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
146
|
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tomstdenis@gmail.com, http://libtom.org
*/
#include "tomcrypt.h"
/**
@file der_decode_generalizedtime.c
ASN.1 DER, decode a GeneralizedTime, Steffen Jaeckel
Based on der_decode_utctime.c
*/
#ifdef LTC_DER
static int char_to_int(unsigned char x)
{
switch (x) {
case '0': return 0;
case '1': return 1;
case '2': return 2;
case '3': return 3;
case '4': return 4;
case '5': return 5;
case '6': return 6;
case '7': return 7;
case '8': return 8;
case '9': return 9;
}
return 100;
}
#define DECODE_V(y, max) do {\
y = char_to_int(buf[x])*10 + char_to_int(buf[x+1]); \
if (y >= max) return CRYPT_INVALID_PACKET; \
x += 2; \
} while(0)
#define DECODE_V4(y, max) do {\
y = char_to_int(buf[x])*1000 + char_to_int(buf[x+1])*100 + char_to_int(buf[x+2])*10 + char_to_int(buf[x+3]); \
if (y >= max) return CRYPT_INVALID_PACKET; \
x += 4; \
} while(0)
/**
Decodes a Generalized time structure in DER format (reads all 6 valid encoding formats)
@param in Input buffer
@param inlen Length of input buffer in octets
@param out [out] Destination of Generalized time structure
@return CRYPT_OK if successful
*/
int der_decode_generalizedtime(const unsigned char *in, unsigned long *inlen,
ltc_generalizedtime *out)
{
unsigned char buf[32];
unsigned long x;
int y;
LTC_ARGCHK(in != NULL);
LTC_ARGCHK(inlen != NULL);
LTC_ARGCHK(out != NULL);
/* check header */
if (*inlen < 2UL || (in[1] >= sizeof(buf)) || ((in[1] + 2UL) > *inlen)) {
return CRYPT_INVALID_PACKET;
}
/* decode the string */
for (x = 0; x < in[1]; x++) {
y = der_ia5_value_decode(in[x+2]);
if (y == -1) {
return CRYPT_INVALID_PACKET;
}
if (!((y >= '0' && y <= '9')
|| y == 'Z' || y == '.'
|| y == '+' || y == '-')) {
return CRYPT_INVALID_PACKET;
}
buf[x] = y;
}
*inlen = 2 + x;
if (x < 15) {
return CRYPT_INVALID_PACKET;
}
/* possible encodings are
YYYYMMDDhhmmssZ
YYYYMMDDhhmmss+hh'mm'
YYYYMMDDhhmmss-hh'mm'
YYYYMMDDhhmmss.fsZ
YYYYMMDDhhmmss.fs+hh'mm'
YYYYMMDDhhmmss.fs-hh'mm'
So let's do a trivial decode upto [including] ss
*/
x = 0;
DECODE_V4(out->YYYY, 10000);
DECODE_V(out->MM, 13);
DECODE_V(out->DD, 32);
DECODE_V(out->hh, 24);
DECODE_V(out->mm, 60);
DECODE_V(out->ss, 60);
/* clear fractional seconds info */
out->fs = 0;
/* now is it Z or . */
if (buf[x] == 'Z') {
return CRYPT_OK;
} else if (buf[x] == '.') {
x++;
while (buf[x] >= '0' && buf[x] <= '9') {
unsigned fs = out->fs;
if (x >= sizeof(buf)) return CRYPT_INVALID_PACKET;
out->fs *= 10;
out->fs += char_to_int(buf[x]);
if (fs > out->fs) return CRYPT_OVERFLOW;
x++;
}
}
/* now is it Z, +, - */
if (buf[x] == 'Z') {
return CRYPT_OK;
} else if (buf[x] == '+' || buf[x] == '-') {
out->off_dir = (buf[x++] == '+') ? 0 : 1;
DECODE_V(out->off_hh, 24);
DECODE_V(out->off_mm, 60);
return CRYPT_OK;
} else {
return CRYPT_INVALID_PACKET;
}
}
#endif
/* $Source$ */
/* $Revision$ */
/* $Date$ */
|
