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15#include <crypto/algapi.h>
16#include <crypto/gf128mul.h>
17#include <crypto/ghash.h>
18#include <crypto/internal/hash.h>
19#include <linux/crypto.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23
24static int ghash_init(struct shash_desc *desc)
25{
26 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
27
28 memset(dctx, 0, sizeof(*dctx));
29
30 return 0;
31}
32
33static int ghash_setkey(struct crypto_shash *tfm,
34 const u8 *key, unsigned int keylen)
35{
36 struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
37
38 if (keylen != GHASH_BLOCK_SIZE) {
39 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
40 return -EINVAL;
41 }
42
43 if (ctx->gf128)
44 gf128mul_free_4k(ctx->gf128);
45 ctx->gf128 = gf128mul_init_4k_lle((be128 *)key);
46 if (!ctx->gf128)
47 return -ENOMEM;
48
49 return 0;
50}
51
52static int ghash_update(struct shash_desc *desc,
53 const u8 *src, unsigned int srclen)
54{
55 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
56 struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
57 u8 *dst = dctx->buffer;
58
59 if (!ctx->gf128)
60 return -ENOKEY;
61
62 if (dctx->bytes) {
63 int n = min(srclen, dctx->bytes);
64 u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
65
66 dctx->bytes -= n;
67 srclen -= n;
68
69 while (n--)
70 *pos++ ^= *src++;
71
72 if (!dctx->bytes)
73 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
74 }
75
76 while (srclen >= GHASH_BLOCK_SIZE) {
77 crypto_xor(dst, src, GHASH_BLOCK_SIZE);
78 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
79 src += GHASH_BLOCK_SIZE;
80 srclen -= GHASH_BLOCK_SIZE;
81 }
82
83 if (srclen) {
84 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
85 while (srclen--)
86 *dst++ ^= *src++;
87 }
88
89 return 0;
90}
91
92static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
93{
94 u8 *dst = dctx->buffer;
95
96 if (dctx->bytes) {
97 u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
98
99 while (dctx->bytes--)
100 *tmp++ ^= 0;
101
102 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
103 }
104
105 dctx->bytes = 0;
106}
107
108static int ghash_final(struct shash_desc *desc, u8 *dst)
109{
110 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
111 struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
112 u8 *buf = dctx->buffer;
113
114 if (!ctx->gf128)
115 return -ENOKEY;
116
117 ghash_flush(ctx, dctx);
118 memcpy(dst, buf, GHASH_BLOCK_SIZE);
119
120 return 0;
121}
122
123static void ghash_exit_tfm(struct crypto_tfm *tfm)
124{
125 struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
126 if (ctx->gf128)
127 gf128mul_free_4k(ctx->gf128);
128}
129
130static struct shash_alg ghash_alg = {
131 .digestsize = GHASH_DIGEST_SIZE,
132 .init = ghash_init,
133 .update = ghash_update,
134 .final = ghash_final,
135 .setkey = ghash_setkey,
136 .descsize = sizeof(struct ghash_desc_ctx),
137 .base = {
138 .cra_name = "ghash",
139 .cra_driver_name = "ghash-generic",
140 .cra_priority = 100,
141 .cra_flags = CRYPTO_ALG_TYPE_SHASH,
142 .cra_blocksize = GHASH_BLOCK_SIZE,
143 .cra_ctxsize = sizeof(struct ghash_ctx),
144 .cra_module = THIS_MODULE,
145 .cra_exit = ghash_exit_tfm,
146 },
147};
148
149static int __init ghash_mod_init(void)
150{
151 return crypto_register_shash(&ghash_alg);
152}
153
154static void __exit ghash_mod_exit(void)
155{
156 crypto_unregister_shash(&ghash_alg);
157}
158
159module_init(ghash_mod_init);
160module_exit(ghash_mod_exit);
161
162MODULE_LICENSE("GPL");
163MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
164MODULE_ALIAS_CRYPTO("ghash");
165MODULE_ALIAS_CRYPTO("ghash-generic");
166