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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.35-RC1 xx-xxxx-201x  Note that the PCRE 8.xx series (PCRE1) is now in a bugfix-only state. All
5  -----------------------------  development is happening in the PCRE2 10.xx series.
6    
7    Version 8.38 xx-xxx-xxxx
8    ------------------------
9    
10    1.  If a group that contained a recursive back reference also contained a
11        forward reference subroutine call followed by a non-forward-reference
12        subroutine call, for example /.((?2)(?R)\1)()/, pcre2_compile() failed to
13        compile correct code, leading to undefined behaviour or an internally
14        detected error. This bug was discovered by the LLVM fuzzer.
15    
16    2.  Quantification of certain items (e.g. atomic back references) could cause
17        incorrect code to be compiled when recursive forward references were
18        involved. For example, in this pattern: /(?1)()((((((\1++))\x85)+)|))/.
19        This bug was discovered by the LLVM fuzzer.
20    
21    3.  A repeated conditional group whose condition was a reference by name caused
22        a buffer overflow if there was more than one group with the given name.
23        This bug was discovered by the LLVM fuzzer.
24    
25    4.  A recursive back reference by name within a group that had the same name as
26        another group caused a buffer overflow. For example:
27        /(?J)(?'d'(?'d'\g{d}))/. This bug was discovered by the LLVM fuzzer.
28    
29    5.  A forward reference by name to a group whose number is the same as the
30        current group, for example in this pattern: /(?|(\k'Pm')|(?'Pm'))/, caused
31        a buffer overflow at compile time. This bug was discovered by the LLVM
32        fuzzer.
33    
34    6.  A lookbehind assertion within a set of mutually recursive subpatterns could
35        provoke a buffer overflow. This bug was discovered by the LLVM fuzzer.
36    
37    7.  Another buffer overflow bug involved duplicate named groups with a
38        reference between their definition, with a group that reset capture
39        numbers, for example: /(?J:(?|(?'R')(\k'R')|((?'R'))))/. This has been
40        fixed by always allowing for more memory, even if not needed. (A proper fix
41        is implemented in PCRE2, but it involves more refactoring.)
42    
43    8.  There was no check for integer overflow in subroutine calls such as (?123).
44    
45    9.  The table entry for \l in EBCDIC environments was incorrect, leading to its
46        being treated as a literal 'l' instead of causing an error.
47    
48    10. There was a buffer overflow if pcre_exec() was called with an ovector of
49        size 1. This bug was found by american fuzzy lop.
50    
51    11. If a non-capturing group containing a conditional group that could match
52        an empty string was repeated, it was not identified as matching an empty
53        string itself. For example: /^(?:(?(1)x|)+)+$()/.
54    
55    12. In an EBCDIC environment, pcretest was mishandling the escape sequences
56        \a and \e in test subject lines.
57    
58    13. In an EBCDIC environment, \a in a pattern was converted to the ASCII
59        instead of the EBCDIC value.
60    
61    14. The handling of \c in an EBCDIC environment has been revised so that it is
62        now compatible with the specification in Perl's perlebcdic page.
63    
64    15. The EBCDIC character 0x41 is a non-breaking space, equivalent to 0xa0 in
65        ASCII/Unicode. This has now been added to the list of characters that are
66        recognized as white space in EBCDIC.
67    
68    16. When PCRE was compiled without UCP support, the use of \p and \P gave an
69        error (correctly) when used outside a class, but did not give an error
70        within a class.
71    
72    17. \h within a class was incorrectly compiled in EBCDIC environments.
73    
74    18. A pattern with an unmatched closing parenthesis that contained a backward
75        assertion which itself contained a forward reference caused buffer
76        overflow. And example pattern is: /(?=di(?<=(?1))|(?=(.))))/.
77    
78    19. JIT should return with error when the compiled pattern requires more stack
79        space than the maximum.
80    
81    20. A possessively repeated conditional group that could match an empty string,
82        for example, /(?(R))*+/, was incorrectly compiled.
