Commit | Line | Data |
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37941236 | 1 | /* -*-c-*- |
2 | * | |
37941236 | 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 | * | |
11ad66c2 MW |
12 | * TrIPE is free software: you can redistribute it and/or modify it under |
13 | * the terms of the GNU General Public License as published by the Free | |
14 | * Software Foundation; either version 3 of the License, or (at your | |
15 | * option) any later version. | |
e04c2d50 | 16 | * |
11ad66c2 MW |
17 | * TrIPE is distributed in the hope that it will be useful, but WITHOUT |
18 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
19 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
20 | * for more details. | |
e04c2d50 | 21 | * |
37941236 | 22 | * You should have received a copy of the GNU General Public License |
11ad66c2 | 23 | * along with TrIPE. If not, see <https://www.gnu.org/licenses/>. |
37941236 | 24 | */ |
25 | ||
26 | /*----- Header files ------------------------------------------------------*/ | |
27 | ||
28 | #include "tripe.h" | |
29 | ||
30 | /*----- Static variables --------------------------------------------------*/ | |
31 | ||
c70a7c5c | 32 | static bulkchal *bulk; |
37941236 | 33 | static uint32 oseq; |
34 | static seqwin iseq; | |
35 | ||
36 | /*----- Main code ---------------------------------------------------------*/ | |
37 | ||
38 | /* --- @c_genkey@ --- * | |
39 | * | |
40 | * Arguments: --- | |
41 | * | |
42 | * Returns: --- | |
43 | * | |
44 | * Use: Generates a new challenge key. | |
45 | */ | |
46 | ||
47 | static void c_genkey(void) | |
48 | { | |
c70a7c5c MW |
49 | if (bulk && bulk->ops == master->algs.bulk->ops && oseq < 0x07ffffff) |
50 | return; | |
51 | if (bulk) bulk->ops->freechal(bulk); | |
52 | bulk = master->algs.bulk->ops->genchal(master->algs.bulk); | |
53 | bulk->ops = master->algs.bulk->ops; | |
37941236 | 54 | oseq = 0; |
55 | seq_reset(&iseq); | |
37941236 | 56 | } |
57 | ||
58 | /* --- @c_new@ --- * | |
59 | * | |
60 | * Arguments: @buf *b@ = where to put the challenge | |
61 | * | |
62 | * Returns: Zero if OK, nonzero on error. | |
63 | * | |
64 | * Use: Issues a new challenge. | |
65 | */ | |
66 | ||
67 | int c_new(buf *b) | |
68 | { | |
69 | octet *p; | |
37941236 | 70 | |
71 | c_genkey(); | |
72 | p = BCUR(b); | |
c70a7c5c MW |
73 | if (buf_putu32(b, oseq++) || !buf_get(b, bulk->tagsz)) return (-1); |
74 | if (bulk->ops->chaltag(bulk, p, 4, p + 4)) return (-1); | |
37941236 | 75 | IF_TRACING(T_CHAL, { |
76 | trace(T_CHAL, "chal: issuing challenge %lu", (unsigned long)(oseq - 1)); | |
77 | trace_block(T_CRYPTO, "chal: challenge block", p, BCUR(b) - p); | |
78 | }) | |
79 | return (0); | |
80 | } | |
81 | ||
82 | /* --- @c_check@ --- * | |
83 | * | |
84 | * Arguments: @buf *b@ = where to find the challenge | |
85 | * | |
86 | * Returns: Zero if OK, nonzero if it didn't work. | |
87 | * | |
88 | * Use: Checks a challenge. On failure, the buffer is broken. | |
89 | */ | |
90 | ||
91 | int c_check(buf *b) | |
92 | { | |
93 | const octet *p; | |
c70a7c5c | 94 | size_t sz; |
37941236 | 95 | uint32 seq; |
37941236 | 96 | |
c70a7c5c MW |
97 | if (!bulk) { |
98 | a_warn("CHAL", "impossible-challenge", A_END); | |
99 | goto fail; | |
100 | } | |
101 | sz = 4 + bulk->tagsz; | |
37941236 | 102 | if ((p = buf_get(b, sz)) == 0) { |
f43df819 | 103 | a_warn("CHAL", "invalid-challenge", A_END); |
37941236 | 104 | goto fail; |
105 | } | |
106 | IF_TRACING(T_CHAL, trace_block(T_CRYPTO, "chal: check challenge", p, sz); ) | |
c70a7c5c | 107 | if (bulk->ops->chalvrf(bulk, p, 4, p + 4)) { |
f43df819 | 108 | a_warn("CHAL", "incorrect-tag", A_END); |
37941236 | 109 | goto fail; |
110 | } | |
111 | seq = LOAD32(p); | |
4416b2ef | 112 | if (seq_check(&iseq, seq, "CHAL")) |
f43df819 | 113 | goto fail; |
37941236 | 114 | T( trace(T_CHAL, "chal: checked challenge %lu", (unsigned long)seq); ) |
115 | return (0); | |
116 | ||
117 | fail: | |
118 | buf_break(b); | |
119 | return (-1); | |
120 | } | |
121 | ||
122 | /*----- That's all, folks -------------------------------------------------*/ |