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 <asm/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(*crcp, data, len); 63 return 0; 64 } 65 66 /* No final XOR 0xFFFFFFFF, like crc32_le */ 67 static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len, 68 u8 *out) 69 { 70 put_unaligned_le32(crc32_le(*crcp, data, len), out); 71 return 0; 72 } 73 74 static int crc32_finup(struct shash_desc *desc, const u8 *data, 75 unsigned int len, u8 *out) 76 { 77 return __crc32_finup(shash_desc_ctx(desc), data, len, out); 78 } 79 80 static int crc32_final(struct shash_desc *desc, u8 *out) 81 { 82 u32 *crcp = shash_desc_ctx(desc); 83 84 put_unaligned_le32(*crcp, out); 85 return 0; 86 } 87 88 static int crc32_digest(struct shash_desc *desc, const u8 *data, 89 unsigned int len, u8 *out) 90 { 91 return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, 92 out); 93 } 94 static struct shash_alg alg = { 95 .setkey = crc32_setkey, 96 .init = crc32_init, 97 .update = crc32_update, 98 .final = crc32_final, 99 .finup = crc32_finup, 100 .digest = crc32_digest, 101 .descsize = sizeof(u32), 102 .digestsize = CHKSUM_DIGEST_SIZE, 103 .base = { 104 .cra_name = "crc32", 105 .cra_driver_name = "crc32-generic", 106 .cra_priority = 100, 107 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY, 108 .cra_blocksize = CHKSUM_BLOCK_SIZE, 109 .cra_ctxsize = sizeof(u32), 110 .cra_module = THIS_MODULE, 111 .cra_init = crc32_cra_init, 112 } 113 }; 114 115 static int __init crc32_mod_init(void) 116 { 117 return crypto_register_shash(&alg); 118 } 119 120 static void __exit crc32_mod_fini(void) 121 { 122 crypto_unregister_shash(&alg); 123 } 124 125 subsys_initcall(crc32_mod_init); 126 module_exit(crc32_mod_fini); 127 128 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>"); 129 MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32"); 130 MODULE_LICENSE("GPL"); 131 MODULE_ALIAS_CRYPTO("crc32"); 132 MODULE_ALIAS_CRYPTO("crc32-generic"); 133