xref: /openbmc/linux/arch/s390/crypto/sha_common.c (revision cfbb9be8)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Cryptographic API.
4  *
5  * s390 generic implementation of the SHA Secure Hash Algorithms.
6  *
7  * Copyright IBM Corp. 2007
8  * Author(s): Jan Glauber (jang@de.ibm.com)
9  */
10 
11 #include <crypto/internal/hash.h>
12 #include <linux/module.h>
13 #include <asm/cpacf.h>
14 #include "sha.h"
15 
16 int s390_sha_update(struct shash_desc *desc, const u8 *data, unsigned int len)
17 {
18 	struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
19 	unsigned int bsize = crypto_shash_blocksize(desc->tfm);
20 	unsigned int index, n;
21 
22 	/* how much is already in the buffer? */
23 	index = ctx->count & (bsize - 1);
24 	ctx->count += len;
25 
26 	if ((index + len) < bsize)
27 		goto store;
28 
29 	/* process one stored block */
30 	if (index) {
31 		memcpy(ctx->buf + index, data, bsize - index);
32 		cpacf_kimd(ctx->func, ctx->state, ctx->buf, bsize);
33 		data += bsize - index;
34 		len -= bsize - index;
35 		index = 0;
36 	}
37 
38 	/* process as many blocks as possible */
39 	if (len >= bsize) {
40 		n = len & ~(bsize - 1);
41 		cpacf_kimd(ctx->func, ctx->state, data, n);
42 		data += n;
43 		len -= n;
44 	}
45 store:
46 	if (len)
47 		memcpy(ctx->buf + index , data, len);
48 
49 	return 0;
50 }
51 EXPORT_SYMBOL_GPL(s390_sha_update);
52 
53 int s390_sha_final(struct shash_desc *desc, u8 *out)
54 {
55 	struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
56 	unsigned int bsize = crypto_shash_blocksize(desc->tfm);
57 	u64 bits;
58 	unsigned int index, end, plen;
59 
60 	/* SHA-512 uses 128 bit padding length */
61 	plen = (bsize > SHA256_BLOCK_SIZE) ? 16 : 8;
62 
63 	/* must perform manual padding */
64 	index = ctx->count & (bsize - 1);
65 	end = (index < bsize - plen) ? bsize : (2 * bsize);
66 
67 	/* start pad with 1 */
68 	ctx->buf[index] = 0x80;
69 	index++;
70 
71 	/* pad with zeros */
72 	memset(ctx->buf + index, 0x00, end - index - 8);
73 
74 	/*
75 	 * Append message length. Well, SHA-512 wants a 128 bit length value,
76 	 * nevertheless we use u64, should be enough for now...
77 	 */
78 	bits = ctx->count * 8;
79 	memcpy(ctx->buf + end - 8, &bits, sizeof(bits));
80 	cpacf_kimd(ctx->func, ctx->state, ctx->buf, end);
81 
82 	/* copy digest to out */
83 	memcpy(out, ctx->state, crypto_shash_digestsize(desc->tfm));
84 	/* wipe context */
85 	memset(ctx, 0, sizeof *ctx);
86 
87 	return 0;
88 }
89 EXPORT_SYMBOL_GPL(s390_sha_final);
90 
91 MODULE_LICENSE("GPL");
92 MODULE_DESCRIPTION("s390 SHA cipher common functions");
93