Root/crypto/sha1_generic.c

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
28static int sha1_init(struct shash_desc *desc)
29{
30    struct sha1_state *sctx = shash_desc_ctx(desc);
31
32    *sctx = (struct sha1_state){
33        .state = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
34    };
35
36    return 0;
37}
38
39static int sha1_update(struct shash_desc *desc, const u8 *data,
40            unsigned int len)
41{
42    struct sha1_state *sctx = shash_desc_ctx(desc);
43    unsigned int partial, done;
44    const u8 *src;
45
46    partial = sctx->count & 0x3f;
47    sctx->count += len;
48    done = 0;
49    src = data;
50
51    if ((partial + len) > 63) {
52        u32 temp[SHA_WORKSPACE_WORDS];
53
54        if (partial) {
55            done = -partial;
56            memcpy(sctx->buffer + partial, data, done + 64);
57            src = sctx->buffer;
58        }
59
60        do {
61            sha_transform(sctx->state, src, temp);
62            done += 64;
63            src = data + done;
64        } while (done + 63 < len);
65
66        memset(temp, 0, sizeof(temp));
67        partial = 0;
68    }
69    memcpy(sctx->buffer + partial, src, len - done);
70
71    return 0;
72}
73
74
75/* Add padding and return the message digest. */
76static int sha1_final(struct shash_desc *desc, u8 *out)
77{
78    struct sha1_state *sctx = shash_desc_ctx(desc);
79    __be32 *dst = (__be32 *)out;
80    u32 i, index, padlen;
81    __be64 bits;
82    static const u8 padding[64] = { 0x80, };
83
84    bits = cpu_to_be64(sctx->count << 3);
85
86    /* Pad out to 56 mod 64 */
87    index = sctx->count & 0x3f;
88    padlen = (index < 56) ? (56 - index) : ((64+56) - index);
89    sha1_update(desc, padding, padlen);
90
91    /* Append length */
92    sha1_update(desc, (const u8 *)&bits, sizeof(bits));
93
94    /* Store state in digest */
95    for (i = 0; i < 5; i++)
96        dst[i] = cpu_to_be32(sctx->state[i]);
97
98    /* Wipe context */
99    memset(sctx, 0, sizeof *sctx);
100
101    return 0;
102}
103
104static int sha1_export(struct shash_desc *desc, void *out)
105{
106    struct sha1_state *sctx = shash_desc_ctx(desc);
107
108    memcpy(out, sctx, sizeof(*sctx));
109    return 0;
110}
111
112static int sha1_import(struct shash_desc *desc, const void *in)
113{
114    struct sha1_state *sctx = shash_desc_ctx(desc);
115
116    memcpy(sctx, in, sizeof(*sctx));
117    return 0;
118}
119
120static struct shash_alg alg = {
121    .digestsize = SHA1_DIGEST_SIZE,
122    .init = sha1_init,
123    .update = sha1_update,
124    .final = sha1_final,
125    .export = sha1_export,
126    .import = sha1_import,
127    .descsize = sizeof(struct sha1_state),
128    .statesize = sizeof(struct sha1_state),
129    .base = {
130        .cra_name = "sha1",
131        .cra_driver_name= "sha1-generic",
132        .cra_flags = CRYPTO_ALG_TYPE_SHASH,
133        .cra_blocksize = SHA1_BLOCK_SIZE,
134        .cra_module = THIS_MODULE,
135    }
136};
137
138static int __init sha1_generic_mod_init(void)
139{
140    return crypto_register_shash(&alg);
141}
142
143static void __exit sha1_generic_mod_fini(void)
144{
145    crypto_unregister_shash(&alg);
146}
147
148module_init(sha1_generic_mod_init);
149module_exit(sha1_generic_mod_fini);
150
151MODULE_LICENSE("GPL");
152MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");
153
154MODULE_ALIAS("sha1");
155

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