1/*
2 * Cryptographic API.
3 *
4 * Digest operations.
5 *
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
11 * any later version.
12 *
13 */
14
15#include <linux/mm.h>
16#include <linux/errno.h>
17#include <linux/hardirq.h>
18#include <linux/highmem.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/scatterlist.h>
22
23#include "internal.h"
24#include "scatterwalk.h"
25
26static int init(struct hash_desc *desc)
27{
28	struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
29
30	tfm->__crt_alg->cra_digest.dia_init(tfm);
31	return 0;
32}
33
34static int update2(struct hash_desc *desc,
35		   struct scatterlist *sg, unsigned int nbytes)
36{
37	struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
38	unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
39
40	if (!nbytes)
41		return 0;
42
43	for (;;) {
44		struct page *pg = sg->page;
45		unsigned int offset = sg->offset;
46		unsigned int l = sg->length;
47
48		if (unlikely(l > nbytes))
49			l = nbytes;
50		nbytes -= l;
51
52		do {
53			unsigned int bytes_from_page = min(l, ((unsigned int)
54							   (PAGE_SIZE)) -
55							   offset);
56			char *src = crypto_kmap(pg, 0);
57			char *p = src + offset;
58
59			if (unlikely(offset & alignmask)) {
60				unsigned int bytes =
61					alignmask + 1 - (offset & alignmask);
62				bytes = min(bytes, bytes_from_page);
63				tfm->__crt_alg->cra_digest.dia_update(tfm, p,
64								      bytes);
65				p += bytes;
66				bytes_from_page -= bytes;
67				l -= bytes;
68			}
69			tfm->__crt_alg->cra_digest.dia_update(tfm, p,
70							      bytes_from_page);
71			crypto_kunmap(src, 0);
72			crypto_yield(desc->flags);
73			offset = 0;
74			pg++;
75			l -= bytes_from_page;
76		} while (l > 0);
77
78		if (!nbytes)
79			break;
80		sg = sg_next(sg);
81	}
82
83	return 0;
84}
85
86static int update(struct hash_desc *desc,
87		  struct scatterlist *sg, unsigned int nbytes)
88{
89	if (WARN_ON_ONCE(in_irq()))
90		return -EDEADLK;
91	return update2(desc, sg, nbytes);
92}
93
94static int final(struct hash_desc *desc, u8 *out)
95{
96	struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
97	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
98	struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
99
100	if (unlikely((unsigned long)out & alignmask)) {
101		unsigned long align = alignmask + 1;
102		unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
103		u8 *dst = (u8 *)ALIGN(addr, align) +
104			  ALIGN(tfm->__crt_alg->cra_ctxsize, align);
105
106		digest->dia_final(tfm, dst);
107		memcpy(out, dst, digest->dia_digestsize);
108	} else
109		digest->dia_final(tfm, out);
110
111	return 0;
112}
113
114static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
115{
116	crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
117	return -ENOSYS;
118}
119
120static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
121{
122	struct crypto_tfm *tfm = crypto_hash_tfm(hash);
123
124	crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
125	return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
126}
127
128static int digest(struct hash_desc *desc,
129		  struct scatterlist *sg, unsigned int nbytes, u8 *out)
130{
131	if (WARN_ON_ONCE(in_irq()))
132		return -EDEADLK;
133
134	init(desc);
135	update2(desc, sg, nbytes);
136	return final(desc, out);
137}
138
139int crypto_init_digest_ops(struct crypto_tfm *tfm)
140{
141	struct hash_tfm *ops = &tfm->crt_hash;
142	struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
143
144	if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
145		return -EINVAL;
146
147	ops->init	= init;
148	ops->update	= update;
149	ops->final	= final;
150	ops->digest	= digest;
151	ops->setkey	= dalg->dia_setkey ? setkey : nosetkey;
152	ops->digestsize	= dalg->dia_digestsize;
153
154	return 0;
155}
156
157void crypto_exit_digest_ops(struct crypto_tfm *tfm)
158{
159}
160