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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.35-RC1 xx-xxxx-201x  Version 8.37 xx-xxx-2015
5  -----------------------------  ------------------------
7    1.  When an (*ACCEPT) is triggered inside capturing parentheses, it arranges
8        for those parentheses to be closed with whatever has been captured so far.
9        However, it was failing to mark any other groups between the hightest
10        capture so far and the currrent group as "unset". Thus, the ovector for
11        those groups contained whatever was previously there. An example is the
12        pattern /(x)|((*ACCEPT))/ when matched against "abcd".
14    2.  If an assertion condition was quantified with a minimum of zero (an odd
15        thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
17    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
18        unrecognized modifier, a crash could occur.
20    4.  An attempt to do global matching in pcretest with a zero-length ovector
21        caused a crash.
23    5.  Fixed a memory leak during matching that could occur for a subpattern
24        subroutine call (recursive or otherwise) if the number of captured groups
25        that had to be saved was greater than ten.
27    6.  Catch a bad opcode during auto-possessification after compiling a bad UTF
28        string with NO_UTF_CHECK. This is a tidyup, not a bug fix, as passing bad
29        UTF with NO_UTF_CHECK is documented as having an undefined outcome.
31    7.  A UTF pattern containing a "not" match of a non-ASCII character and a
32        subroutine reference could loop at compile time. Example: /[^\xff]((?1))/.
34    8. When a pattern is compiled, it remembers the highest back reference so that
35       when matching, if the ovector is too small, extra memory can be obtained to
36       use instead. A conditional subpattern whose condition is a check on a
37       capture having happened, such as, for example in the pattern
38       /^(?:(a)|b)(?(1)A|B)/, is another kind of back reference, but it was not
39       setting the highest backreference number. This mattered only if pcre_exec()
40       was called with an ovector that was too small to hold the capture, and there
41       was no other kind of back reference (a situation which is probably quite
42       rare). The effect of the bug was that the condition was always treated as
43       FALSE when the capture could not be consulted, leading to a incorrect
44       behaviour by pcre2_match(). This bug has been fixed.
46    9. A reference to a duplicated named group (either a back reference or a test
47       for being set in a conditional) that occurred in a part of the pattern where
48       PCRE_DUPNAMES was not set caused the amount of memory needed for the pattern
49       to be incorrectly calculated, leading to overwriting.
51    10. A mutually recursive set of back references such as (\2)(\1) caused a
52        segfault at study time (while trying to find the minimum matching length).
53        The infinite loop is now broken (with the minimum length unset, that is,
54        zero).
56    11. If an assertion that was used as a condition was quantified with a minimum
57        of zero, matching went wrong. In particular, if the whole group had
58        unlimited repetition and could match an empty string, a segfault was
59        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
60        assertions to be quantified, but not if they are being used as conditions,
61        so the above pattern is faulted by Perl. PCRE has now been changed so that
62        it also rejects such patterns.
64    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
65        failed to allow the zero-repeat case if pcre2_exec() was called with an
66        ovector too small to capture the group.
68    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
69        Red Hat Product Security:
71        (a) A crash if /K and /F were both set with the option to save the compiled
72        pattern.
74        (b) Another crash if the option to print captured substrings in a callout
75        was combined with setting a null ovector, for example \O\C+ as a subject
76        string.
78    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
79        forward reference repeated a large (but limited) number of times within a
80        repeated outer group that has a zero minimum quantifier, caused incorrect
81        code to be compiled, leading to the error "internal error:
82        previously-checked referenced subpattern not found" when an incorrect
83        memory address was read. This bug was reported as "heap overflow",
84        discovered by Kai Lu of Fortinet's FortiGuard Labs and given the CVE number
85        CVE-2015-2325.
87    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
88        call within a group that also contained a recursive back reference caused
89        incorrect code to be compiled. This bug was reported as "heap overflow",
90        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
91        number CVE-2015-2326.
93    24. Computing the size of the JIT read-only data in advance has been a source
94        of various issues, and new ones are still appear unfortunately. To fix
95        existing and future issues, size computation is eliminated from the code,
96        and replaced by on-demand memory allocation.
98    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
99        adjacent to the end of the range, and the range contained characters with
100        more than one other case, caused incorrect behaviour when compiled in UTF
101        mode. In that example, the range a-j was left out of the class.
103    26. Fix JIT compilation of conditional blocks, which assertion
104        is converted to (*FAIL). E.g: /(?(?!))/.
106    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
107        discovered by the LLVM fuzzer.
109    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
110        when this assertion was used as a condition, for example (?(?!)a|b). In
111        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
112        error about an unsupported item.
