Move RC4 into crypto.h as a replaceable crypto function

This allows crypto library wrappers to override the internal RC4
implementation in the same way as can already be done for other crypto
algorithms.

src/crypto/crypto.h

@@ -448,4 +448,20 @@ int __must_check crypto_mod_exp(const u8 *base, size_t base_len,
 				const u8 *modulus, size_t modulus_len,
 				u8 *result, size_t *result_len);
 
+/**
+ * rc4_skip - XOR RC4 stream to given data with skip-stream-start
+ * @key: RC4 key
+ * @keylen: RC4 key length
+ * @skip: number of bytes to skip from the beginning of the RC4 stream
+ * @data: data to be XOR'ed with RC4 stream
+ * @data_len: buf length
+ * Returns: 0 on success, -1 on failure
+ *
+ * Generate RC4 pseudo random stream for the given key, skip beginning of the
+ * stream, and XOR the end result with the data buffer to perform RC4
+ * encryption/decryption.
+ */
+int rc4_skip(const u8 *key, size_t keylen, size_t skip,
+	     u8 *data, size_t data_len);
+
 #endif /* CRYPTO_H */

src/crypto/crypto_internal.c

@@ -18,7 +18,6 @@
 #include "crypto.h"
 #include "md5.h"
 #include "sha1.h"
-#include "rc4.h"
 #include "aes.h"
 #include "tls/rsa.h"
 #include "tls/bignum.h"

src/crypto/crypto_libtomcrypt.c

@@ -16,7 +16,6 @@
 #include <tomcrypt.h>
 
 #include "common.h"
-#include "rc4.h"
 #include "crypto.h"
 
 #ifndef mp_init_multi

src/crypto/ms_funcs.c

@@ -18,7 +18,6 @@
 #include "sha1.h"
 #include "ms_funcs.h"
 #include "crypto.h"
-#include "rc4.h"
 
 
 /**

src/crypto/rc4.c

@@ -15,24 +15,12 @@
 #include "includes.h"
 
 #include "common.h"
-#include "rc4.h"
+#include "crypto.h"
 
 #define S_SWAP(a,b) do { u8 t = S[a]; S[a] = S[b]; S[b] = t; } while(0)
 
-/**
- * rc4 - XOR RC4 stream to given data with skip-stream-start
- * @key: RC4 key
- * @keylen: RC4 key length
- * @skip: number of bytes to skip from the beginning of the RC4 stream
- * @data: data to be XOR'ed with RC4 stream
- * @data_len: buf length
- *
- * Generate RC4 pseudo random stream for the given key, skip beginning of the
- * stream, and XOR the end result with the data buffer to perform RC4
- * encryption/decryption.
- */
-void rc4_skip(const u8 *key, size_t keylen, size_t skip,
-	      u8 *data, size_t data_len)
+int rc4_skip(const u8 *key, size_t keylen, size_t skip,
+	     u8 *data, size_t data_len)
 {
 	u32 i, j, k;
 	u8 S[256], *pos;
@@ -67,4 +55,6 @@ void rc4_skip(const u8 *key, size_t keylen, size_t skip,
 		S_SWAP(i, j);
 		*pos++ ^= S[(S[i] + S[j]) & 0xff];
 	}
+
+	return 0;
 }

src/crypto/rc4.h

@@ -1,21 +0,0 @@
-/*
- * RC4 stream cipher
- * Copyright (c) 2002-2005, Jouni Malinen <j@w1.fi>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * Alternatively, this software may be distributed under the terms of BSD
- * license.
- *
- * See README and COPYING for more details.
- */
-
-#ifndef RC4_H
-#define RC4_H
-
-void rc4_skip(const u8 *key, size_t keylen, size_t skip,
-	      u8 *data, size_t data_len);
-
-#endif /* RC4_H */