1 /* 2 * rc4.c 3 * 4 * Copyright (c) 1996-2000 Whistle Communications, Inc. 5 * All rights reserved. 6 * 7 * Subject to the following obligations and disclaimer of warranty, use and 8 * redistribution of this software, in source or object code forms, with or 9 * without modifications are expressly permitted by Whistle Communications; 10 * provided, however, that: 11 * 1. Any and all reproductions of the source or object code must include the 12 * copyright notice above and the following disclaimer of warranties; and 13 * 2. No rights are granted, in any manner or form, to use Whistle 14 * Communications, Inc. trademarks, including the mark "WHISTLE 15 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as 16 * such appears in the above copyright notice or in the software. 17 * 18 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND 19 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO 20 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, 21 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF 22 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. 23 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY 24 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS 25 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. 26 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES 27 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING 28 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 29 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR 30 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY 34 * OF SUCH DAMAGE. 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include <sys/param.h> 41 #include <sys/kernel.h> 42 #include <sys/module.h> 43 #include <sys/types.h> 44 #include <crypto/rc4/rc4.h> 45 46 static __inline void 47 swap_bytes(u_char *a, u_char *b) 48 { 49 u_char temp; 50 51 temp = *a; 52 *a = *b; 53 *b = temp; 54 } 55 56 /* 57 * Initialize an RC4 state buffer using the supplied key, 58 * which can have arbitrary length. 59 */ 60 void 61 rc4_init(struct rc4_state *const state, const u_char *key, int keylen) 62 { 63 u_char j; 64 int i, k; 65 66 /* Initialize state with identity permutation */ 67 for (i = 0; i < 256; i++) 68 state->perm[i] = (u_char)i; 69 state->index1 = 0; 70 state->index2 = 0; 71 72 /* Randomize the permutation using key data */ 73 for (j = i = k = 0; i < 256; i++) { 74 j += state->perm[i] + key[k]; 75 swap_bytes(&state->perm[i], &state->perm[j]); 76 if (++k >= keylen) 77 k = 0; 78 } 79 } 80 81 /* 82 * Encrypt some data using the supplied RC4 state buffer. 83 * The input and output buffers may be the same buffer. 84 * Since RC4 is a stream cypher, this function is used 85 * for both encryption and decryption. 86 */ 87 void 88 rc4_crypt(struct rc4_state *const state, 89 const u_char *inbuf, u_char *outbuf, int buflen) 90 { 91 int i; 92 u_char j; 93 94 for (i = 0; i < buflen; i++) { 95 96 /* Update modification indicies */ 97 state->index1++; 98 state->index2 += state->perm[state->index1]; 99 100 /* Modify permutation */ 101 swap_bytes(&state->perm[state->index1], 102 &state->perm[state->index2]); 103 104 /* Encrypt/decrypt next byte */ 105 j = state->perm[state->index1] + state->perm[state->index2]; 106 outbuf[i] = inbuf[i] ^ state->perm[j]; 107 } 108 } 109 110 static int 111 rc4_modevent(module_t mod, int type, void *unused) 112 { 113 switch (type) { 114 case MOD_LOAD: 115 return 0; 116 case MOD_UNLOAD: 117 return 0; 118 } 119 return EINVAL; 120 } 121 122 static moduledata_t rc4_mod = { 123 "rc4", 124 rc4_modevent, 125 0 126 }; 127 DECLARE_MODULE(rc4, rc4_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 128 MODULE_VERSION(rc4, 1); 129