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Dynamic check of (*MARK) etc name length to avoid the possibility of overflow.

This commit is contained in:
Philip.Hazel 2015-11-03 19:14:31 +00:00
parent 3e24a1b351
commit 4ad83f7103
4 changed files with 114 additions and 86 deletions
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ChangeLog
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@ -9,41 +9,41 @@ Version 10.21 xx-xxx-xxxx
2. Use memchr() to find the first character in an unanchored match in 8-bit
mode in the interpreter. This gives a significant speed improvement.
3. Removed a redundant copy of the opcode_possessify table in the
3. Removed a redundant copy of the opcode_possessify table in the
pcre2_auto_possessify.c source.
4. Fix typos in dftables.c for z/OS.
5. Change 36 for 10.20 broke the handling of [[:>:]] and [[:<:]] in that
processing them could involve a buffer overflow if the following character was
5. Change 36 for 10.20 broke the handling of [[:>:]] and [[:<:]] in that
processing them could involve a buffer overflow if the following character was
an opening parenthesis.
6. Change 36 for 10.20 also introduced a bug in processing this pattern:
/((?x)(*:0))#(?'/. Specifically: if a setting of (?x) was followed by a (*MARK)
setting (which (*:0) is), then (?x) did not get unset at the end of its group
/((?x)(*:0))#(?'/. Specifically: if a setting of (?x) was followed by a (*MARK)
setting (which (*:0) is), then (?x) did not get unset at the end of its group
during the scan for named groups, and hence the external # was incorrectly
treated as a comment and the invalid (?' at the end of the pattern was not
diagnosed. This caused a buffer overflow during the real compile. This bug was
discovered by Karl Skomski with the LLVM fuzzer.
7. Moved the pcre2_find_bracket() function from src/pcre2_compile.c into its
own source module to avoid a circular dependency between src/pcre2_compile.c
7. Moved the pcre2_find_bracket() function from src/pcre2_compile.c into its
own source module to avoid a circular dependency between src/pcre2_compile.c
and src/pcre2_study.c
8. A callout with a string argument containing an opening square bracket, for
example /(?C$[$)(?<]/, was incorrectly processed and could provoke a buffer
overflow. This bug was discovered by Karl Skomski with the LLVM fuzzer.
9. The handling of callouts during the pre-pass for named group identification
9. The handling of callouts during the pre-pass for named group identification
has been tightened up.
10. The quantifier {1} can be ignored, whether greedy, non-greedy, or
10. The quantifier {1} can be ignored, whether greedy, non-greedy, or
possessive. This is a very minor optimization.
11. A possessively repeated conditional group that could match an empty string,
for example, /(?(R))*+/, was incorrectly compiled.
12. The Unicode tables have been updated to Unicode 8.0.0 (thanks to Christian
12. The Unicode tables have been updated to Unicode 8.0.0 (thanks to Christian
Persch).
13. An empty comment (?#) in a pattern was incorrectly processed and could
@ -58,72 +58,72 @@ compiled and could cause reading from uninitialized memory or an incorrect
error diagnosis. Examples are: /[[:\\](?<[::]/ and /[[:\\](?'abc')[a:]. The
first of these bugs was discovered by Karl Skomski with the LLVM fuzzer.
16. Pathological patterns containing many nested occurrences of [: caused
pcre2_compile() to run for a very long time. This bug was found by the LLVM
16. Pathological patterns containing many nested occurrences of [: caused
pcre2_compile() to run for a very long time. This bug was found by the LLVM
fuzzer.
17. A missing closing parenthesis for a callout with a string argument was not
being diagnosed, possibly leading to a buffer overflow. This bug was found by
the LLVM fuzzer.
18. A conditional group with only one branch has an implicit empty alternative
18. A conditional group with only one branch has an implicit empty alternative
branch and must therefore be treated as potentially matching an empty string.
19. If (?R was followed by - or + incorrect behaviour happened instead of a
diagnostic. This bug was discovered by Karl Skomski with the LLVM fuzzer.
20. Another bug that was introduced by change 36 for 10.20: conditional groups
whose condition was an assertion preceded by an explicit callout with a string
20. Another bug that was introduced by change 36 for 10.20: conditional groups
whose condition was an assertion preceded by an explicit callout with a string
argument might be incorrectly processed, especially if the string contained \Q.
