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comparison libtomcrypt/src/pk/asn1/der/generalizedtime/der_decode_generalizedtime.c @ 1471:6dba84798cd5

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Update to libtomcrypt 1.18.1, merged with Dropbear changes
author Matt Johnston <matt@ucc.asn.au>
date Fri, 09 Feb 2018 21:44:05 +0800
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1470:8bba51a55704 1471:6dba84798cd5
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 */
9 #include "tomcrypt.h"
10
11 /**
12 @file der_decode_generalizedtime.c
13 ASN.1 DER, decode a GeneralizedTime, Steffen Jaeckel
14 Based on der_decode_utctime.c
15 */
16
17 #ifdef LTC_DER
18
19 static int _char_to_int(unsigned char x)
20 {
21 switch (x) {
22 case '0': return 0;
23 case '1': return 1;
24 case '2': return 2;
25 case '3': return 3;
26 case '4': return 4;
27 case '5': return 5;
28 case '6': return 6;
29 case '7': return 7;
30 case '8': return 8;
31 case '9': return 9;
32 default: return 100;
33 }
34 }
35
36 #define DECODE_V(y, max) do {\
37 y = _char_to_int(buf[x])*10 + _char_to_int(buf[x+1]); \
38 if (y >= max) return CRYPT_INVALID_PACKET; \
39 x += 2; \
40 } while(0)
41
42 #define DECODE_V4(y, max) do {\
43 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]); \
44 if (y >= max) return CRYPT_INVALID_PACKET; \
45 x += 4; \
46 } while(0)
47
48 /**
49 Decodes a Generalized time structure in DER format (reads all 6 valid encoding formats)
50 @param in Input buffer
51 @param inlen Length of input buffer in octets
52 @param out [out] Destination of Generalized time structure
53 @return CRYPT_OK if successful
54 */
55 int der_decode_generalizedtime(const unsigned char *in, unsigned long *inlen,
56 ltc_generalizedtime *out)
57 {
58 unsigned char buf[32];
59 unsigned long x;
60 int y;
61
62 LTC_ARGCHK(in != NULL);
63 LTC_ARGCHK(inlen != NULL);
64 LTC_ARGCHK(out != NULL);
65
66 /* check header */
67 if (*inlen < 2UL || (in[1] >= sizeof(buf)) || ((in[1] + 2UL) > *inlen)) {
68 return CRYPT_INVALID_PACKET;
69 }
70
71 /* decode the string */
72 for (x = 0; x < in[1]; x++) {
73 y = der_ia5_value_decode(in[x+2]);
74 if (y == -1) {
75 return CRYPT_INVALID_PACKET;
76 }
77 if (!((y >= '0' && y <= '9')
78 || y == 'Z' || y == '.'
79 || y == '+' || y == '-')) {
80 return CRYPT_INVALID_PACKET;
81 }
82 buf[x] = y;
83 }
84 *inlen = 2 + x;
85
86 if (x < 15) {
87 return CRYPT_INVALID_PACKET;
88 }
89
90 /* possible encodings are
91 YYYYMMDDhhmmssZ
92 YYYYMMDDhhmmss+hh'mm'
93 YYYYMMDDhhmmss-hh'mm'
94 YYYYMMDDhhmmss.fsZ
95 YYYYMMDDhhmmss.fs+hh'mm'
96 YYYYMMDDhhmmss.fs-hh'mm'
97
98 So let's do a trivial decode upto [including] ss
99 */
100
101 x = 0;
102 DECODE_V4(out->YYYY, 10000);
103 DECODE_V(out->MM, 13);
104 DECODE_V(out->DD, 32);
105 DECODE_V(out->hh, 24);
106 DECODE_V(out->mm, 60);
107 DECODE_V(out->ss, 60);
108
109 /* clear fractional seconds info */
110 out->fs = 0;
111
112 /* now is it Z or . */
113 if (buf[x] == 'Z') {
114 return CRYPT_OK;
115 } else if (buf[x] == '.') {
116 x++;
117 while (buf[x] >= '0' && buf[x] <= '9') {
118 unsigned fs = out->fs;
119 if (x >= sizeof(buf)) return CRYPT_INVALID_PACKET;
120 out->fs *= 10;
121 out->fs += _char_to_int(buf[x]);
122 if (fs > out->fs) return CRYPT_OVERFLOW;
123 x++;
124 }
125 }
126
127 /* now is it Z, +, - */
128 if (buf[x] == 'Z') {
129 return CRYPT_OK;
130 } else if (buf[x] == '+' || buf[x] == '-') {
131 out->off_dir = (buf[x++] == '+') ? 0 : 1;
132 DECODE_V(out->off_hh, 24);
133 DECODE_V(out->off_mm, 60);
134 return CRYPT_OK;
135 } else {
136 return CRYPT_INVALID_PACKET;
137 }
138 }
139
140 #endif
141
142 /* ref: $Format:%D$ */
143 /* git commit: $Format:%H$ */
144 /* commit time: $Format:%ai$ */