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c215a4bc IJ |
1 | /* |
2 | * This file is part of secnet. | |
3 | * See README for full list of copyright holders. | |
4 | * | |
5 | * secnet is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version d of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * secnet is distributed in the hope that it will be useful, but | |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * version 3 along with secnet; if not, see | |
17 | * https://www.gnu.org/licenses/gpl.html. | |
18 | */ | |
19 | ||
8689b3a9 | 20 | #include "secnet.h" |
2fe58dfd SE |
21 | #include <stdio.h> |
22 | #include <fcntl.h> | |
23 | #include <string.h> | |
2fe58dfd SE |
24 | #include <sys/stat.h> |
25 | #include <unistd.h> | |
4f5e39ec | 26 | #include <assert.h> |
2fe58dfd | 27 | |
2fe58dfd SE |
28 | struct rgen_data { |
29 | closure_t cl; | |
30 | struct random_if ops; | |
31 | struct cloc loc; | |
32 | int fd; | |
33 | }; | |
34 | ||
35 | static random_fn random_generate; | |
1caa23ff | 36 | static bool_t random_generate(void *data, int32_t bytes, uint8_t *buff) |
2fe58dfd SE |
37 | { |
38 | struct rgen_data *st=data; | |
4f5e39ec | 39 | int r; |
2fe58dfd | 40 | |
4f5e39ec SE |
41 | r= read(st->fd,buff,bytes); |
42 | ||
43 | assert(r == bytes); | |
44 | /* This is totally crap error checking, but AFAICT many callers of | |
45 | * this function do not check the return value. This is a minimal | |
46 | * change to make the code not fail silently-but-insecurely. | |
47 | * | |
48 | * A proper fix requires either: | |
49 | * - Declare all random number generation failures as fatal | |
50 | * errors, and make this return void, and fix all callers, | |
51 | * and make this call some appropriate function if it fails. | |
52 | * - Make this have proper error checking (and reporting!) | |
53 | * and make all callers check the error (and report!); | |
54 | * this will be tricky, I think, because you have to report | |
55 | * the errno somewhere. | |
56 | * | |
57 | * There's also the issue that this is only one possible | |
58 | * implementation of a random number source; others may not rely | |
59 | * on reading from a file descriptor, and may not produce | |
60 | * appropriate settings of errno. | |
61 | */ | |
2fe58dfd SE |
62 | |
63 | return True; | |
64 | } | |
65 | ||
66 | static list_t *random_apply(closure_t *self, struct cloc loc, | |
67 | dict_t *context, list_t *args) | |
68 | { | |
69 | struct rgen_data *st; | |
70 | item_t *arg1, *arg2; | |
71 | string_t filename=NULL; | |
72 | ||
b7886fd4 | 73 | NEW(st); |
2fe58dfd SE |
74 | |
75 | st->cl.description="randomsource"; | |
76 | st->cl.type=CL_RANDOMSRC; | |
77 | st->cl.apply=NULL; | |
78 | st->cl.interface=&st->ops; | |
79 | st->ops.st=st; | |
80 | st->ops.blocking=False; | |
81 | st->ops.generate=random_generate; | |
82 | st->loc=loc; | |
83 | ||
84 | arg1=list_elem(args,0); | |
85 | arg2=list_elem(args,1); | |
86 | ||
87 | if (!arg1) { | |
4f5e39ec | 88 | cfgfatal(loc,"randomsource","requires a filename\n"); |
2fe58dfd SE |
89 | } |
90 | if (arg1->type != t_string) { | |
91 | cfgfatal(arg1->loc,"randomsource", | |
92 | "filename (arg1) must be a string\n"); | |
93 | } | |
94 | filename=arg1->data.string; | |
95 | ||
96 | if (arg2) { | |
97 | if (arg2->type != t_bool) { | |
98 | cfgfatal(arg2->loc,"randomsource", | |
99 | "blocking parameter (arg2) must be bool\n"); | |
100 | } | |
101 | st->ops.blocking=arg2->data.bool; | |
102 | } | |
103 | ||
104 | if (!filename) { | |
4f5e39ec | 105 | cfgfatal(loc,"randomsource","requires a filename\n"); |
2fe58dfd SE |
106 | } |
107 | st->fd=open(filename,O_RDONLY); | |
108 | if (st->fd<0) { | |
109 | fatal_perror("randomsource (%s:%d): cannot open %s",arg1->loc.file, | |
110 | arg1->loc.line,filename); | |
111 | } | |
112 | return new_closure(&st->cl); | |
113 | } | |
114 | ||
115 | void random_module(dict_t *d) | |
116 | { | |
117 | add_closure(d,"randomfile",random_apply); | |
118 | } |