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
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
/*
This file is part of GNUnet.
Copyright (C) 2012, 2013 GNUnet e.V.
GNUnet 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, or (at your
option) any later version.
GNUnet 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 GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
/**
* @file util/crypto_mpi.c
* @brief Helper functions for libgcrypt MPIs
* @author Christian Grothoff
* @author Florian Dold
*/
#include "platform.h"
#include <gcrypt.h>
#include "gnunet_crypto_lib.h"
#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
/**
* Log an error message at log-level 'level' that indicates
* a failure of the command 'cmd' with the message given
* by gcry_strerror(rc).
*/
#define LOG_GCRY(level, cmd, rc) do { LOG(level, _("`%s' failed at %s:%d with error: %s\n"), cmd, __FILE__, __LINE__, gcry_strerror(rc)); } while(0)
/**
* If target != size, move @a target bytes to the end of the size-sized
* buffer and zero out the first @a target - @a size bytes.
*
* @param buf original buffer
* @param size number of bytes in @a buf
* @param target target size of the buffer
*/
static void
adjust (void *buf,
size_t size,
size_t target)
{
char *p = buf;
if (size < target)
{
memmove (&p[target - size], buf, size);
memset (buf, 0, target - size);
}
}
/**
* Output the given MPI value to the given buffer in
* network byte order.
* The MPI @a val may not be negative.
*
* @param buf where to output to
* @param size number of bytes in @a buf
* @param val value to write to @a buf
*/
void
GNUNET_CRYPTO_mpi_print_unsigned (void *buf,
size_t size,
gcry_mpi_t val)
{
size_t rsize;
int rc;
if (gcry_mpi_get_flag (val, GCRYMPI_FLAG_OPAQUE))
{
/* Store opaque MPIs left aligned into the buffer. */
unsigned int nbits;
const void *p;
p = gcry_mpi_get_opaque (val, &nbits);
GNUNET_assert (p);
rsize = (nbits+7)/8;
if (rsize > size)
rsize = size;
GNUNET_memcpy (buf, p, rsize);
if (rsize < size)
memset (buf+rsize, 0, size - rsize);
}
else
{
/* Store regular MPIs as unsigned integers right aligned into
the buffer. */
rsize = size;
if (0 !=
(rc = gcry_mpi_print (GCRYMPI_FMT_USG,
buf,
rsize, &rsize,
val)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR,
"gcry_mpi_print",
rc);
GNUNET_assert (0);
}
adjust (buf, rsize, size);
}
}
/**
* Convert data buffer into MPI value.
* The buffer is interpreted as network
* byte order, unsigned integer.
*
* @param result where to store MPI value (allocated)
* @param data raw data (GCRYMPI_FMT_USG)
* @param size number of bytes in @a data
*/
void
GNUNET_CRYPTO_mpi_scan_unsigned (gcry_mpi_t *result,
const void *data,
size_t size)
{
int rc;
if (0 != (rc = gcry_mpi_scan (result,
GCRYMPI_FMT_USG,
data, size, &size)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR,
"gcry_mpi_scan",
rc);
GNUNET_assert (0);
}
}
/* end of crypto_mpi.c */
|
