d03ab969 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: noise.h,v 1.1 1999/09/03 08:41:12 mdw Exp $ |
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 $ |
33 | * Revision 1.1 1999/09/03 08:41:12 mdw |
34 | * Initial import. |
35 | * |
36 | */ |
37 | |
38 | #ifndef NOISE_H |
39 | #define NOISE_H |
40 | |
41 | #ifdef __cplusplus |
42 | extern "C" { |
43 | #endif |
44 | |
45 | /*----- Header files ------------------------------------------------------*/ |
46 | |
47 | #include <sys/types.h> |
48 | |
49 | #ifndef RAND_H |
50 | # include "rand.h" |
51 | #endif |
52 | |
53 | /*----- Noise source definition -------------------------------------------*/ |
54 | |
55 | extern rand_source noise_source; |
56 | |
57 | /*----- Magic numbers -----------------------------------------------------*/ |
58 | |
59 | #define NOISE_NOSETUID ((uid_t)-1) |
60 | #define NOISE_NOSETGID ((gid_t)-1) |
61 | |
62 | /*----- Functions provided ------------------------------------------------*/ |
63 | |
64 | /* --- @noise_timer@ --- * |
65 | * |
66 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
67 | * |
68 | * Returns: Nonzero if some randomness was contributed. |
69 | * |
70 | * Use: Contributes the current time to the randomness pool. |
71 | * A guess at the number of useful bits contributed is made, |
72 | * based on first and second order bit differences. This isn't |
73 | * ever-so reliable, but it's better than nothing. |
74 | */ |
75 | |
76 | extern int noise_timer(rand_pool */*r*/); |
77 | |
78 | /* --- @noise_devrandom@ --- * |
79 | * |
80 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
81 | * |
82 | * Returns: Nonzero if some randomness was contributed. |
83 | * |
84 | * Use: Attempts to obtain some randomness from the system entropy |
85 | * pool. All bits from the device are assumed to be good. |
86 | */ |
87 | |
88 | extern int noise_devrandom(rand_pool */*r*/); |
89 | |
90 | /* --- @noise_setid@ --- * |
91 | * |
92 | * Arguments: @uid_t uid@ = uid to set |
93 | * @gid_t gid@ = gid to set |
94 | * |
95 | * Returns: --- |
96 | * |
97 | * Use: Sets the user and group ids to be used by @noise_filter@ |
98 | * when running child processes. This is useful to avoid |
99 | * giving shell commands (even carefully written ones) undue |
100 | * privileges. |
101 | */ |
102 | |
103 | extern void noise_setid(uid_t /*uid*/, gid_t /*gid*/); |
104 | |
105 | /* --- @noise_filter@ --- * |
106 | * |
107 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
108 | * @int good@ = number of good bits per 1024 bits |
109 | * @const char *c@ = shell command to run |
110 | * |
111 | * Returns: Nonzero if some randomness was contributed. |
112 | * |
113 | * Use: Attempts to execute a shell command, and dump it into the |
114 | * randomness pool. A very rough estimate of the number of |
115 | * good bits is made, based on the size of the command's output. |
116 | * This function calls @waitpid@, so be careful. Before execing |
117 | * the command, the process uid and gid are set to the values |
118 | * given to @noise_setid@, and an attempt is made to reset the |
119 | * list of supplementary groups. The environment passed to |
120 | * the command has been severly lobotimized. If the command |
121 | * fails to complete within a short time period, it is killed. |
122 | * Paranoid use of close-on-exec flags for file descriptors is |
123 | * recommended. |
124 | */ |
125 | |
126 | extern int noise_filter(rand_pool */*r*/, int /*good*/, const char */*c*/); |
127 | |
128 | /* --- @noise_acquire@ --- * |
129 | * |
130 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
131 | * |
132 | * Returns: --- |
133 | * |
134 | * Use: Acquires some randomness from somewhere. |
135 | */ |
136 | |
137 | extern void noise_acquire(rand_pool */*r*/); |
138 | |
139 | /*----- That's all, folks -------------------------------------------------*/ |
140 | |
141 | #ifdef __cplusplus |
142 | } |
143 | #endif |
144 | |
145 | #endif |