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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: noise.h,v 1.2 1999/12/10 23:29:48 mdw Exp $ |
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4 | * |
5 | * Acquisition of environmental noise (Unix specific) |
6 | * |
7 | * (c) 1998 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: noise.h,v $ |
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33 | * Revision 1.2 1999/12/10 23:29:48 mdw |
34 | * Change header file guard names. |
35 | * |
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36 | * Revision 1.1 1999/09/03 08:41:12 mdw |
37 | * Initial import. |
38 | * |
39 | */ |
40 | |
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41 | #ifndef CATACOMB_NOISE_H |
42 | #define CATACOMB_NOISE_H |
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43 | |
44 | #ifdef __cplusplus |
45 | extern "C" { |
46 | #endif |
47 | |
48 | /*----- Header files ------------------------------------------------------*/ |
49 | |
50 | #include <sys/types.h> |
51 | |
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52 | #ifndef CATACOMB_RAND_H |
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53 | # include "rand.h" |
54 | #endif |
55 | |
56 | /*----- Noise source definition -------------------------------------------*/ |
57 | |
58 | extern rand_source noise_source; |
59 | |
60 | /*----- Magic numbers -----------------------------------------------------*/ |
61 | |
62 | #define NOISE_NOSETUID ((uid_t)-1) |
63 | #define NOISE_NOSETGID ((gid_t)-1) |
64 | |
65 | /*----- Functions provided ------------------------------------------------*/ |
66 | |
67 | /* --- @noise_timer@ --- * |
68 | * |
69 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
70 | * |
71 | * Returns: Nonzero if some randomness was contributed. |
72 | * |
73 | * Use: Contributes the current time to the randomness pool. |
74 | * A guess at the number of useful bits contributed is made, |
75 | * based on first and second order bit differences. This isn't |
76 | * ever-so reliable, but it's better than nothing. |
77 | */ |
78 | |
79 | extern int noise_timer(rand_pool */*r*/); |
80 | |
81 | /* --- @noise_devrandom@ --- * |
82 | * |
83 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
84 | * |
85 | * Returns: Nonzero if some randomness was contributed. |
86 | * |
87 | * Use: Attempts to obtain some randomness from the system entropy |
88 | * pool. All bits from the device are assumed to be good. |
89 | */ |
90 | |
91 | extern int noise_devrandom(rand_pool */*r*/); |
92 | |
93 | /* --- @noise_setid@ --- * |
94 | * |
95 | * Arguments: @uid_t uid@ = uid to set |
96 | * @gid_t gid@ = gid to set |
97 | * |
98 | * Returns: --- |
99 | * |
100 | * Use: Sets the user and group ids to be used by @noise_filter@ |
101 | * when running child processes. This is useful to avoid |
102 | * giving shell commands (even carefully written ones) undue |
103 | * privileges. |
104 | */ |
105 | |
106 | extern void noise_setid(uid_t /*uid*/, gid_t /*gid*/); |
107 | |
108 | /* --- @noise_filter@ --- * |
109 | * |
110 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
111 | * @int good@ = number of good bits per 1024 bits |
112 | * @const char *c@ = shell command to run |
113 | * |
114 | * Returns: Nonzero if some randomness was contributed. |
115 | * |
116 | * Use: Attempts to execute a shell command, and dump it into the |
117 | * randomness pool. A very rough estimate of the number of |
118 | * good bits is made, based on the size of the command's output. |
119 | * This function calls @waitpid@, so be careful. Before execing |
120 | * the command, the process uid and gid are set to the values |
121 | * given to @noise_setid@, and an attempt is made to reset the |
122 | * list of supplementary groups. The environment passed to |
123 | * the command has been severly lobotimized. If the command |
124 | * fails to complete within a short time period, it is killed. |
125 | * Paranoid use of close-on-exec flags for file descriptors is |
126 | * recommended. |
127 | */ |
128 | |
129 | extern int noise_filter(rand_pool */*r*/, int /*good*/, const char */*c*/); |
130 | |
131 | /* --- @noise_acquire@ --- * |
132 | * |
133 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
134 | * |
135 | * Returns: --- |
136 | * |
137 | * Use: Acquires some randomness from somewhere. |
138 | */ |
139 | |
140 | extern void noise_acquire(rand_pool */*r*/); |
141 | |
142 | /*----- That's all, folks -------------------------------------------------*/ |
143 | |
144 | #ifdef __cplusplus |
145 | } |
146 | #endif |
147 | |
148 | #endif |