1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2016 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/random.h>
#include <grub/dl.h>
#include <grub/lib/hexdump.h>
#include <grub/command.h>
#include <grub/mm.h>
GRUB_MOD_LICENSE ("GPLv3+");
grub_err_t
grub_crypto_get_random (void *buffer, grub_size_t sz)
{
/* This is an arbitrer between different methods.
TODO: Add more methods in the future. */
/* TODO: Add some PRNG smartness to reduce damage from bad entropy. */
if (grub_crypto_arch_get_random (buffer, sz))
return GRUB_ERR_NONE;
return grub_error (GRUB_ERR_IO, "no random sources found");
}
static int
get_num_digits (int val)
{
int ret = 0;
while (val != 0)
{
ret++;
val /= 10;
}
if (ret == 0)
return 1;
return ret;
}
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
static grub_err_t
grub_cmd_hexdump_random (grub_command_t cmd __attribute__ ((unused)), int argc, char **args)
{
grub_size_t length = 64;
grub_err_t err;
void *buffer;
grub_uint8_t *ptr;
int stats[256];
int i, digits = 2;
char template[10];
if (argc >= 1)
length = grub_strtoull (args[0], 0, 0);
if (length == 0)
return grub_error (GRUB_ERR_BAD_ARGUMENT, "length pust be positive");
buffer = grub_malloc (length);
if (!buffer)
return grub_errno;
err = grub_crypto_get_random (buffer, length);
if (err)
{
grub_free (buffer);
return err;
}
hexdump (0, buffer, length);
grub_memset(stats, 0, sizeof(stats));
for (ptr = buffer; ptr < (grub_uint8_t *) buffer + length; ptr++)
stats[*ptr]++;
grub_printf ("Statistics:\n");
for (i = 0; i < 256; i++)
{
int z = get_num_digits (stats[i]);
if (z > digits)
digits = z;
}
grub_snprintf (template, sizeof (template), "%%0%dd ", digits);
for (i = 0; i < 256; i++)
{
grub_printf ("%s", template);//, stats[i]);
if ((i & 0xf) == 0xf)
grub_printf ("\n");
}
grub_free (buffer);
return 0;
}
static grub_command_t cmd;
GRUB_MOD_INIT (random)
{
cmd = grub_register_command ("hexdump_random", grub_cmd_hexdump_random,
N_("[LENGTH]"),
N_("Hexdump random data."));
}
GRUB_MOD_FINI (random)
{
grub_unregister_command (cmd);
}
|
