1 /*
2 ***************************************************************************
3 * Copyright (C) 2008-2013, International Business Machines Corporation
4 * and others. All Rights Reserved.
5 ***************************************************************************
6 *
7 *  uspoof_impl.h
8 *
9 *    Implemenation header for spoof detection
10 *
11 */
12 
13 #ifndef USPOOFIM_H
14 #define USPOOFIM_H
15 
16 #include "unicode/utypes.h"
17 #include "unicode/uspoof.h"
18 #include "unicode/uscript.h"
19 #include "unicode/udata.h"
20 
21 #include "utrie2.h"
22 
23 #if !UCONFIG_NO_NORMALIZATION
24 
25 #ifdef __cplusplus
26 
27 U_NAMESPACE_BEGIN
28 
29 // The maximium length (in UTF-16 UChars) of the skeleton replacement string resulting from
30 //   a single input code point.  This is function of the unicode.org data.
31 #define USPOOF_MAX_SKELETON_EXPANSION 20
32 
33 // The default stack buffer size for copies or conversions or normalizations
34 // of input strings being checked.  (Used in multiple places.)
35 #define USPOOF_STACK_BUFFER_SIZE 100
36 
37 // Magic number for sanity checking spoof data.
38 #define USPOOF_MAGIC 0x3845fdef
39 
40 class IdentifierInfo;
41 class ScriptSet;
42 class SpoofData;
43 struct SpoofDataHeader;
44 struct SpoofStringLengthsElement;
45 
46 /**
47   *  Class SpoofImpl corresponds directly to the plain C API opaque type
48   *  USpoofChecker.  One can be cast to the other.
49   */
50 class SpoofImpl : public UObject  {
51 public:
52 	SpoofImpl(SpoofData *data, UErrorCode &status);
53 	SpoofImpl();
54 	virtual ~SpoofImpl();
55 
56     /** Copy constructor, used by the user level uspoof_clone() function.
57      */
58     SpoofImpl(const SpoofImpl &src, UErrorCode &status);
59 
60     static SpoofImpl *validateThis(USpoofChecker *sc, UErrorCode &status);
61     static const SpoofImpl *validateThis(const USpoofChecker *sc, UErrorCode &status);
62 
63     /** Get the confusable skeleton transform for a single code point.
64      *  The result is a string with a length between 1 and 18.
65      *  @param    tableMask  bit flag specifying which confusable table to use.
66      *                       One of USPOOF_SL_TABLE_FLAG, USPOOF_MA_TABLE_FLAG, etc.
67      *  @return   The length in UTF-16 code units of the substition string.
68      */
69     int32_t confusableLookup(UChar32 inChar, int32_t tableMask, UnicodeString &destBuf) const;
70 
71     /** Set and Get AllowedLocales, implementations of the corresponding API */
72     void setAllowedLocales(const char *localesList, UErrorCode &status);
73     const char * getAllowedLocales(UErrorCode &status);
74 
75     // Add (union) to the UnicodeSet all of the characters for the scripts used for
76     // the specified locale.  Part of the implementation of setAllowedLocales.
77     void addScriptChars(const char *locale, UnicodeSet *allowedChars, UErrorCode &status);
78 
79 
80     /** parse a hex number.  Untility used by the builders.   */
81     static UChar32 ScanHex(const UChar *s, int32_t start, int32_t limit, UErrorCode &status);
82 
83     // Implementation for Whole Script tests.
84     // Return the test bit flag to be ORed into the eventual user return value
85     //    if a Spoof opportunity is detected.
86     void wholeScriptCheck(
87         const UnicodeString &text, ScriptSet *result, UErrorCode &status) const;
88 
89     static UClassID U_EXPORT2 getStaticClassID(void);
90     virtual UClassID getDynamicClassID(void) const;
91 
92     // IdentifierInfo Cache. IdentifierInfo objects are somewhat expensive to create.
93     //                       Maintain a one-element cache, which is sufficient to avoid repeatedly
94     //                       creating new ones unless we get multi-thread concurrency in spoof
95     //                       check operations, which should be statistically uncommon.
96     IdentifierInfo *getIdentifierInfo(UErrorCode &status) const;
97     void releaseIdentifierInfo(IdentifierInfo *idInfo) const;
98 
99     //
100     // Data Members
101     //
102 
103     int32_t           fMagic;             // Internal sanity check.
104     int32_t           fChecks;            // Bit vector of checks to perform.
105 
106     SpoofData        *fSpoofData;
107 
108     const UnicodeSet *fAllowedCharsSet;   // The UnicodeSet of allowed characters.
109                                           //   for this Spoof Checker.  Defaults to all chars.
110 
111     const char       *fAllowedLocales;    // The list of allowed locales.
