md5.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Crypto API support for MD5 and HMAC-MD5
  4 *
  5 * Copyright 2025 Google LLC
  6 */
  7#include <crypto/internal/hash.h>
  8#include <crypto/md5.h>
  9#include <linux/kernel.h>
 10#include <linux/module.h>
 11
 12/*
 13 * Export and import functions.  crypto_shash wants a particular format that
 14 * matches that used by some legacy drivers.  It currently is the same as the
 15 * library MD5 context, except the value in bytecount must be block-aligned and
 16 * the remainder must be stored in an extra u8 appended to the struct.
 17 */
 18
 19#define MD5_SHASH_STATE_SIZE (sizeof(struct md5_ctx) + 1)
 20static_assert(sizeof(struct md5_ctx) == sizeof(struct md5_state));
 21static_assert(offsetof(struct md5_ctx, state) == offsetof(struct md5_state, hash));
 22static_assert(offsetof(struct md5_ctx, bytecount) == offsetof(struct md5_state, byte_count));
 23static_assert(offsetof(struct md5_ctx, buf) == offsetof(struct md5_state, block));
 24
 25static int __crypto_md5_export(const struct md5_ctx *ctx0, void *out)
 26{
 27	struct md5_ctx ctx = *ctx0;
 28	unsigned int partial;
 29	u8 *p = out;
 30
 31	partial = ctx.bytecount % MD5_BLOCK_SIZE;
 32	ctx.bytecount -= partial;
 33	memcpy(p, &ctx, sizeof(ctx));
 34	p += sizeof(ctx);
 35	*p = partial;
 36	return 0;
 37}
 38
 39static int __crypto_md5_import(struct md5_ctx *ctx, const void *in)
 40{
 41	const u8 *p = in;
 42
 43	memcpy(ctx, p, sizeof(*ctx));
 44	p += sizeof(*ctx);
 45	ctx->bytecount += *p;
 46	return 0;
 47}
 48
 49static int __crypto_md5_export_core(const struct md5_ctx *ctx, void *out)
 50{
 51	memcpy(out, ctx, offsetof(struct md5_ctx, buf));
 52	return 0;
 53}
 54
 55static int __crypto_md5_import_core(struct md5_ctx *ctx, const void *in)
 56{
 57	memcpy(ctx, in, offsetof(struct md5_ctx, buf));
 58	return 0;
 59}
 60
 61const u8 md5_zero_message_hash[MD5_DIGEST_SIZE] = {
 62	0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
 63	0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e,
 64};
 65EXPORT_SYMBOL_GPL(md5_zero_message_hash);
 66
 67#define MD5_CTX(desc) ((struct md5_ctx *)shash_desc_ctx(desc))
 68
 69static int crypto_md5_init(struct shash_desc *desc)
 70{
 71	md5_init(MD5_CTX(desc));
 72	return 0;
 73}
 74
 75static int crypto_md5_update(struct shash_desc *desc,
 76			     const u8 *data, unsigned int len)
 77{
 78	md5_update(MD5_CTX(desc), data, len);
 79	return 0;
 80}
 81
 82static int crypto_md5_final(struct shash_desc *desc, u8 *out)
 83{
 84	md5_final(MD5_CTX(desc), out);
 85	return 0;
 86}
 87
 88static int crypto_md5_digest(struct shash_desc *desc,
 89			     const u8 *data, unsigned int len, u8 *out)
 90{
 91	md5(data, len, out);
 92	return 0;
 93}
 94
 95static int crypto_md5_export(struct shash_desc *desc, void *out)
 96{
 97	return __crypto_md5_export(MD5_CTX(desc), out);
 98}
 99
100static int crypto_md5_import(struct shash_desc *desc, const void *in)
101{
102	return __crypto_md5_import(MD5_CTX(desc), in);
103}
104
105static int crypto_md5_export_core(struct shash_desc *desc, void *out)
106{
107	return __crypto_md5_export_core(MD5_CTX(desc), out);
108}
109
110static int crypto_md5_import_core(struct shash_desc *desc, const void *in)
111{
112	return __crypto_md5_import_core(MD5_CTX(desc), in);
113}
114
115#define HMAC_MD5_KEY(tfm) ((struct hmac_md5_key *)crypto_shash_ctx(tfm))
116#define HMAC_MD5_CTX(desc) ((struct hmac_md5_ctx *)shash_desc_ctx(desc))
117
118static int crypto_hmac_md5_setkey(struct crypto_shash *tfm,
119				  const u8 *raw_key, unsigned int keylen)
120{