83    
84    21. Fix infinite recursion in the JIT compiler when certain patterns such as
85        /(?:|a|){100}x/ are analysed.
86    
87    22. Some patterns with character classes involving [: and \\ were incorrectly
88        compiled and could cause reading from uninitialized memory or an incorrect
89        error diagnosis.
90    
91    23. Pathological patterns containing many nested occurrences of [: caused
92        pcre_compile() to run for a very long time.
93    
94    24. A conditional group with only one branch has an implicit empty alternative
95        branch and must therefore be treated as potentially matching an empty
96        string.
97    
98    25. If (?R was followed by - or + incorrect behaviour happened instead of a
99        diagnostic.
100    
101    26. Arrange to give up on finding the minimum matching length for overly
102        complex patterns.
103    
104    
105    Version 8.37 28-April-2015
106    --------------------------
107    
108    1.  When an (*ACCEPT) is triggered inside capturing parentheses, it arranges
109        for those parentheses to be closed with whatever has been captured so far.
110        However, it was failing to mark any other groups between the hightest
111        capture so far and the currrent group as "unset". Thus, the ovector for
112        those groups contained whatever was previously there. An example is the
113        pattern /(x)|((*ACCEPT))/ when matched against "abcd".
114    
115    2.  If an assertion condition was quantified with a minimum of zero (an odd
116        thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
117    
118    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
119        unrecognized modifier, a crash could occur.
120    
121    4.  An attempt to do global matching in pcretest with a zero-length ovector
122        caused a crash.
123    
124    5.  Fixed a memory leak during matching that could occur for a subpattern
125        subroutine call (recursive or otherwise) if the number of captured groups
126        that had to be saved was greater than ten.
127    
128    6.  Catch a bad opcode during auto-possessification after compiling a bad UTF
129        string with NO_UTF_CHECK. This is a tidyup, not a bug fix, as passing bad
130        UTF with NO_UTF_CHECK is documented as having an undefined outcome.
131    
132    7.  A UTF pattern containing a "not" match of a non-ASCII character and a
133        subroutine reference could loop at compile time. Example: /[^\xff]((?1))/.
134    
135    8. When a pattern is compiled, it remembers the highest back reference so that
136       when matching, if the ovector is too small, extra memory can be obtained to
137       use instead. A conditional subpattern whose condition is a check on a
138       capture having happened, such as, for example in the pattern
139       /^(?:(a)|b)(?(1)A|B)/, is another kind of back reference, but it was not
140       setting the highest backreference number. This mattered only if pcre_exec()
141       was called with an ovector that was too small to hold the capture, and there
142       was no other kind of back reference (a situation which is probably quite
143       rare). The effect of the bug was that the condition was always treated as
144       FALSE when the capture could not be consulted, leading to a incorrect
145       behaviour by pcre_exec(). This bug has been fixed.
146    
147    9. A reference to a duplicated named group (either a back reference or a test
148       for being set in a conditional) that occurred in a part of the pattern where
149       PCRE_DUPNAMES was not set caused the amount of memory needed for the pattern
150       to be incorrectly calculated, leading to overwriting.
151    
152    10. A mutually recursive set of back references such as (\2)(\1) caused a
153        segfault at study time (while trying to find the minimum matching length).
154        The infinite loop is now broken (with the minimum length unset, that is,
155        zero).
156    
157    11. If an assertion that was used as a condition was quantified with a minimum
158        of zero, matching went wrong. In particular, if the whole group had
159        unlimited repetition and could match an empty string, a segfault was
160        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
161        assertions to be quantified, but not if they are being used as conditions,
162        so the above pattern is faulted by Perl. PCRE has now been changed so that
163        it also rejects such patterns.
164    
165    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
166        failed to allow the zero-repeat case if pcre2_exec() was called with an
167        ovector too small to capture the group.
168    
169    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
170        Red Hat Product Security:
171    
172        (a) A crash if /K and /F were both set with the option to save the compiled
173        pattern.
174    
175        (b) Another crash if the option to print captured substrings in a callout
176        was combined with setting a null ovector, for example \O\C+ as a subject
177        string.