This bug was discovered by Karl Skomski with the LLVM fuzzer.
21. Compiling PCRE2 with the sanitize options of clang showed up a number of
very pedantic coding infelicities and a buffer overflow while checking a UTF-8
21. Compiling PCRE2 with the sanitize options of clang showed up a number of
very pedantic coding infelicities and a buffer overflow while checking a UTF-8
string if the final multi-byte UTF-8 character was truncated.
22. For Perl compatibility in EBCDIC environments, ranges such as a-z in a
class, where both values are literal letters in the same case, omit the
class, where both values are literal letters in the same case, omit the
non-letter EBCDIC code points within the range.
23. Finding the minimum matching length of complex patterns with back
references and/or recursions can take a long time. There is now a cut-off that
gives up trying to find a minimum length when things get too complex.
23. Finding the minimum matching length of complex patterns with back
references and/or recursions can take a long time. There is now a cut-off that
gives up trying to find a minimum length when things get too complex.
24. An optimization has been added that speeds up finding the minimum matching
24. An optimization has been added that speeds up finding the minimum matching
length for patterns containing repeated capturing groups or recursions.
25. If a pattern contained a back reference to a group whose number was
duplicated as a result of appearing in a (?|...) group, the computation of the
25. If a pattern contained a back reference to a group whose number was
duplicated as a result of appearing in a (?|...) group, the computation of the
minimum matching length gave a wrong result, which could cause incorrect "no
match" errors. For such patterns, a minimum matching length cannot at present
match" errors. For such patterns, a minimum matching length cannot at present
be computed.
26. Added a check for integer overflow in conditions (?(<digits>) and
26. Added a check for integer overflow in conditions (?(<digits>) and
(?(R<digits>). This omission was discovered by Karl Skomski with the LLVM
fuzzer.
27. Fixed an issue when \p{Any} inside an xclass did not read the current
character.
28. If pcre2grep was given the -q option with -c or -l, or when handling a
28. If pcre2grep was given the -q option with -c or -l, or when handling a
binary file, it incorrectly wrote output to stdout.
29. The JIT compiler did not restore the control verb head in case of *THEN
control verbs. This issue was found by Karl Skomski with a custom LLVM fuzzer.
30. The way recursive references such as (?3) are compiled has been re-written
because the old way was the cause of many issues. Now, conversion of the group
number into a pattern offset does not happen until the pattern has been
30. The way recursive references such as (?3) are compiled has been re-written
because the old way was the cause of many issues. Now, conversion of the group
number into a pattern offset does not happen until the pattern has been
completely compiled. This does mean that detection of all infinitely looping
recursions is postponed till match time. In the past, some easy ones were
detected at compile time. This re-writing was done in response to yet another
recursions is postponed till match time. In the past, some easy ones were
detected at compile time. This re-writing was done in response to yet another
bug found by the LLVM fuzzer.
31. A test for a back reference to a non-existent group was missing for items
such as \987. This caused incorrect code to be compiled. This issue was found
such as \987. This caused incorrect code to be compiled. This issue was found
by Karl Skomski with a custom LLVM fuzzer.
32. Error messages for syntax errors following \g and \k were giving inaccurate
32. Error messages for syntax errors following \g and \k were giving inaccurate
offsets in the pattern.
33. Improve the performance of starting single character repetitions in JIT.
@ -145,8 +145,8 @@ was fixed.
39. Match limit check added to recursion. This issue was found by Karl Skomski
with a custom LLVM fuzzer.
40. Arrange for the UTF check in pcre2_match() and pcre2_dfa_match() to look
only at the part of the subject that is relevant when the starting offset is
40. Arrange for the UTF check in pcre2_match() and pcre2_dfa_match() to look
only at the part of the subject that is relevant when the starting offset is
non-zero.
41. Improve first character match in JIT with SSE2 on x86.
@ -154,17 +154,17 @@ non-zero.
42. Fix two assertion fails in JIT. These issues were found by Karl Skomski
with a custom LLVM fuzzer.
43. Correct the setting of CMAKE_C_FLAGS in CMakeLists.txt (patch from Roy Ivy
43. Correct the setting of CMAKE_C_FLAGS in CMakeLists.txt (patch from Roy Ivy
III).
