Commit | Line | Data |
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37941236 | 1 | /* -*-c-*- |
37941236 | 2 | * |
3 | * Cryptographic challenges | |
4 | * | |
5 | * (c) 2005 Straylight/Edgeware | |
6 | */ | |
7 | ||
e04c2d50 | 8 | /*----- Licensing notice --------------------------------------------------* |
37941236 | 9 | * |
10 | * This file is part of Trivial IP Encryption (TrIPE). | |
11 | * | |
12 | * TrIPE is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License as published by | |
14 | * the Free Software Foundation; either version 2 of the License, or | |
15 | * (at your option) any later version. | |
e04c2d50 | 16 | * |
37941236 | 17 | * TrIPE is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU General Public License for more details. | |
e04c2d50 | 21 | * |
37941236 | 22 | * You should have received a copy of the GNU General Public License |
23 | * along with TrIPE; if not, write to the Free Software Foundation, | |
24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
25 | */ | |
26 | ||
27 | /*----- Header files ------------------------------------------------------*/ | |
28 | ||
29 | #include "tripe.h" | |
30 | ||
31 | /*----- Static variables --------------------------------------------------*/ | |
32 | ||
c70a7c5c | 33 | static bulkchal *bulk; |
37941236 | 34 | static uint32 oseq; |
35 | static seqwin iseq; | |
36 | ||
37 | /*----- Main code ---------------------------------------------------------*/ | |
38 | ||
39 | /* --- @c_genkey@ --- * | |
40 | * | |
41 | * Arguments: --- | |
42 | * | |
43 | * Returns: --- | |
44 | * | |
45 | * Use: Generates a new challenge key. | |
46 | */ | |
47 | ||
48 | static void c_genkey(void) | |
49 | { | |
c70a7c5c MW |
50 | if (bulk && bulk->ops == master->algs.bulk->ops && oseq < 0x07ffffff) |
51 | return; | |
52 | if (bulk) bulk->ops->freechal(bulk); | |
53 | bulk = master->algs.bulk->ops->genchal(master->algs.bulk); | |
54 | bulk->ops = master->algs.bulk->ops; | |
37941236 | 55 | oseq = 0; |
56 | seq_reset(&iseq); | |
37941236 | 57 | } |
58 | ||
59 | /* --- @c_new@ --- * | |
60 | * | |
61 | * Arguments: @buf *b@ = where to put the challenge | |
62 | * | |
63 | * Returns: Zero if OK, nonzero on error. | |
64 | * | |
65 | * Use: Issues a new challenge. | |
66 | */ | |
67 | ||
68 | int c_new(buf *b) | |
69 | { | |
70 | octet *p; | |
37941236 | 71 | |
72 | c_genkey(); | |
73 | p = BCUR(b); | |
c70a7c5c MW |
74 | if (buf_putu32(b, oseq++) || !buf_get(b, bulk->tagsz)) return (-1); |
75 | if (bulk->ops->chaltag(bulk, p, 4, p + 4)) return (-1); | |
37941236 | 76 | IF_TRACING(T_CHAL, { |
77 | trace(T_CHAL, "chal: issuing challenge %lu", (unsigned long)(oseq - 1)); | |
78 | trace_block(T_CRYPTO, "chal: challenge block", p, BCUR(b) - p); | |
79 | }) | |
80 | return (0); | |
81 | } | |
82 | ||
83 | /* --- @c_check@ --- * | |
84 | * | |
85 | * Arguments: @buf *b@ = where to find the challenge | |
86 | * | |
87 | * Returns: Zero if OK, nonzero if it didn't work. | |
88 | * | |
89 | * Use: Checks a challenge. On failure, the buffer is broken. | |
90 | */ | |
91 | ||
92 | int c_check(buf *b) | |
93 | { | |
94 | const octet *p; | |
c70a7c5c | 95 | size_t sz; |
37941236 | 96 | uint32 seq; |
37941236 | 97 | |
c70a7c5c MW |
98 | if (!bulk) { |
99 | a_warn("CHAL", "impossible-challenge", A_END); | |
100 | goto fail; | |
101 | } | |
102 | sz = 4 + bulk->tagsz; | |
37941236 | 103 | if ((p = buf_get(b, sz)) == 0) { |
f43df819 | 104 | a_warn("CHAL", "invalid-challenge", A_END); |
37941236 | 105 | goto fail; |
106 | } | |
107 | IF_TRACING(T_CHAL, trace_block(T_CRYPTO, "chal: check challenge", p, sz); ) | |
c70a7c5c | 108 | if (bulk->ops->chalvrf(bulk, p, 4, p + 4)) { |
f43df819 | 109 | a_warn("CHAL", "incorrect-tag", A_END); |
37941236 | 110 | goto fail; |
111 | } | |
112 | seq = LOAD32(p); | |
4416b2ef | 113 | if (seq_check(&iseq, seq, "CHAL")) |
f43df819 | 114 | goto fail; |
37941236 | 115 | T( trace(T_CHAL, "chal: checked challenge %lu", (unsigned long)seq); ) |
116 | return (0); | |
117 | ||
118 | fail: | |
119 | buf_break(b); | |
120 | return (-1); | |
121 | } | |
122 | ||
123 | /*----- That's all, folks -------------------------------------------------*/ |