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 #include <sys/param.h> 39 #include <sys/kernel.h> 40 #include <sys/module.h> 41 #include <sys/types.h> 42 #include <crypto/rc4/rc4.h> 43 44 static __inline void 45 swap_bytes(u_char *a, u_char *b) 46 { 47 u_char temp; 48 49 temp = *a; 50 *a = *b; 51 *b = temp; 52 } 53 54 /* 55 * Initialize an RC4 state buffer using the supplied key, 56 * which can have arbitrary length. 57 */ 58 void 59 rc4_init(struct rc4_state *const state, const u_char *key, int keylen) 60 { 61 u_char j; 62 int i, k; 63 64 /* Initialize state with identity permutation */ 65 for (i = 0; i < 256; i++) 66 state->perm[i] = (u_char)i; 67 state->index1 = 0; 68 state->index2 = 0; 69 70 /* Randomize the permutation using key data */ 71 for (j = i = k = 0; i < 256; i++) { 72 j += state->perm[i] + key[k]; 73 swap_bytes(&state->perm[i], &state->perm[j]); 74 if (++k >= keylen) 75 k = 0; 76 } 77 } 78 79 /* 80 * Encrypt some data using the supplied RC4 state buffer. 81 * The input and output buffers may be the same buffer. 82 * Since RC4 is a stream cypher, this function is used 83 * for both encryption and decryption. 84 */ 85 void 86 rc4_crypt(struct rc4_state *const state, 87 const u_char *inbuf, u_char *outbuf, int buflen) 88 { 89 int i; 90 u_char j; 91 92 for (i = 0; i < buflen; i++) { 93 94 /* Update modification indicies */ 95 state->index1++; 96 state->index2 += state->perm[state->index1]; 97 98 /* Modify permutation */ 99 swap_bytes(&state->perm[state->index1], 100 &state->perm[state->index2]); 101 102 /* Encrypt/decrypt next byte */ 103 j = state->perm[state->index1] + state->perm[state->index2]; 104 outbuf[i] = inbuf[i] ^ state->perm[j]; 105 } 106 } 107 108 static int 109 rc4_modevent(module_t mod, int type, void *unused) 110 { 111 switch (type) { 112 case MOD_LOAD: 113 return 0; 114 case MOD_UNLOAD: 115 return 0; 116 } 117 return EINVAL; 118 } 119 120 static moduledata_t rc4_mod = { 121 "rc4", 122 rc4_modevent, 123 0 124 }; 125 DECLARE_MODULE(rc4, rc4_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 126 MODULE_VERSION(rc4, 1); 127