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