONAL_KEY,
0108         .cra_blocksize      = CHKSUM_BLOCK_SIZE,
0109         .cra_ctxsize        = sizeof(u32),
0110         .cra_module     = THIS_MODULE,
0111         .cra_init       = crc32_cra_init,
0112     }
0113 };
0114
0115 static int __init crc32_mod_init(void)
0116 {
0117     return crypto_register_shash(&alg);
0118 }
0119
0120 static void __exit crc32_mod_fini(void)
0121 {
0122     crypto_unregister_shash(&alg);
0123 }
0124
0125 subsys_initcall(crc32_mod_init);
0126 module_exit(crc32_mod_fini);
0127
0128 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
0129 MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
0130 MODULE_LICENSE("GPL");
0131 MODULE_ALIAS_CRYPTO("crc32");
0132 MODULE_ALIAS_CRYPTO("crc32-generic");