1 | /* |
2 | * Copyright (c) 2015, Intel Corporation |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without |
5 | * modification, are permitted provided that the following conditions are met: |
6 | * |
7 | * * Redistributions of source code must retain the above copyright notice, |
8 | * this list of conditions and the following disclaimer. |
9 | * * Redistributions in binary form must reproduce the above copyright |
10 | * notice, this list of conditions and the following disclaimer in the |
11 | * documentation and/or other materials provided with the distribution. |
12 | * * Neither the name of Intel Corporation nor the names of its contributors |
13 | * may be used to endorse or promote products derived from this software |
14 | * without specific prior written permission. |
15 | * |
16 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
20 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
26 | * POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
28 | |
29 | #include "config.h" |
30 | |
31 | #include "utf8_validate.h" |
32 | |
33 | #include "ue2common.h" |
34 | #include "util/unicode_def.h" |
35 | |
36 | #include <cstring> |
37 | |
38 | namespace ue2 { |
39 | |
40 | static |
41 | bool hasValidContBytes(const u8 *s, size_t num) { |
42 | /* continuer bytes must all be of the form 10xx xxxx */ |
43 | for (size_t i = 0; i < num; i++) { |
44 | if ((s[i] & 0xc0) != UTF_CONT_BYTE_HEADER) { |
45 | return false; |
46 | } |
47 | } |
48 | return true; |
49 | } |
50 | |
51 | static |
52 | bool isAllowedCodepoint(u32 val) { |
53 | if (val >= 0xd800 && val <= 0xdfff) { |
54 | return false; // High and low surrogate halves |
55 | } |
56 | if (val > 0x10ffff) { |
57 | return false; // As per limit in RFC 3629 |
58 | } |
59 | |
60 | return true; |
61 | } |
62 | |
63 | bool isValidUtf8(const char *expression, const size_t len) { |
64 | if (!expression) { |
65 | return true; |
66 | } |
67 | |
68 | const u8 *s = (const u8 *)expression; |
69 | u32 val; |
70 | |
71 | size_t i = 0; |
72 | while (i < len) { |
73 | DEBUG_PRINTF("byte %zu: 0x%02x\n" , i, s[i]); |
74 | // One octet. |
75 | if (s[i] < 0x7f) { |
76 | DEBUG_PRINTF("one octet\n" ); |
77 | i++; |
78 | continue; |
79 | } |
80 | |
81 | // Two octets. |
82 | if ((s[i] & 0xe0) == UTF_TWO_BYTE_HEADER) { |
83 | DEBUG_PRINTF("two octets\n" ); |
84 | if (i + 2 > len) { |
85 | break; |
86 | } |
87 | if (!hasValidContBytes(&s[i] + 1, 1)) { |
88 | break; |
89 | } |
90 | val = ((s[i] & 0x1f) << 6) | (s[i + 1] & UTF_CONT_BYTE_VALUE_MASK); |
91 | DEBUG_PRINTF("val=0x%x\n" , val); |
92 | if (val < 1U << 7) { |
93 | DEBUG_PRINTF("overlong encoding\n" ); |
94 | break; |
95 | } |
96 | if (!isAllowedCodepoint(val)) { |
97 | DEBUG_PRINTF("codepoint not allowed\n" ); |
98 | break; |
99 | } |
100 | i += 2; |
101 | continue; |
102 | } |
103 | |
104 | // Three octets. |
105 | if ((s[i] & 0xf0) == UTF_THREE_BYTE_HEADER) { |
106 | DEBUG_PRINTF("three octets\n" ); |
107 | if (i + 3 > len) { |
108 | break; |
109 | } |
110 | if (!hasValidContBytes(&s[i] + 1, 2)) { |
111 | break; |
112 | } |
113 | val = ((s[i] & 0xf) << 12) | |
114 | ((s[i + 1] & UTF_CONT_BYTE_VALUE_MASK) << 6) | |
115 | (s[i + 2] & UTF_CONT_BYTE_VALUE_MASK); |
116 | if (val < 1U << 11) { |
117 | DEBUG_PRINTF("overlong encoding\n" ); |
118 | break; |
119 | } |
120 | if (!isAllowedCodepoint(val)) { |
121 | DEBUG_PRINTF("codepoint not allowed\n" ); |
122 | break; |
123 | } |
124 | i += 3; |
125 | continue; |
126 | } |
127 | |
128 | // Four octets. |
129 | if ((s[i] & 0xf8) == UTF_FOUR_BYTE_HEADER) { |
130 | DEBUG_PRINTF("four octets\n" ); |
131 | if (i + 4 > len) { |
132 | break; |
133 | } |
134 | if (!hasValidContBytes(&s[i] + 1, 3)) { |
135 | break; |
136 | } |
137 | val = ((s[i] & 0xf) << 18) | |
138 | ((s[i + 1] & UTF_CONT_BYTE_VALUE_MASK) << 12) | |
139 | ((s[i + 2] & UTF_CONT_BYTE_VALUE_MASK) << 6) | |
140 | (s[i + 3] & UTF_CONT_BYTE_VALUE_MASK); |
141 | if (val < 1U << 16) { |
142 | DEBUG_PRINTF("overlong encoding\n" ); |
143 | break; |
144 | } |
145 | if (!isAllowedCodepoint(val)) { |
146 | DEBUG_PRINTF("codepoint not allowed\n" ); |
147 | break; |
148 | } |
149 | i += 4; |
150 | continue; |
151 | } |
152 | |
153 | // Something else? |
154 | DEBUG_PRINTF("bad byte 0x%02x\n" , s[i]); |
155 | break; |
156 | } |
157 | |
158 | DEBUG_PRINTF("i=%zu, len=%zu\n" , i, len); |
159 | return i == len; |
160 | } |
161 | |
162 | } // namespace ue2 |
163 | |