d03ab969 |
1 | /* -*-c-*- |
d03ab969 |
2 | * |
099355bc |
3 | * Acquisition of environmental noise (Unix-specific) |
d03ab969 |
4 | * |
5 | * (c) 1998 Straylight/Edgeware |
6 | */ |
7 | |
45c0fd36 |
8 | /*----- Licensing notice --------------------------------------------------* |
d03ab969 |
9 | * |
10 | * This file is part of Catacomb. |
11 | * |
12 | * Catacomb is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
45c0fd36 |
16 | * |
d03ab969 |
17 | * Catacomb 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 Library General Public License for more details. |
45c0fd36 |
21 | * |
d03ab969 |
22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
b3f05084 |
28 | #ifndef CATACOMB_NOISE_H |
29 | #define CATACOMB_NOISE_H |
d03ab969 |
30 | |
31 | #ifdef __cplusplus |
32 | extern "C" { |
33 | #endif |
34 | |
35 | /*----- Header files ------------------------------------------------------*/ |
36 | |
37 | #include <sys/types.h> |
38 | |
b3f05084 |
39 | #ifndef CATACOMB_RAND_H |
d03ab969 |
40 | # include "rand.h" |
41 | #endif |
42 | |
43 | /*----- Noise source definition -------------------------------------------*/ |
44 | |
4e66da02 |
45 | extern const rand_source noise_source; |
d03ab969 |
46 | |
47 | /*----- Magic numbers -----------------------------------------------------*/ |
48 | |
49 | #define NOISE_NOSETUID ((uid_t)-1) |
50 | #define NOISE_NOSETGID ((gid_t)-1) |
51 | |
52 | /*----- Functions provided ------------------------------------------------*/ |
53 | |
54 | /* --- @noise_timer@ --- * |
55 | * |
56 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
57 | * |
58 | * Returns: Nonzero if some randomness was contributed. |
59 | * |
60 | * Use: Contributes the current time to the randomness pool. |
61 | * A guess at the number of useful bits contributed is made, |
62 | * based on first and second order bit differences. This isn't |
63 | * ever-so reliable, but it's better than nothing. |
64 | */ |
65 | |
66 | extern int noise_timer(rand_pool */*r*/); |
67 | |
68 | /* --- @noise_devrandom@ --- * |
69 | * |
70 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
71 | * |
72 | * Returns: Nonzero if some randomness was contributed. |
73 | * |
74 | * Use: Attempts to obtain some randomness from the system entropy |
75 | * pool. All bits from the device are assumed to be good. |
76 | */ |
77 | |
78 | extern int noise_devrandom(rand_pool */*r*/); |
79 | |
80 | /* --- @noise_setid@ --- * |
81 | * |
82 | * Arguments: @uid_t uid@ = uid to set |
83 | * @gid_t gid@ = gid to set |
84 | * |
85 | * Returns: --- |
86 | * |
87 | * Use: Sets the user and group ids to be used by @noise_filter@ |
88 | * when running child processes. This is useful to avoid |
89 | * giving shell commands (even carefully written ones) undue |
099355bc |
90 | * privileges. This interface is Unix-specific. |
d03ab969 |
91 | */ |
92 | |
93 | extern void noise_setid(uid_t /*uid*/, gid_t /*gid*/); |
94 | |
95 | /* --- @noise_filter@ --- * |
96 | * |
97 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
98 | * @int good@ = number of good bits per 1024 bits |
99 | * @const char *c@ = shell command to run |
100 | * |
101 | * Returns: Nonzero if some randomness was contributed. |
102 | * |
103 | * Use: Attempts to execute a shell command, and dump it into the |
104 | * randomness pool. A very rough estimate of the number of |
105 | * good bits is made, based on the size of the command's output. |
106 | * This function calls @waitpid@, so be careful. Before execing |
107 | * the command, the process uid and gid are set to the values |
108 | * given to @noise_setid@, and an attempt is made to reset the |
109 | * list of supplementary groups. The environment passed to |
110 | * the command has been severly lobotimized. If the command |
111 | * fails to complete within a short time period, it is killed. |
112 | * Paranoid use of close-on-exec flags for file descriptors is |
113 | * recommended. |
099355bc |
114 | * |
115 | * This interface is Unix-specific. |
d03ab969 |
116 | */ |
117 | |
118 | extern int noise_filter(rand_pool */*r*/, int /*good*/, const char */*c*/); |
119 | |
25f654a7 |
120 | /* --- @noise_freewheel@ --- * |
121 | * |
122 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
123 | * |
124 | * Returns: Nonzero if some randomness was contributed. |
125 | * |
126 | * Use: Runs a free counter for a short while as a desparate attempt |
127 | * to get randomness from somewhere. This is actually quite |
128 | * effective. |
129 | */ |
130 | |
131 | int noise_freewheel(rand_pool */*r*/); |
132 | |
133 | /* --- @noise_enquire@ --- * |
134 | * |
135 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
136 | * |
137 | * Returns: Nonzero if some randomness was contributed. |
138 | * |
139 | * Use: Runs some shell commands to enquire about the prevailing |
140 | * environment. This can gather quite a lot of low-quality |
141 | * entropy. |
142 | */ |
143 | |
144 | extern int noise_enquire(rand_pool */*r*/); |
145 | |
d03ab969 |
146 | /* --- @noise_acquire@ --- * |
147 | * |
148 | * Arguments: @rand_pool *r@ = pointer to a randomness pool |
149 | * |
150 | * Returns: --- |
151 | * |
152 | * Use: Acquires some randomness from somewhere. |
153 | */ |
154 | |
155 | extern void noise_acquire(rand_pool */*r*/); |
156 | |
157 | /*----- That's all, folks -------------------------------------------------*/ |
158 | |
159 | #ifdef __cplusplus |
160 | } |
161 | #endif |
162 | |
163 | #endif |