112     URestrictionLevel fRestrictionLevel;  // The maximum restriction level for an acceptable identifier.
113 
114     IdentifierInfo    *fCachedIdentifierInfo;    // Do not use directly. See getIdentifierInfo().:w
115 };
116 
117 
118 
119 //
120 //  Confusable Mappings Data Structures
121 //
122 //    For the confusable data, we are essentially implementing a map,
123 //       key:    a code point
124 //       value:  a string.  Most commonly one char in length, but can be more.
125 //
126 //    The keys are stored as a sorted array of 32 bit ints.
127 //             bits 0-23    a code point value
128 //             bits 24-31   flags
129 //                24:  1 if entry applies to SL table
130 //                25:  1 if entry applies to SA table
131 //                26:  1 if entry applies to ML table
132 //                27:  1 if entry applies to MA table
133 //                28:  1 if there are multiple entries for this code point.
134 //                29-30:  length of value string, in UChars.
135 //                         values are (1, 2, 3, other)
136 //        The key table is sorted in ascending code point order.  (not on the
137 //        32 bit int value, the flag bits do not participate in the sorting.)
138 //
139 //        Lookup is done by means of a binary search in the key table.
140 //
141 //    The corresponding values are kept in a parallel array of 16 bit ints.
142 //        If the value string is of length 1, it is literally in the value array.
143 //        For longer strings, the value array contains an index into the strings table.
144 //
145 //    String Table:
146 //       The strings table contains all of the value strings (those of length two or greater)
147 //       concatentated together into one long UChar (UTF-16) array.
148 //
149 //       The array is arranged by length of the strings - all strings of the same length
150 //       are stored together.  The sections are ordered by length of the strings -
151 //       all two char strings first, followed by all of the three Char strings, etc.
152 //
153 //       There is no nul character or other mark between adjacent strings.
154 //
155 //    String Lengths table
156 //       The length of strings from 1 to 3 is flagged in the key table.
157 //       For strings of length 4 or longer, the string length table provides a
158 //       mapping between an index into the string table and the corresponding length.
159 //       Strings of these lengths are rare, so lookup time is not an issue.
160 //       Each entry consists of
161 //            uint16_t      index of the _last_ string with this length
162 //            uint16_t      the length
163 //
164 
165 // Flag bits in the Key entries
166 #define USPOOF_SL_TABLE_FLAG (1<<24)
167 #define USPOOF_SA_TABLE_FLAG (1<<25)
168 #define USPOOF_ML_TABLE_FLAG (1<<26)
169 #define USPOOF_MA_TABLE_FLAG (1<<27)
170 #define USPOOF_KEY_MULTIPLE_VALUES (1<<28)
171 #define USPOOF_KEY_LENGTH_SHIFT 29
172 #define USPOOF_KEY_LENGTH_FIELD(x) (((x)>>29) & 3)
173 
174 
175 struct SpoofStringLengthsElement {
176     uint16_t      fLastString;         // index in string table of last string with this length
177     uint16_t      fStrLength;           // Length of strings
178 };
179 
180 
181 
182 //-------------------------------------------------------------------------------------
183 //
184 //  SpoofData
185 //
186 //    A small class that wraps the raw (usually memory mapped) spoof data.
187 //    Serves two primary functions:
188 //      1.  Convenience.  Contains real pointers to the data, to avoid dealing with
189 //          the offsets in the raw data.
190 //      2.  Reference counting.  When a spoof checker is cloned, the raw data is shared
191 //          and must be retained until all checkers using the data are closed.
192 //    Nothing in this struct includes state that is specific to any particular
193 //    USpoofDetector object.
194 //
195 //---------------------------------------------------------------------------------------
196 class SpoofData: public UMemory {
197   public:
198     static SpoofData *getDefault(UErrorCode &status);   // Load standard ICU spoof data.
199     SpoofData(UErrorCode &status);   // Create new spoof data wrapper.
200                                      // Only used when building new data from rules.
201 
202     // Constructor for use when creating from prebuilt default data.
203     //   A UDataMemory is what the ICU internal data loading functions provide.
204     //   The udm is adopted by the SpoofData.
205     SpoofData(UDataMemory *udm, UErrorCode &status);
206 
207     // Constructor for use when creating from serialized data.
208     //
209     SpoofData(const void *serializedData, int32_t length, UErrorCode &status);
210 
211     //  Check raw Spoof Data Version compatibility.
212     //  Return TRUE it looks good.
213     static UBool validateDataVersion(const SpoofDataHeader *rawData, UErrorCode &status);
214     ~SpoofData();                    // Destructor not normally used.
215                                      // Use removeReference() instead.
216     // Reference Counting functions.
217     //    Clone of a user-level spoof detector increments the ref count on the data.
218     //    Close of a user-level spoof detector decrements the ref count.
219     //    If the data is owned by us, it will be deleted when count goes to zero.
220     SpoofData *addReference();
221     void removeReference();
222 
223     // Reserve space in the raw data.  For use by builder when putting together a
224     //   new set of data.  Init the new storage to zero, to prevent inconsistent
225     //   results if it is not all otherwise set by the requester.
