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 <crypto/sha.h> 26 #include <asm/scatterlist.h> 27 #include <asm/byteorder.h> 28 29 struct sha1_ctx { 30 u64 count; 31 u32 state[5]; 32 u8 buffer[64]; 33 }; 34 35 static void sha1_init(struct crypto_tfm *tfm) 36 { 37 struct sha1_ctx *sctx = crypto_tfm_ctx(tfm); 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 47 static void sha1_update(struct crypto_tfm *tfm, const u8 *data, 48 unsigned int len) 49 { 50 struct sha1_ctx *sctx = crypto_tfm_ctx(tfm); 51 unsigned int partial, done; 52 const u8 *src; 53 54 partial = sctx->count & 0x3f; 55 sctx->count += len; 56 done = 0; 57 src = data; 58 59 if ((partial + len) > 63) { 60 u32 temp[SHA_WORKSPACE_WORDS]; 61 62 if (partial) { 63 done = -partial; 64 memcpy(sctx->buffer + partial, data, done + 64); 65 src = sctx->buffer; 66 } 67 68 do { 69 sha_transform(sctx->state, src, temp); 70 done += 64; 71 src = data + done; 72 } while (done + 63 < len); 73 74 memset(temp, 0, sizeof(temp)); 75 partial = 0; 76 } 77 memcpy(sctx->buffer + partial, src, len - done); 78 } 79 80 81 /* Add padding and return the message digest. */ 82 static void sha1_final(struct crypto_tfm *tfm, u8 *out) 83 { 84 struct sha1_ctx *sctx = crypto_tfm_ctx(tfm); 85 __be32 *dst = (__be32 *)out; 86 u32 i, index, padlen; 87 __be64 bits; 88 static const u8 padding[64] = { 0x80, }; 89 90 bits = cpu_to_be64(sctx->count << 3); 91 92 /* Pad out to 56 mod 64 */ 93 index = sctx->count & 0x3f; 94 padlen = (index < 56) ? (56 - index) : ((64+56) - index); 95 sha1_update(tfm, padding, padlen); 96 97 /* Append length */ 98 sha1_update(tfm, (const u8 *)&bits, sizeof(bits)); 99 100 /* Store state in digest */ 101 for (i = 0; i < 5; i++) 102 dst[i] = cpu_to_be32(sctx->state[i]); 103 104 /* Wipe context */ 105 memset(sctx, 0, sizeof *sctx); 106 } 107 108 static struct crypto_alg alg = { 109 .cra_name = "sha1", 110 .cra_driver_name= "sha1-generic", 111 .cra_flags = CRYPTO_ALG_TYPE_DIGEST, 112 .cra_blocksize = SHA1_BLOCK_SIZE, 113 .cra_ctxsize = sizeof(struct sha1_ctx), 114 .cra_module = THIS_MODULE, 115 .cra_alignmask = 3, 116 .cra_list = LIST_HEAD_INIT(alg.cra_list), 117 .cra_u = { .digest = { 118 .dia_digestsize = SHA1_DIGEST_SIZE, 119 .dia_init = sha1_init, 120 .dia_update = sha1_update, 121 .dia_final = sha1_final } } 122 }; 123 124 static int __init init(void) 125 { 126 return crypto_register_alg(&alg); 127 } 128 129 static void __exit fini(void) 130 { 131 crypto_unregister_alg(&alg); 132 } 133 134 module_init(init); 135 module_exit(fini); 136 137 MODULE_LICENSE("GPL"); 138 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm"); 139 140 MODULE_ALIAS("sha1"); 141