178    
179    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
180        forward reference repeated a large (but limited) number of times within a
181        repeated outer group that has a zero minimum quantifier, caused incorrect
182        code to be compiled, leading to the error "internal error:
183        previously-checked referenced subpattern not found" when an incorrect
184        memory address was read. This bug was reported as "heap overflow",
185        discovered by Kai Lu of Fortinet's FortiGuard Labs and given the CVE number
186        CVE-2015-2325.
187    
188    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
189        call within a group that also contained a recursive back reference caused
190        incorrect code to be compiled. This bug was reported as "heap overflow",
191        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
192        number CVE-2015-2326.
193    
194    24. Computing the size of the JIT read-only data in advance has been a source
195        of various issues, and new ones are still appear unfortunately. To fix
196        existing and future issues, size computation is eliminated from the code,
197        and replaced by on-demand memory allocation.
198    
199    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
200        adjacent to the end of the range, and the range contained characters with
201        more than one other case, caused incorrect behaviour when compiled in UTF
202        mode. In that example, the range a-j was left out of the class.
203    
204    26. Fix JIT compilation of conditional blocks, which assertion
205        is converted to (*FAIL). E.g: /(?(?!))/.
206    
207    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
208        discovered by the LLVM fuzzer.
209    
210    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
211        when this assertion was used as a condition, for example (?(?!)a|b). In
212        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
213        error about an unsupported item.
214    
215    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
216        possessification code could take exponential time to complete. A recursion
217        depth limit of 1000 has been imposed to limit the resources used by this
218        optimization.
219    
220    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
221        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
222        because \S ensures they are all in the class. The code for doing this was
223        interacting badly with the code for computing the amount of space needed to
224        compile the pattern, leading to a buffer overflow. This bug was discovered
225        by the LLVM fuzzer.
226    
227    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
228        other kinds of group caused stack overflow at compile time. This bug was
229        discovered by the LLVM fuzzer.
230    
231    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
232        between a subroutine call and its quantifier was incorrectly compiled,
233        leading to buffer overflow or other errors. This bug was discovered by the
234        LLVM fuzzer.
235    
236    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
237        assertion after (?(. The code was failing to check the character after
238        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
239        was discovered by the LLVM fuzzer.
240    
241    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
242        a fixed maximum following a group that contains a subroutine reference was
243        incorrectly compiled and could trigger buffer overflow. This bug was
244        discovered by the LLVM fuzzer.
245    
246    35. A mutual recursion within a lookbehind assertion such as (?<=((?2))((?1)))
247        caused a stack overflow instead of the diagnosis of a non-fixed length
248        lookbehind assertion. This bug was discovered by the LLVM fuzzer.
249    
250    36. The use of \K in a positive lookbehind assertion in a non-anchored pattern
251        (e.g. /(?<=\Ka)/) could make pcregrep loop.
252    
253    37. There was a similar problem to 36 in pcretest for global matches.
254    
255    38. If a greedy quantified \X was preceded by \C in UTF mode (e.g. \C\X*),
256        and a subsequent item in the pattern caused a non-match, backtracking over
257        the repeated \X did not stop, but carried on past the start of the subject,
258        causing reference to random memory and/or a segfault. There were also some
259        other cases where backtracking after \C could crash. This set of bugs was
260        discovered by the LLVM fuzzer.
261    
262    39. The function for finding the minimum length of a matching string could take
263        a very long time if mutual recursion was present many times in a pattern,
264        for example, /((?2){73}(?2))((?1))/. A better mutual recursion detection
265        method has been implemented. This infelicity was discovered by the LLVM
266        fuzzer.
267    
268    40. Static linking against the PCRE library using the pkg-config module was
269        failing on missing pthread symbols.
270    
271    
272    Version 8.36 26-September-2014
273    ------------------------------
274    
275    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
276        -Wmissing-field-initializers and -Wunused-parameter.
277    
278    2.  The tests for quantifiers being too big (greater than 65535) were being
279        applied after reading the number, and stupidly assuming that integer
280        overflow would give a negative number. The tests are now applied as the
281        numbers are read.
