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
31struct sha1_ctx {
32        u64 count;
33        u32 state[5];
34        u8 buffer[64];
35};
36
37static 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
49static 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. */
84static 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
110static 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
126static int __init init(void)
127{
128	return crypto_register_alg(&alg);
129}
130
131static void __exit fini(void)
132{
133	crypto_unregister_alg(&alg);
134}
135
136module_init(init);
137module_exit(fini);
138
139MODULE_LICENSE("GPL");
140MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");
141
142MODULE_ALIAS("sha1-generic");
143