114    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
115        possessification code could take exponential time to complete. A recursion
116        depth limit of 1000 has been imposed to limit the resources used by this
117        optimization.
119    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
120        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
121        because \S ensures they are all in the class. The code for doing this was
122        interacting badly with the code for computing the amount of space needed to
123        compile the pattern, leading to a buffer overflow. This bug was discovered
124        by the LLVM fuzzer.
126    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
127        other kinds of group caused stack overflow at compile time. This bug was
128        discovered by the LLVM fuzzer.
130    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
131        between a subroutine call and its quantifier was incorrectly compiled,
132        leading to buffer overflow or other errors. This bug was discovered by the
133        LLVM fuzzer.
135    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
136        assertion after (?(. The code was failing to check the character after
137        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
138        was discovered by the LLVM fuzzer.
140    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
141        a fixed maximum following a group that contains a subroutine reference was
142        incorrectly compiled and could trigger buffer overflow. This bug was
143        discovered by the LLVM fuzzer.
145    35. A mutual recursion within a lookbehind assertion such as (?<=((?2))((?1)))
146        caused a stack overflow instead of the diagnosis of a non-fixed length
147        lookbehind assertion. This bug was discovered by the LLVM fuzzer.
150    Version 8.36 26-September-2014
151    ------------------------------
153    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
154        -Wmissing-field-initializers and -Wunused-parameter.
156    2.  The tests for quantifiers being too big (greater than 65535) were being
157        applied after reading the number, and stupidly assuming that integer
158        overflow would give a negative number. The tests are now applied as the
159        numbers are read.
161    3.  Tidy code in pcre_exec.c where two branches that used to be different are
162        now the same.
164    4.  The JIT compiler did not generate match limit checks for certain
165        bracketed expressions with quantifiers. This may lead to exponential
166        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
167        issue should be resolved now.
169    5.  Fixed an issue, which occures when nested alternatives are optimized
170        with table jumps.
172    6.  Inserted two casts and changed some ints to size_t in the light of some
173        reported 64-bit compiler warnings (Bugzilla 1477).
175    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
176        an empty string, which sometimes were behaving incorrectly in the
177        interpreter (though correctly in the JIT matcher). This pcretest input is
178        an example:
180          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
183        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
184        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
185        for an empty string was breaking the inner loop and carrying on at a lower
186        level, when possessive repeated groups should always return to a higher
187        level as they have no backtrack points in them. The empty string test now
188        occurs at the outer level.
190    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
191        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
193    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
194        doesn't).
196    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
197        to hold a pattern to be incorrectly computed (too small) when there were
198        named back references to duplicated names. This could cause "internal
199        error: code overflow" or "double free or corruption" or other memory
200        handling errors.
202    11. When named subpatterns had the same prefixes, back references could be
203        confused. For example, in this pattern:
205          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
207        the reference to 'Name' was incorrectly treated as a reference to a
208        duplicate name.
210    12. A pattern such as /^s?c/mi8 where the optional character has more than
211        one "other case" was incorrectly compiled such that it would only try to
212        match starting at "c".
214    13. When a pattern starting with \s was studied, VT was not included in the
215        list of possible starting characters; this should have been part of the
216        8.34/18 patch.
218    14. If a character class started [\Qx]... where x is any character, the class
219        was incorrectly terminated at the ].
221    15. If a pattern that started with a caseless match for a character with more
222        than one "other case" was studied, PCRE did not set up the starting code
223        unit bit map for the list of possible characters. Now it does. This is an
224        optimization improvement, not a bug fix.
226    16. The Unicode data tables have been updated to Unicode 7.0.0.
228    17. Fixed a number of memory leaks in pcregrep.
230    18. Avoid a compiler warning (from some compilers) for a function call with
231        a cast that removes "const" from an lvalue by using an intermediate
232        variable (to which the compiler does not object).
234    19. Incorrect code was compiled if a group that contained an internal recursive
235        back reference was optional (had quantifier with a minimum of zero). This
236        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
237        caused segmentation faults because of stack overflows at compile time.
239    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
240        group that is quantified with an indefinite repeat, caused a compile-time
241        loop which used up all the system stack and provoked a segmentation fault.
242        This was not the same bug as 19 above.
244    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
245        Patch by Mike Frysinger.
248    Version 8.35 04-April-2014
249    --------------------------
251  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.
252      When this flag is not set, PCRE can perform certain optimizations      When this flag is not set, PCRE can perform certain optimizations
253      such as studying these XCLASS-es.      such as studying these XCLASS-es.