44. Fix bug in RunTest.bat for new test 14, and adjust the script for the added
44. Fix bug in RunTest.bat for new test 14, and adjust the script for the added
test (there are now 20 in total).
45. Fixed a corner case of range optimization in JIT.
46. Add the ${*MARK} facility to pcre2_substitute().
47. Modifier lists in pcre2test were splitting at spaces without the required
47. Modifier lists in pcre2test were splitting at spaces without the required
commas.
48. Implemented PCRE2_ALT_VERBNAMES.
@ -172,11 +172,11 @@ commas.
49. Fixed two issues in JIT. These were found by Karl Skomski with a custom
LLVM fuzzer.
50. The pcre2test program has been extended by adding the #newline_default
command. This has made it possible to run the standard tests when PCRE2 is
compiled with either CR or CRLF as the default newline convention. As part of
this work, the new command was added to several test files and the testing
scripts were modified. The pcre2grep tests can now also be run when there is no
50. The pcre2test program has been extended by adding the #newline_default
command. This has made it possible to run the standard tests when PCRE2 is
compiled with either CR or CRLF as the default newline convention. As part of
this work, the new command was added to several test files and the testing
scripts were modified. The pcre2grep tests can now also be run when there is no
LF in the default newline convention.
51. The RunTest script has been modified so that, when JIT is used and valgrind
@ -184,72 +184,72 @@ is specified, a valgrind suppressions file is set up to ignore "Invalid read of
size 16" errors because these are false positives when the hardware supports
the SSE2 instruction set.
52. It is now possible to have comment lines amid the subject strings in
52. It is now possible to have comment lines amid the subject strings in
pcre2test (and perltest.sh) input.
53. Implemented PCRE2_USE_OFFSET_LIMIT and pcre2_set_offset_limit().
54. Add the null_context modifier to pcre2test so that calling pcre2_compile()
54. Add the null_context modifier to pcre2test so that calling pcre2_compile()
and the matching functions with NULL contexts can be tested.
55. Implemented PCRE2_SUBSTITUTE_EXTENDED.
56. In a character class such as [\W\p{Any}] where both a negative-type escape
("not a word character") and a property escape were present, the property
56. In a character class such as [\W\p{Any}] where both a negative-type escape
("not a word character") and a property escape were present, the property
escape was being ignored.
57. Fixed integer overflow for patterns whose minimum matching length is very,
57. Fixed integer overflow for patterns whose minimum matching length is very,
very large.
58. Implemented --never-backslash-C.
59. Change 55 above introduced a bug by which certain patterns provoked the
59. Change 55 above introduced a bug by which certain patterns provoked the
erroneous error "\ at end of pattern".
60. The special sequences [[:<:]] and [[:>:]] gave rise to incorrect compiling
errors or other strange effects if compiled in UCP mode. Found with libFuzzer
and AddressSanitizer.
61. Whitespace at the end of a pcre2test pattern line caused a spurious error
61. Whitespace at the end of a pcre2test pattern line caused a spurious error
message if there were only single-character modifiers. It should be ignored.
62. The use of PCRE2_NO_AUTO_CAPTURE could cause incorrect compilation results
or segmentation errors for some patterns. Found with libFuzzer and
AddressSanitizer.
63. Very long names in (*MARK) or (*THEN) etc. items could provoke a buffer
63. Very long names in (*MARK) or (*THEN) etc. items could provoke a buffer
overflow.
64. Improve error message for overly-complicated patterns.
65. Implemented an optional replication feature for patterns in pcre2test, to
make it easier to test long repetitive patterns. The tests for 63 above are
65. Implemented an optional replication feature for patterns in pcre2test, to
make it easier to test long repetitive patterns. The tests for 63 above are
converted to use the new feature.
66. In the POSIX wrapper, if regerror() was given too small a buffer, it could
66. In the POSIX wrapper, if regerror() was given too small a buffer, it could
misbehave.
67. In pcre2_substitute() in UTF mode, the UTF validity check on the
replacement string was happening before the length setting when the replacement
string was zero-terminated.
