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comparison libtomcrypt/src/pk/asn1/der/utctime/der_decode_utctime.c @ 389:5ff8218bcee9

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propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 2af95f00ebd5bb7a28b3817db1218442c935388e) to branch 'au.asn.ucc.matt.dropbear' (head ecd779509ef23a8cdf64888904fc9b31d78aa933)
author Matt Johnston <matt@ucc.asn.au>
date Thu, 11 Jan 2007 03:14:55 +0000
parents 0cbe8f6dbf9e
children f849a5ca2efc
comparison
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388:fb54020f78e1 389:5ff8218bcee9
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 * Tom St Denis, [email protected], http://libtomcrypt.com
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file der_decode_utctime.c
15 ASN.1 DER, decode a UTCTIME, Tom St Denis
16 */
17
18 #ifdef LTC_DER
19
20 static int char_to_int(unsigned char x)
21 {
22 switch (x) {
23 case '0': return 0;
24 case '1': return 1;
25 case '2': return 2;
26 case '3': return 3;
27 case '4': return 4;
28 case '5': return 5;
29 case '6': return 6;
30 case '7': return 7;
31 case '8': return 8;
32 case '9': return 9;
33 }
34 return 100;
35 }
36
37 #define DECODE_V(y, max) \
38 y = char_to_int(buf[x])*10 + char_to_int(buf[x+1]); \
39 if (y >= max) return CRYPT_INVALID_PACKET; \
40 x += 2;
41
42 /**
43 Decodes a UTC time structure in DER format (reads all 6 valid encoding formats)
44 @param in Input buffer
45 @param inlen Length of input buffer in octets
46 @param out [out] Destination of UTC time structure
47 @return CRYPT_OK if successful
48 */
49 int der_decode_utctime(const unsigned char *in, unsigned long *inlen,
50 ltc_utctime *out)
51 {
52 unsigned char buf[32];
53 unsigned long x;
54 int y;
55
56 LTC_ARGCHK(in != NULL);
57 LTC_ARGCHK(inlen != NULL);
58 LTC_ARGCHK(out != NULL);
59
60 /* check header */
61 if (*inlen < 2UL || (in[1] >= sizeof(buf)) || ((in[1] + 2UL) > *inlen)) {
62 return CRYPT_INVALID_PACKET;
63 }
64
65 /* decode the string */
66 for (x = 0; x < in[1]; x++) {
67 y = der_ia5_value_decode(in[x+2]);
68 if (y == -1) {
69 return CRYPT_INVALID_PACKET;
70 }
71 buf[x] = y;
72 }
73 *inlen = 2 + x;
74
75
76 /* possible encodings are
77 YYMMDDhhmmZ
78 YYMMDDhhmm+hh'mm'
79 YYMMDDhhmm-hh'mm'
80 YYMMDDhhmmssZ
81 YYMMDDhhmmss+hh'mm'
82 YYMMDDhhmmss-hh'mm'
83
84 So let's do a trivial decode upto [including] mm
85 */
86
87 x = 0;
88 DECODE_V(out->YY, 100);
89 DECODE_V(out->MM, 13);
90 DECODE_V(out->DD, 32);
91 DECODE_V(out->hh, 24);
92 DECODE_V(out->mm, 60);
93
94 /* clear timezone and seconds info */
95 out->off_dir = out->off_hh = out->off_mm = out->ss = 0;
96
97 /* now is it Z, +, - or 0-9 */
98 if (buf[x] == 'Z') {
99 return CRYPT_OK;
100 } else if (buf[x] == '+' || buf[x] == '-') {
101 out->off_dir = (buf[x++] == '+') ? 0 : 1;
102 DECODE_V(out->off_hh, 24);
103 DECODE_V(out->off_mm, 60);
104 return CRYPT_OK;
105 }
106
107 /* decode seconds */
108 DECODE_V(out->ss, 60);
109
110 /* now is it Z, +, - */
111 if (buf[x] == 'Z') {
112 return CRYPT_OK;
113 } else if (buf[x] == '+' || buf[x] == '-') {
114 out->off_dir = (buf[x++] == '+') ? 0 : 1;
115 DECODE_V(out->off_hh, 24);
116 DECODE_V(out->off_mm, 60);
117 return CRYPT_OK;
118 } else {
119 return CRYPT_INVALID_PACKET;
120 }
121 }
122
123 #endif
124
125 /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/utctime/der_decode_utctime.c,v $ */
126 /* $Revision: 1.8 $ */
127 /* $Date: 2006/03/31 14:15:35 $ */