1: /*************************************************
2: * Perl-Compatible Regular Expressions *
3: *************************************************/
4:
5: /* PCRE is a library of functions to support regular expressions whose syntax
6: and semantics are as close as possible to those of the Perl 5 language.
7:
8: Written by Philip Hazel
9: Copyright (c) 1997-2013 University of Cambridge
10:
11: -----------------------------------------------------------------------------
12: Redistribution and use in source and binary forms, with or without
13: modification, are permitted provided that the following conditions are met:
14:
15: * Redistributions of source code must retain the above copyright notice,
16: this list of conditions and the following disclaimer.
17:
18: * Redistributions in binary form must reproduce the above copyright
19: notice, this list of conditions and the following disclaimer in the
20: documentation and/or other materials provided with the distribution.
21:
22: * Neither the name of the University of Cambridge nor the names of its
23: contributors may be used to endorse or promote products derived from
24: this software without specific prior written permission.
25:
26: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
27: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
30: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36: POSSIBILITY OF SUCH DAMAGE.
37: -----------------------------------------------------------------------------
38: */
39:
40:
41: /* This module contains an internal function for validating UTF-8 character
42: strings. */
43:
44:
45: #ifdef HAVE_CONFIG_H
46: #include "config.h"
47: #endif
48:
49: #include "pcre_internal.h"
50:
51:
52: /*************************************************
53: * Validate a UTF-8 string *
54: *************************************************/
55:
56: /* This function is called (optionally) at the start of compile or match, to
57: check that a supposed UTF-8 string is actually valid. The early check means
58: that subsequent code can assume it is dealing with a valid string. The check
59: can be turned off for maximum performance, but the consequences of supplying an
60: invalid string are then undefined.
61:
62: Originally, this function checked according to RFC 2279, allowing for values in
63: the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in
64: the canonical format. Once somebody had pointed out RFC 3629 to me (it
65: obsoletes 2279), additional restrictions were applied. The values are now
66: limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the
67: subrange 0xd000 to 0xdfff is excluded. However, the format of 5-byte and 6-byte
68: characters is still checked.
69:
70: From release 8.13 more information about the details of the error are passed
71: back in the returned value:
72:
73: PCRE_UTF8_ERR0 No error
74: PCRE_UTF8_ERR1 Missing 1 byte at the end of the string
75: PCRE_UTF8_ERR2 Missing 2 bytes at the end of the string
76: PCRE_UTF8_ERR3 Missing 3 bytes at the end of the string
77: PCRE_UTF8_ERR4 Missing 4 bytes at the end of the string
78: PCRE_UTF8_ERR5 Missing 5 bytes at the end of the string
79: PCRE_UTF8_ERR6 2nd-byte's two top bits are not 0x80
80: PCRE_UTF8_ERR7 3rd-byte's two top bits are not 0x80
81: PCRE_UTF8_ERR8 4th-byte's two top bits are not 0x80
82: PCRE_UTF8_ERR9 5th-byte's two top bits are not 0x80
83: PCRE_UTF8_ERR10 6th-byte's two top bits are not 0x80
84: PCRE_UTF8_ERR11 5-byte character is not permitted by RFC 3629
85: PCRE_UTF8_ERR12 6-byte character is not permitted by RFC 3629
86: PCRE_UTF8_ERR13 4-byte character with value > 0x10ffff is not permitted
87: PCRE_UTF8_ERR14 3-byte character with value 0xd000-0xdfff is not permitted
88: PCRE_UTF8_ERR15 Overlong 2-byte sequence
89: PCRE_UTF8_ERR16 Overlong 3-byte sequence
90: PCRE_UTF8_ERR17 Overlong 4-byte sequence
91: PCRE_UTF8_ERR18 Overlong 5-byte sequence (won't ever occur)
92: PCRE_UTF8_ERR19 Overlong 6-byte sequence (won't ever occur)
93: PCRE_UTF8_ERR20 Isolated 0x80 byte (not within UTF-8 character)
94: PCRE_UTF8_ERR21 Byte with the illegal value 0xfe or 0xff
95: PCRE_UTF8_ERR22 Unused (was non-character)
96:
97: Arguments:
98: string points to the string
99: length length of string, or -1 if the string is zero-terminated
100: errp pointer to an error position offset variable
101:
102: Returns: = 0 if the string is a valid UTF-8 string
103: > 0 otherwise, setting the offset of the bad character
104: */
105:
106: int
107: PRIV(valid_utf)(PCRE_PUCHAR string, int length, int *erroroffset)
108: {
109: #ifdef SUPPORT_UTF
110: register PCRE_PUCHAR p;
111:
112: if (length < 0)
113: {
114: for (p = string; *p != 0; p++);
115: length = (int)(p - string);
116: }
117:
118: for (p = string; length-- > 0; p++)
119: {
120: register pcre_uchar ab, c, d;
121:
122: c = *p;
123: if (c < 128) continue; /* ASCII character */
124:
125: if (c < 0xc0) /* Isolated 10xx xxxx byte */
126: {
127: *erroroffset = (int)(p - string);
