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1 | /* |
2 | * Blowfish |
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 | */ |
11 | |
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12 | #include "forwarder.h" |
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13 | #include "blowfish.h" |
14 | |
15 | struct mechdata { |
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16 | unsigned char iv[BLOWFISH_BLOCKBYTES]; |
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17 | struct blowfish_cbc_state cbc; |
18 | }; |
19 | |
20 | static void mds_blowfish(struct mechdata **md_r) { |
21 | struct mechdata *md; |
22 | unsigned long keysize; |
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23 | unsigned char key[BLOWFISH_MAXKEYBYTES]; |
24 | |
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25 | XMALLOC(md); |
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26 | |
27 | keysize= getarg_ulong(); |
28 | arg_assert(!(keysize & 7)); |
29 | keysize >>= 3; |
30 | arg_assert(keysize > 0 && keysize <= BLOWFISH_MAXKEYBYTES); |
31 | |
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32 | random_key(md->iv,sizeof(md->iv)); |
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33 | random_key(key,keysize); |
34 | |
35 | blowfish_loadkey(&md->cbc.ek, key,keysize); |
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36 | *md_r= md; |
37 | } |
38 | |
39 | static void mes_blowfish(struct mechdata **md_r, int *maxprefix_io, int *maxsuffix_io) { |
40 | mds_blowfish(md_r); |
41 | } |
42 | |
43 | static void mds_bfmac(struct mechdata **md_r) { |
44 | mds_blowfish(md_r); |
45 | } |
46 | |
47 | static void mes_bfmac(struct mechdata **md_r, int *maxprefix_io, int *maxsuffix_io) { |
48 | mds_blowfish(md_r); |
49 | *maxprefix_io += BLOWFISH_BLOCKBYTES; |
50 | } |
51 | |
52 | #define MSGSIZE_OUT \ |
53 | msgsize= buf->size; \ |
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54 | arg_assert(!(msgsize & (BLOWFISH_BLOCKBYTES-1))); |
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55 | |
56 | #define MSGSIZE_IN \ |
57 | msgsize= buf->size; \ |
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58 | if (msgsize & (BLOWFISH_BLOCKBYTES-1)) return "not multiple of block size" |
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59 | |
60 | #define FOREACH_BLOCK(func,inptr,outptr) \ |
61 | { \ |
62 | unsigned char *ptr; \ |
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63 | blowfish_cbc_setiv(&md->cbc, md->iv); \ |
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64 | for (ptr= buf->start; \ |
65 | ptr < buf->start + msgsize; \ |
66 | ptr += BLOWFISH_BLOCKBYTES) { \ |
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67 | func(&md->cbc,inptr,outptr); \ |
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68 | } \ |
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69 | } |
70 | |
71 | static void menc_blowfish(struct mechdata *md, struct buffer *buf) { |
72 | unsigned long msgsize; |
73 | MSGSIZE_OUT; |
74 | FOREACH_BLOCK(blowfish_cbc_encrypt,ptr,ptr); |
75 | } |
76 | |
77 | static const char *mdec_blowfish(struct mechdata *md, struct buffer *buf) { |
78 | unsigned long msgsize; |
79 | MSGSIZE_IN; |
80 | FOREACH_BLOCK(blowfish_cbc_decrypt,ptr,ptr); |
81 | return 0; |
82 | } |
83 | |
84 | static void menc_bfmac(struct mechdata *md, struct buffer *buf) { |
85 | unsigned long msgsize; |
86 | unsigned char outblock[BLOWFISH_BLOCKBYTES]; |
87 | |
88 | MSGSIZE_OUT; |
89 | FOREACH_BLOCK(blowfish_cbc_encrypt,ptr,outblock); |
90 | memcpy(buf_prepend(buf,BLOWFISH_BLOCKBYTES), outblock, BLOWFISH_BLOCKBYTES); |
91 | } |
92 | |
93 | static const char *mdec_bfmac(struct mechdata *md, struct buffer *buf) { |
94 | unsigned long msgsize; |
95 | unsigned char outblock[BLOWFISH_BLOCKBYTES]; |
96 | unsigned char *checkblock; |
97 | |
98 | BUF_UNPREPEND(checkblock,buf,BLOWFISH_BLOCKBYTES); |
99 | MSGSIZE_IN; |
100 | FOREACH_BLOCK(blowfish_cbc_encrypt,ptr,outblock); |
101 | if (memcmp(checkblock,outblock,BLOWFISH_BLOCKBYTES)) return "verify failed"; |
102 | return 0; |
103 | } |
104 | |
105 | const struct mechanism mechlist_blowfish[]= { |
106 | STANDARD_MECHANISM("blowfish-cbcmac", bfmac) |
107 | STANDARD_MECHANISM("blowfish-cbc", blowfish) |
108 | { 0 } |
109 | }; |