Commit 8e979aab authored by Eric Biggers's avatar Eric Biggers Committed by Steve French
Browse files

smb: Use arc4 library instead of duplicate arc4 code 



fs/smb/common/cifs_arc4.c has an implementation of ARC4, but a copy of
this same code is also present in lib/crypto/arc4.c to serve the other
users of this legacy algorithm in the kernel.  Remove the duplicate
implementation in fs/smb/, which seems to have been added because of a
misunderstanding, and just use the lib/crypto/ one.

Signed-off-by: default avatarEric Biggers <ebiggers@kernel.org>
Reviewed-by: default avatarPaulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 02696ac0

fs/smb/client/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ config CIFS 
	select CRYPTO_GCM

	select CRYPTO_ECB

	select CRYPTO_AES

	select CRYPTO_LIB_ARC4

	select KEYS

	select DNS_RESOLVER

	select ASN1

fs/smb/client/cifsencrypt.c

+4 −4
Original line number Diff line number Diff line
@@ -22,8 +22,8 @@ 
#include <linux/highmem.h>

#include <linux/fips.h>

#include <linux/iov_iter.h>

#include "../common/arc4.h"

#include <crypto/aead.h>

#include <crypto/arc4.h>



static size_t cifs_shash_step(void *iter_base, size_t progress, size_t len,

			      void *priv, void *priv2)
@@ -725,8 +725,8 @@ calc_seckey(struct cifs_ses *ses) 
		return -ENOMEM;

	}



	cifs_arc4_setkey(ctx_arc4, ses->auth_key.response, CIFS_SESS_KEY_SIZE);

	cifs_arc4_crypt(ctx_arc4, ses->ntlmssp->ciphertext, sec_key,

	arc4_setkey(ctx_arc4, ses->auth_key.response, CIFS_SESS_KEY_SIZE);

	arc4_crypt(ctx_arc4, ses->ntlmssp->ciphertext, sec_key,

		   CIFS_CPHTXT_SIZE);



	/* make secondary_key/nonce as session key */

fs/smb/common/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -3,5 +3,4 @@ 
# Makefile for Linux filesystem routines that are shared by client and server.

#



obj-$(CONFIG_SMBFS) += cifs_arc4.o

obj-$(CONFIG_SMBFS) += cifs_md4.o

fs/smb/common/arc4.h

deleted100644 → 0
+0 −23
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0+ */

/*

 * Common values for ARC4 Cipher Algorithm

 */



#ifndef _CRYPTO_ARC4_H

#define _CRYPTO_ARC4_H



#include <linux/types.h>



#define ARC4_MIN_KEY_SIZE	1

#define ARC4_MAX_KEY_SIZE	256

#define ARC4_BLOCK_SIZE		1



struct arc4_ctx {

	u32 S[256];

	u32 x, y;

};



int cifs_arc4_setkey(struct arc4_ctx *ctx, const u8 *in_key, unsigned int key_len);

void cifs_arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in, unsigned int len);



#endif /* _CRYPTO_ARC4_H */

fs/smb/common/cifs_arc4.c

deleted100644 → 0
+0 −75
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * Cryptographic API

 *

 * ARC4 Cipher Algorithm

 *

 * Jon Oberheide <jon@oberheide.org>

 */



#include <linux/module.h>

#include "arc4.h"



MODULE_DESCRIPTION("ARC4 Cipher Algorithm");

MODULE_LICENSE("GPL");



int cifs_arc4_setkey(struct arc4_ctx *ctx, const u8 *in_key, unsigned int key_len)

{

	int i, j = 0, k = 0;



	ctx->x = 1;

	ctx->y = 0;



	for (i = 0; i < 256; i++)

		ctx->S[i] = i;



	for (i = 0; i < 256; i++) {

		u32 a = ctx->S[i];



		j = (j + in_key[k] + a) & 0xff;

		ctx->S[i] = ctx->S[j];

		ctx->S[j] = a;

		if (++k >= key_len)

			k = 0;

	}



	return 0;

}

EXPORT_SYMBOL_GPL(cifs_arc4_setkey);



void cifs_arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in, unsigned int len)

{

	u32 *const S = ctx->S;

	u32 x, y, a, b;

	u32 ty, ta, tb;



	if (len == 0)

		return;



	x = ctx->x;

	y = ctx->y;



	a = S[x];

	y = (y + a) & 0xff;

	b = S[y];



	do {

		S[y] = a;

		a = (a + b) & 0xff;

		S[x] = b;

		x = (x + 1) & 0xff;

		ta = S[x];

		ty = (y + ta) & 0xff;

		tb = S[ty];

		*out++ = *in++ ^ S[a];

		if (--len == 0)

			break;

		y = ty;

		a = ta;

		b = tb;

	} while (true);



	ctx->x = x;

	ctx->y = y;

}

EXPORT_SYMBOL_GPL(cifs_arc4_crypt);