xref: /openbmc/linux/arch/s390/crypto/sha_common.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f)
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 "sha.h"
18 #include "crypt_s390.h"
19 
20 int s390_sha_update(struct shash_desc *desc, const u8 *data, unsigned int len)
21 {
22 	struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
23 	unsigned int bsize = crypto_shash_blocksize(desc->tfm);
24 	unsigned int index;
25 	int ret;
26 
27 	/* how much is already in the buffer? */
28 	index = ctx->count & (bsize - 1);
29 	ctx->count += len;
30 
31 	if ((index + len) < bsize)
32 		goto store;
33 
34 	/* process one stored block */
35 	if (index) {
36 		memcpy(ctx->buf + index, data, bsize - index);
37 		ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, bsize);
38 		BUG_ON(ret != bsize);
39 		data += bsize - index;
40 		len -= bsize - index;
41 	}
42 
43 	/* process as many blocks as possible */
44 	if (len >= bsize) {
45 		ret = crypt_s390_kimd(ctx->func, ctx->state, data,
46 				      len & ~(bsize - 1));
47 		BUG_ON(ret != (len & ~(bsize - 1)));
48 		data += ret;
49 		len -= ret;
50 	}
51 store:
52 	if (len)
53 		memcpy(ctx->buf + index , data, len);
54 
55 	return 0;
56 }
57 EXPORT_SYMBOL_GPL(s390_sha_update);
58 
59 int s390_sha_final(struct shash_desc *desc, u8 *out)
60 {
61 	struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
62 	unsigned int bsize = crypto_shash_blocksize(desc->tfm);
63 	u64 bits;
64 	unsigned int index, end, plen;
65 	int ret;
66 
67 	/* SHA-512 uses 128 bit padding length */
68 	plen = (bsize > SHA256_BLOCK_SIZE) ? 16 : 8;
69 
70 	/* must perform manual padding */
71 	index = ctx->count & (bsize - 1);
72 	end = (index < bsize - plen) ? bsize : (2 * bsize);
73 
74 	/* start pad with 1 */
75 	ctx->buf[index] = 0x80;
76 	index++;
77 
78 	/* pad with zeros */
79 	memset(ctx->buf + index, 0x00, end - index - 8);
80 
81 	/*
82 	 * Append message length. Well, SHA-512 wants a 128 bit length value,
83 	 * nevertheless we use u64, should be enough for now...
84 	 */
85 	bits = ctx->count * 8;
86 	memcpy(ctx->buf + end - 8, &bits, sizeof(bits));
87 
88 	ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, end);
89 	BUG_ON(ret != end);
90 
91 	/* copy digest to out */
92 	memcpy(out, ctx->state, crypto_shash_digestsize(desc->tfm));
93 	/* wipe context */
94 	memset(ctx, 0, sizeof *ctx);
95 
96 	return 0;
97 }
98 EXPORT_SYMBOL_GPL(s390_sha_final);
99 
100 MODULE_LICENSE("GPL");
101 MODULE_DESCRIPTION("s390 SHA cipher common functions");
102