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smb: Use arc4 library instead of duplicate arc4 code

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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: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Eric Biggers
2025-09-06 20:20:03 -07:00
committed by Steve French
parent 02696ac090
commit 8e979aab34
7 changed files with 10 additions and 108 deletions
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1
fs/smb/client/Kconfig
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@@ -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

8
fs/smb/client/cifsencrypt.c
View File

@@ -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)
@@ -725,9 +725,9 @@ 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,
CIFS_CPHTXT_SIZE);
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 */
memcpy(ses->auth_key.response, sec_key, CIFS_SESS_KEY_SIZE);

1
fs/smb/common/Makefile
View File

@@ -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

23
fs/smb/common/arc4.h
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@@ -1,23 +0,0 @@
/* 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 */

75
fs/smb/common/cifs_arc4.c
View File

@@ -1,75 +0,0 @@
// 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);

1
fs/smb/server/Kconfig
View File

@@ -10,6 +10,7 @@ config SMB_SERVER
select CRYPTO_MD5
select CRYPTO_HMAC
select CRYPTO_ECB
select CRYPTO_LIB_ARC4
select CRYPTO_LIB_DES
select CRYPTO_LIB_SHA256
select CRYPTO_SHA256

9
fs/smb/server/auth.c
View File

@@ -20,6 +20,7 @@
#include "glob.h"
#include <linux/fips.h>
#include <crypto/arc4.h>
#include <crypto/des.h>
#include "server.h"
@@ -29,7 +30,6 @@
#include "mgmt/user_config.h"
#include "crypto_ctx.h"
#include "transport_ipc.h"
#include "../common/arc4.h"
/*
* Fixed format data defining GSS header and fixed string
@@ -365,10 +365,9 @@ int ksmbd_decode_ntlmssp_auth_blob(struct authenticate_message *authblob,
if (!ctx_arc4)
return -ENOMEM;
cifs_arc4_setkey(ctx_arc4, sess->sess_key,
SMB2_NTLMV2_SESSKEY_SIZE);
cifs_arc4_crypt(ctx_arc4, sess->sess_key,
(char *)authblob + sess_key_off, sess_key_len);
arc4_setkey(ctx_arc4, sess->sess_key, SMB2_NTLMV2_SESSKEY_SIZE);
arc4_crypt(ctx_arc4, sess->sess_key,
(char *)authblob + sess_key_off, sess_key_len);
kfree_sensitive(ctx_arc4);
}