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(void *ctx) 38 { 39 struct sha1_ctx *sctx = ctx; 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(void *ctx, const u8 *data, unsigned int len) 50 { 51 struct sha1_ctx *sctx = ctx; 52 unsigned int partial, done; 53 const u8 *src; 54 55 partial = sctx->count & 0x3f; 56 sctx->count += len; 57 done = 0; 58 src = data; 59 60 if ((partial + len) > 63) { 61 u32 temp[SHA_WORKSPACE_WORDS]; 62 63 if (partial) { 64 done = -partial; 65 memcpy(sctx->buffer + partial, data, done + 64); 66 src = sctx->buffer; 67 } 68 69 do { 70 sha_transform(sctx->state, src, temp); 71 done += 64; 72 src = data + done; 73 } while (done + 63 < len); 74 75 memset(temp, 0, sizeof(temp)); 76 partial = 0; 77 } 78 memcpy(sctx->buffer + partial, src, len - done); 79 } 80 81 82 /* Add padding and return the message digest. */ 83 static void sha1_final(void* ctx, u8 *out) 84 { 85 struct sha1_ctx *sctx = ctx; 86 __be32 *dst = (__be32 *)out; 87 u32 i, index, padlen; 88 __be64 bits; 89 static const u8 padding[64] = { 0x80, }; 90 91 bits = cpu_to_be64(sctx->count << 3); 92 93 /* Pad out to 56 mod 64 */ 94 index = sctx->count & 0x3f; 95 padlen = (index < 56) ? (56 - index) : ((64+56) - index); 96 sha1_update(sctx, padding, padlen); 97 98 /* Append length */ 99 sha1_update(sctx, (const u8 *)&bits, sizeof(bits)); 100 101 /* Store state in digest */ 102 for (i = 0; i < 5; i++) 103 dst[i] = cpu_to_be32(sctx->state[i]); 104 105 /* Wipe context */ 106 memset(sctx, 0, sizeof *sctx); 107 } 108 109 static struct crypto_alg alg = { 110 .cra_name = "sha1", 111 .cra_flags = CRYPTO_ALG_TYPE_DIGEST, 112 .cra_blocksize = SHA1_HMAC_BLOCK_SIZE, 113 .cra_ctxsize = sizeof(struct sha1_ctx), 114 .cra_module = THIS_MODULE, 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