Commit ba8ee22a authored by Eric Biggers's avatar Eric Biggers
Browse files

crypto: md5 - Wrap library and add HMAC support 

Reimplement crypto/md5.c on top of the new MD5 library functions.  Also
add support for HMAC-MD5, again just wrapping the library functions.

This closely mirrors crypto/sha1.c.

Link: https://lore.kernel.org/r/20250805222855.10362-7-ebiggers@kernel.org


Signed-off-by: default avatarEric Biggers <ebiggers@kernel.org>
parent a1848f6e

crypto/Kconfig

+2 −1
Original line number Diff line number Diff line
@@ -938,8 +938,9 @@ config CRYPTO_MD4 
config CRYPTO_MD5

	tristate "MD5"

	select CRYPTO_HASH

	select CRYPTO_LIB_MD5

	help

	  MD5 message digest algorithm (RFC1321)

	  MD5 message digest algorithm (RFC1321), including HMAC support.



config CRYPTO_MICHAEL_MIC

	tristate "Michael MIC"

crypto/md5.c

+166 −193
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * Cryptographic API.

 *

 * MD5 Message Digest Algorithm (RFC1321).

 *

 * Derived from cryptoapi implementation, originally based on the

 * public domain implementation written by Colin Plumb in 1993.

 *

 * Copyright (c) Cryptoapi developers.

 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>

 * 

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the Free

 * Software Foundation; either version 2 of the License, or (at your option) 

 * any later version.

 * Crypto API support for MD5 and HMAC-MD5

 *

 * Copyright 2025 Google LLC

 */

#include <crypto/internal/hash.h>

#include <crypto/md5.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/string.h>



/*

 * Export and import functions.  crypto_shash wants a particular format that

 * matches that used by some legacy drivers.  It currently is the same as the

 * library MD5 context, except the value in bytecount must be block-aligned and

 * the remainder must be stored in an extra u8 appended to the struct.

 */



#define MD5_SHASH_STATE_SIZE (sizeof(struct md5_ctx) + 1)

static_assert(sizeof(struct md5_ctx) == sizeof(struct md5_state));

static_assert(offsetof(struct md5_ctx, state) == offsetof(struct md5_state, hash));

static_assert(offsetof(struct md5_ctx, bytecount) == offsetof(struct md5_state, byte_count));

static_assert(offsetof(struct md5_ctx, buf) == offsetof(struct md5_state, block));



static int __crypto_md5_export(const struct md5_ctx *ctx0, void *out)

{

	struct md5_ctx ctx = *ctx0;

	unsigned int partial;

	u8 *p = out;



	partial = ctx.bytecount % MD5_BLOCK_SIZE;

	ctx.bytecount -= partial;

	memcpy(p, &ctx, sizeof(ctx));

	p += sizeof(ctx);

	*p = partial;

	return 0;

}



static int __crypto_md5_import(struct md5_ctx *ctx, const void *in)

{

	const u8 *p = in;



	memcpy(ctx, p, sizeof(*ctx));

	p += sizeof(*ctx);

	ctx->bytecount += *p;

	return 0;

}



const u8 md5_zero_message_hash[MD5_DIGEST_SIZE] = {

	0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
@@ -27,198 +52,146 @@ const u8 md5_zero_message_hash[MD5_DIGEST_SIZE] = { 
};

EXPORT_SYMBOL_GPL(md5_zero_message_hash);



#define F1(x, y, z)	(z ^ (x & (y ^ z)))

#define F2(x, y, z)	F1(z, x, y)

#define F3(x, y, z)	(x ^ y ^ z)

#define F4(x, y, z)	(y ^ (x | ~z))



#define MD5STEP(f, w, x, y, z, in, s) \

	(w += f(x, y, z) + in, w = (w<<s | w>>(32-s)) + x)



static void md5_transform(__u32 *hash, __u32 const *in)

{

	u32 a, b, c, d;



	a = hash[0];

	b = hash[1];

	c = hash[2];

	d = hash[3];



	MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);

	MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);

	MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);

	MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);

	MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);

	MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);

	MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);

	MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);

	MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);

	MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);

	MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);

	MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);

	MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);

	MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);

	MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);

	MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);



	MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);

	MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);

	MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);

	MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);

	MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);

	MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);

	MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);

	MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);

	MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);

	MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);

	MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);

	MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);

	MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);

	MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);

	MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);

	MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);



	MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);

	MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);

	MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);

	MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);

	MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);

	MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);

	MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);

	MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);

	MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);

	MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);

	MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);

	MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);

	MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);

	MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);

	MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);

	MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);



	MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);

	MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);

	MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);

	MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);

	MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);

	MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);

	MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);

	MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);

	MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);

	MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);

	MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);

	MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);

	MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);

	MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);

	MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);

	MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);



	hash[0] += a;

	hash[1] += b;

	hash[2] += c;

	hash[3] += d;