282    
283    3.  Tidy code in pcre_exec.c where two branches that used to be different are
284        now the same.
285    
286    4.  The JIT compiler did not generate match limit checks for certain
287        bracketed expressions with quantifiers. This may lead to exponential
288        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
289        issue should be resolved now.
290    
291    5.  Fixed an issue, which occures when nested alternatives are optimized
292        with table jumps.
293    
294    6.  Inserted two casts and changed some ints to size_t in the light of some
295        reported 64-bit compiler warnings (Bugzilla 1477).
296    
297    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
298        an empty string, which sometimes were behaving incorrectly in the
299        interpreter (though correctly in the JIT matcher). This pcretest input is
300        an example:
301    
302          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
303          NON QUOTED "QUOT""ED" AFTER "NOT MATCHED
304    
305        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
306        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
307        for an empty string was breaking the inner loop and carrying on at a lower
308        level, when possessive repeated groups should always return to a higher
309        level as they have no backtrack points in them. The empty string test now
310        occurs at the outer level.
311    
312    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
313        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
314    
315    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
316        doesn't).
317    
318    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
319        to hold a pattern to be incorrectly computed (too small) when there were
320        named back references to duplicated names. This could cause "internal
321        error: code overflow" or "double free or corruption" or other memory
322        handling errors.
323    
324    11. When named subpatterns had the same prefixes, back references could be
325        confused. For example, in this pattern:
326    
327          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
328    
329        the reference to 'Name' was incorrectly treated as a reference to a
330        duplicate name.
331    
332    12. A pattern such as /^s?c/mi8 where the optional character has more than
333        one "other case" was incorrectly compiled such that it would only try to
334        match starting at "c".
335    
336    13. When a pattern starting with \s was studied, VT was not included in the
337        list of possible starting characters; this should have been part of the
338        8.34/18 patch.
339    
340    14. If a character class started [\Qx]... where x is any character, the class
341        was incorrectly terminated at the ].
342    
343    15. If a pattern that started with a caseless match for a character with more
344        than one "other case" was studied, PCRE did not set up the starting code
345        unit bit map for the list of possible characters. Now it does. This is an
346        optimization improvement, not a bug fix.
347    
348    16. The Unicode data tables have been updated to Unicode 7.0.0.
349    
350    17. Fixed a number of memory leaks in pcregrep.
351    
352    18. Avoid a compiler warning (from some compilers) for a function call with
353        a cast that removes "const" from an lvalue by using an intermediate
354        variable (to which the compiler does not object).
355    
356    19. Incorrect code was compiled if a group that contained an internal recursive
357        back reference was optional (had quantifier with a minimum of zero). This
358        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
359        caused segmentation faults because of stack overflows at compile time.
360    
361    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
362        group that is quantified with an indefinite repeat, caused a compile-time
363        loop which used up all the system stack and provoked a segmentation fault.
364        This was not the same bug as 19 above.
365    
366    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
367        Patch by Mike Frysinger.
368    
369    
370    Version 8.35 04-April-2014
371    --------------------------
372    
373  1.  A new flag is set, when property checks are present in an XCLASS.  1.  A new flag is set, when property checks are present in an XCLASS.
374      When this flag is not set, PCRE can perform certain optimizations      When this flag is not set, PCRE can perform certain optimizations
# Line 27  Version 8.35-RC1 xx-xxxx-201x Line 393  Version 8.35-RC1 xx-xxxx-201x
393    
394  6.  Improve character range checks in JIT. Characters are read by an inprecise  6.  Improve character range checks in JIT. Characters are read by an inprecise
395      function now, which returns with an unknown value if the character code is      function now, which returns with an unknown value if the character code is
396      above a certain treshold (e.g: 256). The only limitation is that the value      above a certain threshold (e.g: 256). The only limitation is that the value
397      must be bigger than the treshold as well. This function is useful, when      must be bigger than the threshold as well. This function is useful when
398      the characters above the treshold are handled in the same way.      the characters above the threshold are handled in the same way.