255    2.  The auto-possessification of character sets were improved: a normal
256        and an extended character set can be compared now. Furthermore
257        the JIT compiler optimizes more character set checks.
259    3.  Got rid of some compiler warnings for potentially uninitialized variables
260        that show up only when compiled with -O2.
262    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
263        of a match later then the end of the match. The pcretest program was not
264        handling the case sensibly - it was outputting from the start to the next
265        binary zero. It now reports this situation in a message, and outputs the
266        text from the end to the start.
268    5.  Fast forward search is improved in JIT. Instead of the first three
269        characters, any three characters with fixed position can be searched.
270        Search order: first, last, middle.
272    6.  Improve character range checks in JIT. Characters are read by an inprecise
273        function now, which returns with an unknown value if the character code is
274        above a certain threshold (e.g: 256). The only limitation is that the value
275        must be bigger than the threshold as well. This function is useful when
276        the characters above the threshold are handled in the same way.
278    7.  The macros whose names start with RAWUCHAR are placeholders for a future
279        mode in which only the bottom 21 bits of 32-bit data items are used. To
280        make this more memorable for those maintaining the code, the names have
281        been changed to start with UCHAR21, and an extensive comment has been added
282        to their definition.
284    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
285        to the export list in Makefile.am (they were accidentally omitted from the
286        8.34 tarball).
288    9.  The informational output from pcretest used the phrase "starting byte set"
289        which is inappropriate for the 16-bit and 32-bit libraries. As the output
290        for "first char" and "need char" really means "non-UTF-char", I've changed
291        "byte" to "char", and slightly reworded the output. The documentation about
292        these values has also been (I hope) clarified.
294    10. Another JIT related optimization: use table jumps for selecting the correct
295        backtracking path, when more than four alternatives are present inside a
296        bracket.
298    11. Empty match is not possible, when the minimum length is greater than zero,
299        and there is no \K in the pattern. JIT should avoid empty match checks in
300        such cases.
302    12. In a caseless character class with UCP support, when a character with more
303        than one alternative case was not the first character of a range, not all
304        the alternative cases were added to the class. For example, s and \x{17f}
305        are both alternative cases for S: the class [RST] was handled correctly,
306        but [R-T] was not.
308    13. The configure.ac file always checked for pthread support when JIT was
309        enabled. This is not used in Windows, so I have put this test inside a
310        check for the presence of windows.h (which was already tested for).
312    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
313        The algorithm provides a way to skip certain starting offsets, and usually
314        faster than linear prefix searches.
316    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
317        as for 'fr_FR' and 'french'. For some reason, however, it then used the
318        Windows-specific input and output files, which have 'french' screwed in.
319        So this could never have worked. One of the problems with locales is that
320        they aren't always the same. I have now updated RunTest so that it checks
321        the output of the locale test (test 3) against three different output
322        files, and it allows the test to pass if any one of them matches. With luck
323        this should make the test pass on some versions of Solaris where it was
324        failing. Because of the uncertainty, the script did not used to stop if
325        test 3 failed; it now does. If further versions of a French locale ever
326        come to light, they can now easily be added.
328    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
329        there was a message during ./configure, but it did not stop. This now
330        provokes an error. The invalid example in README has been corrected.
331        If a value less than the minimum is given, the minimum value has always
332        been used, but now a warning is given.
334    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
335        was a bug in the test system, which is now fixed. Also, the list of various
336        configurations that are tested for each release did not have one with both
337        16/32 bits and --enable-bar-anycrlf. It now does.
339    18. pcretest was missing "-C bsr" for displaying the \R default setting.
341    19. Little endian PowerPC systems are supported now by the JIT compiler.
343    20. The fast forward newline mechanism could enter to an infinite loop on
344        certain invalid UTF-8 input. Although we don't support these cases
345        this issue can be fixed by a performance optimization.
347    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
348        not take account if existing stack usage. There is now a new global
349        variable called pcre_stack_guard that can be set to point to an external
350        function to check stack availability. It is called at the start of
351        processing every parenthesized group.
353    22. A typo in the code meant that in ungreedy mode the max/min qualifier
354        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
355        not match "ab".
357    23. When UTF was disabled, the JIT program reported some incorrect compile
358        errors. These messages are silenced now.
360    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
361        compiler.
363    25. Change all the temporary files used in RunGrepTest to be different to those
364        used by RunTest so that the tests can be run simultaneously, for example by
365        "make -j check".
368  Version 8.34 15-December-2013  Version 8.34 15-December-2013
369  -----------------------------  -----------------------------

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