226     //  Return:
227     //    pointer to the new space that was added by this function.
228     void *reserveSpace(int32_t numBytes, UErrorCode &status);
229 
230     // initialize the pointers from this object to the raw data.
231     void initPtrs(UErrorCode &status);
232 
233     // Reset all fields to an initial state.
234     // Called from the top of all constructors.
235     void reset();
236 
237     SpoofDataHeader             *fRawData;          // Ptr to the raw memory-mapped data
238     UBool                       fDataOwned;         // True if the raw data is owned, and needs
239                                                     //  to be deleted when refcount goes to zero.
240     UDataMemory                 *fUDM;              // If not NULL, our data came from a
241                                                     //   UDataMemory, which we must close when
242                                                     //   we are done.
243 
244     uint32_t                    fMemLimit;          // Limit of available raw data space
245     u_atomic_int32_t            fRefCount;
246 
247     // Confusable data
248     int32_t                     *fCFUKeys;
249     uint16_t                    *fCFUValues;
250     SpoofStringLengthsElement   *fCFUStringLengths;
251     UChar                       *fCFUStrings;
252 
253     // Whole Script Confusable Data
254     UTrie2                      *fAnyCaseTrie;
255     UTrie2                      *fLowerCaseTrie;
256     ScriptSet                   *fScriptSets;
257     };
258 
259 
260 //---------------------------------------------------------------------------------------
261 //
262 //  Raw Binary Data Formats, as loaded from the ICU data file,
263 //    or as built by the builder.
264 //
265 //---------------------------------------------------------------------------------------
266 struct SpoofDataHeader {
267     int32_t       fMagic;                // (0x3845fdef)
268     uint8_t       fFormatVersion[4];     // Data Format. Same as the value in struct UDataInfo
269                                          //   if there is one associated with this data.
270     int32_t       fLength;               // Total lenght in bytes of this spoof data,
271                                          //   including all sections, not just the header.
272 
273     // The following four sections refer to data representing the confusable data
274     //   from the Unicode.org data from "confusables.txt"
275 
276     int32_t       fCFUKeys;               // byte offset to Keys table (from SpoofDataHeader *)
277     int32_t       fCFUKeysSize;           // number of entries in keys table  (32 bits each)
278 
279     // TODO: change name to fCFUValues, for consistency.
280     int32_t       fCFUStringIndex;        // byte offset to String Indexes table
281     int32_t       fCFUStringIndexSize;    // number of entries in String Indexes table (16 bits each)
282                                           //     (number of entries must be same as in Keys table
283 
284     int32_t       fCFUStringTable;        // byte offset of String table
285     int32_t       fCFUStringTableLen;     // length of string table (in 16 bit UChars)
286 
287     int32_t       fCFUStringLengths;      // byte offset to String Lengths table
288     int32_t       fCFUStringLengthsSize;  // number of entries in lengths table. (2 x 16 bits each)
289 
290 
291     // The following sections are for data from confusablesWholeScript.txt
292 
293     int32_t       fAnyCaseTrie;           // byte offset to the serialized Any Case Trie
294     int32_t       fAnyCaseTrieLength;     // Length (bytes) of the serialized Any Case Trie
295 
296     int32_t       fLowerCaseTrie;         // byte offset to the serialized Lower Case Trie
297     int32_t       fLowerCaseTrieLength;   // Length (bytes) of the serialized Lower Case Trie
298 
299     int32_t       fScriptSets;            // byte offset to array of ScriptSets
300     int32_t       fScriptSetsLength;      // Number of ScriptSets (24 bytes each)
301 
302 
303     // The following sections are for data from xidmodifications.txt
304 
305 
306     int32_t       unused[15];              // Padding, Room for Expansion
307 
308  };
309 
310 
311 
312 
313 //
314 //  Structure for the Whole Script Confusable Data
315 //    See Unicode UAX-39, Unicode Security Mechanisms, for a description of the
316 //    Whole Script confusable data
317 //
318 //  The data provides mappings from code points to a set of scripts
319 //    that contain characters that might be confused with the code point.
320 //  There are two mappings, one for lower case only, and one for characters
321 //    of any case.
322 //
323 //  The actual data consists of a utrie2 to map from a code point to an offset,
324 //  and an array of UScriptSets (essentially bit maps) that is indexed
325 //  by the offsets obtained from the Trie.
326 //
327 //
328 
329 
330 U_NAMESPACE_END
331 #endif /* __cplusplus */
332 
333 /**
334   * Endianness swap function for binary spoof data.
335   * @internal
336   */
337 U_CAPI int32_t U_EXPORT2
338 uspoof_swap(const UDataSwapper *ds, const void *inData, int32_t length, void *outData,
339             UErrorCode *status);
340 
341 
342 #endif
343 
344 #endif  /* USPOOFIM_H */
345 
346