From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Thu, 19 Aug 2021 20:34:59 +1000
Subject: [PATCH] cifs: fork arc4 and create a separate module for it for cifs
and other users
Git-commit: 71c02863246167b3d1639b8278681ca8ebedcb4e
References: bsc#1193629
Patch-mainline: v5.14
We can not drop ARC4 and basically destroy CIFS connectivity for
almost all CIFS users so create a new forked ARC4 module that CIFS and other
subsystems that have a hard dependency on ARC4 can use.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
fs/Kconfig | 7 +++
fs/Makefile | 1 +
fs/cifs/Kconfig | 1 -
fs/cifs/cifsencrypt.c | 8 ++--
fs/cifs_common/Makefile | 6 +++
fs/cifs_common/arc4.h | 23 ++++++++++
fs/cifs_common/cifs_arc4.c | 87 ++++++++++++++++++++++++++++++++++++++
7 files changed, 128 insertions(+), 5 deletions(-)
create mode 100644 fs/cifs_common/Makefile
create mode 100644 fs/cifs_common/arc4.h
create mode 100644 fs/cifs_common/cifs_arc4.c
diff --git a/fs/Kconfig b/fs/Kconfig
index a7749c126b8e..6d719f2c5828 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -358,7 +358,14 @@ config NFS_V4_2_SSC_HELPER
source "net/sunrpc/Kconfig"
source "fs/ceph/Kconfig"
+
source "fs/cifs/Kconfig"
+
+config CIFS_COMMON
+ tristate
+ default y if CIFS=y
+ default m if CIFS=m
+
source "fs/coda/Kconfig"
source "fs/afs/Kconfig"
source "fs/9p/Kconfig"
diff --git a/fs/Makefile b/fs/Makefile
index f98f3e691c37..77b0e79c8b4f 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -96,6 +96,7 @@ obj-$(CONFIG_LOCKD) += lockd/
obj-$(CONFIG_NLS) += nls/
obj-$(CONFIG_UNICODE) += unicode/
obj-$(CONFIG_SYSV_FS) += sysv/
+obj-$(CONFIG_CIFS_COMMON) += cifs_common/
obj-$(CONFIG_CIFS) += cifs/
obj-$(CONFIG_HPFS_FS) += hpfs/
obj-$(CONFIG_NTFS_FS) += ntfs/
diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index 2e8b132efdbc..aa4457d72392 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -10,7 +10,6 @@ config CIFS
select CRYPTO_SHA512
select CRYPTO_CMAC
select CRYPTO_HMAC
- select CRYPTO_LIB_ARC4
select CRYPTO_AEAD2
select CRYPTO_CCM
select CRYPTO_GCM
diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 7680e0a9bea3..6679e07e533e 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -22,7 +22,7 @@
#include <linux/random.h>
#include <linux/highmem.h>
#include <linux/fips.h>
-#include <crypto/arc4.h>
+#include "../cifs_common/arc4.h"
#include <crypto/aead.h>
int __cifs_calc_signature(struct smb_rqst *rqst,
@@ -699,9 +699,9 @@ calc_seckey(struct cifs_ses *ses)
return -ENOMEM;
}
- arc4_setkey(ctx_arc4, ses->auth_key.response, CIFS_SESS_KEY_SIZE);
- arc4_crypt(ctx_arc4, ses->ntlmssp->ciphertext, sec_key,
- CIFS_CPHTXT_SIZE);
+ 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);
/* make secondary_key/nonce as session key */
memcpy(ses->auth_key.response, sec_key, CIFS_SESS_KEY_SIZE);
diff --git a/fs/cifs_common/Makefile b/fs/cifs_common/Makefile
new file mode 100644
index 000000000000..2fc9b40345c4
--- /dev/null
+++ b/fs/cifs_common/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for Linux filesystem routines that are shared by client and server.
+#
+
+obj-$(CONFIG_CIFS_COMMON) += cifs_arc4.o
diff --git a/fs/cifs_common/arc4.h b/fs/cifs_common/arc4.h
new file mode 100644
index 000000000000..12e71ec033a1
--- /dev/null
+++ b/fs/cifs_common/arc4.h
@@ -0,0 +1,23 @@
+/* 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 */
diff --git a/fs/cifs_common/cifs_arc4.c b/fs/cifs_common/cifs_arc4.c
new file mode 100644
index 000000000000..b964cc682944
--- /dev/null
+++ b/fs/cifs_common/cifs_arc4.c
@@ -0,0 +1,87 @@
+// 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_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);
+
+static int __init
+init_cifs_common(void)
+{
+ return 0;
+}
+static void __init
+exit_cifs_common(void)
+{
+}
+
+module_init(init_cifs_common)
+module_exit(exit_cifs_common)
--
2.34.1