1 /* $OpenBSD: a_time_tm.c,v 1.15 2018/04/25 11:48:21 tb Exp $ */
2 /*
3  * Copyright (c) 2015 Bob Beck <beck@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include "config.h"
19 
20 #include <ctype.h>
21 #include <limits.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <time.h>
25 
26 #define GENTIME_LENGTH 15
27 #define UTCTIME_LENGTH 13
28 
29 #define V_ASN1_UTCTIME          23
30 #define V_ASN1_GENERALIZEDTIME  24
31 
32 #ifndef HAVE_ASN1_TIME_TM_CMP
33 int
34 ASN1_time_tm_cmp(struct tm *tm1, struct tm *tm2)
35 {
36         if (tm1->tm_year < tm2->tm_year)
37                 return (-1);
38         if (tm1->tm_year > tm2->tm_year)
39                 return (1);
40         if (tm1->tm_mon < tm2->tm_mon)
41                 return (-1);
42         if (tm1->tm_mon > tm2->tm_mon)
43                 return (1);
44         if (tm1->tm_mday < tm2->tm_mday)
45                 return (-1);
46         if (tm1->tm_mday > tm2->tm_mday)
47                 return (1);
48         if (tm1->tm_hour < tm2->tm_hour)
49                 return (-1);
50         if (tm1->tm_hour > tm2->tm_hour)
51                 return (1);
52         if (tm1->tm_min < tm2->tm_min)
53                 return (-1);
54         if (tm1->tm_min > tm2->tm_min)
55                 return (1);
56         if (tm1->tm_sec < tm2->tm_sec)
57                 return (-1);
58         if (tm1->tm_sec > tm2->tm_sec)
59                 return (1);
60         return 0;
61 }
62 #endif
63 
64 #ifndef HAVE_ASN1_TIME_TM_CLAMP_NOTAFTER
65 int
66 ASN1_time_tm_clamp_notafter(struct tm *tm)
67 {
68 #ifdef SMALL_TIME_T
69         struct tm broken_os_epoch_tm;
70         time_t broken_os_epoch_time = INT_MAX;
71 
72         if (gmtime_r(&broken_os_epoch_time, &broken_os_epoch_tm) == NULL)
73                 return 0;
74 
75         if (ASN1_time_tm_cmp(tm, &broken_os_epoch_tm) == 1)
76                 memcpy(tm, &broken_os_epoch_tm, sizeof(*tm));
77 #endif
78         return 1;
79 }
80 #endif
81 
82 /*
83  * Parse an RFC 5280 format ASN.1 time string.
84  *
85  * mode must be:
86  * 0 if we expect to parse a time as specified in RFC 5280 for an X509 object.
87  * V_ASN1_UTCTIME if we wish to parse an RFC5280 format UTC time.
88  * V_ASN1_GENERALIZEDTIME if we wish to parse an RFC5280 format Generalized time.
89  *
90  * Returns:
91  * -1 if the string was invalid.
92  * V_ASN1_UTCTIME if the string validated as a UTC time string.
93  * V_ASN1_GENERALIZEDTIME if the string validated as a Generalized time string.
94  *
95  * Fills in *tm with the corresponding time if tm is non NULL.
96  */
97 #ifndef HAVE_ASN1_TIME_PARSE
98 #define	ATOI2(ar)	((ar) += 2, ((ar)[-2] - '0') * 10 + ((ar)[-1] - '0'))
99 int
100 ASN1_time_parse(const char *bytes, size_t len, struct tm *tm, int mode)
101 {
102 	size_t i;
103 	int type = 0;
104 	struct tm ltm;
105 	struct tm *lt;
106 	const char *p;
107 
108 	if (bytes == NULL)
109 		return (-1);
110 
111 	/* Constrain to valid lengths. */
112 	if (len != UTCTIME_LENGTH && len != GENTIME_LENGTH)
113 		return (-1);
114 
115 	lt = tm;
116 	if (lt == NULL) {
117 		memset(&ltm, 0, sizeof(ltm));
118 		lt = &ltm;
119 	}
120 
121 	/* Timezone is required and must be GMT (Zulu). */
122 	if (bytes[len - 1] != 'Z')
123 		return (-1);
124 
125 	/* Make sure everything else is digits. */
126 	for (i = 0; i < len - 1; i++) {
127 		if (isdigit((unsigned char)bytes[i]))
128 			continue;
129 		return (-1);
130 	}
131 
132 	/*
133 	 * Validate and convert the time
134 	 */
135 	p = bytes;
136 	switch (len) {
137 	case GENTIME_LENGTH:
138 		if (mode == V_ASN1_UTCTIME)
139 			return (-1);
140 		lt->tm_year = (ATOI2(p) * 100) - 1900;	/* cc */
141 		type = V_ASN1_GENERALIZEDTIME;
142 		/* FALLTHROUGH */
143 	case UTCTIME_LENGTH:
144 		if (type == 0) {
145 			if (mode == V_ASN1_GENERALIZEDTIME)
146 				return (-1);
147 			type = V_ASN1_UTCTIME;
148 		}
149 		lt->tm_year += ATOI2(p);		/* yy */
150 		if (type == V_ASN1_UTCTIME) {
151 			if (lt->tm_year < 50)
152 				lt->tm_year += 100;
153 		}
154 		lt->tm_mon = ATOI2(p) - 1;		/* mm */
155 		if (lt->tm_mon < 0 || lt->tm_mon > 11)
156 			return (-1);
157 		lt->tm_mday = ATOI2(p);			/* dd */
158 		if (lt->tm_mday < 1 || lt->tm_mday > 31)
159 			return (-1);
160 		lt->tm_hour = ATOI2(p);			/* HH */
161 		if (lt->tm_hour < 0 || lt->tm_hour > 23)
162 			return (-1);
163 		lt->tm_min = ATOI2(p);			/* MM */
164 		if (lt->tm_min < 0 || lt->tm_min > 59)
165 			return (-1);
166 		lt->tm_sec = ATOI2(p);			/* SS */
167 		/* Leap second 60 is not accepted. Reconsider later? */
168 		if (lt->tm_sec < 0 || lt->tm_sec > 59)
169 			return (-1);
170 		break;
171 	default:
172 		return (-1);
173 	}
174 
175 	return (type);
176 }
177 #endif