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revision 1477 by ph10, Wed May 21 17:53:49 2014 UTC revision 1545 by ph10, Wed Apr 8 16:34:24 2015 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.36 xx-xxx-2014  Version 8.37 xx-xxx-2015
5  ------------------------  ------------------------
6    
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".
13    
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.
16    
17    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
18        unrecognized modifier, a crash could occur.
19    
20    4.  An attempt to do global matching in pcretest with a zero-length ovector
21        caused a crash.
22    
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.
26    
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.
30    
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))/.
33    
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.
45    
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.
50    
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).
55    
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.
63    
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.
67    
68    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
69        Red Hat Product Security:
70    
71        (a) A crash if /K and /F were both set with the option to save the compiled
72        pattern.
73    
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.
77    
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.
86    
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.
92    
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.
97    
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.
102    
103    26. Fix JIT compilation of conditional blocks, which assertion
104        is converted to (*FAIL). E.g: /(?(?!))/.
105    
106    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
107        discovered by the LLVM fuzzer.
108    
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.
113    
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.
118    
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.
125    
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.
129    
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.
134    
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.
139    
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.
144    
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.
148    
149    36. The use of \K in a positive lookbehind assertion in a non-anchored pattern
150        (e.g. /(?<=\Ka)/) could make pcregrep loop.
151    
152    37. There was a similar problem to 36 in pcretest for global matches.
153    
154    38. If a greedy quantified \X was preceded by \C in UTF mode (e.g. \C\X*),
155        and a subsequent item in the pattern caused a non-match, backtracking over
156        the repeated \X did not stop, but carried on past the start of the subject,
157        causing reference to random memory and/or a segfault.  This bug was
158        discovered by the LLVM fuzzer.
159    
160    
161    Version 8.36 26-September-2014
162    ------------------------------
163    
164  1.  Got rid of some compiler warnings in the C++ modules that were shown up by  1.  Got rid of some compiler warnings in the C++ modules that were shown up by
165      -Wmissing-field-initializers and -Wunused-parameter.      -Wmissing-field-initializers and -Wunused-parameter.
166    
167  2.  The tests for quantifiers being too big (greater than 65535) were being  2.  The tests for quantifiers being too big (greater than 65535) were being
168      applied after reading the number, and stupidly assuming that integer      applied after reading the number, and stupidly assuming that integer
169      overflow would give a negative number. The tests are now applied as the      overflow would give a negative number. The tests are now applied as the
170      numbers are read.      numbers are read.
171    
172  3.  Tidy code in pcre_exec.c where two branches that used to be different are  3.  Tidy code in pcre_exec.c where two branches that used to be different are
173      now the same.      now the same.
174    
175  4.  The JIT compiler did not generate match limit checks for certain  4.  The JIT compiler did not generate match limit checks for certain
176      bracketed expressions with quantifiers. This may lead to exponential      bracketed expressions with quantifiers. This may lead to exponential
# Line 22  Version 8.36 xx-xxx-2014 Line 179  Version 8.36 xx-xxx-2014
179    
180  5.  Fixed an issue, which occures when nested alternatives are optimized  5.  Fixed an issue, which occures when nested alternatives are optimized
181      with table jumps.      with table jumps.
182    
183  6.  Inserted two casts and changed some ints to size_t in the light of some  6.  Inserted two casts and changed some ints to size_t in the light of some
184      reported 64-bit compiler warnings (Bugzilla 1477).      reported 64-bit compiler warnings (Bugzilla 1477).
185    
186    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
187        an empty string, which sometimes were behaving incorrectly in the
188        interpreter (though correctly in the JIT matcher). This pcretest input is
189        an example:
190    
191          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
192          NON QUOTED "QUOT""ED" AFTER "NOT MATCHED
193    
194        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
195        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
196        for an empty string was breaking the inner loop and carrying on at a lower
197        level, when possessive repeated groups should always return to a higher
198        level as they have no backtrack points in them. The empty string test now
199        occurs at the outer level.
200    
201    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
202        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
203    
204    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
205        doesn't).
206    
207    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
208        to hold a pattern to be incorrectly computed (too small) when there were
209        named back references to duplicated names. This could cause "internal
210        error: code overflow" or "double free or corruption" or other memory
211        handling errors.
212    
213    11. When named subpatterns had the same prefixes, back references could be
214        confused. For example, in this pattern:
215    
216          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
217    
218        the reference to 'Name' was incorrectly treated as a reference to a
219        duplicate name.
220    
221    12. A pattern such as /^s?c/mi8 where the optional character has more than
222        one "other case" was incorrectly compiled such that it would only try to
223        match starting at "c".
224    
225    13. When a pattern starting with \s was studied, VT was not included in the
226        list of possible starting characters; this should have been part of the
227        8.34/18 patch.
228    
229    14. If a character class started [\Qx]... where x is any character, the class
230        was incorrectly terminated at the ].
231    
232    15. If a pattern that started with a caseless match for a character with more
233        than one "other case" was studied, PCRE did not set up the starting code
234        unit bit map for the list of possible characters. Now it does. This is an
235        optimization improvement, not a bug fix.
236    
237    16. The Unicode data tables have been updated to Unicode 7.0.0.
238    
239    17. Fixed a number of memory leaks in pcregrep.
240    
241    18. Avoid a compiler warning (from some compilers) for a function call with
242        a cast that removes "const" from an lvalue by using an intermediate
243        variable (to which the compiler does not object).
244    
245    19. Incorrect code was compiled if a group that contained an internal recursive
246        back reference was optional (had quantifier with a minimum of zero). This
247        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
248        caused segmentation faults because of stack overflows at compile time.
249    
250    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
251        group that is quantified with an indefinite repeat, caused a compile-time
252        loop which used up all the system stack and provoked a segmentation fault.
253        This was not the same bug as 19 above.
254    
255    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
256        Patch by Mike Frysinger.
257    
258    
259  Version 8.35 04-April-2014  Version 8.35 04-April-2014
# Line 53  Version 8.35 04-April-2014 Line 282  Version 8.35 04-April-2014
282    
283  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
284      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
285      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
286      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
287      the characters above the treshold are handled in the same way.      the characters above the threshold are handled in the same way.
288    
289  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
290      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

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