d03ab969 |
1 | /* -*-c-*- |
2 | * |
25f654a7 |
3 | * $Id: noise.h,v 1.4 2000/06/17 12:57:47 mdw Exp $ |
d03ab969 |
4 | * |
099355bc |
5 | * Acquisition of environmental noise (Unix-specific) |
d03ab969 |
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 $ |
25f654a7 |
33 | * Revision 1.4 2000/06/17 12:57:47 mdw |
34 | * New free counter noise generator, for use if /dev/random is |
35 | * unavailable. |
36 | * |
099355bc |
37 | * Revision 1.3 1999/12/22 15:57:55 mdw |
38 | * Label system-specific parts more clearly. |
39 | * |
b3f05084 |
40 | * Revision 1.2 1999/12/10 23:29:48 mdw |
41 | * Change header file guard names. |
42 | * |
d03ab969 |
43 | * Revision 1.1 1999/09/03 08:41:12 mdw |
44 | * Initial import. |
45 | * |
46 | */ |
47 | |
b3f05084 |
48 | #ifndef CATACOMB_NOISE_H |
49 | #define CATACOMB_NOISE_H |
d03ab969 |
50 | |
51 | #ifdef __cplusplus |
52 | extern "C" { |
53 | #endif |
54 | |
55 | /*----- Header files ------------------------------------------------------*/ |
56 | |
57 | #include <sys/types.h> |
58 | |
b3f05084 |
59 | #ifndef CATACOMB_RAND_H |
d03ab969 |
60 | # include "rand.h" |
61 | #endif |
62 | |
63 | /*----- Noise source definition -------------------------------------------*/ |
64 | |
65 | extern rand_source noise_source; |
66 | |
67 | /*----- Magic numbers -----------------------------------------------------*/ |
68 | |
69 | #define NOISE_NOSETUID ((uid_t)-1) |
70 | #define NOISE_NOSETGID ((gid_t)-1) |
71 | |
72 | /*----- Functions provided ------------------------------------------------*/ |
73 | |
74 | /* --- @noise_timer@ --- * |
75 | * |
76 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
77 | * |
78 | * Returns: Nonzero if some randomness was contributed. |
79 | * |
80 | * Use: Contributes the current time to the randomness pool. |
81 | * A guess at the number of useful bits contributed is made, |
82 | * based on first and second order bit differences. This isn't |
83 | * ever-so reliable, but it's better than nothing. |
84 | */ |
85 | |
86 | extern int noise_timer(rand_pool */*r*/); |
87 | |
88 | /* --- @noise_devrandom@ --- * |
89 | * |
90 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
91 | * |
92 | * Returns: Nonzero if some randomness was contributed. |
93 | * |
94 | * Use: Attempts to obtain some randomness from the system entropy |
95 | * pool. All bits from the device are assumed to be good. |
96 | */ |
97 | |
98 | extern int noise_devrandom(rand_pool */*r*/); |
99 | |
100 | /* --- @noise_setid@ --- * |
101 | * |
102 | * Arguments: @uid_t uid@ = uid to set |
103 | * @gid_t gid@ = gid to set |
104 | * |
105 | * Returns: --- |
106 | * |
107 | * Use: Sets the user and group ids to be used by @noise_filter@ |
108 | * when running child processes. This is useful to avoid |
109 | * giving shell commands (even carefully written ones) undue |
099355bc |
110 | * privileges. This interface is Unix-specific. |
d03ab969 |
111 | */ |
112 | |
113 | extern void noise_setid(uid_t /*uid*/, gid_t /*gid*/); |
114 | |
115 | /* --- @noise_filter@ --- * |
116 | * |
117 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
118 | * @int good@ = number of good bits per 1024 bits |
119 | * @const char *c@ = shell command to run |
120 | * |
121 | * Returns: Nonzero if some randomness was contributed. |
122 | * |
123 | * Use: Attempts to execute a shell command, and dump it into the |
124 | * randomness pool. A very rough estimate of the number of |
125 | * good bits is made, based on the size of the command's output. |
126 | * This function calls @waitpid@, so be careful. Before execing |
127 | * the command, the process uid and gid are set to the values |
128 | * given to @noise_setid@, and an attempt is made to reset the |
129 | * list of supplementary groups. The environment passed to |
130 | * the command has been severly lobotimized. If the command |
131 | * fails to complete within a short time period, it is killed. |
132 | * Paranoid use of close-on-exec flags for file descriptors is |
133 | * recommended. |
099355bc |
134 | * |
135 | * This interface is Unix-specific. |
d03ab969 |
136 | */ |
137 | |
138 | extern int noise_filter(rand_pool */*r*/, int /*good*/, const char */*c*/); |
139 | |
25f654a7 |
140 | /* --- @noise_freewheel@ --- * |
141 | * |
142 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
143 | * |
144 | * Returns: Nonzero if some randomness was contributed. |
145 | * |
146 | * Use: Runs a free counter for a short while as a desparate attempt |
147 | * to get randomness from somewhere. This is actually quite |
148 | * effective. |
149 | */ |
150 | |
151 | int noise_freewheel(rand_pool */*r*/); |
152 | |
153 | /* --- @noise_enquire@ --- * |
154 | * |
155 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
156 | * |
157 | * Returns: Nonzero if some randomness was contributed. |
158 | * |
159 | * Use: Runs some shell commands to enquire about the prevailing |
160 | * environment. This can gather quite a lot of low-quality |
161 | * entropy. |
162 | */ |
163 | |
164 | extern int noise_enquire(rand_pool */*r*/); |
165 | |
d03ab969 |
166 | /* --- @noise_acquire@ --- * |
167 | * |
168 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
169 | * |
170 | * Returns: --- |
171 | * |
172 | * Use: Acquires some randomness from somewhere. |
173 | */ |
174 | |
175 | extern void noise_acquire(rand_pool */*r*/); |
176 | |
177 | /*----- That's all, folks -------------------------------------------------*/ |
178 | |
179 | #ifdef __cplusplus |
180 | } |
181 | #endif |
182 | |
183 | #endif |