}



static inline void md5_transform_helper(struct md5_state *ctx,

					u32 block[MD5_BLOCK_WORDS])

{

	le32_to_cpu_array(block, MD5_BLOCK_WORDS);

	md5_transform(ctx->hash, block);

}



static int md5_init(struct shash_desc *desc)

{

	struct md5_state *mctx = shash_desc_ctx(desc);



	mctx->hash[0] = MD5_H0;

	mctx->hash[1] = MD5_H1;

	mctx->hash[2] = MD5_H2;

	mctx->hash[3] = MD5_H3;

	mctx->byte_count = 0;

#define MD5_CTX(desc) ((struct md5_ctx *)shash_desc_ctx(desc))



static int crypto_md5_init(struct shash_desc *desc)

{

	md5_init(MD5_CTX(desc));

	return 0;

}



static int crypto_md5_update(struct shash_desc *desc,

			     const u8 *data, unsigned int len)

{

	md5_update(MD5_CTX(desc), data, len);

	return 0;

}



static int crypto_md5_final(struct shash_desc *desc, u8 *out)

{

	md5_final(MD5_CTX(desc), out);

	return 0;

}



static int md5_update(struct shash_desc *desc, const u8 *data, unsigned int len)

static int crypto_md5_digest(struct shash_desc *desc,

			     const u8 *data, unsigned int len, u8 *out)

{

	struct md5_state *mctx = shash_desc_ctx(desc);

	u32 block[MD5_BLOCK_WORDS];

	md5(data, len, out);

	return 0;

}



	mctx->byte_count += len;

	do {

		memcpy(block, data, sizeof(block));

		md5_transform_helper(mctx, block);

		data += sizeof(block);

		len -= sizeof(block);

	} while (len >= sizeof(block));

	memzero_explicit(block, sizeof(block));

	mctx->byte_count -= len;

	return len;

static int crypto_md5_export(struct shash_desc *desc, void *out)

{

	return __crypto_md5_export(MD5_CTX(desc), out);

}



static int md5_finup(struct shash_desc *desc, const u8 *data, unsigned int len,

		     u8 *out)

static int crypto_md5_import(struct shash_desc *desc, const void *in)

{

	struct md5_state *mctx = shash_desc_ctx(desc);

	u32 block[MD5_BLOCK_WORDS];

	unsigned int offset;

	int padding;

	char *p;

	return __crypto_md5_import(MD5_CTX(desc), in);

}



	memcpy(block, data, len);

#define HMAC_MD5_KEY(tfm) ((struct hmac_md5_key *)crypto_shash_ctx(tfm))

#define HMAC_MD5_CTX(desc) ((struct hmac_md5_ctx *)shash_desc_ctx(desc))



	offset = len;

	p = (char *)block + offset;

	padding = 56 - (offset + 1);

static int crypto_hmac_md5_setkey(struct crypto_shash *tfm,

				  const u8 *raw_key, unsigned int keylen)

{

	hmac_md5_preparekey(HMAC_MD5_KEY(tfm), raw_key, keylen);

	return 0;

}



	*p++ = 0x80;

	if (padding < 0) {

		memset(p, 0x00, padding + sizeof (u64));

		md5_transform_helper(mctx, block);

		p = (char *)block;

		padding = 56;

static int crypto_hmac_md5_init(struct shash_desc *desc)

{

	hmac_md5_init(HMAC_MD5_CTX(desc), HMAC_MD5_KEY(desc->tfm));

	return 0;

}



	memset(p, 0, padding);

	mctx->byte_count += len;

	block[14] = mctx->byte_count << 3;

	block[15] = mctx->byte_count >> 29;

	le32_to_cpu_array(block, (sizeof(block) - sizeof(u64)) / sizeof(u32));

	md5_transform(mctx->hash, block);

	memzero_explicit(block, sizeof(block));

	cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(u32));

	memcpy(out, mctx->hash, sizeof(mctx->hash));

static int crypto_hmac_md5_update(struct shash_desc *desc,

				  const u8 *data, unsigned int len)

{

	hmac_md5_update(HMAC_MD5_CTX(desc), data, len);

	return 0;

}



static int crypto_hmac_md5_final(struct shash_desc *desc, u8 *out)

{

	hmac_md5_final(HMAC_MD5_CTX(desc), out);

	return 0;

}



static struct shash_alg alg = {

	.digestsize	=	MD5_DIGEST_SIZE,

	.init		=	md5_init,

	.update		=	md5_update,

	.finup		=	md5_finup,

	.descsize	=	MD5_STATE_SIZE,

	.base		=	{

		.cra_name	 =	"md5",

		.cra_driver_name =	"md5-generic",

		.cra_flags	 =	CRYPTO_AHASH_ALG_BLOCK_ONLY,

		.cra_blocksize	 =	MD5_HMAC_BLOCK_SIZE,

		.cra_module	 =	THIS_MODULE,

static int crypto_hmac_md5_digest(struct shash_desc *desc,

				  const u8 *data, unsigned int len, u8 *out)

