84f87e82 |
1 | /* |
935da5a4 |
2 | * Blowfish mechanism for udp tunnel |
84f87e82 |
3 | * |
4 | * arguments: key size in bits (must be multiple of 8) |
5 | * |
6 | * key values: 8 byte random IV and n byte random key |
7 | * |
8 | * encoding: do CBC encryption overwriting message |
9 | * encoding for MAC: do CBC and prepend last ciphertext block |
10 | */ |
935da5a4 |
11 | /* |
12 | * Copyright (C) 2000 Ian Jackson |
13 | * |
14 | * This is free software; you can redistribute it and/or modify it |
15 | * under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * This program is distributed in the hope that it will be useful, but |
20 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
22 | * General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with userv-utils; if not, write to the Free Software |
26 | * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
84f87e82 |
28 | |
aaa9ab3a |
29 | #include "forwarder.h" |
84f87e82 |
30 | #include "blowfish.h" |
31 | |
32 | struct mechdata { |
8bb9d875 |
33 | unsigned char iv[BLOWFISH_BLOCKBYTES]; |
84f87e82 |
34 | struct blowfish_cbc_state cbc; |
35 | }; |
36 | |
37 | static void mds_blowfish(struct mechdata **md_r) { |
38 | struct mechdata *md; |
39 | unsigned long keysize; |
84f87e82 |
40 | unsigned char key[BLOWFISH_MAXKEYBYTES]; |
41 | |
244a0e99 |
42 | XMALLOC(md); |
84f87e82 |
43 | |
44 | keysize= getarg_ulong(); |
45 | arg_assert(!(keysize & 7)); |
46 | keysize >>= 3; |
47 | arg_assert(keysize > 0 && keysize <= BLOWFISH_MAXKEYBYTES); |
48 | |
8bb9d875 |
49 | random_key(md->iv,sizeof(md->iv)); |
84f87e82 |
50 | random_key(key,keysize); |
51 | |
52 | blowfish_loadkey(&md->cbc.ek, key,keysize); |
84f87e82 |
53 | *md_r= md; |
54 | } |
55 | |
56 | static void mes_blowfish(struct mechdata **md_r, int *maxprefix_io, int *maxsuffix_io) { |
57 | mds_blowfish(md_r); |
58 | } |
59 | |
60 | static void mds_bfmac(struct mechdata **md_r) { |
61 | mds_blowfish(md_r); |
62 | } |
63 | |
64 | static void mes_bfmac(struct mechdata **md_r, int *maxprefix_io, int *maxsuffix_io) { |
65 | mds_blowfish(md_r); |
66 | *maxprefix_io += BLOWFISH_BLOCKBYTES; |
67 | } |
68 | |
69 | #define MSGSIZE_OUT \ |
70 | msgsize= buf->size; \ |
244a0e99 |
71 | arg_assert(!(msgsize & (BLOWFISH_BLOCKBYTES-1))); |
84f87e82 |
72 | |
73 | #define MSGSIZE_IN \ |
74 | msgsize= buf->size; \ |
244a0e99 |
75 | if (msgsize & (BLOWFISH_BLOCKBYTES-1)) return "not multiple of block size" |
84f87e82 |
76 | |
77 | #define FOREACH_BLOCK(func,inptr,outptr) \ |
78 | { \ |
79 | unsigned char *ptr; \ |
8bb9d875 |
80 | blowfish_cbc_setiv(&md->cbc, md->iv); \ |
244a0e99 |
81 | for (ptr= buf->start; \ |
82 | ptr < buf->start + msgsize; \ |
83 | ptr += BLOWFISH_BLOCKBYTES) { \ |
84f87e82 |
84 | func(&md->cbc,inptr,outptr); \ |
244a0e99 |
85 | } \ |
84f87e82 |
86 | } |
87 | |
88 | static void menc_blowfish(struct mechdata *md, struct buffer *buf) { |
89 | unsigned long msgsize; |
90 | MSGSIZE_OUT; |
91 | FOREACH_BLOCK(blowfish_cbc_encrypt,ptr,ptr); |
92 | } |
93 | |
94 | static const char *mdec_blowfish(struct mechdata *md, struct buffer *buf) { |
95 | unsigned long msgsize; |
96 | MSGSIZE_IN; |
97 | FOREACH_BLOCK(blowfish_cbc_decrypt,ptr,ptr); |
98 | return 0; |
99 | } |
100 | |
101 | static void menc_bfmac(struct mechdata *md, struct buffer *buf) { |
102 | unsigned long msgsize; |
103 | unsigned char outblock[BLOWFISH_BLOCKBYTES]; |
104 | |
105 | MSGSIZE_OUT; |
106 | FOREACH_BLOCK(blowfish_cbc_encrypt,ptr,outblock); |
107 | memcpy(buf_prepend(buf,BLOWFISH_BLOCKBYTES), outblock, BLOWFISH_BLOCKBYTES); |
108 | } |
109 | |
110 | static const char *mdec_bfmac(struct mechdata *md, struct buffer *buf) { |
111 | unsigned long msgsize; |
112 | unsigned char outblock[BLOWFISH_BLOCKBYTES]; |
113 | unsigned char *checkblock; |
114 | |
115 | BUF_UNPREPEND(checkblock,buf,BLOWFISH_BLOCKBYTES); |
116 | MSGSIZE_IN; |
117 | FOREACH_BLOCK(blowfish_cbc_encrypt,ptr,outblock); |
118 | if (memcmp(checkblock,outblock,BLOWFISH_BLOCKBYTES)) return "verify failed"; |
119 | return 0; |
120 | } |
121 | |
122 | const struct mechanism mechlist_blowfish[]= { |
123 | STANDARD_MECHANISM("blowfish-cbcmac", bfmac) |
124 | STANDARD_MECHANISM("blowfish-cbc", blowfish) |
125 | { 0 } |
126 | }; |