xref: /openbmc/linux/arch/s390/crypto/sha_common.c (revision 95e9fd10)
1 /*
2  * Cryptographic API.
3  *
4  * s390 generic implementation of the SHA Secure Hash Algorithms.
5  *
6  * Copyright IBM Corp. 2007
7  * Author(s): Jan Glauber (jang@de.ibm.com)
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU General Public License as published by the Free
11  * Software Foundation; either version 2 of the License, or (at your option)
12  * any later version.
13  *
14  */
15 
16 #include <crypto/internal/hash.h>
17 #include <linux/module.h>
18 #include "sha.h"
19 #include "crypt_s390.h"
20 
21 int s390_sha_update(struct shash_desc *desc, const u8 *data, unsigned int len)
22 {
23 	struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
24 	unsigned int bsize = crypto_shash_blocksize(desc->tfm);
25 	unsigned int index;
26 	int ret;
27 
28 	/* how much is already in the buffer? */
29 	index = ctx->count & (bsize - 1);
30 	ctx->count += len;
31 
32 	if ((index + len) < bsize)
33 		goto store;
34 
35 	/* process one stored block */
36 	if (index) {
37 		memcpy(ctx->buf + index, data, bsize - index);
38 		ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, bsize);
39 		BUG_ON(ret != bsize);
40 		data += bsize - index;
41 		len -= bsize - index;
42 		index = 0;
43 	}
44 
45 	/* process as many blocks as possible */
46 	if (len >= bsize) {
47 		ret = crypt_s390_kimd(ctx->func, ctx->state, data,
48 				      len & ~(bsize - 1));
49 		BUG_ON(ret != (len & ~(bsize - 1)));
50 		data += ret;
51 		len -= ret;
52 	}
53 store:
54 	if (len)
55 		memcpy(ctx->buf + index , data, len);
56 
57 	return 0;
58 }
59 EXPORT_SYMBOL_GPL(s390_sha_update);
60 
61 int s390_sha_final(struct shash_desc *desc, u8 *out)
62 {
63 	struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
64 	unsigned int bsize = crypto_shash_blocksize(desc->tfm);
65 	u64 bits;
66 	unsigned int index, end, plen;
67 	int ret;
68 
69 	/* SHA-512 uses 128 bit padding length */
70 	plen = (bsize > SHA256_BLOCK_SIZE) ? 16 : 8;
71 
72 	/* must perform manual padding */
73 	index = ctx->count & (bsize - 1);
74 	end = (index < bsize - plen) ? bsize : (2 * bsize);
75 
76 	/* start pad with 1 */
77 	ctx->buf[index] = 0x80;
78 	index++;
79 
80 	/* pad with zeros */
81 	memset(ctx->buf + index, 0x00, end - index - 8);
82 
83 	/*
84 	 * Append message length. Well, SHA-512 wants a 128 bit length value,
85 	 * nevertheless we use u64, should be enough for now...
86 	 */
87 	bits = ctx->count * 8;
88 	memcpy(ctx->buf + end - 8, &bits, sizeof(bits));
89 
90 	ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, end);
91 	BUG_ON(ret != end);
92 
93 	/* copy digest to out */
94 	memcpy(out, ctx->state, crypto_shash_digestsize(desc->tfm));
95 	/* wipe context */
96 	memset(ctx, 0, sizeof *ctx);
97 
98 	return 0;
99 }
100 EXPORT_SYMBOL_GPL(s390_sha_final);
101 
102 MODULE_LICENSE("GPL");
103 MODULE_DESCRIPTION("s390 SHA cipher common functions");
104