68. In pcre2_substitute() in UTF mode, PCRE2_NO_UTF_CHECK can be set for the
68. In pcre2_substitute() in UTF mode, PCRE2_NO_UTF_CHECK can be set for the
second and subsequent calls to pcre2_match().
69. There was no check for integer overflow for a replacement group number in
pcre2_substitute(). An added check for a number greater than the largest group
69. There was no check for integer overflow for a replacement group number in
pcre2_substitute(). An added check for a number greater than the largest group
number in the pattern means this is not now needed.
70. The PCRE2-specific VERSION condition didn't work correctly if only one
digit was given after the decimal point, or if more than two digits were given.
It now works with one or two digits, and gives a compile time error if more are
70. The PCRE2-specific VERSION condition didn't work correctly if only one
digit was given after the decimal point, or if more than two digits were given.
It now works with one or two digits, and gives a compile time error if more are
given.
71. In pcre2_substitute() there was the possibility of reading one code unit
71. In pcre2_substitute() there was the possibility of reading one code unit
beyond the end of the replacement string.
72. The code for checking a subject's UTF-32 validity for a pattern with a
lookbehind involved an out-of-bounds pointer, which could potentially cause
lookbehind involved an out-of-bounds pointer, which could potentially cause
trouble in some environments.
73. The maximum lookbehind length was incorrectly calculated for patterns such
@ -260,6 +260,9 @@ as /(?<=(a)(?-1))x/ which have a recursion within a backreference.
75. Give an error in pcre2_substitute() if a match ends before it starts (as a
result of the use of \K).
76. Check the length of the name in (*MARK:xx) etc. dynamically to avoid the
possibility of integer overflow.
Version 10.20 30-June-2015
--------------------------

56
src/pcre2_compile.c
View File

@ -584,19 +584,19 @@ enum { ERR0 = COMPILE_ERROR_BASE,
ERR61, ERR62, ERR63, ERR64, ERR65, ERR66, ERR67, ERR68, ERR69, ERR70,
ERR71, ERR72, ERR73, ERR74, ERR75, ERR76, ERR77, ERR78, ERR79, ERR80,
ERR81, ERR82, ERR83, ERR84, ERR85, ERR86, ERR87 };
/* Error codes that correspond to negative error codes returned by
find_fixedlength(). */
static int fixed_length_errors[] =
static int fixed_length_errors[] =
{
ERR0, /* Not an error */
ERR0, /* Not an error; -1 is used for "process later" */
ERR25, /* Lookbehind is not fixed length */
ERR36, /* \C in lookbehind is not allowed */
ERR36, /* \C in lookbehind is not allowed */
ERR87, /* Lookbehind is too long */
ERR70 /* Internal error: unknown opcode encountered */
};
ERR70 /* Internal error: unknown opcode encountered */
};
/* This is a table of start-of-pattern options such as (*UTF) and settings such
as (*LIMIT_MATCH=nnnn) and (*CRLF). For completeness and backward
@ -803,7 +803,7 @@ However, we cannot do this when the assertion contains subroutine calls,
because they can be forward references. We solve this by remembering this case
and doing the check at the end; a flag specifies which mode we are running in.
Lookbehind lengths are held in 16-bit fields and the maximum value is defined
Lookbehind lengths are held in 16-bit fields and the maximum value is defined
as LOOKBEHIND_MAX.
