1 /*
2 * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <stdio.h>
11 #include "internal/cryptlib.h"
12 #include "internal/unicode.h"
13 #include <openssl/asn1.h>
14
15 /* UTF8 utilities */
16
17 /*-
18 * This parses a UTF8 string one character at a time. It is passed a pointer
19 * to the string and the length of the string. It sets 'value' to the value of
20 * the current character. It returns the number of characters read or a
21 * negative error code:
22 * -1 = string too short
23 * -2 = illegal character
24 * -3 = subsequent characters not of the form 10xxxxxx
25 * -4 = character encoded incorrectly (not minimal length).
26 */
27
UTF8_getc(const unsigned char * str,int len,unsigned long * val)28 int UTF8_getc(const unsigned char *str, int len, unsigned long *val)
29 {
30 const unsigned char *p;
31 unsigned long value;
32 int ret;
33 if (len <= 0)
34 return 0;
35 p = str;
36
37 /* Check syntax and work out the encoded value (if correct) */
38 if ((*p & 0x80) == 0) {
39 value = *p++ & 0x7f;
40 ret = 1;
41 } else if ((*p & 0xe0) == 0xc0) {
42 if (len < 2)
43 return -1;
44 if ((p[1] & 0xc0) != 0x80)
45 return -3;
46 value = (*p++ & 0x1f) << 6;
47 value |= *p++ & 0x3f;
48 if (value < 0x80)
49 return -4;
50 ret = 2;
51 } else if ((*p & 0xf0) == 0xe0) {
52 if (len < 3)
53 return -1;
54 if (((p[1] & 0xc0) != 0x80)
55 || ((p[2] & 0xc0) != 0x80))
56 return -3;
57 value = (*p++ & 0xf) << 12;
58 value |= (*p++ & 0x3f) << 6;
59 value |= *p++ & 0x3f;
60 if (value < 0x800)
61 return -4;
62 if (is_unicode_surrogate(value))
63 return -2;
64 ret = 3;
65 } else if ((*p & 0xf8) == 0xf0) {
66 if (len < 4)
67 return -1;
68 if (((p[1] & 0xc0) != 0x80)
69 || ((p[2] & 0xc0) != 0x80)
70 || ((p[3] & 0xc0) != 0x80))
71 return -3;
72 value = ((unsigned long)(*p++ & 0x7)) << 18;
73 value |= (*p++ & 0x3f) << 12;
74 value |= (*p++ & 0x3f) << 6;
75 value |= *p++ & 0x3f;
76 if (value < 0x10000)
77 return -4;
78 ret = 4;
79 } else
80 return -2;
81 *val = value;
82 return ret;
83 }
84
85 /*
86 * This takes a character 'value' and writes the UTF8 encoded value in 'str'
87 * where 'str' is a buffer containing 'len' characters. Returns the number of
88 * characters written, -1 if 'len' is too small or -2 if 'value' is out of
89 * range. 'str' can be set to NULL in which case it just returns the number of
90 * characters. It will need at most 4 characters.
91 */
92
UTF8_putc(unsigned char * str,int len,unsigned long value)93 int UTF8_putc(unsigned char *str, int len, unsigned long value)
94 {
95 if (!str)
96 len = 4; /* Maximum we will need */
97 else if (len <= 0)
98 return -1;
99 if (value < 0x80) {
100 if (str)
101 *str = (unsigned char)value;
102 return 1;
103 }
104 if (value < 0x800) {
105 if (len < 2)
106 return -1;
107 if (str) {
108 *str++ = (unsigned char)(((value >> 6) & 0x1f) | 0xc0);
109 *str = (unsigned char)((value & 0x3f) | 0x80);
110 }
111 return 2;
112 }
113 if (value < 0x10000) {
114 if (is_unicode_surrogate(value))
115 return -2;
116 if (len < 3)
117 return -1;
118 if (str) {
119 *str++ = (unsigned char)(((value >> 12) & 0xf) | 0xe0);
120 *str++ = (unsigned char)(((value >> 6) & 0x3f) | 0x80);
121 *str = (unsigned char)((value & 0x3f) | 0x80);
122 }
123 return 3;
124 }
125 if (value < UNICODE_LIMIT) {
126 if (len < 4)
127 return -1;
128 if (str) {
129 *str++ = (unsigned char)(((value >> 18) & 0x7) | 0xf0);
130 *str++ = (unsigned char)(((value >> 12) & 0x3f) | 0x80);
131 *str++ = (unsigned char)(((value >> 6) & 0x3f) | 0x80);
132 *str = (unsigned char)((value & 0x3f) | 0x80);
133 }
134 return 4;
135 }
136 return -2;
137 }
138