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(*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, u8 *out) 68 { 69 put_unaligned_le32(crc32_le(*crcp, data, len), out); 70 return 0; 71 } 72 73 static int crc32_finup(struct shash_desc *desc, const u8 *data, 74 unsigned int len, u8 *out) 75 { 76 return __crc32_finup(shash_desc_ctx(desc), data, len, out); 77 } 78 79 static int crc32_final(struct shash_desc *desc, u8 *out) 80 { 81 u32 *crcp = shash_desc_ctx(desc); 82 83 put_unaligned_le32(*crcp, out); 84 return 0; 85 } 86 87 static int crc32_digest(struct shash_desc *desc, const u8 *data, 88 unsigned int len, u8 *out) 89 { 90 return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, out); 91 } 92 93 static struct shash_alg alg = { 94 .setkey = crc32_setkey, 95 .init = crc32_init, 96 .update = crc32_update, 97 .final = crc32_final, 98 .finup = crc32_finup, 99 .digest = crc32_digest, 100 .descsize = sizeof(u32), 101 .digestsize = CHKSUM_DIGEST_SIZE, 102 103 .base.cra_name = "crc32", 104 .base.cra_driver_name = "crc32-lib", 105 .base.cra_priority = 100, 106 .base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY, 107 .base.cra_blocksize = CHKSUM_BLOCK_SIZE, 108 .base.cra_ctxsize = sizeof(u32), 109 .base.cra_module = THIS_MODULE, 110 .base.cra_init = crc32_cra_init, 111 }; 112 113 static int __init crc32_mod_init(void) 114 { 115 return crypto_register_shash(&alg); 116 } 117 118 static void __exit crc32_mod_fini(void) 119 { 120 crypto_unregister_shash(&alg); 121 } 122 123 module_init(crc32_mod_init); 124 module_exit(crc32_mod_fini); 125 126 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>"); 127 MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32"); 128 MODULE_LICENSE("GPL"); 129 MODULE_ALIAS_CRYPTO("crc32"); 130