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 <crypto/internal/hash.h>
20 #include <linux/init.h>
21 #include <linux/module.h>
22 #include <linux/mm.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
sha1_init(struct shash_desc * desc)34 static int sha1_init(struct shash_desc *desc)
35 {
36 struct sha1_ctx *sctx = shash_desc_ctx(desc);
37
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 return 0;
47 }
48
sha1_update(struct shash_desc * desc,const u8 * data,unsigned int len)49 static int sha1_update(struct shash_desc *desc, const u8 *data,
50 unsigned int len)
51 {
52 struct sha1_ctx *sctx = shash_desc_ctx(desc);
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 return 0;
82 }
83
84
85 /* Add padding and return the message digest. */
sha1_final(struct shash_desc * desc,u8 * out)86 static int sha1_final(struct shash_desc *desc, u8 *out)
87 {
88 struct sha1_ctx *sctx = shash_desc_ctx(desc);
89 __be32 *dst = (__be32 *)out;
90 u32 i, index, padlen;
91 __be64 bits;
92 static const u8 padding[64] = { 0x80, };
93
94 bits = cpu_to_be64(sctx->count << 3);
95
96 /* Pad out to 56 mod 64 */
97 index = sctx->count & 0x3f;
98 padlen = (index < 56) ? (56 - index) : ((64+56) - index);
99 sha1_update(desc, padding, padlen);
100
101 /* Append length */
102 sha1_update(desc, (const u8 *)&bits, sizeof(bits));
103
104 /* Store state in digest */
105 for (i = 0; i < 5; i++)
106 dst[i] = cpu_to_be32(sctx->state[i]);
107
108 /* Wipe context */
109 memset(sctx, 0, sizeof *sctx);
110
111 return 0;
112 }
113
114 static struct shash_alg alg = {
115 .digestsize = SHA1_DIGEST_SIZE,
116 .init = sha1_init,
117 .update = sha1_update,
118 .final = sha1_final,
119 .descsize = sizeof(struct sha1_ctx),
120 .base = {
121 .cra_name = "sha1",
122 .cra_driver_name= "sha1-generic",
123 .cra_flags = CRYPTO_ALG_TYPE_SHASH,
124 .cra_blocksize = SHA1_BLOCK_SIZE,
125 .cra_module = THIS_MODULE,
126 }
127 };
128
sha1_generic_mod_init(void)129 static int __init sha1_generic_mod_init(void)
130 {
131 return crypto_register_shash(&alg);
132 }
133
sha1_generic_mod_fini(void)134 static void __exit sha1_generic_mod_fini(void)
135 {
136 crypto_unregister_shash(&alg);
137 }
138
139 module_init(sha1_generic_mod_init);
140 module_exit(sha1_generic_mod_fini);
141
142 MODULE_LICENSE("GPL");
143 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");
144
145 MODULE_ALIAS("sha1");
146