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 <linux/init.h> 20 #include <linux/module.h> 21 #include <linux/mm.h> 22 #include <linux/crypto.h> 23 #include <linux/cryptohash.h> 24 #include <linux/types.h> 25 #include <asm/scatterlist.h> 26 #include <asm/byteorder.h> 27 28 #define SHA1_DIGEST_SIZE 20 29 #define SHA1_HMAC_BLOCK_SIZE 64 30 31 struct sha1_ctx { 32 u64 count; 33 u32 state[5]; 34 u8 buffer[64]; 35 }; 36 37 static void sha1_init(struct crypto_tfm *tfm) 38 { 39 struct sha1_ctx *sctx = crypto_tfm_ctx(tfm); 40 static const struct sha1_ctx initstate = { 41 0, 42 { 0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0 }, 43 { 0, } 44 }; 45 46 *sctx = initstate; 47 } 48 49 static void sha1_update(struct crypto_tfm *tfm, const u8 *data, 50 unsigned int len) 51 { 52 struct sha1_ctx *sctx = crypto_tfm_ctx(tfm); 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 82 83 /* Add padding and return the message digest. */ 84 static void sha1_final(struct crypto_tfm *tfm, u8 *out) 85 { 86 struct sha1_ctx *sctx = crypto_tfm_ctx(tfm); 87 __be32 *dst = (__be32 *)out; 88 u32 i, index, padlen; 89 __be64 bits; 90 static const u8 padding[64] = { 0x80, }; 91 92 bits = cpu_to_be64(sctx->count << 3); 93 94 /* Pad out to 56 mod 64 */ 95 index = sctx->count & 0x3f; 96 padlen = (index < 56) ? (56 - index) : ((64+56) - index); 97 sha1_update(tfm, padding, padlen); 98 99 /* Append length */ 100 sha1_update(tfm, (const u8 *)&bits, sizeof(bits)); 101 102 /* Store state in digest */ 103 for (i = 0; i < 5; i++) 104 dst[i] = cpu_to_be32(sctx->state[i]); 105 106 /* Wipe context */ 107 memset(sctx, 0, sizeof *sctx); 108 } 109 110 static struct crypto_alg alg = { 111 .cra_name = "sha1", 112 .cra_driver_name= "sha1-generic", 113 .cra_flags = CRYPTO_ALG_TYPE_DIGEST, 114 .cra_blocksize = SHA1_HMAC_BLOCK_SIZE, 115 .cra_ctxsize = sizeof(struct sha1_ctx), 116 .cra_module = THIS_MODULE, 117 .cra_alignmask = 3, 118 .cra_list = LIST_HEAD_INIT(alg.cra_list), 119 .cra_u = { .digest = { 120 .dia_digestsize = SHA1_DIGEST_SIZE, 121 .dia_init = sha1_init, 122 .dia_update = sha1_update, 123 .dia_final = sha1_final } } 124 }; 125 126 static int __init init(void) 127 { 128 return crypto_register_alg(&alg); 129 } 130 131 static void __exit fini(void) 132 { 133 crypto_unregister_alg(&alg); 134 } 135 136 module_init(init); 137 module_exit(fini); 138 139 MODULE_LICENSE("GPL"); 140 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm"); 141 142 MODULE_ALIAS("sha1-generic"); 143