{

	hmac_md5(HMAC_MD5_KEY(desc->tfm), data, len, out);

	return 0;

}

};



static int __init md5_mod_init(void)

static int crypto_hmac_md5_export(struct shash_desc *desc, void *out)

{

	return crypto_register_shash(&alg);

	return __crypto_md5_export(&HMAC_MD5_CTX(desc)->hash_ctx, out);

}



static void __exit md5_mod_fini(void)

static int crypto_hmac_md5_import(struct shash_desc *desc, const void *in)

{

	struct hmac_md5_ctx *ctx = HMAC_MD5_CTX(desc);



	ctx->ostate = HMAC_MD5_KEY(desc->tfm)->ostate;

	return __crypto_md5_import(&ctx->hash_ctx, in);

}



static struct shash_alg algs[] = {

	{

		.base.cra_name		= "md5",

		.base.cra_driver_name	= "md5-lib",

		.base.cra_priority	= 300,

		.base.cra_blocksize	= MD5_BLOCK_SIZE,

		.base.cra_module	= THIS_MODULE,

		.digestsize		= MD5_DIGEST_SIZE,

		.init			= crypto_md5_init,

		.update			= crypto_md5_update,

		.final			= crypto_md5_final,

		.digest			= crypto_md5_digest,

		.export			= crypto_md5_export,

		.import			= crypto_md5_import,

		.descsize		= sizeof(struct md5_ctx),

		.statesize		= MD5_SHASH_STATE_SIZE,

	},

	{

		.base.cra_name		= "hmac(md5)",

		.base.cra_driver_name	= "hmac-md5-lib",

		.base.cra_priority	= 300,

		.base.cra_blocksize	= MD5_BLOCK_SIZE,

		.base.cra_ctxsize	= sizeof(struct hmac_md5_key),

		.base.cra_module	= THIS_MODULE,

		.digestsize		= MD5_DIGEST_SIZE,

		.setkey			= crypto_hmac_md5_setkey,

		.init			= crypto_hmac_md5_init,

		.update			= crypto_hmac_md5_update,

		.final			= crypto_hmac_md5_final,

		.digest			= crypto_hmac_md5_digest,

		.export			= crypto_hmac_md5_export,

		.import			= crypto_hmac_md5_import,

		.descsize		= sizeof(struct hmac_md5_ctx),

		.statesize		= MD5_SHASH_STATE_SIZE,

	},

};



static int __init crypto_md5_mod_init(void)

{

	crypto_unregister_shash(&alg);

	return crypto_register_shashes(algs, ARRAY_SIZE(algs));

}

module_init(crypto_md5_mod_init);



module_init(md5_mod_init);

module_exit(md5_mod_fini);

static void __exit crypto_md5_mod_exit(void)

{

	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));

}

module_exit(crypto_md5_mod_exit);



MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("MD5 Message Digest Algorithm");

MODULE_DESCRIPTION("Crypto API support for MD5 and HMAC-MD5");



MODULE_ALIAS_CRYPTO("md5");

MODULE_ALIAS_CRYPTO("md5-lib");

MODULE_ALIAS_CRYPTO("hmac(md5)");

MODULE_ALIAS_CRYPTO("hmac-md5-lib");

crypto/testmgr.c

+3 −0
Original line number Diff line number Diff line
@@ -4178,6 +4178,7 @@ static const struct alg_test_desc alg_test_descs[] = { 
		}

	}, {

		.alg = "authenc(hmac(md5),ecb(cipher_null))",

		.generic_driver = "authenc(hmac-md5-lib,ecb-cipher_null)",

		.test = alg_test_aead,

		.suite = {

			.aead = __VECS(hmac_md5_ecb_cipher_null_tv_template)
@@ -5064,6 +5065,7 @@ static const struct alg_test_desc alg_test_descs[] = { 
		}

	}, {

		.alg = "hmac(md5)",

		.generic_driver = "hmac-md5-lib",

		.test = alg_test_hash,

		.suite = {

			.hash = __VECS(hmac_md5_tv_template)
@@ -5250,6 +5252,7 @@ static const struct alg_test_desc alg_test_descs[] = { 
		}

	}, {

		.alg = "md5",

		.generic_driver = "md5-lib",

		.test = alg_test_hash,

		.suite = {

			.hash = __VECS(md5_tv_template)

drivers/crypto/img-hash.c

+1 −1
Original line number Diff line number Diff line
@@ -700,7 +700,7 @@ static int img_hash_cra_init(struct crypto_tfm *tfm, const char *alg_name) 


static int img_hash_cra_md5_init(struct crypto_tfm *tfm)

{

	return img_hash_cra_init(tfm, "md5-generic");

	return img_hash_cra_init(tfm, "md5-lib");

}



static int img_hash_cra_sha1_init(struct crypto_tfm *tfm)