121	hmac_md5_preparekey(HMAC_MD5_KEY(tfm), raw_key, keylen);
122	return 0;
123}
124
125static int crypto_hmac_md5_init(struct shash_desc *desc)
126{
127	hmac_md5_init(HMAC_MD5_CTX(desc), HMAC_MD5_KEY(desc->tfm));
128	return 0;
129}
130
131static int crypto_hmac_md5_update(struct shash_desc *desc,
132				  const u8 *data, unsigned int len)
133{
134	hmac_md5_update(HMAC_MD5_CTX(desc), data, len);
135	return 0;
136}
137
138static int crypto_hmac_md5_final(struct shash_desc *desc, u8 *out)
139{
140	hmac_md5_final(HMAC_MD5_CTX(desc), out);
141	return 0;
142}
143
144static int crypto_hmac_md5_digest(struct shash_desc *desc,
145				  const u8 *data, unsigned int len, u8 *out)
146{
147	hmac_md5(HMAC_MD5_KEY(desc->tfm), data, len, out);
148	return 0;
149}
150
151static int crypto_hmac_md5_export(struct shash_desc *desc, void *out)
152{
153	return __crypto_md5_export(&HMAC_MD5_CTX(desc)->hash_ctx, out);
154}
155
156static int crypto_hmac_md5_import(struct shash_desc *desc, const void *in)
157{
158	struct hmac_md5_ctx *ctx = HMAC_MD5_CTX(desc);
159
160	ctx->ostate = HMAC_MD5_KEY(desc->tfm)->ostate;
161	return __crypto_md5_import(&ctx->hash_ctx, in);
162}
163
164static int crypto_hmac_md5_export_core(struct shash_desc *desc, void *out)
165{
166	return __crypto_md5_export_core(&HMAC_MD5_CTX(desc)->hash_ctx, out);
167}
168
169static int crypto_hmac_md5_import_core(struct shash_desc *desc, const void *in)
170{
171	struct hmac_md5_ctx *ctx = HMAC_MD5_CTX(desc);
172
173	ctx->ostate = HMAC_MD5_KEY(desc->tfm)->ostate;
174	return __crypto_md5_import_core(&ctx->hash_ctx, in);
175}
176
177static struct shash_alg algs[] = {
178	{
179		.base.cra_name		= "md5",
180		.base.cra_driver_name	= "md5-lib",
181		.base.cra_priority	= 300,
182		.base.cra_blocksize	= MD5_BLOCK_SIZE,
183		.base.cra_module	= THIS_MODULE,
184		.digestsize		= MD5_DIGEST_SIZE,
185		.init			= crypto_md5_init,
186		.update			= crypto_md5_update,
187		.final			= crypto_md5_final,
188		.digest			= crypto_md5_digest,
189		.export			= crypto_md5_export,
190		.import			= crypto_md5_import,
191		.export_core		= crypto_md5_export_core,
192		.import_core		= crypto_md5_import_core,
193		.descsize		= sizeof(struct md5_ctx),
194		.statesize		= MD5_SHASH_STATE_SIZE,
195	},
196	{
197		.base.cra_name		= "hmac(md5)",
198		.base.cra_driver_name	= "hmac-md5-lib",
199		.base.cra_priority	= 300,
200		.base.cra_blocksize	= MD5_BLOCK_SIZE,
201		.base.cra_ctxsize	= sizeof(struct hmac_md5_key),
202		.base.cra_module	= THIS_MODULE,
203		.digestsize		= MD5_DIGEST_SIZE,
204		.setkey			= crypto_hmac_md5_setkey,
205		.init			= crypto_hmac_md5_init,
206		.update			= crypto_hmac_md5_update,
207		.final			= crypto_hmac_md5_final,
208		.digest			= crypto_hmac_md5_digest,
209		.export			= crypto_hmac_md5_export,
210		.import			= crypto_hmac_md5_import,
211		.export_core		= crypto_hmac_md5_export_core,
212		.import_core		= crypto_hmac_md5_import_core,
213		.descsize		= sizeof(struct hmac_md5_ctx),
214		.statesize		= MD5_SHASH_STATE_SIZE,
215	},
216};
217
218static int __init crypto_md5_mod_init(void)
219{
220	return crypto_register_shashes(algs, ARRAY_SIZE(algs));
221}
222module_init(crypto_md5_mod_init);
223
224static void __exit crypto_md5_mod_exit(void)
225{
226	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
227}
228module_exit(crypto_md5_mod_exit);
229
230MODULE_LICENSE("GPL");
231MODULE_DESCRIPTION("Crypto API support for MD5 and HMAC-MD5");
232
233MODULE_ALIAS_CRYPTO("md5");
234MODULE_ALIAS_CRYPTO("md5-lib");
235MODULE_ALIAS_CRYPTO("hmac(md5)");
236MODULE_ALIAS_CRYPTO("hmac-md5-lib");