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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.
87    Version 8.36 26-September-2014
88    ------------------------------
90    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
91        -Wmissing-field-initializers and -Wunused-parameter.
93    2.  The tests for quantifiers being too big (greater than 65535) were being
94        applied after reading the number, and stupidly assuming that integer
95        overflow would give a negative number. The tests are now applied as the
96        numbers are read.
98    3.  Tidy code in pcre_exec.c where two branches that used to be different are
99        now the same.
101    4.  The JIT compiler did not generate match limit checks for certain
102        bracketed expressions with quantifiers. This may lead to exponential
103        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
104        issue should be resolved now.
106    5.  Fixed an issue, which occures when nested alternatives are optimized
107        with table jumps.
109    6.  Inserted two casts and changed some ints to size_t in the light of some
110        reported 64-bit compiler warnings (Bugzilla 1477).
112    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
113        an empty string, which sometimes were behaving incorrectly in the
114        interpreter (though correctly in the JIT matcher). This pcretest input is
115        an example:
117          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
120        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
121        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
122        for an empty string was breaking the inner loop and carrying on at a lower
123        level, when possessive repeated groups should always return to a higher
124        level as they have no backtrack points in them. The empty string test now
125        occurs at the outer level.
127    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
128        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
130    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
131        doesn't).
133    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
134        to hold a pattern to be incorrectly computed (too small) when there were
135        named back references to duplicated names. This could cause "internal
136        error: code overflow" or "double free or corruption" or other memory
137        handling errors.
139    11. When named subpatterns had the same prefixes, back references could be
140        confused. For example, in this pattern:
142          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
144        the reference to 'Name' was incorrectly treated as a reference to a
145        duplicate name.
147    12. A pattern such as /^s?c/mi8 where the optional character has more than
148        one "other case" was incorrectly compiled such that it would only try to
149        match starting at "c".
151    13. When a pattern starting with \s was studied, VT was not included in the
152        list of possible starting characters; this should have been part of the
153        8.34/18 patch.
155    14. If a character class started [\Qx]... where x is any character, the class
156        was incorrectly terminated at the ].
158    15. If a pattern that started with a caseless match for a character with more
159        than one "other case" was studied, PCRE did not set up the starting code
160        unit bit map for the list of possible characters. Now it does. This is an
161        optimization improvement, not a bug fix.
163    16. The Unicode data tables have been updated to Unicode 7.0.0.
165    17. Fixed a number of memory leaks in pcregrep.
167    18. Avoid a compiler warning (from some compilers) for a function call with
168        a cast that removes "const" from an lvalue by using an intermediate
169        variable (to which the compiler does not object).
171    19. Incorrect code was compiled if a group that contained an internal recursive
172        back reference was optional (had quantifier with a minimum of zero). This
173        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
174        caused segmentation faults because of stack overflows at compile time.
176    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
177        group that is quantified with an indefinite repeat, caused a compile-time
178        loop which used up all the system stack and provoked a segmentation fault.
179        This was not the same bug as 19 above.
181    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
182        Patch by Mike Frysinger.
185    Version 8.35 04-April-2014
186    --------------------------
188  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.
189      When this flag is not set, PCRE can perform certain optimizations      When this flag is not set, PCRE can perform certain optimizations
190      such as studying these XCLASS-es.      such as studying these XCLASS-es.
192    2.  The auto-possessification of character sets were improved: a normal
193        and an extended character set can be compared now. Furthermore
194        the JIT compiler optimizes more character set checks.
196    3.  Got rid of some compiler warnings for potentially uninitialized variables
197        that show up only when compiled with -O2.
199    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
200        of a match later then the end of the match. The pcretest program was not
201        handling the case sensibly - it was outputting from the start to the next
202        binary zero. It now reports this situation in a message, and outputs the
203        text from the end to the start.
205    5.  Fast forward search is improved in JIT. Instead of the first three
206        characters, any three characters with fixed position can be searched.