128: return PCRE_UTF8_ERR20;
129: }
130:
131: if (c >= 0xfe) /* Invalid 0xfe or 0xff bytes */
132: {
133: *erroroffset = (int)(p - string);
134: return PCRE_UTF8_ERR21;
135: }
136:
137: ab = PRIV(utf8_table4)[c & 0x3f]; /* Number of additional bytes */
138: if (length < ab)
139: {
140: *erroroffset = (int)(p - string); /* Missing bytes */
141: return ab - length; /* Codes ERR1 to ERR5 */
142: }
143: length -= ab; /* Length remaining */
144:
145: /* Check top bits in the second byte */
146:
147: if (((d = *(++p)) & 0xc0) != 0x80)
148: {
149: *erroroffset = (int)(p - string) - 1;
150: return PCRE_UTF8_ERR6;
151: }
152:
153: /* For each length, check that the remaining bytes start with the 0x80 bit
154: set and not the 0x40 bit. Then check for an overlong sequence, and for the
155: excluded range 0xd800 to 0xdfff. */
156:
157: switch (ab)
158: {
159: /* 2-byte character. No further bytes to check for 0x80. Check first byte
160: for for xx00 000x (overlong sequence). */
161:
162: case 1: if ((c & 0x3e) == 0)
163: {
164: *erroroffset = (int)(p - string) - 1;
165: return PCRE_UTF8_ERR15;
166: }
167: break;
168:
169: /* 3-byte character. Check third byte for 0x80. Then check first 2 bytes
170: for 1110 0000, xx0x xxxx (overlong sequence) or
171: 1110 1101, 1010 xxxx (0xd800 - 0xdfff) */
172:
173: case 2:
174: if ((*(++p) & 0xc0) != 0x80) /* Third byte */
175: {
176: *erroroffset = (int)(p - string) - 2;
177: return PCRE_UTF8_ERR7;
178: }
179: if (c == 0xe0 && (d & 0x20) == 0)
180: {
181: *erroroffset = (int)(p - string) - 2;
182: return PCRE_UTF8_ERR16;
183: }
184: if (c == 0xed && d >= 0xa0)
185: {
186: *erroroffset = (int)(p - string) - 2;
187: return PCRE_UTF8_ERR14;
188: }
189: break;
190:
191: /* 4-byte character. Check 3rd and 4th bytes for 0x80. Then check first 2
192: bytes for for 1111 0000, xx00 xxxx (overlong sequence), then check for a
193: character greater than 0x0010ffff (f4 8f bf bf) */
194:
195: case 3:
196: if ((*(++p) & 0xc0) != 0x80) /* Third byte */
197: {
198: *erroroffset = (int)(p - string) - 2;
199: return PCRE_UTF8_ERR7;
200: }
201: if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */
202: {
203: *erroroffset = (int)(p - string) - 3;
204: return PCRE_UTF8_ERR8;
205: }
206: if (c == 0xf0 && (d & 0x30) == 0)
207: {
208: *erroroffset = (int)(p - string) - 3;
209: return PCRE_UTF8_ERR17;
210: }
211: if (c > 0xf4 || (c == 0xf4 && d > 0x8f))
212: {
213: *erroroffset = (int)(p - string) - 3;
214: return PCRE_UTF8_ERR13;
215: }
216: break;
217:
218: /* 5-byte and 6-byte characters are not allowed by RFC 3629, and will be
219: rejected by the length test below. However, we do the appropriate tests
220: here so that overlong sequences get diagnosed, and also in case there is
221: ever an option for handling these larger code points. */
222:
223: /* 5-byte character. Check 3rd, 4th, and 5th bytes for 0x80. Then check for
224: 1111 1000, xx00 0xxx */
225:
226: case 4:
227: if ((*(++p) & 0xc0) != 0x80) /* Third byte */
228: {
229: *erroroffset = (int)(p - string) - 2;
230: return PCRE_UTF8_ERR7;
231: }
232: if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */
233: {
234: *erroroffset = (int)(p - string) - 3;
235: return PCRE_UTF8_ERR8;
236: }
237: if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */
238: {
239: *erroroffset = (int)(p - string) - 4;
240: return PCRE_UTF8_ERR9;
241: }
242: if (c == 0xf8 && (d & 0x38) == 0)
243: {
244: *erroroffset = (int)(p - string) - 4;
245: return PCRE_UTF8_ERR18;
246: }
247: break;
248:
249: /* 6-byte character. Check 3rd-6th bytes for 0x80. Then check for
250: 1111 1100, xx00 00xx. */
251:
252: case 5:
253: if ((*(++p) & 0xc0) != 0x80) /* Third byte */
254: {
255: *erroroffset = (int)(p - string) - 2;
256: return PCRE_UTF8_ERR7;
257: }
258: if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */
259: {
260: *erroroffset = (int)(p - string) - 3;
261: return PCRE_UTF8_ERR8;
262: }
263: if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */
264: {
265: *erroroffset = (int)(p - string) - 4;
266: return PCRE_UTF8_ERR9;
267: }
268: if ((*(++p) & 0xc0) != 0x80) /* Sixth byte */
269: {
270: *erroroffset = (int)(p - string) - 5;
271: return PCRE_UTF8_ERR10;
272: }
273: if (c == 0xfc && (d & 0x3c) == 0)
274: {
275: *erroroffset = (int)(p - string) - 5;
276: return PCRE_UTF8_ERR19;
277: }
278: break;
279: }
280:
281: /* Character is valid under RFC 2279, but 4-byte and 5-byte characters are
282: excluded by RFC 3629. The pointer p is currently at the last byte of the
283: character. */
284:
285: if (ab > 3)
286: {
287: *erroroffset = (int)(p - string) - ab;
288: return (ab == 4)? PCRE_UTF8_ERR11 : PCRE_UTF8_ERR12;
289: }
290: }
291:
292: #else /* Not SUPPORT_UTF */
293: (void)(string); /* Keep picky compilers happy */
294: (void)(length);
295: (void)(erroroffset);
296: #endif
297:
298: return PCRE_UTF8_ERR0; /* This indicates success */
299: }
300:
301: /* End of pcre_valid_utf8.c */
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