399    
400  7.  The macros whose names start with RAWUCHAR are placeholders for a future  7.  The macros whose names start with RAWUCHAR are placeholders for a future
401      mode in which only the bottom 21 bits of 32-bit data items are used. To      mode in which only the bottom 21 bits of 32-bit data items are used. To
402      make this more memorable for those maintaining the code, the names have      make this more memorable for those maintaining the code, the names have
403      been changed to start with UCHAR21, and an extensive comment has been added      been changed to start with UCHAR21, and an extensive comment has been added
404      to their definition.      to their definition.
405    
406    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
407        to the export list in Makefile.am (they were accidentally omitted from the
408        8.34 tarball).
409    
410    9.  The informational output from pcretest used the phrase "starting byte set"
411        which is inappropriate for the 16-bit and 32-bit libraries. As the output
412        for "first char" and "need char" really means "non-UTF-char", I've changed
413        "byte" to "char", and slightly reworded the output. The documentation about
414        these values has also been (I hope) clarified.
415    
416    10. Another JIT related optimization: use table jumps for selecting the correct
417        backtracking path, when more than four alternatives are present inside a
418        bracket.
419    
420    11. Empty match is not possible, when the minimum length is greater than zero,
421        and there is no \K in the pattern. JIT should avoid empty match checks in
422        such cases.
423    
424    12. In a caseless character class with UCP support, when a character with more
425        than one alternative case was not the first character of a range, not all
426        the alternative cases were added to the class. For example, s and \x{17f}
427        are both alternative cases for S: the class [RST] was handled correctly,
428        but [R-T] was not.
429    
430    13. The configure.ac file always checked for pthread support when JIT was
431        enabled. This is not used in Windows, so I have put this test inside a
432        check for the presence of windows.h (which was already tested for).
433    
434    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
435        The algorithm provides a way to skip certain starting offsets, and usually
436        faster than linear prefix searches.
437    
438    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
439        as for 'fr_FR' and 'french'. For some reason, however, it then used the
440        Windows-specific input and output files, which have 'french' screwed in.
441        So this could never have worked. One of the problems with locales is that
442        they aren't always the same. I have now updated RunTest so that it checks
443        the output of the locale test (test 3) against three different output
444        files, and it allows the test to pass if any one of them matches. With luck
445        this should make the test pass on some versions of Solaris where it was
446        failing. Because of the uncertainty, the script did not used to stop if
447        test 3 failed; it now does. If further versions of a French locale ever
448        come to light, they can now easily be added.
449    
450    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
451        there was a message during ./configure, but it did not stop. This now
452        provokes an error. The invalid example in README has been corrected.
453        If a value less than the minimum is given, the minimum value has always
454        been used, but now a warning is given.
455    
456    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
457        was a bug in the test system, which is now fixed. Also, the list of various
458        configurations that are tested for each release did not have one with both
459        16/32 bits and --enable-bar-anycrlf. It now does.
460    
461    18. pcretest was missing "-C bsr" for displaying the \R default setting.
462    
463    19. Little endian PowerPC systems are supported now by the JIT compiler.
464    
465    20. The fast forward newline mechanism could enter to an infinite loop on
466        certain invalid UTF-8 input. Although we don't support these cases
467        this issue can be fixed by a performance optimization.
468    
469    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
470        not take account if existing stack usage. There is now a new global
471        variable called pcre_stack_guard that can be set to point to an external
472        function to check stack availability. It is called at the start of
473        processing every parenthesized group.
474    
475    22. A typo in the code meant that in ungreedy mode the max/min qualifier
476        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
477        not match "ab".
478    
479    23. When UTF was disabled, the JIT program reported some incorrect compile
480        errors. These messages are silenced now.
481    
482    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
483        compiler.
484    
485    25. Change all the temporary files used in RunGrepTest to be different to those
486        used by RunTest so that the tests can be run simultaneously, for example by
487        "make -j check".
488    
489    
490  Version 8.34 15-December-2013  Version 8.34 15-December-2013

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