Arguments:
@ -817,7 +817,7 @@ Returns: if non-negative, the fixed length,
or -1 if an OP_RECURSE item was encountered and atend is FALSE
or -2 if there is no fixed length,
or -3 if \C was encountered (in UTF-8 mode only)
or -4 length is too long
or -4 length is too long
or -5 if an unknown opcode was encountered (internal error)
*/
@ -844,8 +844,8 @@ for (;;)
int d;
PCRE2_UCHAR *ce, *cs;
register PCRE2_UCHAR op = *cc;
if (branchlength > LOOKBEHIND_MAX) return FFL_TOOLONG;
if (branchlength > LOOKBEHIND_MAX) return FFL_TOOLONG;
switch (op)
{
@ -2875,7 +2875,7 @@ static int
process_verb_name(PCRE2_SPTR *ptrptr, PCRE2_UCHAR **codeptr, int *errorcodeptr,
uint32_t options, BOOL utf, compile_block *cb)
{
int arglen = 0;
int32_t arglen = 0;
BOOL inescq = FALSE;
PCRE2_SPTR ptr = *ptrptr;
PCRE2_UCHAR *code = (codeptr == NULL)? NULL : *codeptr;
@ -2900,8 +2900,8 @@ for (; ptr < cb->end_pattern; ptr++)
{
if (x == CHAR_RIGHT_PARENTHESIS) break;
/* Skip over comments and whitespace in extended mode. Need a loop to handle
whitespace after a comment. */
/* Skip over comments and whitespace in extended mode. Need a loop to
handle whitespace after a comment. */
if ((options & PCRE2_EXTENDED) != 0)
{
@ -2912,8 +2912,8 @@ for (; ptr < cb->end_pattern; ptr++)
ptr++;
while (*ptr != CHAR_NULL)
{
if (IS_NEWLINE(ptr)) /* For non-fixed-length newline cases, */
{ /* IS_NEWLINE sets cb->nllen. */
if (IS_NEWLINE(ptr)) /* For non-fixed-length newline cases, */
{ /* IS_NEWLINE sets cb->nllen. */
ptr += cb->nllen;
break;
}
@ -2984,6 +2984,12 @@ for (; ptr < cb->end_pattern; ptr++)
}
arglen++;
if ((unsigned int)arglen > MAX_MARK)
{
*errorcodeptr = ERR76;
return -1;
}
}
/* Update the pointers before returning. */
@ -5613,21 +5619,25 @@ for (;; ptr++)
if ((options & PCRE2_ALT_VERBNAMES) == 0)
{
while (*ptr != CHAR_NULL && *ptr != CHAR_RIGHT_PARENTHESIS) ptr++;
arglen = (int)(ptr - arg);
arglen = 0;
while (*ptr != CHAR_NULL && *ptr != CHAR_RIGHT_PARENTHESIS)
{
ptr++; /* Check length as we go */
arglen++; /* along, to avoid the */
if ((unsigned int)arglen > MAX_MARK) /* possibility of overflow. */
{
*errorcodeptr = ERR76;
goto FAILED;
}
}
}
else
{
/* The length check is in process_verb_names() */
arglen = process_verb_name(&ptr, NULL, errorcodeptr, options,
utf, cb);
if (arglen < 0) goto FAILED;
}
if ((unsigned int)arglen > MAX_MARK)
{
*errorcodeptr = ERR76;
goto FAILED;
}
}
if (*ptr != CHAR_RIGHT_PARENTHESIS)
@ -7484,7 +7494,7 @@ for (;;)
/* If lookbehind, check that this branch matches a fixed-length string, and
put the length into the OP_REVERSE item. Temporarily mark the end of the
branch with OP_END. If the branch contains OP_RECURSE, the result is
branch with OP_END. If the branch contains OP_RECURSE, the result is
FFL_LATER (a negative value) because there may be forward references that
we can't check here. Set a flag to cause another lookbehind check at the
end. Why not do it all at the end? Because common errors can be picked up

6
testdata/testinput9 vendored
View File

@ -239,9 +239,15 @@
/(*:0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF)XX/mark
XX
/(*:0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF)XX/mark,alt_verbnames
XX
/(*:0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDE)XX/mark
XX
/(*:0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDE)XX/mark,alt_verbnames
XX
/\u0100/alt_bsux,allow_empty_class,match_unset_backref,dupnames
/[\u0100-\u0200]/alt_bsux,allow_empty_class,match_unset_backref,dupnames

9
testdata/testoutput9 vendored
View File

@ -313,11 +313,20 @@ Failed: error 151 at offset 3: octal value is greater than \377 in 8-bit non-UTF
Failed: error 176 at offset 259: name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN)
XX
/(*:0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF)XX/mark,alt_verbnames
Failed: error 176 at offset 3: name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN)
XX
/(*:0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDE)XX/mark
XX
0: XX
MK: 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDE
/(*:0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDE)XX/mark,alt_verbnames
XX
0: XX
MK: 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDE
/\u0100/alt_bsux,allow_empty_class,match_unset_backref,dupnames
Failed: error 177 at offset 5: character code point value in \u.... sequence is too large