1 /* 2 * Cryptographic API. 3 * 4 * SHA1 Secure Hash Algorithm. 5 * 6 * Derived from cryptoapi implementation, adapted for in-place 7 * scatterlist interface. 8 * 9 * Copyright (c) Alan Smithee. 10 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk> 11 * Copyright (c) Jean-Francois Dive <jef@linuxbe.org> 12 * 13 * This program is free software; you can redistribute it and/or modify it 14 * under the terms of the GNU General Public License as published by the Free 15 * Software Foundation; either version 2 of the License, or (at your option) 16 * any later version. 17 * 18 */ 19 #include <crypto/internal/hash.h> 20 #include <linux/init.h> 21 #include <linux/module.h> 22 #include <linux/mm.h> 23 #include <linux/cryptohash.h> 24 #include <linux/types.h> 25 #include <crypto/sha.h> 26 #include <asm/byteorder.h> 27 28 struct sha1_ctx { 29 u64 count; 30 u32 state[5]; 31 u8 buffer[64]; 32 }; 33 34 static int sha1_init(struct shash_desc *desc) 35 { 36 struct sha1_ctx *sctx = shash_desc_ctx(desc); 37 38 static const struct sha1_ctx initstate = { 39 0, 40 { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 }, 41 { 0, } 42 }; 43 44 *sctx = initstate; 45 46 return 0; 47 } 48 49 static int sha1_update(struct shash_desc *desc, const u8 *data, 50 unsigned int len) 51 { 52 struct sha1_ctx *sctx = shash_desc_ctx(desc); 53 unsigned int partial, done; 54 const u8 *src; 55 56 partial = sctx->count & 0x3f; 57 sctx->count += len; 58 done = 0; 59 src = data; 60 61 if ((partial + len) > 63) { 62 u32 temp[SHA_WORKSPACE_WORDS]; 63 64 if (partial) { 65 done = -partial; 66 memcpy(sctx->buffer + partial, data, done + 64); 67 src = sctx->buffer; 68 } 69 70 do { 71 sha_transform(sctx->state, src, temp); 72 done += 64; 73 src = data + done; 74 } while (done + 63 < len); 75 76 memset(temp, 0, sizeof(temp)); 77 partial = 0; 78 } 79 memcpy(sctx->buffer + partial, src, len - done); 80 81 return 0; 82 } 83 84 85 /* Add padding and return the message digest. */ 86 static int sha1_final(struct shash_desc *desc, u8 *out) 87 { 88 struct sha1_ctx *sctx = shash_desc_ctx(desc); 89 __be32 *dst = (__be32 *)out; 90 u32 i, index, padlen; 91 __be64 bits; 92 static const u8 padding[64] = { 0x80, }; 93 94 bits = cpu_to_be64(sctx->count << 3); 95 96 /* Pad out to 56 mod 64 */ 97 index = sctx->count & 0x3f; 98 padlen = (index < 56) ? (56 - index) : ((64+56) - index); 99 sha1_update(desc, padding, padlen); 100 101 /* Append length */ 102 sha1_update(desc, (const u8 *)&bits, sizeof(bits)); 103 104 /* Store state in digest */ 105 for (i = 0; i < 5; i++) 106 dst[i] = cpu_to_be32(sctx->state[i]); 107 108 /* Wipe context */ 109 memset(sctx, 0, sizeof *sctx); 110 111 return 0; 112 } 113 114 static struct shash_alg alg = { 115 .digestsize = SHA1_DIGEST_SIZE, 116 .init = sha1_init, 117 .update = sha1_update, 118 .final = sha1_final, 119 .descsize = sizeof(struct sha1_ctx), 120 .base = { 121 .cra_name = "sha1", 122 .cra_driver_name= "sha1-generic", 123 .cra_flags = CRYPTO_ALG_TYPE_SHASH, 124 .cra_blocksize = SHA1_BLOCK_SIZE, 125 .cra_module = THIS_MODULE, 126 } 127 }; 128 129 static int __init sha1_generic_mod_init(void) 130 { 131 return crypto_register_shash(&alg); 132 } 133 134 static void __exit sha1_generic_mod_fini(void) 135 { 136 crypto_unregister_shash(&alg); 137 } 138 139 module_init(sha1_generic_mod_init); 140 module_exit(sha1_generic_mod_fini); 141 142 MODULE_LICENSE("GPL"); 143 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm"); 144 145 MODULE_ALIAS("sha1"); 146