207        Search order: first, last, middle.
209    6.  Improve character range checks in JIT. Characters are read by an inprecise
210        function now, which returns with an unknown value if the character code is
211        above a certain threshold (e.g: 256). The only limitation is that the value
212        must be bigger than the threshold as well. This function is useful when
213        the characters above the threshold are handled in the same way.
215    7.  The macros whose names start with RAWUCHAR are placeholders for a future
216        mode in which only the bottom 21 bits of 32-bit data items are used. To
217        make this more memorable for those maintaining the code, the names have
218        been changed to start with UCHAR21, and an extensive comment has been added
219        to their definition.
221    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
222        to the export list in Makefile.am (they were accidentally omitted from the
223        8.34 tarball).
225    9.  The informational output from pcretest used the phrase "starting byte set"
226        which is inappropriate for the 16-bit and 32-bit libraries. As the output
227        for "first char" and "need char" really means "non-UTF-char", I've changed
228        "byte" to "char", and slightly reworded the output. The documentation about
229        these values has also been (I hope) clarified.
231    10. Another JIT related optimization: use table jumps for selecting the correct
232        backtracking path, when more than four alternatives are present inside a
233        bracket.
235    11. Empty match is not possible, when the minimum length is greater than zero,
236        and there is no \K in the pattern. JIT should avoid empty match checks in
237        such cases.
239    12. In a caseless character class with UCP support, when a character with more
240        than one alternative case was not the first character of a range, not all
241        the alternative cases were added to the class. For example, s and \x{17f}
242        are both alternative cases for S: the class [RST] was handled correctly,
243        but [R-T] was not.
245    13. The configure.ac file always checked for pthread support when JIT was
246        enabled. This is not used in Windows, so I have put this test inside a
247        check for the presence of windows.h (which was already tested for).
249    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
250        The algorithm provides a way to skip certain starting offsets, and usually
251        faster than linear prefix searches.
253    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
254        as for 'fr_FR' and 'french'. For some reason, however, it then used the
255        Windows-specific input and output files, which have 'french' screwed in.
256        So this could never have worked. One of the problems with locales is that
257        they aren't always the same. I have now updated RunTest so that it checks
258        the output of the locale test (test 3) against three different output
259        files, and it allows the test to pass if any one of them matches. With luck
260        this should make the test pass on some versions of Solaris where it was
261        failing. Because of the uncertainty, the script did not used to stop if
262        test 3 failed; it now does. If further versions of a French locale ever
263        come to light, they can now easily be added.
265    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
266        there was a message during ./configure, but it did not stop. This now
267        provokes an error. The invalid example in README has been corrected.
268        If a value less than the minimum is given, the minimum value has always
269        been used, but now a warning is given.
271    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
272        was a bug in the test system, which is now fixed. Also, the list of various
273        configurations that are tested for each release did not have one with both
274        16/32 bits and --enable-bar-anycrlf. It now does.
276    18. pcretest was missing "-C bsr" for displaying the \R default setting.
278    19. Little endian PowerPC systems are supported now by the JIT compiler.
280    20. The fast forward newline mechanism could enter to an infinite loop on
281        certain invalid UTF-8 input. Although we don't support these cases
282        this issue can be fixed by a performance optimization.
284    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
285        not take account if existing stack usage. There is now a new global
286        variable called pcre_stack_guard that can be set to point to an external
287        function to check stack availability. It is called at the start of
288        processing every parenthesized group.
290    22. A typo in the code meant that in ungreedy mode the max/min qualifier
291        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
292        not match "ab".
294    23. When UTF was disabled, the JIT program reported some incorrect compile
295        errors. These messages are silenced now.
297    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
298        compiler.
300    25. Change all the temporary files used in RunGrepTest to be different to those
301        used by RunTest so that the tests can be run simultaneously, for example by
302        "make -j check".
305  Version 8.34 15-December-2013  Version 8.34 15-December-2013
306  -----------------------------  -----------------------------

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