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/byteorder.h> 27 28 struct sha1_ctx { 29 u64 count; 30 u32 state[5]; 31 u8 buffer[64]; 32 }; 33 34 static void sha1_init(struct crypto_tfm *tfm) 35 { 36 struct sha1_ctx *sctx = crypto_tfm_ctx(tfm); 37 static const struct sha1_ctx initstate = { 38 0, 39 { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 }, 40 { 0, } 41 }; 42 43 *sctx = initstate; 44 } 45 46 static void sha1_update(struct crypto_tfm *tfm, const u8 *data, 47 unsigned int len) 48 { 49 struct sha1_ctx *sctx = crypto_tfm_ctx(tfm); 50 unsigned int partial, done; 51 const u8 *src; 52 53 partial = sctx->count & 0x3f; 54 sctx->count += len; 55 done = 0; 56 src = data; 57 58 if ((partial + len) > 63) { 59 u32 temp[SHA_WORKSPACE_WORDS]; 60 61 if (partial) { 62 done = -partial; 63 memcpy(sctx->buffer + partial, data, done + 64); 64 src = sctx->buffer; 65 } 66 67 do { 68 sha_transform(sctx->state, src, temp); 69 done += 64; 70 src = data + done; 71 } while (done + 63 < len); 72 73 memset(temp, 0, sizeof(temp)); 74 partial = 0; 75 } 76 memcpy(sctx->buffer + partial, src, len - done); 77 } 78 79 80 /* Add padding and return the message digest. */ 81 static void sha1_final(struct crypto_tfm *tfm, u8 *out) 82 { 83 struct sha1_ctx *sctx = crypto_tfm_ctx(tfm); 84 __be32 *dst = (__be32 *)out; 85 u32 i, index, padlen; 86 __be64 bits; 87 static const u8 padding[64] = { 0x80, }; 88 89 bits = cpu_to_be64(sctx->count << 3); 90 91 /* Pad out to 56 mod 64 */ 92 index = sctx->count & 0x3f; 93 padlen = (index < 56) ? (56 - index) : ((64+56) - index); 94 sha1_update(tfm, padding, padlen); 95 96 /* Append length */ 97 sha1_update(tfm, (const u8 *)&bits, sizeof(bits)); 98 99 /* Store state in digest */ 100 for (i = 0; i < 5; i++) 101 dst[i] = cpu_to_be32(sctx->state[i]); 102 103 /* Wipe context */ 104 memset(sctx, 0, sizeof *sctx); 105 } 106 107 static struct crypto_alg alg = { 108 .cra_name = "sha1", 109 .cra_driver_name= "sha1-generic", 110 .cra_flags = CRYPTO_ALG_TYPE_DIGEST, 111 .cra_blocksize = SHA1_BLOCK_SIZE, 112 .cra_ctxsize = sizeof(struct sha1_ctx), 113 .cra_module = THIS_MODULE, 114 .cra_alignmask = 3, 115 .cra_list = LIST_HEAD_INIT(alg.cra_list), 116 .cra_u = { .digest = { 117 .dia_digestsize = SHA1_DIGEST_SIZE, 118 .dia_init = sha1_init, 119 .dia_update = sha1_update, 120 .dia_final = sha1_final } } 121 }; 122 123 static int __init init(void) 124 { 125 return crypto_register_alg(&alg); 126 } 127 128 static void __exit fini(void) 129 { 130 crypto_unregister_alg(&alg); 131 } 132 133 module_init(init); 134 module_exit(fini); 135 136 MODULE_LICENSE("GPL"); 137 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm"); 138 139 MODULE_ALIAS("sha1"); 140