From dc51f25752bfcb5f1edbac1ca4ce16af7b3bd507 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Wed, 12 Jun 2019 18:19:53 +0200
Subject: [PATCH] crypto: arc4 - refactor arc4 core code into separate library
Refactor the core rc4 handling so we can move most users to a library
interface, permitting us to drop the cipher interface entirely in a
future patch. This is part of an effort to simplify the crypto API
and improve its robustness against incorrect use.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
MAINTAINERS | 1 +
crypto/Kconfig | 4 +++
crypto/arc4.c | 60 +----------------------------------
include/crypto/arc4.h | 10 ++++++
lib/Makefile | 2 +-
lib/crypto/Makefile | 4 +++
lib/crypto/arc4.c | 74 +++++++++++++++++++++++++++++++++++++++++++
7 files changed, 95 insertions(+), 60 deletions(-)
create mode 100644 lib/crypto/Makefile
create mode 100644 lib/crypto/arc4.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 5cfbea4ce5750..8d579935ffb90 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4229,6 +4229,7 @@ F: crypto/
F: drivers/crypto/
F: include/crypto/
F: include/linux/crypto*
+F: lib/crypto/
CRYPTOGRAPHIC RANDOM NUMBER GENERATOR
M: Neil Horman <nhorman@tuxdriver.com>
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 8c588ed362534..e801450bcb1cf 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1237,9 +1237,13 @@ config CRYPTO_ANUBIS
<https://www.cosic.esat.kuleuven.be/nessie/reports/>
<http://www.larc.usp.br/~pbarreto/AnubisPage.html>
+config CRYPTO_LIB_ARC4
+ tristate
+
config CRYPTO_ARC4
tristate "ARC4 cipher algorithm"
select CRYPTO_BLKCIPHER
+ select CRYPTO_LIB_ARC4
help
ARC4 cipher algorithm.
diff --git a/crypto/arc4.c b/crypto/arc4.c
index b78dcb390a7e2..d303b7ff1fed8 100644
--- a/crypto/arc4.c
+++ b/crypto/arc4.c
@@ -18,33 +18,12 @@
#include <linux/init.h>
#include <linux/module.h>
-struct arc4_ctx {
- u32 S[256];
- u32 x, y;
-};
-
static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
- 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;
+ return arc4_setkey(ctx, in_key, key_len);
}
static int arc4_set_key_skcipher(struct crypto_skcipher *tfm, const u8 *in_key,
@@ -53,43 +32,6 @@ static int arc4_set_key_skcipher(struct crypto_skcipher *tfm, const u8 *in_key,
return arc4_set_key(&tfm->base, in_key, key_len);
}
-static void 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;
-}
-
static void arc4_crypt_one(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
arc4_crypt(crypto_tfm_ctx(tfm), out, in, 1);
diff --git a/include/crypto/arc4.h b/include/crypto/arc4.h
index 5b2c24ab0139c..f3c22fe01704c 100644
--- a/include/crypto/arc4.h
+++ b/include/crypto/arc4.h
@@ -6,8 +6,18 @@
#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 arc4_setkey(struct arc4_ctx *ctx, const u8 *in_key, unsigned int key_len);
+void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in, unsigned int len);
+
#endif /* _CRYPTO_ARC4_H */
diff --git a/lib/Makefile b/lib/Makefile
index fb7697031a797..d3daedf93c5a7 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -102,7 +102,7 @@ endif
obj-$(CONFIG_DEBUG_INFO_REDUCED) += debug_info.o
CFLAGS_debug_info.o += $(call cc-option, -femit-struct-debug-detailed=any)
-obj-y += math/
+obj-y += math/ crypto/
obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
obj-$(CONFIG_GENERIC_PCI_IOMAP) += pci_iomap.o
diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
new file mode 100644
index 0000000000000..88195c34932d7
--- /dev/null
+++ b/lib/crypto/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_CRYPTO_LIB_ARC4) += libarc4.o
+libarc4-y := arc4.o
diff --git a/lib/crypto/arc4.c b/lib/crypto/arc4.c
new file mode 100644
index 0000000000000..c2020f19c652c
--- /dev/null
+++ b/lib/crypto/arc4.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Cryptographic API
+ *
+ * ARC4 Cipher Algorithm
+ *
+ * Jon Oberheide <jon@oberheide.org>
+ */
+
+#include <crypto/arc4.h>
+#include <linux/module.h>
+
+int 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(arc4_setkey);
+
+void 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(arc4_crypt);
+
+MODULE_LICENSE("GPL");
--
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